Academic literature on the topic 'Mosquitoes Control Philippines'

Intervention planning for dengue requires reliable estimates of dengue transmission intensity. However, current maps of dengue risk provide estimates of disease burden or the boundaries of endemicity rather than transmission intensity. We therefore developed a global high-resolution map of dengue transmission intensity by fitting environmentally driven geospatial models to geolocated force of infection estimates derived from cross-sectional serological surveys and routine case surveillance data. We assessed the impact of interventions on dengue transmission and disease using Wolbachia-infected mosquitoes and the Sanofi-Pasteur vaccine as specific examples. We predicted high transmission intensity in all continents straddling the tropics, with hot spots in South America (Colombia, Venezuela, and Brazil), Africa (western and central African countries), and Southeast Asia (Thailand, Indonesia, and the Philippines). We estimated that 105 [95% confidence interval (CI), 95 to 114] million dengue infections occur each year with 51 (95% CI, 32 to 66) million febrile disease cases. Our analysis suggests that transmission-blocking interventions such as Wolbachia, even at intermediate efficacy (50% transmission reduction), might reduce global annual disease incidence by up to 90%. The Sanofi-Pasteur vaccine, targeting only seropositive recipients, might reduce global annual disease incidence by 20 to 30%, with the greatest impact in high-transmission settings. The transmission intensity map presented here, and made available for download, may help further assessment of the impact of dengue control interventions and prioritization of global public health efforts.

Dengue is the most common mosquito-borne, viral disease in the world. Dengue virus is a single stranded positive polarity RNA virus, belongs to the family Flaviviridae. It is transmitted through the bite of an infected female mosquito of Aedes species - mainly the species Aedes aegypti and, to a lesser extent, Aedes albopictus. This mosquito also transmits Chikungunya, Zika and Yellow fever viruses.1-4 There are 4 distinct, but closely related, serotypes of the virus (DEN-1, DEN-2, DEN-3 and DEN-4). Recovery from infection by one serotype provides heterotypic or cross-immunity to the other serotypes. This is only partial and temporary, lasts only a few months, but homotype immunity is lifelong. For this reason, a person can be infected with a dengue virus as many as four times in his or her lifetime. Subsequent infections (secondary infection) by other serotypes increase the risk of developing severe dengue.1-5 The fifth variant DENV-5 has been isolated in October 2013. DENV-5 has been detected during screening of viral samples taken from a 37 year old farmer admitted in a hospital in Sarawak state of Malaysia in the year 2007.6 The first record of a case of probable dengue fever reported in a Chinese medical encyclopedia from the Jin Dynasty (265–420AD).The first recognized dengue epidemics occurred almost simultaneously in Asia, Africa, and North America in the 1780s, shortly after the identification and naming of the disease in 1779. The first confirmed case report dates from 1789 and is by Benjamin Rush, who coined the term "breakbone fever" because of the symptoms of myalgia and arthralgia.7 Haemorrhagic dengue was first recognised in the 1950s during dengue epidemics in the Philippines and Thailand. 8 The incidence of dengue has grown dramatically around the world in recent decades. A vast majority of the cases are asymptomatic and hence the actual numbers of dengue cases are underreported and many cases are misclassified. Dengue is common in more than 100 countries around the globe, with its endemicity in Asia, the Pacific, Africa and the Latin American countries. Forty percent of the world’s population, about 3 billion people live in the areas with a risk of dengue. Annually, some 400 million people get infected with dengue, with an occurrence of 100 million clinically apparent infections, and 22,000 die from severe dengue across the globe. The increasing incidence, severity and frequency of dengue epidemics are linked to trends in human ecology, demography and globalisation, and may have been influenced by climate change. 8,9 In Bangladesh, dengue occurred sporadically since 1964.10 Literature shows, the first documented case of dengue like fever occurred in 1964, popularly known as "Dacca fever" which later on serologically proved as dengue fever.11 Bangladesh has been experiencing episodes of dengue fever in every year since 2000. All four serotypes have been detected, with DENV-3 predominance until 2002.12,13 After that, no DENV-3 or DENV-4 was reported from Bangladesh. During 2013-2016, DEN2 was predominant followed by DEN-1 in circulation. Institute of Epidemiology, Disease Control & Research (IEDCR) predicted that as the serotypes DENV-3 and DENV-4 are in circulation in the neighbouring countries, they may create epidemics of secondary dengue in the near future in Bangladesh.14 In 2017, reemergence of DENV-3 was identified; subsequently there was a sharp rise in dengue cases from the beginning of the monsoon season in 2018.15 In 2000, dengue attacked 5,551 individuals and the number of deaths was 93. Since 2003, the death rate has declined gradually, with zero fatalities in subsequent couple of years, but a devastating turn with 10,148 cases and 26 deaths in 2018. In 2019, during January to July, number total cases were 18,484, with 57 deaths.16 Directorate General of Health Services conducts periodical (Pre-monsoon, Monsoon and Post- monsoon) Aedes survey to estimate the vector density of the mosquito. The monsoon survey (18-27 July 2019) of 100 sites of 98 wards in Dhaka city both North and South revealed that the number of adult aedes mosquito was increased by 13.52 folds, in compare to the pre-monsoon (3-12 March 2019) survey.17 The aedes larvae were also increased by 12.5 folds in this period. Breteau Index (BI) was considered in the study. Report shows that the BI was more than 20 in 57% and 64% of total wards in Dhaka North and Dhaka South respectively. Furthermore, in terms of House Index (HI) or percentage of houses infested, 75% and 83% of total wards in North and South city respectively having HI more than 5.17 Furthermore, recent studies show that mosquitoes have grown resistant, and how certain insecticides are completely ineffective against them.18 Considering the situation, the Ministry of Health and Family Welfare, has taken commendable steps including training on case management for nurses and doctors across the country, review of the national guidelines on case management, expansion of dengue services along with increasing bed capacities in hospitals, strengthened mass awareness with special attention to the school children and the community people, ensuring availability of dengue diagnostic kits, diagnostic services at free of cost in public health facilities and fixed and reduced rate in private sectors, strengthening collaboration with city corporations, municipalities and other agencies both in public and private sectors and development partners. Prevention and control of dengue in Bangladesh, is not a sole responsibility for any single ministry and or its agencies. It needs effective and timely coordination, collaboration and partnership, among all the concerned ministries and their agencies, led by the Ministry of Health and Family Welfare. Furthermore, strengthening of the existing efforts including capacity building and resource mobilisation, and integrated surveillance, sustainable vector control, optimum and active community participation, and adequate monitoring and periodic evaluation throughout the year across the country, considering it an endemic disease, are strongly recommended. Bangladesh Med Res Counc Bull 2019; 45: 66-68

