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1.
Insects ; 14(2)2023 Jan 19.
Article in English | MEDLINE | ID: mdl-36835677

ABSTRACT

Mosquito-borne diseases are among the most important public health problems worldwide [...].

3.
Front Epidemiol ; 3: 1201038, 2023.
Article in English | MEDLINE | ID: mdl-38455935

ABSTRACT

Background: French Polynesia is a French overseas collectivity in the Southeast Pacific, comprising 75 inhabited islands across five archipelagoes. The human settlement of the region corresponds to the last massive migration of humans to empty territories, but its timeline is still debated. Despite their recent population history and geographical isolation, inhabitants of French Polynesia experience health issues similar to those of continental countries. Modern lifestyles and increased longevity have led to a rise in non-communicable diseases (NCDs) such as obesity, diabetes, hypertension, and cardiovascular diseases. Likewise, international trade and people mobility have caused the emergence of communicable diseases (CDs) including mosquito-borne and respiratory diseases. Additionally, chronic pathologies including acute rheumatic fever, liver diseases, and ciguatera, are highly prevalent in French Polynesia. However, data on such diseases are scarce and not representative of the geographic fragmentation of the population. Objectives: The present project aims to estimate the prevalence of several NCDs and CDs in the population of the five archipelagoes, and identify associated risk factors. Moreover, genetic analyses will contribute to determine the sequence and timings of the peopling history of French Polynesia, and identify causal links between past genetic adaptation to island environments, and present-day susceptibility to certain diseases. Methods: This cross-sectional survey is based on the random selection of 2,100 adults aged 18-69 years and residing on 18 islands from the five archipelagoes. Each participant answered a questionnaire on a wide range of topics (including demographic characteristics, lifestyle habits and medical history), underwent physical measurements (height, weight, waist circumference, arterial pressure, and skin pigmentation), and provided biological samples (blood, saliva, and stool) for biological, genetic and microbiological analyses. Conclusion: For the first time in French Polynesia, the present project allows to collect a wide range of data to explore the existence of indicators and/or risk factors for multiple pathologies of public health concern. The results will help health authorities to adapt actions and preventive measures aimed at reducing the incidence of NCDs and CDs. Moreover, the new genomic data generated in this study, combined with anthropological data, will increase our understanding of the peopling history of French Polynesia. Clinical trial registration: https://clinicaltrials.gov/, identifier: NCT06133400.

4.
Math Biosci ; 348: 108811, 2022 06.
Article in English | MEDLINE | ID: mdl-35378165

ABSTRACT

BACKGROUND: The mosquito Aedes polynesiensis inhabits Pacific islands and territories and transmits arboviruses and parasites. In the context of rapid environmental change, understanding the effects of environmental heterogeneity on mosquitoes is crucial. METHODS: First, empirical field data and remote sensing data were combined to model spatial heterogeneity in the environmental suitability for Ae. polynesiensis. Second, a model of mosquito population dynamics was applied to predict mosquito distributions over a heterogeneous landscape assuming different dispersal behaviours. Motu Tautau, French Polynesia, was used as a case study of the utility of this methodological approach. Ae. polynesiensis use land crab Cardisoma carnifex burrows for oviposition in French Polynesia; environmental suitability was therefore quantified using C. carnifex burrow density. RESULTS: Micro-regions with large Ae. polynesiensis populations facilitated by high C. carnifex burrow density were accurately captured by our methodology. Preferential dispersal towards oviposition sites promoted larger population sizes than non-preferential dispersal but did not offer greater resilience to environmental change. Reduced environmental suitability for Ae. polynesiensis resulted in spatially non-linear effects upon the mosquito distribution. CONCLUSIONS: Environmental change has complex spatial effects upon mosquito populations. Mosquito control strategies must carefully balance spatial effects with net effects.


