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1.
Mem Inst Oswaldo Cruz ; 115: e200043, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32667459

RESUMEN

BACKGROUND The number of malaria cases in Roraima nearly tripled from 2016 to 2018. The capital, Boa Vista, considered a low-risk area for malaria transmission, reported an increasing number of autochthonous and imported cases. OBJECTIVES This study describes a spatial analysis on malaria cases in an urban region of Boa Vista, which sought to identify the autochthonous and imported cases and associated them with Anopheles habitats and the potential risk of local transmission. METHODS In a cross-sectional study at the Polyclinic Cosme e Silva, 520 individuals were interviewed and diagnosed with malaria by microscopic examination. Using a global positional system, the locations of malaria cases by type and origin and the breeding sites of anopheline vectors were mapped and the risk of malaria transmission was evaluated by spatial point pattern analysis. FINDINGS Malaria was detected in 57.5% of the individuals and there was a disproportionate number of imported cases (90.6%) linked to Brazilian coming from gold mining sites in Venezuela and Guyana. MAIN CONCLUSIONS The increase in imported malaria cases circulating in the west region of Boa Vista, where there are positive breeding sites for the main vectors, may represent a potential condition for increased autochthonous malaria transmission in this space.


Asunto(s)
Anopheles/parasitología , Malaria/diagnóstico , Malaria/transmisión , Mineros/estadística & datos numéricos , Mosquitos Vectores/parasitología , Plasmodium/aislamiento & purificación , Viaje , Adulto , Animales , Anopheles/clasificación , Brasil/epidemiología , Estudios Transversales , Femenino , Sistemas de Información Geográfica , Oro , Guyana , Humanos , Malaria/epidemiología , Malaria/parasitología , Masculino , Persona de Mediana Edad , Plasmodium/clasificación , Análisis Espacial , Población Urbana , Venezuela
2.
Mem Inst Oswaldo Cruz ; 115: e200046, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32667460

RESUMEN

BACKGROUND Fluctuations in climate have been associated with variations in mosquito abundance. OBJECTIVES To analyse the influence of precipitation, temperature, solar radiation, wind speed and humidity on the oviposition dynamics of Aedes aegypti in three distinct environmental areas (Brasília Teimosa, Morro da Conceição/Alto José do Pinho and Dois Irmãos/Pintos) of the city of Recife and the Fernando de Noronha Archipelago northeastern Brazil. METHODS Time series study using a database of studies previously carried out in the areas. The eggs were collected using spatially distributed geo-referenced sentinel ovitraps (S-OVTs). Meteorological satellite data were obtained from the IRI climate data library. The association between meteorological variables and egg abundance was analysed using autoregressive models. FINDINGS Precipitation was positively associated with egg abundance in three of the four study areas with a lag of one month. Higher humidity (ß = 45.7; 95% CI: 26.3 - 65.0) and lower wind speed (ß = -125.2; 95% CI: -198.8 - -51.6) were associated with the average number of eggs in the hill area. MAIN CONCLUSIONS The effect of climate variables on oviposition varied according to local environmental conditions. Precipitation was a main predictor of egg abundance in the study settings.


Asunto(s)
Aedes/fisiología , Oviposición/fisiología , Animales , Brasil , Ciudades , Femenino , Mosquitos Vectores/fisiología , Dinámica Poblacional , Estaciones del Año , Población Urbana
3.
Mem Inst Oswaldo Cruz ; 115: e200070, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32667462

RESUMEN

BACKGROUND Nyssorhynchus deaneorum is a potential malaria vector because it has been shown to be competent to transmit Plasmodium vivax and Plasmodium falciparum, and because it exhibits antropophilic and endophilic behaviors in some regions of the Amazon. This profile makes Ny. deaneorum a useful mosquito for experiments that model Plasmodium-vector interactions in the Amazon. OBJECTIVE Herein we describe how a free-mating colony of Ny. deaneorum has been established using an automated light stimulation system. METHODS Mosquitoes were captured in São Francisco do Guaporé, Rondônia. The F1 generation was reared until adult emergence at which point copulation was induced using an automatic copulation induction system (ACIS). FINDINGS After four generations, natural mating and oviposition began to occur without light stimulation. The number of pupae and adult mosquitoes increased from the F5 to F10 generations. The new Ny. deaneorum colony exhibited susceptibility to P. vivax. MAIN CONCLUSIONS Automated light stimulation is an effective method for establishing an Ny. deaneorum colony under laboratory conditions as it produces enough adults to create a stenogamic colony. The establishment of a stable, P. vivax-susceptible colony of Ny. deaneorum makes it possible to model parasite-vector interactions and to test novel drug therapies that target parasite development in mosquitoes.


