Publications by authors named "Dave Chadee"

This study investigated the sources and microbiological quality of domestic water used by rural communities of Speightstown, Barbados; Carriacou, Grenada; and Nariva, Trinidad. The primary water source was harvested rainwater in Carriacou, and the public water supply for Nariva and Speightstown. Secondary water supplies of the communities came from untreated sources including rainwater, wells, boreholes and springs.

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Efforts directed at genetic modification of mosquitoes for population control or replacement are highly dependent on the initial mating success of transgenic male mosquitoes following their release into natural populations. Adult mosquito phenotypes are influenced by the environmental conditions experienced as larvae. Semifield studies conducted to date have not taken that under consideration when testing male mating fitness, and have compared mating success of males reared under identical environmental conditions.

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Surveillance for blood-fed female mosquitoes was performed between August 2015 and February 2016 at sites along the periphery of the Aripo Savannas Environmentally Reserve (ASSR) located in northeastern Trinidad, West Indies. We collected engorged female mosquitoes representing 13 species. DNA extractions from dissected abdomens were subjected to PCR amplification with three primer pairs targeting the mitochondrial cytochrome oxidase I and cytochrome b gene sequences.

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Members of the Culex pipiens complex differ in physiological traits that facilitate their survival in diverse environments. Assortative mating within the complex occurs in some regions where autogenous (the ability to lay a batch of eggs without a blood meal) and anautogenous populations are sympatric, and differences in mating behaviors may be involved. For example, anautogenous populations mate in flight/swarms, while autogenous populations often mate at rest.

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Populations of Aedes aegypti naturally exhibit variable susceptibility to dengue viruses. This natural variation can be impacted by nutritional stress resulting from larval-stage crowding, indicating the influence of environment components on the adult mosquito immune response. In particular, larval crowding was previously shown to reduce the susceptibility of adult females of a Trinidad field isolate of A.

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In addition to genetic history, environmental conditions during larval stages are critical to the development, success and phenotypic fate of the Aedes aegypti mosquito. In particular, previous studies have shown a strong genotype-by-environment component to adult mosquito body size in response to optimal vs stressed larval conditions. Here, we expand upon those results by investigating the effects of larval-stage crowding and nutritional limitation on the susceptibility of a recent field isolate of Aedes aegypti to dengue virus serotype-2.

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In this paper, we describe and illustrate a new species of parasitoid wasp as Brachymeria philornisae Delvare, sp. nov. The new species was reared from Philornis trinitensis Dodge & Aitken (Diptera: Muscidae) puparia that were found in the nests of the bird species Mimus gilvus (Vieillot) (Mimidae) and Tiaris bicolor (L.

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Few laboratory and field studies have reported long survival periods for Ae. aegypti females and even fewer have designed experiments to characterize this important life history trait. This study was conducted under laboratory conditions to determine the number of blood meals taken by individual females, the number of eggs laid per individual female, the length of the gonotrophic cycle, and the duration of female survival.

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The 2014 enterovirus D68 (EV-D68) outbreak in the United States raised concerns about the introduction of the virus in the Caribbean region. The objective of this study was to provide rapid evidence of the introduction of EV-D68 strains in the Caribbean region during the 2014 outbreak in the United States, using a relatively simple phylogenetic approach. From October 2014 to May 2015, four EV-D68 cases from two countries (Bermuda and Dominica) were detected at the regional referral laboratory at the Caribbean Public Health Agency (Port of Spain, Trinidad and Tobago) based on molecular testing of respiratory specimens.

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Background: The purpose of the study is to determine the epidemiology of road traffic collisions (RTCs) in Trinidad and Tobago by characterizing RTCs in terms of number of collisions, fatalities, victim profiles, and locations for the purpose of informing accident prevention programs. Previous studies of RTCs in Trinidad and Tobago were primarily concerned with patterns of drivers use of seat belts, road collisions as a cause of mortality in young men, and the economic burden of road collisions. Attempts were made to model road fatalities, but limited epidemiological data meant that it was difficult to determine trends or develop models.