Epidemics of dengue fever occur every 3 to 4 years in the Philippines. The risk of a dengue fever outbreak in the Philippines has been heightened since Typhoon Haiyan struck the region in November 2013 because recovery efforts have been slow to progress. The structural damage caused by the typhoon resulted in an abundance of standing water, which can serve as mosquito breeding grounds. Should an outbreak of dengue occur, infected travelers departing the Philippines pose a risk because they may introduce the dengue virus into local vector populations (of Aedes aegypti and Aedes albopictus) at their destinations. This study quantifies the risk posed by potentially infected travelers departing the Philippines by using a network model that incorporates predictive species distribution models, demographic features of destination areas, and air traffic volumes. The analysis reveals that a majority of travelers departing Philippine airports deplane in regions suitable for harboring Aedes aegypti or Aedes albopictus; this factor increases the likelihood of further spread of the disease if an outbreak were to occur. Because it is impractical to implement all possible monitoring and control measures at all locations connected to the Philippines, this analysis ranks the set of candidates and thus allows surveillance resources to be optimally deployed.

Background: Knowledge, attitude, and practice (KAP) of in-patients with dengue fever (DF) through hospital-based surveillance has not been done. This study aimed to assess and compare the KAP, identify its predictors, correlation, and protective factors among pediatric and adult patients with DF and community-based controls to structure proactive community-wide DF prevention and control programs. Methods: This case-control study involved clinically or serologically confirmed patients (pediatrics n = 233; adults n = 17) with DF admitted in three public hospitals and community-based controls in Metro Manila, Philippines. A pretested structured KAP questionnaire was administered to participants to assess their KAP. Results: Pediatric and adult patients had significantly lower mean scores in the practice (p < 0.001) domain compared with the pediatric and adult controls. Being in senior high school, having had days in hospital, and rash were predictors of KAP among pediatric patients. Knowledge and attitude of patients with DF did not correlate with their practices against DF. Use of mosquito-eating fish, screen windows, and dengue vaccine were protective factors against DF. Conclusion: The study highlights the importance of behavioral change for knowledge and attitude to have significant effect to practices against DF. Thus, we recommend two comprehensive health programs, Communication for Behavioral Impact (COMBI) and Health Belief Model (HBM).

