Journal articles on the topic 'Parasite'
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1
Schmid, Carl W. "Alu: a parasite's parasite?" Nature Genetics 35, no. 1 (September 2003): 15–16. http://dx.doi.org/10.1038/ng0903-15.
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Ellis, Vincenzo A., Michael D. Collins, Matthew C. I. Medeiros, Eloisa H. R. Sari, Elyse D. Coffey, Rebecca C. Dickerson, Camile Lugarini, et al. "Local host specialization, host-switching, and dispersal shape the regional distributions of avian haemosporidian parasites." Proceedings of the National Academy of Sciences 112, no. 36 (August 24, 2015): 11294–99. http://dx.doi.org/10.1073/pnas.1515309112.
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The drivers of regional parasite distributions are poorly understood, especially in comparison with those of free-living species. For vector-transmitted parasites, in particular, distributions might be influenced by host-switching and by parasite dispersal with primary hosts and vectors. We surveyed haemosporidian blood parasites (Plasmodium and Haemoproteus) of small land birds in eastern North America to characterize a regional parasite community. Distributions of parasite populations generally reflected distributions of their hosts across the region. However, when the interdependence between hosts and parasites was controlled statistically, local host assemblages were related to regional climatic gradients, but parasite assemblages were not. Moreover, because parasite assemblage similarity does not decrease with distance when controlling for host assemblages and climate, parasites evidently disperse readily within the distributions of their hosts. The degree of specialization on hosts varied in some parasite lineages over short periods and small geographic distances independently of the diversity of available hosts and potentially competing parasite lineages. Nonrandom spatial turnover was apparent in parasite lineages infecting one host species that was well-sampled within a single year across its range, plausibly reflecting localized adaptations of hosts and parasites. Overall, populations of avian hosts generally determine the geographic distributions of haemosporidian parasites. However, parasites are not dispersal-limited within their host distributions, and they may switch hosts readily.
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Westby, Katie M., Brenden M. Sweetman, Solny A. Adalsteinsson, Elizabeth G. Biro, and Kim A. Medley. "Host food quality and quantity differentially affect Ascogregarina barretti parasite burden, development and within-host competition in the mosquito Aedes triseriatus." Parasitology 146, no. 13 (August 29, 2019): 1665–72. http://dx.doi.org/10.1017/s0031182019000994.
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AbstractHost condition depends in large part on the quality and quantity of available food and heavily influences the outcome of parasite infection. Although parasite fitness traits such as growth rate and size may depend on host condition, whether host food quality or quantity is more important to parasite fitness and within-host interactions is poorly understood. We provided individual mosquito hosts with a standard dose of a gregarine parasite and reared mosquitoes on two food types of different quality and two quantities. We measured host size, total parasite count and area, and average size of parasites within each treatment. Food quality significantly influenced the number of parasites in a host; hosts fed a low-quality diet were infected with more parasites than those provided a high-quality diet. In addition, we found evidence of within-host competition; there was a negative relationship between parasite size and count though this relationship was dependent on host food quality. Host food quantity significantly affected total parasite area and parasite size; lower food quantity resulted in smaller parasites and reduced overall parasite area inside the host. Thus both food quality and quantity have the potential to influence parasite fitness and population dynamics.
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Teixeira, Adonias A. Martins, Pablo Riul, Samuel Vieira Brito, João A. Araujo-Filho, Diêgo Alves Teles, Waltécio de Oliveira Almeida, and Daniel Oliveira Mesquita. "Ecological release in lizard endoparasites from the Atlantic Forest, northeast of the Neotropical Region." Parasitology 147, no. 4 (January 22, 2020): 491–500. http://dx.doi.org/10.1017/s0031182020000025.
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AbstractWe compared lizard endoparasite assemblages between the Atlantic Forest and naturally isolated forest enclaves to test the ecological release hypothesis, which predicts that host specificity should be lower (large niche breadth) and parasite abundance should be greater for parasites from isolated forest enclaves (poor assemblages) than for parasites from the coastal Atlantic Forest (rich assemblages). Parasite richness per specimen showed no difference between the isolated and non-isolated areas. Parasite abundance did not differ between the isolated and non-isolated areas but showed a positive relationship with parasite richness considering all areas (isolated and non-isolated). Furthermore, host specificity was positively related to parasite richness. Considering that host specificity is inversely proportional to the host range infected by a parasite, our results indicate that in assemblages with greater parasite richness, parasites tend to infect a smaller range of hosts than do those in simple assemblages. In summary, our study partially supports the ecological release hypothesis: in assemblages with greater parasite richness, lizard parasites from Atlantic Forest are able to increase their parasite abundance (per host), possibly through facilitated infection; however, the amplitude of infected hosts only expands in poor assemblages (lower parasite richness).
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Mahony, Kate E., Sharon A. Lynch, Xavier de Montaudouin, and Sarah C. Culloty. "Extrinsic and intrinsic drivers of parasite prevalence and parasite species richness in a marine bivalve." PLOS ONE 17, no. 9 (September 26, 2022): e0274474. http://dx.doi.org/10.1371/journal.pone.0274474.
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Parasite species richness is influenced by a range of drivers including host related factors (e.g. host size) and environmental factors (e.g. seawater temperature). However, identification of modulators of parasite species richness remains one of the great unanswered questions in ecology. The common cockle Cerastoderma edule is renowned for its diversity and abundance of parasites, yet drivers of parasite species richness in cockles have not been examined to investigate the association of both macro and microparasite communities. Using cockles as a model species, some of the key drivers of parasite prevalence and parasite species richness were investigated. Objectives of this 19-month survey were to determine the influence of the environment, host-parasite dynamics and parasite associations on parasite species richness and prevalence at two different geographic latitudes, chosen based on environmental differences. The highest parasite species richness was recorded in the northern sites, and this was potentially influenced by a range of interactions between the host, the pathogens and the environment. Parasite prevalence increased with host size and age, and parasite species richness increased with reduced salinity. A number of interactions between parasites, and between parasites and pathologies may be influencing parasite infection dynamics. New and concerning information is also presented regarding interactions between parasites and their environment. A number of parasites and potential pathogens (bacteria, Trichodina ciliates, metacercariae, trematode sporocysts) may be advantaged under climate change conditions (warming seas, increased precipitation), increasing disease incidence, which may prove detrimental not just for cockles, but for other bivalve species in the future.
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May, R. M., and R. M. Anderson. "Parasite—host coevolution." Parasitology 100, S1 (June 1990): S89—S101. http://dx.doi.org/10.1017/s0031182000073042.
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In this paper we wish to develop three themes, each having to do with evolutionary aspects of associations between hosts and parasites (with parasite defined broadly, to include viruses, bacteria and protozoans, along with the more conventionally defined helminth and arthropod parasites). The three themes are: the evolution of virulence; the population dynamics and population genetics of host–parasite associations; and invasions by, or ‘emergence’ of, new parasites.
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Strauss, Alexander T., Jessica L. Hite, David J. Civitello, Marta S. Shocket, Carla E. Cáceres, and Spencer R. Hall. "Genotypic variation in parasite avoidance behaviour and other mechanistic, nonlinear components of transmission." Proceedings of the Royal Society B: Biological Sciences 286, no. 1915 (November 20, 2019): 20192164. http://dx.doi.org/10.1098/rspb.2019.2164.
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Traditional epidemiological models assume that transmission increases proportionally to the density of parasites. However, empirical data frequently contradict this assumption. General yet mechanistic models can explain why transmission depends nonlinearly on parasite density and thereby identify potential defensive strategies of hosts. For example, hosts could decrease their exposure rates at higher parasite densities (via behavioural avoidance) or decrease their per-parasite susceptibility when encountering more parasites (e.g. via stronger immune responses). To illustrate, we fitted mechanistic transmission models to 19 genotypes of Daphnia dentifera hosts over gradients of the trophically acquired parasite, Metschnikowia bicuspidata . Exposure rate (foraging, F ) frequently decreased with parasite density ( Z ), and per-parasite susceptibility ( U ) frequently decreased with parasite encounters ( F × Z ). Consequently, infection rates ( F × U × Z ) often peaked at intermediate parasite densities. Moreover, host genotypes varied substantially in these responses. Exposure rates remained constant for some genotypes but decreased sensitively with parasite density for others (up to 78%). Furthermore, genotypes with more sensitive foraging/exposure also foraged faster in the absence of parasites (suggesting ‘fast and sensitive’ versus ‘slow and steady’ strategies). These relationships suggest that high densities of parasites can inhibit transmission by decreasing exposure rates and/or per-parasite susceptibility, and identify several intriguing axes for the evolution of host defence.