Subject(s)
Aedes , Animals , Female , Mosquito Control/methods , Mosquito Vectors , Oviposition , Polynesia/epidemiology , Population Density
5.
J Am Mosq Control Assoc ; 37(4): 224-241, 2021 12 01.
Article in English | MEDLINE | ID: mdl-34817602

ABSTRACT

Mosquito surveillance is an essential component of mosquito control and mosquito traps are a universally employed tool to monitor adult populations. The objective of this paper was to evaluate the new modular Biogents BG-Pro mosquito trap (BGP) and compare its performance to 4 widely used traps for adult mosquitoes: the BG-Sentinel (BGS), the BG Mosquitaire (BGM), the CDC miniature light trap (CDC), and the encephalitis vector survey trap (EVS). One semi-field and 9 field Latin square trials were performed in 7 countries. Results showed that the collection performance of the BGP was equivalent to or exceeded that of the BGS, BGM, CDC, and EVS traps in head-to-head comparisons. The BGP uses 35% less power than the CDC and 75% less than the BGS and BGM. This lower power consumption allows it to run at 5 V for 2 days using a small lightweight 10,000-mAh rechargeable power bank. The BG-Pro is an excellent alternative for the surveillance of mosquito species that are usually monitored with BG-Sentinel, CDC, or EVS traps.


Subject(s)
Aedes , Encephalitis , Animals , Centers for Disease Control and Prevention, U.S. , Mosquito Control , Surveys and Questionnaires , United States
6.
Am J Trop Med Hyg ; 104(5): 1907-1916, 2021 03 22.
Article in English | MEDLINE | ID: mdl-33755583

ABSTRACT

Mosquitoes are the main arthropod vectors of human pathogens. The current methods for mosquito identification include morphological and molecular methods. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), now routinely used for bacterial identification, has recently emerged in the field of entomology. The aim of this study was to use MALDI-TOF MS to identify mosquito colonies from French Polynesia. Five hundred specimens from French Polynesia belonging to three species, Aedes aegypti, Aedes polynesiensis, and Culex quinquefasciatus, were included in the study. Testing the legs of these mosquitoes by MALDI-TOF MS revealed a 100% correct identification of all specimens at the species level. The MALDI-TOF MS profiles obtained allowed differentiation of male from female mosquitoes and the specific identification of female mosquito colonies of the same species but different geographic origin.


Subject(s)
Aedes/chemistry , Culex/chemistry , Sex Determination Analysis/standards , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/standards , Animals , Entomology/methods , Female , Humans , Male , Mosquito Vectors/chemistry , Polynesia , Sex Determination Analysis/methods , Species Specificity , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods
7.
Insects ; 12(3)2021 Feb 24.
Article in English | MEDLINE | ID: mdl-33668374

ABSTRACT

Aedes albopictus and Aedes aegypti are invasive mosquito species that impose a substantial risk to human health. To control the abundance and spread of these arboviral pathogen vectors, the sterile insect technique (SIT) is emerging as a powerful complement to most commonly-used approaches, in part, because this technique is ecologically benign, specific, and non-persistent in the environment if releases are stopped. Because SIT and other similar vector control strategies are becoming of increasing interest to many countries, we offer here a pragmatic and accessible 'roadmap' for the pre-pilot and pilot phases to guide any interested party. This will support stakeholders, non-specialist scientists, implementers, and decision-makers. Applying these concepts will ensure, given adequate resources, a sound basis for local field trialing and for developing experience with the technique in readiness for potential operational deployment. This synthesis is based on the available literature, in addition to the experience and current knowledge of the expert contributing authors in this field. We describe a typical path to successful pilot testing, with the four concurrent development streams of Laboratory, Field, Stakeholder Relations, and the Business and Compliance Case. We provide a graphic framework with criteria that must be met in order to proceed.

8.
Parasit Vectors ; 11(Suppl 2): 654, 2018 Dec 24.
Article in English | MEDLINE | ID: mdl-30583720

ABSTRACT

Major efforts are currently underway to develop novel, complementary methods to combat mosquito-borne diseases. Mosquito genetic control strategies (GCSs) have become an increasingly important area of research on account of their species-specificity, track record in targeting agricultural insect pests, and their environmentally non-polluting nature. A number of programs targeting Aedes and Anopheles mosquitoes, vectors of human arboviruses and malaria respectively, are currently being developed or deployed in many parts of the world. Operationally implementing these technologies on a large scale however, beyond proof-of-concept pilot programs, is hampered by the absence of adequate sex separation methods. Sex separation eliminates females in the laboratory from male mosquitoes prior to release. Despite the need for sex separation for the control of mosquitoes, there have been limited efforts in recent years in developing systems that are fit-for-purpose. In this special issue of Parasites and Vectors we report on the progress of the global Coordinated Research Program on "Exploring genetic, molecular, mechanical and behavioural methods for sex separation in mosquitoes" that is led by the Insect Pest Control Subprogramme of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture with the specific aim of building efficient sex separation systems for mosquito species. In an effort to overcome current barriers we briefly highlight what we believe are the three main reasons why progress has been so slow in developing appropriate sex separation systems: the availability of methods that are not scalable, the difficulty of building the ideal genetic systems and, finally, the lack of research efforts in this area.