Our study assessed the impact of using ovitraps with pyriproxyfen on mosquito populations and the feasibility of using human saliva samples to test for seroconversion to dengue virus (DENV). We used a quasi-experimental research design by forming the intervention (n = 220) and the control (n = 223) groups in neighboring Taguig City, Philippines, over 4 months. Socio-demographic data, entomological indices, and IgG antibodies against DENV were measured. Associations between the implementation of ovitraps dosed with pyriproxyfen and mosquito densities (percentage positive ovitraps and container indices) and DENV seroconversion were calculated post-intervention in Months 2, 3, and 4. Among the participants recruited at baseline, 17 and 13 were seropositive for dengue (DENV) in the intervention and control groups, respectively. Both entomological indices were lower in the treated area than the control site at post-intervention Months 2, 3, and 4, but not earlier. Dengue seroconversions rates decreased in the treated population, but not significantly so. In conclusion, the use of PPF-treated ovitraps may have impacted the mosquito population, but not seroconversion rates. Compliance in providing saliva samples and the ability to detect IgG antibodies within these samples was encouraging and suggests that further studies on larger populations for longer durations are warranted.

Dengue is one of the most important vector-borne diseases worldwide and is a significant public health problem in the tropics. Mosquito control continues to be the primary approach to reducing the disease burden and spread of dengue virus (DENV). Aside from the traditional larviciding and adulticiding interventions, autodissemination using pyriproxyfen-treated (AD-PPF) ovitraps is one of the promising methods to complement existing vector control strategies. Our paper assessed the efficacy of AD-PPF in reducing DENV infections in two barangays in Parañaque City. Using saliva samples from the participants from both the control and intervention sites, we collected the seroprevalence data for three months in each of the two years. Spatial analysis was conducted to determine hotspot areas and identify DENV infection distributions across the trial periods. The results showed that the intervention site was identified as having a clustering of DENV infections in Month 0 of Year 1 and shifted to a random dispersion of dengue cases at the end of Month 3 in Year 2. The disappearance of the clustering of the intervention site translates to a decrease in the cases of DENV infection relative to the control site. Furthermore, we also identified that DENV transmission occurred at a small-scale level that did not go beyond 86 m. In conclusion, AD-PPF is suggested to be an effective strategy and may be used as an additional vector control approach, albeit based on this short-term implementation.

Background Vector surveillance is an essential public health tool to aid in the prediction and prevention of mosquito borne diseases. This study compared spatial and temporal trends of vector surveillance indices for Aedes vectors in the southern Philippines, and assessed potential links between vector indices and climate factors. Methods We analysed routinely collected larval and pupal surveillance data from residential areas of 14 cities and 51 municipalities during 2013–2018 (House, Container, Breteau and Pupal Indices), and used linear regression to explore potential relationships between vector indices and climate variables (minimum temperature, maximum temperature and precipitation). Results We found substantial spatial and temporal variation in monthly Aedes vector indices between cities during the study period, and no seasonal trend apparent. The House (HI), Container (CI) and Breteau (BI) Indices remained at comparable levels across most surveys (mean HI = 15, mean CI = 16, mean BI = 24), while the Pupal Productivity Index (PPI) was relatively lower in most months (usually below 5) except for two main peak periods (mean = 49 overall). A small proportion of locations recorded high values across all entomological indices in multiple surveys. Each of the vector indices were significantly correlated with one or more climate variables when matched to data from the same month or the previous 1 or 2 months, although the effect sizes were small. Significant associations were identified between minimum temperature and HI, CI and BI in the same month (R2 = 0.038, p = 0.007; R2 = 0.029, p = 0.018; and R2 = 0.034, p = 0.011, respectively), maximum temperature and PPI with a 2-month lag (R2 = 0.031, p = 0.032), and precipitation and HI in the same month (R2 = 0.023, p = 0.04). Conclusions Our findings indicated that larval and pupal surveillance indices were highly variable, were regularly above the threshold for triggering vector control responses, and that vector indices based on household surveys were weakly yet significantly correlated with city-level climate variables. We suggest that more detailed spatial and temporal analyses of entomological, climate, socio-environmental and Aedes-borne disease incidence data are necessary to ascertain the most effective use of entomological indices in guiding vector control responses, and reduction of human disease risk.