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SEARLE, C. L., J. H. OCHS, C. E. CÁCERES, S. L. CHIANG, N. M. GERARDO, S. R. HALL, and M. A. DUFFY. "Plasticity, not genetic variation, drives infection success of a fungal parasite." Parasitology 142, no. 6 (February 25, 2015): 839–48. http://dx.doi.org/10.1017/s0031182015000013.
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SUMMARYHosts strongly influence parasite fitness. However, it is challenging to disentangle host effects on genetic vs plasticity-driven traits of parasites, since parasites can evolve quickly. It remains especially difficult to determine the causes and magnitude of parasite plasticity. In successive generations, parasites may respond plastically to better infect their current type of host, or hosts may produce generally ‘good’ or ‘bad’ quality parasites. Here, we characterized parasite plasticity by taking advantage of a system in which the parasite (the yeast Metschnikowia bicuspidata, which infects Daphnia) has no detectable heritable variation, preventing rapid evolution. In experimental infection assays, we found an effect of rearing host genotype on parasite infectivity, where host genotypes produced overall high or low quality parasite spores. Additionally, these plastically induced differences were gained or lost in just a single host generation. Together, these results demonstrate phenotypic plasticity in infectivity driven by the within-host rearing environment. Such plasticity is rarely investigated in parasites, but could shape epidemiologically important traits.
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Lafferty, Kevin D. "Biodiversity loss decreases parasite diversity: theory and patterns." Philosophical Transactions of the Royal Society B: Biological Sciences 367, no. 1604 (October 19, 2012): 2814–27. http://dx.doi.org/10.1098/rstb.2012.0110.
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Past models have suggested host–parasite coextinction could lead to linear, or concave down relationships between free-living species richness and parasite richness. I explored several models for the relationship between parasite richness and biodiversity loss. Life cycle complexity, low generality of parasites and sensitivity of hosts reduced the robustness of parasite species to the loss of free-living species diversity. Food-web complexity and the ordering of extinctions altered these relationships in unpredictable ways. Each disassembly of a food web resulted in a unique relationship between parasite richness and the richness of free-living species, because the extinction trajectory of parasites was sensitive to the order of extinctions of free-living species. However, the average of many disassemblies tended to approximate an analytical model. Parasites of specialist hosts and hosts higher on food chains were more likely to go extinct in food-web models. Furthermore, correlated extinctions between hosts and parasites (e.g. if parasites share a host with a specialist predator) led to steeper declines in parasite richness with biodiversity loss. In empirical food webs with random removals of free-living species, the relationship between free-living species richness and parasite richness was, on average, quasi-linear, suggesting biodiversity loss reduces parasite diversity more than previously thought.
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Penley, McKenna J., and Levi T. Morran. "Host mating system and coevolutionary dynamics shape the evolution of parasite avoidance in Caenorhabditis elegans host populations." Parasitology 145, no. 6 (June 28, 2017): 724–30. http://dx.doi.org/10.1017/s0031182017000804.
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AbstractHosts exhibit a variety of defence mechanisms against parasites, including avoidance. Both host–parasite coevolutionary dynamics and the host mating system can alter the evolutionary trajectories of populations. Does the nature of host–parasite interactions and the host mating system affect the mechanisms that evolve to confer host defence? In a previous experimental evolution study, mixed mating and obligately outcrossing Caenorhabditis elegans host populations adapted to either coevolving or static Serratia marcescens parasite populations. Here, we assessed parasite avoidance as a mechanism underlying host adaptation. We measured host feeding preference for the coevolved and static parasites vs preference for Escherichia coli, to assess the evolution of avoidance behaviour within our experiment. We found that mixed mating host populations evolved a preference for E. coli relative to the static parasite strain; therefore, the hosts evolved parasite avoidance as a defence. However, mixed mating hosts did not exhibit E. coli preference when exposed to coevolved parasites, so avoidance cannot account for host adaptation to coevolving parasites. Further, the obligately outcrossing host populations did not exhibit parasite avoidance in the presence of either static or coevolved parasites. Therefore, both the nature of host–parasite interactions and the host mating system shaped the evolution of host defence.
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WOOD, CHELSEA L., and KEVIN D. LAFFERTY. "How have fisheries affected parasite communities?" Parasitology 142, no. 1 (March 3, 2014): 134–44. http://dx.doi.org/10.1017/s003118201400002x.
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SUMMARYTo understand how fisheries affect parasites, we conducted a meta-analysis of studies that contrasted parasite assemblages in fished and unfished areas. Parasite diversity was lower in hosts from fished areas. Larger hosts had a greater abundance of parasites, suggesting that fishing might reduce the abundance of parasites by selectively removing the largest, most heavily parasitized individuals. After controlling for size, the effect of fishing on parasite abundance varied according to whether the host was fished and the parasite's life cycle. Parasites of unfished hosts were more likely to increase in abundance in response to fishing than were parasites of fished hosts, possibly due to compensatory increases in the abundance of unfished hosts. While complex life cycle parasites tended to decline in abundance in response to fishing, directly transmitted parasites tended to increase. Among complex life cycle parasites, those with fished hosts tended to decline in abundance in response to fishing, while those with unfished hosts tended to increase. However, among directly transmitted parasites, responses did not differ between parasites with and without fished hosts. This work suggests that parasite assemblages are likely to change substantially in composition in increasingly fished ecosystems, and that parasite life history and fishing status of the host are important in predicting the response of individual parasite species or groups to fishing.
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DALLAS, TAD, ANDREW W. PARK, and JOHN M. DRAKE. "Predictability of helminth parasite host range using information on geography, host traits and parasite community structure." Parasitology 144, no. 2 (October 20, 2016): 200–205. http://dx.doi.org/10.1017/s0031182016001608.
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SUMMARYHost–parasite associations are complex interactions dependent on aspects of hosts (e.g. traits, phylogeny or coevolutionary history), parasites (e.g. traits and parasite interactions) and geography (e.g. latitude). Predicting the permissive host set or the subset of the host community that a parasite can infect is a central goal of parasite ecology. Here we develop models that accurately predict the permissive host set of 562 helminth parasites in five different parasite taxonomic groups. We developed predictive models using host traits, host taxonomy, geographic covariates, and parasite community composition, finding that models trained on parasite community variables were more accurate than any other covariate group, even though parasite community covariates only captured a quarter of the variance in parasite community composition. This suggests that it is possible to predict the permissive host set for a given parasite, and that parasite community structure is an important predictor, potentially because parasite communities are interacting non-random assemblages.
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Zheng, Yadong, Xuepeng Cai, and Janette E. Bradley. "microRNAs in parasites and parasite infection." RNA Biology 10, no. 3 (March 2013): 371–79. http://dx.doi.org/10.4161/rna.23716.
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Tadiri, Christina P., Marilyn E. Scott, and Gregor F. Fussmann. "Microparasite dispersal in metapopulations: a boon or bane to the host population?" Proceedings of the Royal Society B: Biological Sciences 285, no. 1885 (August 29, 2018): 20181519. http://dx.doi.org/10.1098/rspb.2018.1519.
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Although connectivity can promote host species persistence in a metapopulation, dispersal may also enable disease transmission, an effect further complicated by the impact that parasite distribution may have on host–parasite population dynamics. We investigated the effects of connectivity and initial parasite distribution (clustered or dispersed) on microparasite–host dynamics in experimental metapopulations, using guppies and Gyrodactylus turnbulli . We created metapopulations of guppies divided into four subpopulations and introduced either a low level of parasites to all subpopulations (dispersed) or a high level of parasites to one subpopulation (clustered). Controlled migration among subpopulations occurred every 10 days. In additional trials, we introduced low or high levels of parasites to isolated populations. Parasites persisted longer in metapopulations than in isolated populations. Mortality was lowest in isolated populations with low-level introductions. The interaction of connectivity and initial parasite distribution influenced parasite abundance. With low-level introductions, connectivity helped the parasite persist longer but had little effect on the hosts. With high levels, connectivity also benefited the hosts, lowering parasite burdens. These findings have implications for disease management and species conservation.
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VAN DER VEEN, I. T., and J. KURTZ. "To avoid or eliminate: cestode infections in copepods." Parasitology 124, no. 4 (April 2002): 465–74. http://dx.doi.org/10.1017/s0031182001001275.
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The outcome of a parasite infection is the result of the interaction between the host and the parasite. In the system we studied, there are 3 critical stages for the outcome of infection of the (intermediate) host, the copepod Macrocyclops albidus, with the cestode Schistocephalus solidus. During the establishment phase of the parasite, the host may firstly avoid ingesting the parasite and, secondly, may prevent the parasite from entering the body cavity and, thirdly, during the growth phase of the parasite, the host's immune system may eliminate the parasite from the body cavity. We were able to study the growth phase separately from the establishment phase. The establishment phase was influenced by characteristics of the host as well as characteristics of the parasites. Small copepods and males performed poorly; they were more often infected and had a lower survival. Parasites from different sib-groups differed in infectivity. During the growth phase some disappearance of parasites was observed. However, this could not be related to any of the studied characteristics of the host, and the sib-groups of parasites did not seem to differ in their likelihood to disappear. Instead, we suggest that disappearance of parasites, once they have entered the body cavity, may be due to intrinsic mortality of the parasites, independent of the host or the sib-group that the parasites belong to. This indicates that the crucial interactions between host and parasite determining the outcome of infection takes place in the short time-period between ingestion and penetration of the gut-wall.