Subject(s)
Aedes/genetics , Anopheles/genetics , Malaria/prevention & control , Mosquito Control , Mosquito Vectors/genetics , Aedes/physiology , Animals , Anopheles/physiology , Female , Gene Drive Technology , Humans , Infertility , Malaria/transmission , Male , Mosquito Vectors/physiology , Sex Determination Analysis
9.
Parasit Vectors ; 11(Suppl 2): 656, 2018 Dec 24.
Article in English | MEDLINE | ID: mdl-30583722

ABSTRACT

BACKGROUND: Several mosquito population suppression strategies based on the rearing and release of sterile males have provided promising results. However, the lack of an efficient male selection method has hampered the expansion of these approaches into large-scale operational programmes. Currently, most of these programmes targeting Aedes mosquitoes rely on sorting methods based on the sexual size dimorphism (SSD) at the pupal stage. The currently available sorting methods have not been developed based on biometric analysis, and there is therefore potential for improvement. We applied an automated pupal size estimator developed by Grupo Tragsa with laboratory samples of Anopheles arabiensis, Aedes albopictus, Ae. polynesiensis, and three strains of Ae. aegypti. The frequency distribution of the pupal size was analyzed. We propose a general model for the analysis of the frequency distribution of mosquito pupae in the context of SSD-sorting methods, which is based on a Gaussian mixture distribution functions, thus making possible the analysis of performance (% males recovery) and purity (% males on the sorted sample). RESULTS: For the three Aedes species, the distribution of the pupae size can be modeled by a mixture of two Gaussian distribution functions and the proposed model fitted the experimental data. For a given population, each size threshold is linked to a specific outcome of male recovery. Two dimensionless parameters that measure the suitability for SSD-based sorting of a specific batch of pupae are provided. The optimal sorting results are predicted for the highest values of SSD and lowest values of intra-batch variance. Rearing conditions have a strong influence in the performance of the SSD-sorting methods and non-standard rearing can lead to increase pupae size heterogeneity. CONCLUSIONS: Sex sorting of pupae based on size dimorphism can be achieved with a high performance (% males recovery) and a reasonably high purity (% males on the sorted sample) for the different Aedes species and strains. The purity and performance of a sex sorting operation in the tested Aedes species are linked parameters whose relation can be modeled. The conclusions of this analysis are applicable to all the existing SSD-sorting methods. The efficiency of the SSD-sorting methods can be improved by reducing the heterogeneity of pupae size within rearing containers. The heterogeneity between batches does not strongly affect the quality of the sex sorting, as long as a specific separation threshold is not pre-set before the sorting process. For new developments, we recommend using adaptive and precise threshold selection methods applied individually to each batch or to a mix of batches. Adaptive and precise thresholds will allow the sex-sorting of mixed batches in operational conditions maintaining the target purity at the cost of a reduction in performance. We also recommend a strategy whereby an acceptable level of purity is pre-selected and remains constant across the different batches of pupae while the performance varies from batch to batch to fit with the desired purity.


Subject(s)
Aedes/anatomy & histology , Anopheles/anatomy & histology , Mosquito Vectors/anatomy & histology , Sex Characteristics , Aedes/physiology , Animals , Anopheles/physiology , Biometry , Female , Infertility , Male , Models, Statistical , Mosquito Vectors/physiology , Pupa , Sex Determination Analysis
10.
PLoS Negl Trop Dis ; 12(7): e0006660, 2018 07.
Article in English | MEDLINE | ID: mdl-30040826