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Mosquitoes, especially Aedes aegypti, are becoming important models for studying invasion biology. We characterized genetic variation at 12 microsatellite loci in 79 populations of Ae. aegypti from 30 countries in six continents, and used them to infer historical and modern patterns of invasion.

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The epidemiology of dengue fever is characterized by highly seasonal, multi-annual fluctuations, and the irregular circulation of its four serotypes. It is believed that this behaviour arises from the interplay between environmental drivers and serotype interactions. The exact mechanism, however, is uncertain.

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Background: Given the continued successes of the world's lymphatic filariasis (LF) elimination programs and the growing successes of many malaria elimination efforts, the necessity of low cost tools and methodologies applicable to long-term disease surveillance is greater than ever before. As many countries reach the end of their LF mass drug administration programs and a growing number of countries realize unprecedented successes in their malaria intervention efforts, the need for practical molecular xenomonitoring (MX), capable of providing surveillance for disease recrudescence in settings of decreased parasite prevalence is increasingly clear. Current protocols, however, require testing of mosquitoes in pools of 25 or fewer, making high-throughput examination a challenge.

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Within Latin America and the Caribbean region the impact of climate change has been associated with the effects of rainfall and temperature on seasonal outbreaks of dengue but few studies have been conducted on the impacts of climate on the behaviour and ecology of Aedes aegypti mosquitoes.This study was conducted to examine the adaptive behaviours currently being employed by A. aegypti mosquitoes exposed to the force of climate change in LAC countries.

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The Anopheles arabiensis genetic sexing strain ANO IPCL1 was developed based on a dieldrin resistant mutation. The strain has been shown to be practical and reliable in terms of female elimination by dieldrin treatments at larval stages, but has provided some difficulties when treatments were applied at the egg stage. The high natural sterility of this strain has advantages and disadvantages in both mass rearing and the sterilization process.

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Article Synopsis
  • Dengue is an acute viral disease prevalent in tropical areas, and its outbreak activity has surged in the Caribbean over the past 25 years, emphasizing the need for understanding its spatial and temporal dynamics.
  • Using Geographic Information System (GIS) software, researchers analyzed Dengue Haemorrhagic Fever cases from 1998 to 2004, uncovering patterns indicating that closer incidence events are linked to increased outbreak risk and expansion in urban areas.
  • Findings suggest that DHF cases cluster more closely before outbreaks, and time factors play a critical role in accelerating disease distribution, offering valuable insights for public health officials to manage and respond to dengue effectively.
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Background: Effective malaria control relies on accurate identification of those Anopheles mosquitoes responsible for the transmission of Plasmodium parasites. Anopheles oswaldoi s.l.

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The enormous burden placed on populations worldwide by mosquito-borne diseases, most notably malaria and dengue, is currently being tackled by the use of insecticides sprayed in residences or applied to bednets, and in the case of dengue vectors through reduction of larval breeding sites or larviciding with insecticides thereof. However, these methods are under threat from, amongst other issues, the development of insecticide resistance and the practical difficulty of maintaining long-term community-wide efforts. The sterile insect technique (SIT), whose success hinges on having a good understanding of the biology and behaviour of the male mosquito, is an additional weapon in the limited arsenal against mosquito vectors.

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Studies on the diel sugar feeding periodicity of male and female Aedes aegypti were conducted under laboratory conditions and monitored in single cages using the polyphagometer device and examined every 2h. Males mosquitoes displayed two peaks in sugar feeding, a small morning peak at 06.00-08.

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Background: Historically, Aedes aegypti (L.) mosquitoes were controlled/eradicated by fumigation, residual spraying and the elimination of breeding sites. However, the underlying mechanisms of how these vector populations were managed have never been evaluated.

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The diel copulation periodicity of domestic Aedes aegypti in the field in Trinidad, West Indies was monitored weekly at indoor and outdoor sites over a 16 month period. At indoor sites two significant (P<0.02) peaks in copulation occurred between 06.

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We report here the development of 65 novel microsatellite loci and construction of a composite genetic linkage map for Culex pipiens complex mosquitoes. Microsatellites were identified by in silico screening of the Culex quinquefasciatus genome assembly. Cross-species utility of 73 microsatellites for population studies in C.

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