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Paterson, Rachel A., Gustavo P. Viozzi, Carlos A. Rauque, Verónica R. Flores, and Robert Poulin. "A Global Assessment of Parasite Diversity in Galaxiid Fishes." Diversity 13, no. 1 (January 14, 2021): 27. http://dx.doi.org/10.3390/d13010027.
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Free-living species often receive greater conservation attention than the parasites they support, with parasite conservation often being hindered by a lack of parasite biodiversity knowledge. This study aimed to determine the current state of knowledge regarding parasites of the Southern Hemisphere freshwater fish family Galaxiidae, in order to identify knowledge gaps to focus future research attention. Specifically, we assessed how galaxiid–parasite knowledge differs among geographic regions in relation to research effort (i.e., number of studies or fish individuals examined, extent of tissue examination, taxonomic resolution), in addition to ecological traits known to influence parasite richness. To date, ~50% of galaxiid species have been examined for parasites, though the majority of studies have focused on single parasite taxa rather than assessing the full diversity of macro- and microparasites. The highest number of parasites were observed from Argentinean galaxiids, and studies in all geographic regions were biased towards the highly abundant and most widely distributed galaxiid species, Galaxias maculatus. Parasite diversity generally increased with the number of studies and individual fish examined, however studies which examined parasites from all body tissues could overcome the effects of low study effort. In order to promote further understanding of galaxiid–parasite biodiversity, we provide a series of recommendations, including the use of molecular techniques to verify parasite identity, and highlight the future roles both fish biologists and parasitologists can play.
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MUÑOZ, G., A. S. GRUTTER, and T. H. CRIBB. "Endoparasite communities of five fish species (Labridae: Cheilininae) from Lizard Island: how important is the ecology and phylogeny of the hosts?" Parasitology 132, no. 3 (December 7, 2005): 363–74. http://dx.doi.org/10.1017/s0031182005009133.
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The parasite community of animals is generally influenced by host physiology, ecology, and phylogeny. Therefore, sympatric and phylogenetically related hosts with similar ecologies should have similar parasite communities. To test this hypothesis we surveyed the endoparasites of 5 closely related cheilinine fishes (Labridae) from the Great Barrier Reef. They were Cheilinus chlorourus, C. trilobatus, C. fasciatus, Epibulus insidiator and Oxycheilinus diagramma. We examined the relationship between parasitological variables (richness, abundance and diversity) and host characteristics (body weight, diet and phylogeny). The 5 fishes had 31 parasite species with 9–18 parasite species per fish species. Cestode larvae (mostly Tetraphyllidea) were the most abundant and prevalent parasites followed by nematodes and digeneans. Parasites, body size and diet of hosts differed between fish species. In general, body weight, diet and host phylogeny each explained some of the variation in richness and composition of parasites among the fishes. The 2 most closely related species, Cheilinus chlorourus and C. trilobatus, had broadly similar parasites but the other fish species differed significantly in all variables. However, there was no all-encompassing pattern. This may be because different lineages of parasites may react differently to ecological variables. We also argue that adult parasites may respond principally to host diet. In contrast, larval parasite composition may respond both to host diet and predator-prey interactions because this is the path by which many parasites complete their life-cycles. Finally, variation in parasite phylogeny and parasite life-cycles among hosts likely increase the complexity of the system making it difficult to find all-encompassing patterns between host characteristics and parasites, particularly when all the species in rich parasite communities are considered.
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FENTON, ANDY, and SARAH E. PERKINS. "Applying predator-prey theory to modelling immune-mediated, within-host interspecific parasite interactions." Parasitology 137, no. 6 (February 15, 2010): 1027–38. http://dx.doi.org/10.1017/s0031182009991788.
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SUMMARYPredator-prey models are often applied to the interactions between host immunity and parasite growth. A key component of these models is the immune system's functional response, the relationship between immune activity and parasite load. Typically, models assume a simple, linear functional response. However, based on the mechanistic interactions between parasites and immunity we argue that alternative forms are more likely, resulting in very different predictions, ranging from parasite exclusion to chronic infection. By extending this framework to consider multiple infections we show that combinations of parasites eliciting different functional responses greatly affect community stability. Indeed, some parasites may stabilize other species that would be unstable if infecting alone. Therefore hosts' immune systems may have adapted to tolerate certain parasites, rather than clear them and risk erratic parasite dynamics. We urge for more detailed empirical information relating immune activity to parasite load to enable better predictions of the dynamic consequences of immune-mediated interspecific interactions within parasite communities.
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White, P. Signe, Angela Choi, Rishika Pandey, Arthur Menezes, McKenna Penley, Amanda K. Gibson, Jacobus de Roode, and Levi Morran. "Host heterogeneity mitigates virulence evolution." Biology Letters 16, no. 1 (January 2020): 20190744. http://dx.doi.org/10.1098/rsbl.2019.0744.
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Parasites often infect genetically diverse host populations, and the evolutionary trajectories of parasite populations may be shaped by levels of host heterogeneity. Mixed genotype host populations, compared to homogeneous host populations, can reduce parasite prevalence and potentially reduce rates of parasite adaptation due to trade-offs associated with adapting to specific host genotypes. Here, we used experimental evolution to select for increased virulence in populations of the bacterial parasite Serratia marcescens exposed to either heterogeneous or homogeneous populations of Caenorhabditis elegans . We found that parasites exposed to heterogeneous host populations evolved significantly less virulence than parasites exposed to homogeneous host populations over several hundred bacterial generations. Thus, host heterogeneity impeded parasite adaptation to host populations. While we detected trade-offs in virulence evolution, parasite adaptation to two specific host genotypes also resulted in modestly increased virulence against the reciprocal host genotypes. These results suggest that parasite adaptation to heterogeneous host populations may be impeded by both trade-offs and a reduction in the efficacy of selection as different host genotypes exert different selective pressures on a parasite population.
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Byers, James E., J. P. Schmidt, Paula Pappalardo, Sarah E. Haas, and Patrick R. Stephens. "What factors explain the geographical range of mammalian parasites?" Proceedings of the Royal Society B: Biological Sciences 286, no. 1903 (May 22, 2019): 20190673. http://dx.doi.org/10.1098/rspb.2019.0673.
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Free-living species vary substantially in the extent of their spatial distributions. However, distributions of parasitic species have not been comprehensively compared in this context. We investigated which factors most influence the geographical extent of mammal parasites. Using the Global Mammal Parasite Database we analysed 17 818 individual geospatial records on 1806 parasite species (encompassing viruses, bacteria, protozoa, arthropods and helminths) that infect 396 carnivore, ungulate and primate host species. As a measure of the geographical extent of each parasite species we quantified the number and area of world ecoregions occupied by each. To evaluate the importance of variables influencing the summed area of ecoregions occupied by a parasite species, we used Bayesian network analysis of a subset ( n = 866) of the parasites in our database that had at least two host species and complete information on parasite traits. We found that parasites that covered more geographical area had a greater number of host species, higher average phylogenetic relatedness between host species and more sampling effort. Host and parasite taxonomic groups had weak and indirect effects on parasite ecoregion area; parasite transmission mode had virtually no effect. Mechanistically, a greater number of host species probably increases both the collective abundance and habitat breadth of hosts, providing more opportunities for a parasite to have an expansive range. Furthermore, even though mammals are one of the best-studied animal classes, the ecoregion area occupied by their parasites is strongly sensitive to sampling effort, implying mammal parasites are undersampled. Overall, our results support that parasite geographical extent is largely controlled by host characteristics, many of which are subsumed within host taxonomic identity.
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Beechler, Brianna R., Kate S. Boersma, Peter E. Buss, Courtney A. C. Coon, Erin E. Gorsich, Brian S. Henrichs, Adam M. Siepielski, et al. "Bovine tuberculosis disturbs parasite functional trait composition in African buffalo." Proceedings of the National Academy of Sciences 116, no. 29 (July 1, 2019): 14645–50. http://dx.doi.org/10.1073/pnas.1903674116.