ABSTRACT

BACKGROUND: Aedes mosquitoes severely affect the health and wellbeing of human populations by transmitting infectious diseases. In French Polynesia, Aedes aegypti is the main vector of dengue, chikungunya and Zika, and Aedes polynesiensis the primary vector of Bancroftian filariasis and a secondary vector of arboviruses. Tools for assessing the risk of disease transmission or for measuring the efficacy of vector control programmes are scarce. A promising approach to quantify the human-vector contact relies on the detection and the quantification of antibodies directed against mosquito salivary proteins. METHODOLOGY/PRINCIPAL FINDINGS: An ELISA test was developed to detect and quantify the presence of immunoglobulin G (IgG) directed against proteins from salivary gland extracts (SGE) of Ae. aegypti and Ae. polynesiensis in human populations exposed to either species, through a cross-sectional study. In Tahiti and Moorea islands where Ae. aegypti and Ae. polynesiensis are present, the test revealed that 98% and 68% of individuals have developed IgG directed against Ae. aegypti and Ae. polynesiensis SGE, respectively. By comparison, ELISA tests conducted on a cohort of people from metropolitan France, not exposed to these Aedes mosquitoes, indicated that 97% of individuals had no IgG directed against SGE of either mosquito species. The analysis of additional cohorts representing different entomological Aedes contexts showed no ELISA IgG cross-reactivity between Ae. aegypti and Ae. polynesiensis SGE. CONCLUSIONS/SIGNIFICANCE: The IgG response to salivary gland extracts seems to be a valid and specific biomarker of human exposure to the bites of Ae. aegypti and Ae. polynesiensis. This new immuno-epidemiological tool will enhance our understanding of people exposure to mosquito bites, facilitate the identification of areas where disease transmission risk is high and permit to evaluate the efficacy of novel vector control strategies in Pacific islands and other tropical settings.


Subject(s)
Aedes/immunology , Insect Bites and Stings/blood , Insect Proteins/immunology , Mosquito Vectors/immunology , Saliva/immunology , Salivary Proteins and Peptides/immunology , Adolescent , Adult , Aedes/classification , Animals , Antibody Formation , Child , Cohort Studies , Cross-Sectional Studies , Enzyme-Linked Immunosorbent Assay , Female , Humans , Insect Bites and Stings/epidemiology , Insect Bites and Stings/parasitology , Insect Proteins/genetics , Male , Middle Aged , Mosquito Vectors/classification , Pacific Islands/epidemiology , Polynesia/epidemiology , Saliva/chemistry , Young Adult
11.
PeerJ ; 6: e4860, 2018.
Article in English | MEDLINE | ID: mdl-29868273

ABSTRACT

BACKGROUND: The Lepidopteran ambidensovirus 1 isolated from Junonia coenia (hereafter JcDV) is an invertebrate parvovirus considered as a viral transduction vector as well as a potential tool for the biological control of insect pests. Previous works showed that JcDV-based circular plasmids experimentally integrate into insect cells genomic DNA. METHODS: In order to approach the natural conditions of infection and possible integration, we generated linear JcDV-gfp based molecules which were transfected into non permissive Spodoptera frugiperda (Sf9) cultured cells. Cells were monitored for the expression of green fluorescent protein (GFP) and DNA was analyzed for integration of transduced viral sequences. Non-structural protein modulation of the VP-gene cassette promoter activity was additionally assayed. RESULTS: We show that linear JcDV-derived molecules are capable of long term genomic integration and sustained transgene expression in Sf9 cells. As expected, only the deletion of both inverted terminal repeats (ITR) or the polyadenylation signals of NS and VP genes dramatically impairs the global transduction/expression efficiency. However, all the integrated viral sequences we characterized appear "scrambled" whatever the viral content of the transfected vector. Despite a strong GFP expression, we were unable to recover any full sequence of the original constructs and found rearranged viral and non-viral sequences as well. Cellular flanking sequences were identified as non-coding ones. On the other hand, the kinetics of GFP expression over time led us to investigate the apparent down-regulation by non-structural proteins of the VP-gene cassette promoter. CONCLUSION: Altogether, our results show that JcDV-derived sequences included in linear DNA molecules are able to drive efficiently the integration and expression of a foreign gene into the genome of insect cells, whatever their composition, provided that at least one ITR is present. However, the transfected sequences were extensively rearranged with cellular DNA during or after random integration in the host cell genome. Lastly, the non-structural proteins seem to participate in the regulation of p9 promoter activity rather than to the integration of viral sequences.