Dengue is a mosquito-transmitted virus infection that causes epidemics of febrile illness and hemorrhagic fever across the tropics and subtropics worldwide. Annual epidemics are commonly observed, but there is substantial spatiotemporal heterogeneity in intensity. A better understanding of this heterogeneity in dengue transmission could lead to improved epidemic prediction and disease control. Time series decomposition methods enable the isolation and study of temporal epidemic dynamics with a specific periodicity (e.g., annual cycles related to climatic drivers and multiannual cycles caused by dynamics in population immunity). We collected and analyzed up to 18 y of monthly dengue surveillance reports on a total of 3.5 million reported dengue cases from 273 provinces in eight countries in Southeast Asia, covering ∼107 km2. We detected strong patterns of synchronous dengue transmission across the entire region, most markedly during a period of high incidence in 1997–1998, which was followed by a period of extremely low incidence in 2001–2002. This synchrony in dengue incidence coincided with elevated temperatures throughout the region in 1997–1998 and the strongest El Niño episode of the century. Multiannual dengue cycles (2–5 y) were highly coherent with the Oceanic Niño Index, and synchrony of these cycles increased with temperature. We also detected localized traveling waves of multiannual dengue epidemic cycles in Thailand, Laos, and the Philippines that were dependent on temperature. This study reveals forcing mechanisms that drive synchronization of dengue epidemics on a continental scale across Southeast Asia.

Abstract Background Vector control measures are critical for the prevention and reduction of dengue virus (DENV) transmission. Effective vector control is reliant not only on knowledge of mosquito abundance, but also on the timely and accurate detection of mosquito-borne infection. Mosquito-based virus surveillance programs typically rely on pool-based mosquito testing, although whether individual-based mosquito testing is a feasible alternative to this has not been widely studied. Applying an individual-based mosquito testing approach, we conducted a 1-month surveillance study of DENV in adult Aedes aegypti mosquitoes in homes of suspected dengue patients during the 2015 peak dengue season in Tarlac City, Philippines to more accurately assess the mosquito infection rate and identify the DENV serotypes and genotypes concurrently co-circulating in mosquitoes and patients there. Methods We performed a one-step multiplex real-time reverse transcription-polymerase chain reaction (RT-PCR) assay for the simultaneous detection and serotyping of DENV in patients and individual female Ae. aegypti mosquitoes. Additionally, we performed sequencing and phylogenetic analyses to further characterize the detected DENV serotypes in mosquitoes and patients at the genotype level. Results We collected a total of 583 adult Ae. aegypti mosquitoes, of which we individually tested 359 female mosquitoes for the presence of DENV. Ten (2.8%) of the 359 female mosquitoes were positive for the presence of DENV. We detected DENV-1, DENV-2, and DENV-4 in the field-collected mosquitoes, which was consistent with the serotypes concurrently found in infected patients. Sequencing and phylogenetic analyses of the detected DENV serotypes based on the partial sequence of the evelope (E) gene revealed three genotypes concurrently present in the sampled mosquitoes and patients during the study period, namely DENV-1 genotype IV, DENV-2 Cosmopolitan genotype, and DENV-4 genotype II. Conclusions We demonstrated the utility of a one-step multiplex real-time RT-PCR assay for the individual-based DENV surveillance of mosquitoes. Our findings reinforce the importance of detecting and monitoring virus activity in local mosquito populations, which are critical for dengue prevention and control.

Dengue is a viral mosquito-borne infection transmitted primarily by the Aedes mosquitoes. It is one of the several emerging tropical diseases which progressively spread geographically to virtually all tropical countries like the Philippines. Recent climate changes related to global warming have increased the potential risk of dengue outbreaks in the world. In this paper, we study and investigate temperature and precipitation as climatological factors affecting dengue incidence in the Philippines from the year 2015 to 2018. Monthly dengue cases and climate data were gathered for the said study period. A correlation and wavelet coherence analyses were performed to determine a relationship between dengue incidence and climatological factors in the Philippines. Results show that the amount of rainfall is strongly correlated to the increase of dengue cases in the country as compared to the temperature. Evidence shows that dengue incidence in the Philippines mostly occur during the rainy season. Thus, intensified surveillance and control of mosquitoes during the rainy season are recommended.

This is part of the ReMoVE Dengue Program (i.e., research on mosquito, virus, and eco-socioeconomics of dengue) initiated under the auspices of the National Research Council of the Philippines, which started in 2012 aimed to develop locally adapted technologies, products, and systems, which would control the spread of dengue virus and reduce the eco-socioeconomic impact of dengue. Here, will be reported the results of the genomic surveillance of community-collected mosquitoes from a dengue hotspot community of Barangay Old Balara in Quezon City, Philippines using serotype-specific dengue PCR, and the developed antisense RNA product platform for dengue virus control based on surveillance results. Implications and recommendations for this work are outlined.