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Novel parasites can have wide-ranging impacts, not only on host populations, but also on the resident parasite community. Historically, impacts of novel parasites have been assessed by examining pairwise interactions between parasite species. However, parasite communities are complex networks of interacting species. Here we used multivariate taxonomic and trait-based approaches to determine how parasite community composition changed when African buffalo (Syncerus caffer) acquired an emerging disease, bovine tuberculosis (BTB). Both taxonomic and functional parasite richness increased significantly in animals that acquired BTB than in those that did not. Thus, the presence of BTB seems to catalyze extraordinary shifts in community composition. There were no differences in overall parasite taxonomic composition between infected and uninfected individuals, however. The trait-based analysis revealed an increase in direct-transmitted, quickly replicating parasites following BTB infection. This study demonstrates that trait-based approaches provide insight into parasite community dynamics in the context of emerging infections.
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Enslow, Chelsea, Rachel Vallender, Emily Rondel, and Nicola Koper. "Host dispersal and landscape conversion are associated with the composition of haemosporidian parasites of the golden-winged warbler." Parasitology 147, no. 1 (September 18, 2019): 96–107. http://dx.doi.org/10.1017/s0031182019001240.
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AbstractUnderstanding factors that influence the spatial and temporal distributions of blood parasites is important to help predict how host species and their parasites may respond to global change. Factors that may influence parasite distributions are land cover and host dispersal patterns, which may result in exposure of a host to novel parasites, or escape from parasites of their origin. We screened golden-winged warblers from across the United States and Canada for blood parasites, and investigated whether land-use patterns or host dispersal affected the prevalence and composition of haemosporidian assemblages. Parasite prevalence varied strongly with study area, and areas with high agricultural cover had a significantly higher prevalence of Leucocytozoon and Parahaemoproteus parasites. Lineages of Parahaemoproteus and Leucocytozoon were genetically differentiated among study areas, and prevalence and composition of parasite assemblages indicated an increase in parasite prevalence and accumulation of unique parasite lineages from the southeast to the northwest. This matches the historical range expansion and natal dispersal patterns of golden-winged warblers, and suggests that golden-winged warblers may have been sensitive to novel parasites as they dispersed. The high prevalence and diversity of parasite lineages in the north-west extent of their breeding range (Manitoba) indicates that this population may face unique pressures.
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Pfenning-Butterworth, Alaina C., T. Jonathan Davies, and Clayton E. Cressler. "Identifying co-phylogenetic hotspots for zoonotic disease." Philosophical Transactions of the Royal Society B: Biological Sciences 376, no. 1837 (September 20, 2021): 20200363. http://dx.doi.org/10.1098/rstb.2020.0363.
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The incidence of zoonotic diseases is increasing worldwide, which makes identifying parasites likely to become zoonotic and hosts likely to harbour zoonotic parasites a critical concern. Prior work indicates that there is a higher risk of zoonotic spillover accruing from closely related hosts and from hosts that are infected with a high phylogenetic diversity of parasites. This suggests that host and parasite evolutionary history may be important drivers of spillover, but identifying whether host–parasite associations are more strongly structured by the host, parasite or both requires co-phylogenetic analyses that combine host–parasite association data with host and parasite phylogenies. Here, we use host–parasite datasets containing associations between helminth taxa and free-range mammals in combination with phylogenetic models to explore whether host, parasite, or both host and parasite evolutionary history influences host–parasite associations. We find that host phylogenetic history is most important for driving patterns of helminth-mammal association, indicating that zoonoses are most likely to come from a host's close relatives. More broadly, our results suggest that co-phylogenetic analyses across broad taxonomic scales can provide a novel perspective for surveying potential emerging infectious diseases. This article is part of the theme issue ‘Infectious disease macroecology: parasite diversity and dynamics across the globe’.
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PATTERSON, JESSE E. H., and KATHREEN E. RUCKSTUHL. "Parasite infection and host group size: a meta-analytical review." Parasitology 140, no. 7 (February 21, 2013): 803–13. http://dx.doi.org/10.1017/s0031182012002259.
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SUMMARYMany studies have identified various host behavioural and ecological traits that are associated with parasite infection, including host gregariousness. By use of meta-analyses, we investigated to what degree parasite prevalence, intensity and species richness are correlated with group size in gregarious species. We predicted that larger groups would have more parasites and higher parasite species richness. We analysed a total of 70 correlations on parasite prevalence, intensity and species richness across different host group sizes. Parasite intensity and prevalence both increased positively with group size, as expected. No significant relationships were found between host group size and parasite species richness, suggesting that larger groups do not harbour more rare or novel parasite species than smaller groups. We further predicted that the mobility of the host (mobile, sedentary) and the mode of parasite transmission (direct, indirect, mobile) would be important predictors of the effects of group sizes on parasite infection. It was found that group size was positively correlated with the prevalence and intensity of directly and indirectly transmitted parasites. However, a negative relationship was observed between group size and mobile parasite intensity, with larger groups having lower parasite intensities. Further, intensities of parasites did not increase with group size of mobile hosts, suggesting that host mobility may negate parasite infection risk. The implications for the evolution and maintenance of sociality in host species are discussed, and future research directions are highlighted.
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Wolinska, Justyna, Sabine Giessler, and Henrike Koerner. "Molecular Identification and Hidden Diversity of Novel Daphnia Parasites from European Lakes." Applied and Environmental Microbiology 75, no. 22 (September 18, 2009): 7051–59. http://dx.doi.org/10.1128/aem.01306-09.
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ABSTRACT Parasites play important roles in local population dynamics and genetic structure. However, due to insufficient diagnostic tools, detailed host-parasite interactions may remain concealed by hidden parasite diversity in natural systems. Microscopic examination of 19 European lake Daphnia populations revealed the presence of three groups of parasites: fungi, microsporidia, and oomycetes. For most of these parasites no genetic markers have been described so far. Based on sequence similarities of the nuclear small-subunit and internal transcribed spacer (ITS) rRNA gene regions, one fungus, four microsporidian, and nine oomycete taxa were discovered in 147 infected Daphnia (and/or three other zooplankton crustaceans). Additionally, cloning of rRNA gene regions revealed parasite sequence variation within host individuals. This was most pronounced in the ITS region of one microsporidian taxon, where the within-host sequence variation ranged from 1.7% to 5.3% polymorphic sites for parasite isolates from 14 different geographical locations. Interestingly, the parasite isolates from close locations grouped together based on sequence similarities, suggesting that there was parasite dispersal. Taken together, the data obtained in this study revealed hidden diversity of parasite communities in Daphnia lake populations. Moreover, a higher level of resolution for identifying parasite strains makes it possible to test new hypotheses with respect to parasite dispersal, transmission routes, and coinfection.
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Ezenwa, Vanessa O., Elizabeth A. Archie, Meggan E. Craft, Dana M. Hawley, Lynn B. Martin, Janice Moore, and Lauren White. "Host behaviour–parasite feedback: an essential link between animal behaviour and disease ecology." Proceedings of the Royal Society B: Biological Sciences 283, no. 1828 (April 13, 2016): 20153078. http://dx.doi.org/10.1098/rspb.2015.3078.
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Animal behaviour and the ecology and evolution of parasites are inextricably linked. For this reason, animal behaviourists and disease ecologists have been interested in the intersection of their respective fields for decades. Despite this interest, most research at the behaviour–disease interface focuses either on how host behaviour affects parasites or how parasites affect behaviour, with little overlap between the two. Yet, the majority of interactions between hosts and parasites are probably reciprocal, such that host behaviour feeds back on parasites and vice versa. Explicitly considering these feedbacks is essential for understanding the complex connections between animal behaviour and parasite ecology and evolution. To illustrate this point, we discuss how host behaviour–parasite feedbacks might operate and explore the consequences of feedback for studies of animal behaviour and parasites. For example, ignoring the feedback of host social structure on parasite dynamics can limit the accuracy of predictions about parasite spread. Likewise, considering feedback in studies of parasites and animal personalities may provide unique insight about the maintenance of variation in personality types. Finally, applying the feedback concept to links between host behaviour and beneficial, rather than pathogenic, microbes may shed new light on transitions between mutualism and parasitism. More generally, accounting for host behaviour–parasite feedbacks can help identify critical gaps in our understanding of how key host behaviours and parasite traits evolve and are maintained.
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Wright, Ian. "Parasite roundup for 2021." Veterinary Nurse 13, no. 1 (February 2, 2022): 46–48. http://dx.doi.org/10.12968/vetn.2022.13.1.46.
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The year 2021 has proven to be another challenging year for UK veterinary professionals in many specialities, and parasite control has presented its own set of challenges. These have focused largely around the high numbers of rescue dogs continuing to be imported from abroad and the challenges of ensuring responsible parasiticide use in increasingly busy veterinary practices. Throughout, the European Council for Companion Animal Parasites UK & Ireland has continued to give parasite control advice, raise awareness of the changing parasite landscape in the UK and promote the need for risk-based parasite control and routine diagnostic surveillance. So what did 2021 hold for parasites and their control?