12.
J Med Entomol ; 55(5): 1299-1306, 2018 Aug 29.
Article in English | MEDLINE | ID: mdl-29635382

ABSTRACT

First autochthonous Zika clinical case was reported in the Republic of Marshall Islands (RMI) on Majuro Atoll in February 2016. An entomological survey of mosquito larvae and adult populations was carried out in four areas of Majuro, the most populated atoll of RMI encompassing different habitats (forest, rural, or urban) including some with confirmed clinical Zika cases to evaluate which mosquito species could be involved in the Zika transmission. A total of 2,367 immature and adult mosquito specimens were collected and identified to the species level. In total, five mosquito species were detected, Aedes aegypti (Linnaeus), Aedes albopictus (Skuse), Aedes marshallensis (Stone and Bohart), Culex quinquefasciatus (Say), and Culex annulirostris (Skuse) (Diptera: Culicidae), a first record for RMI. The most abundant species was Ae. aegypti presumed to be the main vector of Zika virus followed by Ae. albopictus. Improved management of breeding containers through better public awareness and community engagement, mosquito surveillance and innovative mosquito control strategies using the sterile insect technique (SIT) and/or the incompatible insect technique (IIT) could help prevent outbreaks of arboviruses in the RMI.


Subject(s)
Culicidae , Mosquito Vectors , Zika Virus Infection/transmission , Animals , Micronesia
13.
Lancet Infect Dis ; 18(5): e172-e182, 2018 05.
Article in English | MEDLINE | ID: mdl-29150310

ABSTRACT

The Zika virus crisis exemplified the risk associated with emerging pathogens and was a reminder that preparedness for the worst-case scenario, although challenging, is needed. Herein, we review all data reported during the unexpected emergence of Zika virus in French Polynesia in late 2013. We focus on the new findings reported during this outbreak, especially the first description of severe neurological complications in adults and the retrospective description of CNS malformations in neonates, the isolation of Zika virus in semen, the potential for blood-transfusion transmission, mother-to-child transmission, and the development of new diagnostic assays. We describe the effect of this outbreak on health systems, the implementation of vector-borne control strategies, and the line of communication used to alert the international community of the new risk associated with Zika virus. This outbreak highlighted the need for careful monitoring of all unexpected events that occur during an emergence, to implement surveillance and research programmes in parallel to management of cases, and to be prepared to the worst-case scenario.


Subject(s)
Disease Outbreaks/prevention & control , Zika Virus Infection/epidemiology , Humans , Polynesia/epidemiology , Risk Factors
14.
Gigascience ; 5: 14, 2016.
Article in English | MEDLINE | ID: mdl-26998258

ABSTRACT

Systems biology promises to revolutionize medicine, yet human wellbeing is also inherently linked to healthy societies and environments (sustainability). The IDEA Consortium is a systems ecology open science initiative to conduct the basic scientific research needed to build use-oriented simulations (avatars) of entire social-ecological systems. Islands are the most scientifically tractable places for these studies and we begin with one of the best known: Moorea, French Polynesia. The Moorea IDEA will be a sustainability simulator modeling links and feedbacks between climate, environment, biodiversity, and human activities across a coupled marine-terrestrial landscape. As a model system, the resulting knowledge and tools will improve our ability to predict human and natural change on Moorea and elsewhere at scales relevant to management/conservation actions.


Subject(s)
Conservation of Natural Resources/methods , Ecology/methods , Ecosystem , Models, Theoretical , Climate , Conservation of Natural Resources/trends , Ecology/trends , Forecasting , Human Activities , Humans , Islands , Polynesia
15.
PLoS Negl Trop Dis ; 10(1): e0004374, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26799213

ABSTRACT

BACKGROUND: The Pacific region is an area unique in the world, composed of thousands of islands with differing climates and environments. The spreading and establishment of the mosquito Aedes aegypti in these islands might be linked to human migration. Ae. aegypti is the major vector of arboviruses (dengue, chikungunya and Zika viruses) in the region. The intense circulation of these viruses in the Pacific during the last decade led to an increase of vector control measures by local health authorities. The aim of this study is to analyze the genetic relationships among Ae. aegypti populations in this region. METHODOLOGY/PRINCIPAL FINDING: We studied the genetic variability and population genetics of 270 Ae. aegypti, sampled from 9 locations in New Caledonia, Fiji, Tonga and French Polynesia by analyzing nine microsatellites and two mitochondrial DNA regions (CO1 and ND4). Microsatellite markers revealed heterogeneity in the genetic structure between the western, central and eastern Pacific island countries. The microsatellite markers indicate a statistically moderate differentiation (FST = 0.136; P < = 0.001) in relation to island isolation. A high degree of mixed ancestry can be observed in the most important towns (e.g. Noumea, Suva and Papeete) compared with the most isolated islands (e.g. Ouvea and Vaitahu). Phylogenetic analysis indicated that most of samples are related to Asian and American specimens. CONCLUSIONS/SIGNIFICANCE: Our results suggest a link between human migrations in the Pacific region and the origin of Ae. aegypti populations. The genetic pattern observed might be linked to the island isolation and to the different environmental conditions or ecosystems.


Subject(s)
Aedes/genetics , Aedes/virology , Arboviruses/physiology , Genetic Variation , Insect Vectors , Phylogeny , Animals , DNA , DNA, Mitochondrial/genetics , Microsatellite Repeats , Pacific Islands
16.
Parasit Vectors ; 8: 287, 2015 May 28.
Article in English | MEDLINE | ID: mdl-26016830

ABSTRACT

BACKGROUND: Elimination of lymphatic filariasis (LF) in Samoa continues to be challenging despite multiple annual mass drug campaigns aimed at stopping transmission by reducing the prevalence and density of microfilaraemia. The persistence of transmission may be partly related to the highly efficient Aedes vectors. The assessment of pathogen transmission by mosquito vectors and of vector control relies on the ability to capture mosquitoes efficiently. The aims of this study are to compare trapping methods to capture LF-infected mosquitoes and determine the role in transmission of the species of Aedes mosquitoes in the area. METHODS: Fasitoo-Tai village was the chosen site because of persistent transmission despite annual mass drug administration. Sampling methods included BioGents Sentinel (BGS) trap, human-baited collections (HBC) and the Centers for Disease Control (CDC) trap. BGS and CDC traps were baited with BG-lure, CO2, and/or octenol. Individual trap locations were geo-located and efficiency of sampling methods was evaluated using a randomized Latin-square design in two locations. Number of mosquitoes collected (male and female), as well as species for each trapping method were determined. Additionally, Ae. polynesiensis and Ae. (Finlaya) spp. females were pooled by trap method and analysed for filarial DNA. Infection prevalence was estimated using the PoolScreen software. RESULTS: The BGS trap with any type of bait collected more mosquitoes compared to both the CDC trap and the HBC. The BGS trap baited with BG-lure collected more mosquitoes than with CO2 and octenol. There were no significant differences between trapping methods in terms of proportions of infected females collected. The prevalence of filarial infection in Ae. polynesiensis and Ae. (Finlaya) spp. was estimated at 4.7% and 0.67% respectively. CONCLUSIONS: This study supports the use of the BGS trap for research on and surveillance of the mosquito vectors of LF in Samoa. The BGS trap is a suitable and safer alternative to HBC for sampling Ae. polynesiensis and Ae. (Finlaya) spp., which continue to be the predominant vectors of LF. Of concern was the high prevalence of LF in mosquitoes despite a recent mass drug administration programme. This highlights the urgency for updated policies concerning filariasis elimination in Samoa.


Subject(s)
Aedes/parasitology , Elephantiasis, Filarial/prevention & control , Insect Vectors/parasitology , Mosquito Control/methods , Wuchereria bancrofti/physiology , Animals , Elephantiasis, Filarial/epidemiology , Elephantiasis, Filarial/parasitology , Elephantiasis, Filarial/transmission , Female , Humans , Male , Mosquito Control/instrumentation , Prevalence , Rural Health , Samoa/epidemiology
17.
J Am Mosq Control Assoc ; 30(2): 126-9, 2014 Jun.
Article in English | MEDLINE | ID: mdl-25102597

ABSTRACT

The efficiency of the recently developed handheld InsectaZooka (IZ) aspirator was compared to that of the Centers for Disease Control and Prevention-Backpack (CDC-BP) aspirator by conducting human bait collections on 2 islets (locally called motus) of the atoll of Tetiaroa, French Polynesia. Abundance of mosquitoes was compared between the wind-exposed and wind-protected sides of each motu to measure the effect of wind on mosquito distribution. The number of host-seeking Aedes polynesiensis mosquitoes collected on the 2 motus with either sampling device was not significantly different. Collection of male mosquitoes was low irrespective of the type of aspirator used. Wind had an effect on mosquito distribution, as females were more abundant on the protected sides of both motus. The IZ aspirator is a lighter and equally efficient alternative to the CDC-BP aspirator for collecting Ae. polynesiensis.