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Wright, Ian. "Parasite roundup for 2021." Companion Animal 27, no. 3 (March 2, 2022): 6–8. http://dx.doi.org/10.12968/coan.2022.0008.
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The year 2021 has proven to be another challenging year for UK veterinary professionals in many specialities, and parasite control has presented its own set of challenges. These have focused largely around the high numbers of rescue dogs continuing to be imported from abroad and the challenges of ensuring responsible parasiticide use in increasingly busy veterinary practices. Throughout, the European Council for Companion Animal Parasites UK & Ireland has continued to give parasite control advice, raise awareness of the changing parasite landscape in the UK and promote the need for risk-based parasite control and routine diagnostic surveillance. So what did 2021 hold for parasites and their control?
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Wright, Ian. "Parasite roundup for 2022." Companion Animal 27, no. 12 (December 2, 2022): 166–70. http://dx.doi.org/10.12968/coan.2022.0033.
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The year 2022 has proven to be another tricky year for UK veterinary professionals, and parasite control has presented its own set of challenges. These have focused largely around the high numbers of rescue dogs being imported from abroad, in particular as a result of the war in Ukraine, and the challenges of ensuring responsible parasiticide use. Throughout, the European Council for Companion Animal Parasites UK & Ireland has continued to give parasite control advice, raise awareness of the changing parasite landscape in the UK and promote the need for risk-based parasite control and routine diagnostic surveillance. So what did 2022 hold for parasites and their control?
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Hadiroseyani, Y., P. Hariyadi, and Sri Nuryati. "Inventarisation of Parasite in ”Dumbo” Catfish Clarias sp. from Bogor Region." Jurnal Akuakultur Indonesia 5, no. 2 (July 1, 2007): 167. http://dx.doi.org/10.19027/jai.5.167-177.
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<p>Outbreak of parasites can reduce aquaculture productivity or even cause mass mortality of fish. Few quantities of parasite infection may still be tolerated by the host, however high intensity of infection can impair to fish metabolism or even damage of organelle. Proper treatment can be done when parasite infecting fish is known. This study was conducted to record parasite infecting "dumbo" catfish <em>Clarias</em> sp. that is reared by farmers in three location at Bogor, i.e. Cimanggu, Cijeruk and Cibinong. Data included prevalence and intensity of parasite were analyzed descriptively. There were 7 kinds of parasite infecting catfish from Cimanggu, i.e. <em>Trichodina, </em>Myxosporea,<em> </em><em>Ichthyophthirius multifiliis</em><em>, </em>Metacercaria<em>, Gyrodactylus, Dactylogyrus </em>and <em>Lytocestus parvulus</em>. Monogenean was dominant parasite infecting catfish from Cimanggu, i.e. 61% was <em>Dactylogyrus </em>with 83.33% of prevalence and 12.37 of intensity levels. <em>Ichthyophthirius multifiliis, </em>Metacercaria<em> </em>and<em> </em>Myxosporea were only found from Cimanggu samples. Catfish from Cijeruk infected by 5 kinds of parasites, i.e. <em>Cryptobia </em>sp<em>., Vorticella, Gyrodactylus, Dactylogyrus</em> and <em>Lytocestus parvulus.</em> Same pattern with Cimanggu, samples from Cijeruk were also dominant infected by monogenean, i.e. 46% was <em>Dactylogyrus </em>with 96.667% of prevalence and 20.694 of intensity levels. Samples from Cibinong were infected by 6 kinds of parasites, i.e. <em>Vorticella,</em><em> </em><em>Trichodina,</em><em> </em><em>Gyrodactylus, Dactylogyrus</em>, <em>Lytocestus parvulus </em>and <em>Branchionus</em>. <em>Branchionus</em> was not parasite, but is as ectocomensal. Parasite dominating in Cibinong samples was <em>Branchionus </em>by 32% with 33.333% of prevalence and 0.555 of intensity levels.</p> <p>Keywords: parasite, "dumbo" catfish, <em>Clarias</em> sp., inventarisation, Bogor</p> <p> </p> <p>ABSTRAK</p> <p>Parasit yang menginfeksi ikan budidaya dapat mengakibatkan menurunnya produksi bahkan kematian masal. Dalam jumlah sedikit, parasit yang menginfeksi masih dapat ditolerir oleh inang, tetapi dapat menyebabkan gangguan metabolisme bahkan kerusakan organ jika terjadi dalam intensitas yang tinggi. Dengan mengetahui jenis organisme parasit yang menyerang lele, penanggulangannya akan lebih mudah. Penelitian ini bertujuan untuk menginventarisasi parasit yang terdapat pada ikan lele dumbo <em>Clarias </em>sp. yang dibudidayakan oleh petani di 3 lokasi di Kabupaten Bogor yaitu Cimanggu, Cijeruk dan Cibinong. Data meliputi prevalensi dan intensitas parasit yang diperoleh dianalisa secara deskriptif. Sebanyak 7 jenis parasit yang teridentifikasi menginfeksi ikan lele dari Cimanggu, yaitu <em>Trichodina, </em>Myxosporea,<em> </em><em>Ichthyophthirius multifiliis</em><em>, </em>Metacercaria<em>, Gyrodactylus, Dactylogyrus </em>dan<em> Lytocestus parvulus. </em>Monogenea merupakan parasit yang mendominasi lele dari daerah ini. yaitu <em>Dactylogyrus </em>sebesar 61% dengan nilai prevalensi sebesar 83,333% dan intensitas sebesar 12,370. Terdapat <em>Ichthyophthirius multifiliis, </em>Metacercaria<em> </em>dan<em> </em>Myxosporea yang didentifikasi dari ikan sampel yang hanya berasal dari Cimanggu. Ikan sample dari Cijeruk mengandung sebanyak 5 jenis parasit yaitu <em>Cryptobia </em>sp<em>., Vorticella, Gyrodactylus, Dactylogyrus</em> dan <em>Lytocestus parvulus. </em>Sama halnya dengan Cimanggu, pada daerah Cijeruk juga didominasi oleh jenis monogenea yaitu <em>Dactylogyrus </em>sebesar 46% dengan nilai prevalensi sebesar 96,667% dan nilai intensitas sebesar 20,694.<em> </em>Sampel dari Cibinong ditemukan sebanyak 6 jenis parasit yaitu <em>Vorticella,</em><em> </em><em>Trichodina,</em><em> </em><em>Gyrodactylus, Dactylogyrus</em>, <em>Lytocestus parvulus </em>dan <em>Branchionus</em>. <em>Branchionus</em> diduga bukan merupakan parasit tetapi ektokomensal. Dari Cibinong didominasi oleh <em>Branchionus </em>sebesar 32% dengan nilai prevalensi sebesar 33,333% dan nilai intensitas sebesar 0,555.</p> <p>Kata kunci : parasit, lele dimbo, <em>Clarias </em>sp., inventarisasi dan Bogor</p>
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IMHOOF, B., and P. SCHMID-HEMPEL. "Single-clone and mixed-clone infections versus host environment in Crithidia bombi infecting bumblebees." Parasitology 117, no. 4 (October 1998): 331–36. http://dx.doi.org/10.1017/s0031182098003138.
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Current theories assume that adaptive parasite evolution explains variation in the level of virulence and parasite success. In particular, mixed-genotype infections by parasites should generally be more virulent, and faster multiplying strains more successful, either because fixed strategies have evolved or because parasites facultatively alter virulence in response to co-infecting competitors. We compared several measures of parasite success and virulence between single-clone and mixed-clone infections of 2 strains of the trypanosome Crithidia bombi in its bumblebee host, Bombus terrestris. Contrary to expectation, we could not find differences between single-clone and mixed-clone infections in parasite prevalence, infection success, duration and clearance rate. However, a clearly significant effect of colony on infection intensity was present, and the colony effect emerged in virtually all other measures. We thus conclude that host environment as defined by the family (colony) genotype and thus host heterogeneity are more important in determining parasite virulence than the parasite characteristics. This does not invalidate modern theories of parasite evolution but suggests that variation in both hosts and parasites must be taken into account in more detail.
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Hernandez-Caballero, Irene, Luz Garcia-Longoria, Ivan Gomez-Mestre, and Alfonso Marzal. "The Adaptive Host Manipulation Hypothesis: Parasites Modify the Behaviour, Morphology, and Physiology of Amphibians." Diversity 14, no. 9 (September 8, 2022): 739. http://dx.doi.org/10.3390/d14090739.