Subject(s)
Aedes/physiology , Mosquito Control/instrumentation , Animals , Female , Male , Polynesia , Population Density , Specimen Handling
18.
Acta Trop ; 132 Suppl: S150-63, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24252486

ABSTRACT

Mosquito species, members of the genera Aedes, Anopheles and Culex, are the major vectors of human pathogens including protozoa (Plasmodium sp.), filariae and of a variety of viruses (causing dengue, chikungunya, yellow fever, West Nile). There is lack of efficient methods and tools to treat many of the diseases caused by these major human pathogens, since no efficient vaccines or drugs are available; even in malaria where insecticide use and drug therapies have reduced incidence, 219 million cases still occurred in 2010. Therefore efforts are currently focused on the control of vector populations. Insecticides alone are insufficient to control mosquito populations since reduced susceptibility and even resistance is being observed more and more frequently. There is also increased concern about the toxic effects of insecticides on non-target (even beneficial) insect populations, on humans and the environment. During recent years, the role of symbionts in the biology, ecology and evolution of insect species has been well-documented and has led to suggestions that they could potentially be used as tools to control pests and therefore diseases. Wolbachia is perhaps the most renowned insect symbiont, mainly due to its ability to manipulate insect reproduction and to interfere with major human pathogens thus providing new avenues for pest control. We herein present recent achievements in the field of mosquito-Wolbachia symbiosis with an emphasis on Aedes albopictus. We also discuss how Wolbachia symbiosis can be harnessed for vector control as well as the potential to combine the sterile insect technique and Wolbachia-based approaches for the enhancement of population suppression programs.


Subject(s)
Aedes/growth & development , Aedes/microbiology , Insect Vectors , Mosquito Control/methods , Pest Control, Biological/methods , Symbiosis , Wolbachia/physiology , Animals , Wolbachia/growth & development
19.
Acta Trop ; 132 Suppl: S2-11, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24252487

ABSTRACT

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. The successful production and release of sterile males, which is the mechanism of population suppression by SIT, relies on the release of mass-reared sterile males able to confer sterility in the target population by mating with wild females. A five year Joint FAO/IAEA Coordinated Research Project brought together researchers from around the world to investigate the pre-mating conditions of male mosquitoes (physiology and behaviour, resource acquisition and allocation, and dispersal), the mosquito mating systems and the contribution of molecular or chemical approaches to the understanding of male mosquito mating behaviour. A summary of the existing knowledge and the main novel findings of this group is reviewed here, and further presented in the reviews and research articles that form this Acta Tropica special issue.


Subject(s)
Biological Phenomena , Culicidae/genetics , Culicidae/physiology , Mosquito Control/methods , Pest Control, Biological/methods , Animals , Male
20.
Acta Trop ; 132 Suppl: S108-15, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24316237

ABSTRACT

Aedes polynesiensis Marks (Diptera: Culicidae) larvae were reared to adulthood in the laboratory under a range of temperatures and larval densities. We studied the effect of these variables on several life table parameters of relevance to male-release-based vector control strategies including: larval survivorship, developmental time to pupation, male to female ratio, male pupae yield, adult male size and survival. The range of tested rearing temperatures (20, 25, 27, and 30 °C) and larval densities (50, 100, 200, and 400 larvae/L) was selected within the conditions allowing larval growth and survival. Larval survivorship was the highest when larvae were reared at 200 larvae/L for all temperatures except 20 °C. Male to female ratio was male biased at all temperatures and densities. Time to pupation decreased with increasing temperatures. Larval density and temperature influenced the proportion of males pupating on first day of pupation with 43-47% of total male pupae produced at 25 °C. No significant differences in mean wing length were observed between male mosquitoes reared in the laboratory (except at 20 and 30 °C for some densities) and field collected males. Altogether, the study allowed the identification of rearing conditions delivering high male yield with essentially no female contamination, adequate adult male size and survival. Ae. polynesiensis thus appears particularly amenable to biological and mechanical sex separation offering good prospects for Ae. polynesiensis population suppression trials that rely on the production and release of large numbers of incompatible or sterile males.


Subject(s)
Aedes/physiology , Aedes/radiation effects , Reproduction/radiation effects , Animals , Animals, Laboratory , Efficiency , Female , Larva/physiology , Larva/radiation effects , Male , Sex Ratio , Survival Analysis , Temperature
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