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Parasites have evolved different strategies to increase their transmission from one host to another. The Adaptive Host Manipulation hypothesis states that parasites induce modifications of host phenotypes that could maximise parasite fitness. There are numerous examples of parasite manipulation across a wide range of host and parasite taxa. However, the number of studies exploring the manipulative effects of parasites on amphibians is still scarce. Herein, we extensively review the current knowledge on phenotypic alterations in amphibians following parasite infection. Outcomes from different studies show that parasites may manipulate amphibian behaviours to favour their transmission among conspecifics or to enhance the predation of infected amphibians by a suitable definite host. In addition, parasites also modify the limb morphology and impair locomotor activity of infected toads, frogs, and salamanders, hence facilitating their ingestion by a final host and completing the parasite life cycle. Additionally, parasites may alter host physiology to enhance pathogen proliferation, survival, and transmission. We examined the intrinsic (hosts traits) and extrinsic (natural and anthropogenic events) factors that may determine the outcome of infection, where human-induced changes of environmental conditions are the most harmful stressors that enhance amphibian exposure and susceptibility to parasites.
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CAMPIÃO, K. M., A. RIBAS, and L. E. R. TAVARES. "Diversity and patterns of interaction of an anuran–parasite network in a neotropical wetland." Parasitology 142, no. 14 (October 7, 2015): 1751–57. http://dx.doi.org/10.1017/s0031182015001262.
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SUMMARYWe describe the diversity and structure of a host–parasite network of 11 anuran species and their helminth parasites in the Pantanal wetland, Brazil. Specifically, we investigate how the heterogeneous use of space by hosts changes parasite community diversity, and how the local pool of parasites exploits sympatric host species of different habits. We examined 229 anuran specimens, interacting with 32 helminth parasite taxa. Mixed effect models indicated the influence of anuran body size, but not habit, as a determinant of parasite species richness. Variation in parasite taxonomic diversity, however, was not significantly correlated with host size or habit. Parasite community composition was not correlated with host phylogeny, indicating no strong effect of the evolutionary relationships among anurans on the similarities in their parasite communities. Host–parasite network showed a nested and non-modular pattern of interaction, which is probably a result of the low host specificity observed for most helminths in this study. Overall, we found host body size was important in determining parasite community richness, whereas low parasite specificity was important to network structure.
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Harris, Nyeema C., and Robert R. Dunn. "Species loss on spatial patterns and composition of zoonotic parasites." Proceedings of the Royal Society B: Biological Sciences 280, no. 1771 (November 22, 2013): 20131847. http://dx.doi.org/10.1098/rspb.2013.1847.
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Species loss can result in the subsequent loss of affiliate species. Though largely ignored to date, these coextinctions can pose threats to human health by altering the composition, quantity and distribution of zoonotic parasites. We simulated host extinctions from more than 1300 host–parasite associations for 29 North American carnivores to investigate changes in parasite composition and species richness. We also explored the geography of zoonotic parasite richness under three carnivore composition scenarios and examined corresponding levels of human exposure. We found that changes in parasite assemblages differed among parasite groups. Because viruses tend to be generalists, the proportion of parasites that are viruses increased as more carnivores went extinct. Coextinction of carnivore parasites is unlikely to be common, given that few specialist parasites exploit hosts of conservation concern. However, local extirpations of widespread carnivore hosts can reduce overall zoonotic richness and shift distributions of parasite-rich areas. How biodiversity influences disease risks remains the subject of debate. Our results make clear that hosts vary in their contribution to human health risks. As a consequence, so too does the loss (or gain) of particular hosts. Anticipating changes in host composition in future environments may help inform parasite conservation and disease mitigation efforts.
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Lester, R. J. G., and R. McVinish. "Does moving up a food chain increase aggregation in parasites?" Journal of The Royal Society Interface 13, no. 118 (May 2016): 20160102. http://dx.doi.org/10.1098/rsif.2016.0102.
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General laws in ecological parasitology are scarce. Here, we evaluate data on numbers of fish parasites published by over 200 authors to determine whether acquiring parasites via prey is associated with an increase in parasite aggregation. Parasite species were grouped taxonomically to produce 20 or more data points per group as far as possible. Most parasites that remained at one trophic level were less aggregated than those that had passed up a food chain. We use a stochastic model to show that high parasite aggregation in predators can be solely the result of the accumulation of parasites in their prey. The model is further developed to show that a change in the predators feeding behaviour with age may further increase parasite aggregation.
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Pedersen, Amy B., and Janis Antonovics. "Anthelmintic treatment alters the parasite community in a wild mouse host." Biology Letters 9, no. 4 (August 23, 2013): 20130205. http://dx.doi.org/10.1098/rsbl.2013.0205.
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Individuals are often co-infected with several parasite species, yet the consequences of drug treatment on the dynamics of parasite communities in wild populations have rarely been measured. Here, we experimentally reduced nematode infection in a wild mouse population and measured the effects on other non-target parasites. A single oral dose of the anthelmintic, ivermectin, significantly reduced nematode infection, but resulted in a reciprocal increase in other gastrointestinal parasites, specifically coccidial protozoans and cestodes. These results highlight the possibility that drug therapy may have unintended consequences for non-target parasites and that host–parasite dynamics cannot always be fully understood in the framework of single host–parasite interactions.
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Bruce, M. C., P. Alano, S. Duthie, and R. Carter. "Commitment of the malaria parasite Plasmodium falciparum to sexual and asexual development." Parasitology 100, no. 2 (April 1990): 191–200. http://dx.doi.org/10.1017/s0031182000061199.
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SUMMARYBlood-stage malaria parasites in the vertebrate host can develop either into the asexual, multiplying forms, called schizonts, or into gametocytes, the sexual stages of the parasite. In the present work we studied the differentiation into asexual parasites or gametocytes of the progeny of single, isolated schizonts of the clone 3D7A of Plasinodium falciparum, using monoclonal antibodies specific for the sexual or asexual stages of the parasite. We observed that schizonts obtained from a continuous culture undergoing serial cycles of growth and dilution with fresh red blood cells produced either only gametocytes or only asexual parasites, showing a high degree of commitment to one or the other developmental pathway.The relative proportion of schizonts which produced gametocytes was very low at low parasite densities in culture, while at high parasite densities a much greater proportion of schizonts produced gametocytes. Nevertheless, at both low and high parasite densities individual schizonts were almost always fully committed to producing only gametocytes or only asexual parasites.
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Carlson, Colin J., Tad A. Dallas, Laura W. Alexander, Alexandra L. Phelan, and Anna J. Phillips. "What would it take to describe the global diversity of parasites?" Proceedings of the Royal Society B: Biological Sciences 287, no. 1939 (November 18, 2020): 20201841. http://dx.doi.org/10.1098/rspb.2020.1841.
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How many parasites are there on Earth? Here, we use helminth parasites to highlight how little is known about parasite diversity, and how insufficient our current approach will be to describe the full scope of life on Earth. Using the largest database of host–parasite associations and one of the world’s largest parasite collections, we estimate a global total of roughly 100 000–350 000 species of helminth endoparasites of vertebrates, of which 85–95% are unknown to science. The parasites of amphibians and reptiles remain the most poorly described, but the majority of undescribed species are probably parasites of birds and bony fish. Missing species are disproportionately likely to be smaller parasites of smaller hosts in undersampled countries. At current rates, it would take centuries to comprehensively sample, collect and name vertebrate helminths. While some have suggested that macroecology can work around existing data limitations, we argue that patterns described from a small, biased sample of diversity aren’t necessarily reliable, especially as host–parasite networks are increasingly altered by global change. In the spirit of moonshots like the Human Genome Project and the Global Virome Project, we consider the idea of a Global Parasite Project: a global effort to transform parasitology and inventory parasite diversity at an unprecedented pace.
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PAGENKOPP LOHAN, KATRINA M., KRISTINA M. HILL-SPANIK, MARK E. TORCHIN, LEOPOLDINA AGUIRRE-MACEDO, ROBERT C. FLEISCHER, and GREGORY M. RUIZ. "Richness and distribution of tropical oyster parasites in two oceans." Parasitology 143, no. 9 (June 6, 2016): 1119–32. http://dx.doi.org/10.1017/s0031182015001900.
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SUMMARYParasites can exert strong effects on population to ecosystem level processes, but data on parasites are limited for many global regions, especially tropical marine systems. Characterizing parasite diversity and distributions are the first steps towards understanding the potential impacts of parasites. The Panama Canal serves as an interesting location to examine tropical parasite diversity and distribution, as it is a conduit between two oceans and a hub for international trade. We examined metazoan and protistan parasites associated with ten oyster species collected from both Panamanian coasts, including the Panama Canal and Bocas del Toro. We found multiple metazoan taxa (pea crabs, Stylochus spp., Urastoma cyrinae). Our molecular screening for protistan parasites detected four species of Perkinsus (Perkinsus marinus, Perkinsus chesapeaki, Perkinsus olseni, Perkinsus beihaiensis) and several haplosporidians, including two genera (Minchinia, Haplosporidium). Species richness was higher for the protistan parasites than for the metazoans, with haplosporidian richness being higher than Perkinsus richness. Perkinsus species were the most frequently detected and most geographically widespread among parasite groups. Parasite richness and overlap differed between regions, locations and oyster hosts. These results have important implications for tropical parasite richness and the dispersal of parasites due to shipping associated with the Panama Canal.
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DE LEO, GIULIO A., ANDREW P. DOBSON, and MARINO GATTO. "Body size and meta-community structure: the allometric scaling of parasitic worm communities in their mammalian hosts." Parasitology 143, no. 7 (March 22, 2016): 880–93. http://dx.doi.org/10.1017/s0031182015001444.
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SUMMARYIn this paper we derive from first principles the expected body sizes of the parasite communities that can coexist in a mammal of given body size. We use a mixture of mathematical models and known allometric relationships to examine whether host and parasite life histories constrain the diversity of parasite species that can coexist in the population of any host species. The model consists of one differential equation for each parasite species and a single density-dependent nonlinear equation for the affected host under the assumption of exploitation competition. We derive threshold conditions for the coexistence and competitive exclusion of parasite species using invasion criteria and stability analysis of the resulting equilibria. These results are then used to evaluate the range of parasites species that can invade and establish in a target host and identify the ‘optimal’ size of a parasite species for a host of a given body size; ‘optimal’ is defined as the body size of a parasite species that cannot be outcompeted by any other parasite species. The expected distributions of parasites body sizes in hosts of different sizes are then compared with those observed in empirical studies. Our analysis predicts the relative abundance of parasites of different size that establish in the host and suggests that increasing the ratio of parasite body size to host body size above a minimum threshold increases the persistence of the parasite population.
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de ROODE, J. C., L. R. GOLD, and S. ALTIZER. "Virulence determinants in a natural butterfly-parasite system." Parasitology 134, no. 5 (May 2006): 657–68. http://dx.doi.org/10.1017/s0031182006002009.
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SUMMARYMuch evolutionary theory assumes that parasite virulence (i.e. parasite-induced host mortality) is determined by within-host parasite reproduction and by the specific parasite genotypes causing infection. However, many other factors could influence the level of virulence experienced by hosts. We studied the protozoan parasite Ophryocystis elektroscirrha in its host, the monarch butterfly, Danaus plexippus. We exposed monarch larvae to wild-isolated parasites and assessed the effects of within-host replication and parasite genotype on host fitness measures, including pre-adult development time and adult weight and longevity. Per capita replication rates of parasites were high, and infection resulted in high parasite loads. Of all host fitness traits, adult longevity showed the clearest relationship with infection status, and decreased continuously with increasing parasite loads. Parasite genotypes differed in their virulence, and these differences were maintained across ecologically relevant variables, including inoculation dose, host sex and host age at infection. Thus, virulence appears to be a robust genetic parasite trait in this system. Although parasite loads and genotypes had strong effects on virulence, inoculation dose, host sex and age at infection were also important. These results have implications for virulence evolution and emphasize the need for a detailed understanding of specific host-parasite systems for addressing theory.
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Roth, E. Jr, V. Joulin, S. Miwa, A. Yoshida, J. Akatsuka, M. Cohen-Solal, and R. Rosa. "The use of enzymopathic human red cells in the study of malarial parasite glucose metabolism." Blood 71, no. 5 (May 1, 1988): 1408–13. http://dx.doi.org/10.1182/blood.v71.5.1408.1408.
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Abstract The in vitro growth of Plasmodium falciparum malaria parasites was assayed in mutant red cells deficient in either diphosphoglycerate mutase (DPGM) or phosphoglycerate kinase (PGK). In addition, cDNA probes developed for human DNA sequences coding for these enzymes were used to examine the parasite genome by means of restriction endonuclease digestion and Southern blot analysis of parasite DNA. In both types of enzymopathic red cells, parasite growth was normal. In infected DPGM deficient red cells, no DPGM activity could be detected, and in normal red cells, DPGM activity declined slightly in a manner suggestive of parasite catabolism of host protein. However, in infected PGK deficient red cells, there was a 100-fold increase in PGK activity, and in normal red cells, a threefold increase in PGK activity was observed. Parasite PGK could be recovered from isolated parasites, and a marked increase in heat instability of parasite PGK as compared with the host cell enzyme was noted. Neither cDNA probe was found to cross- react with DNA sequences in the parasite genome. It is concluded that the parasite has no requirement for DPGM, and probably has no gene for this enzyme. On the other hand, the parasite does require PGK, (an adenosine triphosphate [ATP] generating enzyme) and synthesizes its own enzyme, which must have been encoded in the parasite genome. The parasite PGK gene most likely lacks sufficient homology to be detected by a human cDNA probe. Enzymopathic red cells are useful tools for elucidating the glycolytic enzymology of parasites and their co- evolution with their human hosts.
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Roth, E. Jr, V. Joulin, S. Miwa, A. Yoshida, J. Akatsuka, M. Cohen-Solal, and R. Rosa. "The use of enzymopathic human red cells in the study of malarial parasite glucose metabolism." Blood 71, no. 5 (May 1, 1988): 1408–13. http://dx.doi.org/10.1182/blood.v71.5.1408.bloodjournal7151408.
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The in vitro growth of Plasmodium falciparum malaria parasites was assayed in mutant red cells deficient in either diphosphoglycerate mutase (DPGM) or phosphoglycerate kinase (PGK). In addition, cDNA probes developed for human DNA sequences coding for these enzymes were used to examine the parasite genome by means of restriction endonuclease digestion and Southern blot analysis of parasite DNA. In both types of enzymopathic red cells, parasite growth was normal. In infected DPGM deficient red cells, no DPGM activity could be detected, and in normal red cells, DPGM activity declined slightly in a manner suggestive of parasite catabolism of host protein. However, in infected PGK deficient red cells, there was a 100-fold increase in PGK activity, and in normal red cells, a threefold increase in PGK activity was observed. Parasite PGK could be recovered from isolated parasites, and a marked increase in heat instability of parasite PGK as compared with the host cell enzyme was noted. Neither cDNA probe was found to cross- react with DNA sequences in the parasite genome. It is concluded that the parasite has no requirement for DPGM, and probably has no gene for this enzyme. On the other hand, the parasite does require PGK, (an adenosine triphosphate [ATP] generating enzyme) and synthesizes its own enzyme, which must have been encoded in the parasite genome. The parasite PGK gene most likely lacks sufficient homology to be detected by a human cDNA probe. Enzymopathic red cells are useful tools for elucidating the glycolytic enzymology of parasites and their co- evolution with their human hosts.
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Dunn, A. M., M. J. Hatcher, R. S. Terry, and C. Tofts. "Evolutionary ecology of vertically transmitted parasites: transovarial transmission of a microsporidian sex ratio distorter in Gammarus duebeni." Parasitology 111, S1 (January 1995): S91—S109. http://dx.doi.org/10.1017/s0031182000075843.
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SUMMARYVertically transmitted parasites are transmitted from generation to generation of hosts usually via the host's gametes. Owing to gamete size dimorphism, the major transmission route is transovarial and selection (on the parasite) favours strategies which increase the relative frequency of the transmitting (female) host sex. These strategies impose unusual selection pressures on the host, and coevolution between hosts and vertically transmitted parasites has been implicated in speciation, in the evolution of symbiosis, and in the evolution of novel systems of host reproduction and sex determination. We review the evolutionary implications of vertically transmitted parasites in arthropods before focusing on strategies of transmission of a parasitic sex ratio distorter in Gammarus duebeni. The efficiency of parasite transmission to new hosts is a key factor underlying the relationship between vertically transmitted parasites and their hosts. Vertically transmitted parasites must overcome 2 bottlenecks in order to ensure successful infection of future host generations: first, transmission from adult to gamete; and secondly, transmission to the germ-line of the infected host. We investigate these 2 processes with regard to transovarial transmission by a microsporidian parasite in Gammarus duebeni. Parasite transmission from adult to eggs is highly efficient, with 96% of eggs of infected mothers inheriting the infection, whereas transmission to germ-line within infected embryos is relatively inefficient (72%). We measure parasite distribution between cells of developing embryos, and use these distributions to infer possible mechanisms of parasite transmission to germ-line. Parasite distribution within the embryo is dependent on host cell lineage, and is not consistent with unbiased segregation between daughter cells. These results indicate that parasites segregate together at host cell division, and may reflect a strategy of differential segregation to the host germ-line. We consider alternative parasite strategies at the cell-level in terms of their evolutionary implications.
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Herrera, James P., James Moody, and Charles L. Nunn. "Predictions of primate–parasite coextinction." Philosophical Transactions of the Royal Society B: Biological Sciences 376, no. 1837 (September 20, 2021): 20200355. http://dx.doi.org/10.1098/rstb.2020.0355.
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Future biodiversity loss threatens the integrity of complex ecological associations, including among hosts and parasites. Almost half of primate species are threatened with extinction, and the loss of threatened hosts could negatively impact parasite associations and ecosystem functions. If endangered hosts are highly connected in host–parasite networks, then future host extinctions will also drive parasite extinctions, destabilizing ecological networks. If threatened hosts are not highly connected, however, then network structure should not be greatly affected by the loss of threatened hosts. Networks with high connectance, modularity, nestedness and robustness are more resilient to perturbations such as the loss of interactions than sparse, nonmodular and non-nested networks. We analysed the interaction network involving 213 primates and 763 parasites and removed threatened primates (114 species) to simulate the effects of extinction. Our analyses revealed that connections to 23% of primate parasites (176 species) may be lost if threatened primates go extinct. In addition, measures of network structure were affected, but in varying ways because threatened hosts have fewer parasite interactions than non-threatened hosts. These results reveal that host extinctions will perturb the host–parasite network and potentially lead to secondary extinctions of parasites. The ecological consequences of these extinctions remain unclear. This article is part of the theme issue ‘Infectious disease macroecology: parasite diversity and dynamics across the globe’.
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Grüter, Christoph, Evelien Jongepier, and Susanne Foitzik. "Insect societies fight back: the evolution of defensive traits against social parasites." Philosophical Transactions of the Royal Society B: Biological Sciences 373, no. 1751 (June 4, 2018): 20170200. http://dx.doi.org/10.1098/rstb.2017.0200.
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Insect societies face many social parasites that exploit their altruistic behaviours or their resources. Due to the fitness costs these social parasites incur, hosts have evolved various behavioural, chemical, architectural and morphological defence traits. Similar to bacteria infecting multicellular hosts, social parasites have to successfully go through several steps to exploit their hosts. Here, we review how social insects try to interrupt this sequence of events. They can avoid parasite contact by choosing to nest in parasite-free locales or evade attacks by adapting their colony structure. Once social parasites attack, hosts attempt to detect them, which can be facilitated by adjustments in colony odour. If social parasites enter the nest, hosts can either aggressively defend their colony or take their young and flee. Nest structures are often shaped to prevent social parasite invasion or to safeguard host resources. Finally, if social parasites successfully establish themselves in host nests, hosts can rebel by killing the parasite brood or by reproducing in the parasites' presence. Hosts of social parasites can therefore develop multiple traits, leading to the evolution of complex defence portfolios of co-dependent traits. Social parasites can respond to these multi-level defences with counter-adaptations, potentially leading to geographical mosaics of coevolution. This article is part of the Theo Murphy meeting issue ‘Evolution of pathogen and parasite avoidance behaviours’.
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Farrell, Maxwell J., Andrew W. Park, Clayton E. Cressler, Tad Dallas, Shan Huang, Nicole Mideo, Ignacio Morales-Castilla, T. Jonathan Davies, and Patrick Stephens. "The ghost of hosts past: impacts of host extinction on parasite specificity." Philosophical Transactions of the Royal Society B: Biological Sciences 376, no. 1837 (September 20, 2021): 20200351. http://dx.doi.org/10.1098/rstb.2020.0351.
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A growing body of research is focused on the extinction of parasite species in response to host endangerment and declines. Beyond the loss of parasite species richness, host extinction can impact apparent parasite host specificity, as measured by host richness or the phylogenetic distances among hosts. Such impacts on the distribution of parasites across the host phylogeny can have knock-on effects that may reshape the adaptation of both hosts and parasites, ultimately shifting the evolutionary landscape underlying the potential for emergence and the evolution of virulence across hosts. Here, we examine how the reshaping of host phylogenies through extinction may impact the host specificity of parasites, and offer examples from historical extinctions, present-day endangerment, and future projections of biodiversity loss. We suggest that an improved understanding of the impact of host extinction on contemporary host–parasite interactions may shed light on core aspects of disease ecology, including comparative studies of host specificity, virulence evolution in multi-host parasite systems, and future trajectories for host and parasite biodiversity. This article is part of the theme issue ‘Infectious disease macroecology: parasite diversity and dynamics across the globe’.
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Vermeulen, Elke T., Michelle L. Power, David A. Nipperess, Ian Beveridge, and Mark D. B. Eldridge. "Biodiversity of parasite assemblages in the genus Petrogale and its relation to the phylogeny and biogeography of their hosts." Australian Journal of Zoology 64, no. 1 (2016): 61. http://dx.doi.org/10.1071/zo16023.
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Parasites form an integral part of overall biodiversity although they are often overlooked in conservation management, where emphasis is primarily directed towards the host. Parasites are often highly specialised to particular hosts, and thus may be just as threatened as the host they inhabit. For many of Australia’s wildlife species, little is known about their associated parasite communities. To begin to address this knowledge gap, we documented the parasite fauna described in the genetically diverse marsupial genus Petrogale, which contains seven species of conservation concern. The literature evaluation showed parasites of Petrogale to be highly diverse, with 17 species of protozoa, 8 species of cestodes, 102 species of nematodes and 30 species of ectoparasites identified in 16 of 17 Petrogale host species. A comparison of the parasite communities amongst Petrogale host species indicated a highly significant correlation between the parasite community similarity, and the phylogeny (P = 0.008) and biogeography (P = 0.0001) of their Petrogale hosts, suggesting high host specificity within their associated parasite assemblages. Five Petrogale species have established species recovery programs and their parasite communities should also be considered threatened, and management of parasite diversity required as part of these conservation programs.
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MUÑOZ, G., and Y. CORTÉS. "Parasite communities of a fish assemblage from the intertidal rocky zone of central Chile: similarity and host specificity between temporal and resident fish." Parasitology 136, no. 11 (August 3, 2009): 1291–303. http://dx.doi.org/10.1017/s0031182009990758.
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SUMMARYThe different species of a fish assemblage can, to some extent, be similar in terms of their parasite communities, which can be associated with certain ecological host traits. This study compared the parasite community descriptors between temporal and resident fish species composing an intertidal assemblage from central Chile. Host specificity and similarity indices of parasite communities among the fish species were also considered. A total of 1097 fish representing 14 species were collected during spring and summer of 2 consecutive years. A total spectrum of 40 parasite species was found, of which copepods and trematodes were the commonest. Congeneric fish species had the highest similarities in their parasite communities. Based on a cluster analysis, using only some fish species, no group was distinguished using abundance or prevalence of parasites, because 50% of parasite species had high host specificity and only few of them were shared among fish species. Adult parasites showed high host specificity and were found mainly in resident intertidal fish, whereas the temporal fish had parasites with different degrees of specificity. Consequently, resident intertidal fish were characterized by their own parasite species, meaning that their transmissions might be restricted to the intertidal zone.
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Owolabi, Alíz T. Y., Sarah E. Reece, and Petra Schneider. "Daily rhythms of both host and parasite affect antimalarial drug efficacy." Evolution, Medicine, and Public Health 9, no. 1 (January 1, 2021): 208–19. http://dx.doi.org/10.1093/emph/eoab013.
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ABSTRACT Background and objectives Circadian rhythms contribute to treatment efficacy in several non-communicable diseases. However, chronotherapy (administering drugs at a particular time-of-day) against infectious diseases has been overlooked. Yet, the daily rhythms of both hosts and disease-causing agents can impact the efficacy of drug treatment. We use the rodent malaria parasite Plasmodium chabaudi, to test whether the daily rhythms of hosts, parasites and their interactions affect sensitivity to the key antimalarial, artemisinin. Methodology Asexual malaria parasites develop rhythmically in the host’s blood, in a manner timed to coordinate with host daily rhythms. Our experiments coupled or decoupled the timing of parasite and host rhythms, and we administered artemisinin at different times of day to coincide with when parasites were either at an early (ring) or later (trophozoite) developmental stage. We quantified the impacts of parasite developmental stage, and alignment of parasite and host rhythms, on drug sensitivity. Results We find that rings were less sensitive to artemisinin than trophozoites, and this difference was exacerbated when parasite and host rhythms were misaligned, with little direct contribution of host time-of-day on its own. Furthermore, the blood concentration of haem at the point of treatment correlated positively with artemisinin efficacy but only when parasite and host rhythms were aligned. Conclusions and implications Parasite rhythms influence drug sensitivity in vivo. The hitherto unknown modulation by alignment between parasite and host daily rhythms suggests that disrupting the timing of parasite development could be a novel chronotherapeutic approach. Lay Summary We reveal that chronotherapy (providing medicines at a particular time-of-day) could improve treatment for malaria infections. Specifically, parasites’ developmental stage at the time of treatment and the coordination of timing between parasite and host both affect how well antimalarial drug treatment works.