Asunto(s)
Anopheles/parasitología , Copulación/fisiología , Malaria , Mosquitos Vectores/parasitología , Oviposición , Animales , Anopheles/fisiología , Brasil , Femenino , Insectos Vectores/crecimiento & desarrollo , Insectos Vectores/fisiología , Plasmodium falciparum , Plasmodium vivax
5.
PLoS Biol ; 18(6): e3000633, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32584814

RESUMEN

Mitigating the threat of insecticide resistance in African malaria vector populations requires comprehensive information about where resistance occurs, to what degree, and how this has changed over time. Estimating these trends is complicated by the sparse, heterogeneous distribution of observations of resistance phenotypes in field populations. We use 6,423 observations of the prevalence of resistance to the most important vector control insecticides to inform a Bayesian geostatistical ensemble modelling approach, generating fine-scale predictive maps of resistance phenotypes in mosquitoes from the Anopheles gambiae complex across Africa. Our models are informed by a suite of 111 predictor variables describing potential drivers of selection for resistance. Our maps show alarming increases in the prevalence of resistance to pyrethroids and DDT across sub-Saharan Africa from 2005 to 2017, with mean mortality following insecticide exposure declining from almost 100% to less than 30% in some areas, as well as substantial spatial variation in resistance trends.


Asunto(s)
Resistencia a los Insecticidas , Malaria/parasitología , Mosquitos Vectores/parasitología , África , DDT/toxicidad , Resistencia a los Insecticidas/efectos de los fármacos , Aprendizaje Automático , Mosquitos Vectores/efectos de los fármacos , Nitrilos/toxicidad , Fenotipo , Prevalencia , Piretrinas/toxicidad , Análisis Espacio-Temporal
6.
Proc Biol Sci ; 287(1927): 20200838, 2020 05 27.
Artículo en Inglés | MEDLINE | ID: mdl-32453986

RESUMEN

The putative synergistic action of target-site mutations and enhanced detoxification in pyrethroid resistance in insects has been hypothesized as a major evolutionary mechanism responsible for dramatic consequences in malaria incidence and crop production. Combining genetic transformation and CRISPR/Cas9 genome modification, we generated transgenic Drosophila lines expressing pyrethroid metabolizing P450 enzymes in a genetic background along with engineered mutations in the voltage-gated sodium channel (para) known to confer target-site resistance. Genotypes expressing the yellow fever mosquito Aedes aegypti Cyp9J28 while also bearing the paraV1016G mutation displayed substantially greater resistance ratio (RR) against deltamethrin than the product of each individual mechanism (RRcombined: 19.85 > RRCyp9J28: 1.77 × RRV1016G: 3.00). Genotypes expressing Brassicogethes aeneus pollen beetle Cyp6BQ23 and also bearing the paraL1014F (kdr) mutation, displayed an almost multiplicative RR (RRcombined: 75.19 ≥ RRCyp6BQ23: 5.74 × RRL1014F: 12.74). Reduced pyrethroid affinity at the target site, delaying saturation while simultaneously extending the duration of P450-driven detoxification, is proposed as a possible underlying mechanism. Combinations of target site and P450 resistance loci might be unfavourable in field populations in the absence of insecticide selection, as they exert some fitness disadvantage in development time and fecundity. These are major considerations from the insecticide resistance management viewpoint in both public health and agriculture.


Asunto(s)
Resistencia a los Insecticidas , Insecticidas/química , Aedes , Animales , Escarabajos , Sistema Enzimático del Citocromo P-450/genética , Mosquitos Vectores , Piretrinas
7.
PLoS One ; 15(5): e0232286, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32369525

RESUMEN

BACKGROUND: Creating National Sanitary City (CNSC) promotes appearance, environment sanitation and public health including vector management of cities in China. However, vector management especially mosquito management and the related administrative productivity of Patriotic Health Campaign System (PHCS) of National Sanitary Cities (NSCs) were questioned by many pest control professionals and citizens. In this study, we studied mosquito management of NSCs taking Wuhan as an example. The study aimed to (1) determine the distribution and abundance of immature mosquito habitats in built-up areas of Wuhan and (2) better understand the related administration procedure in CNSC. METHODS: Immature mosquito habitat surveillance was carried out in randomly selected premises of driving schools (DSs), schools or kindergartens (SKs), property management residential areas (PMRAs), construction sites (CSs), wide roads with storm drains (WRSDs) and urban creeks (UCs) in built-up areas of Wuhan from July to October 2015 followed by questionnaire interviews with one each of premise occupants and district departments responsible for mosquito management in these premises. RESULTS: Total of 64.1 km of route were inspected in 36 DSs, 36 SKs, 36 PMRAs, 36 CSs and 36 segments of WRSD and 2,158 potential mosquito habitats with 749 (35%) mosquito-positive habitats were found. The route index (RI) was 11.7, which was 14.6 times higher than the grade C criteria for vector density control (RI = 0.8 positive habitats/km) in CNSC. Occupants of 36 DSs, 36 SKs, 36 PMRAs, 34 CSs were interviewed and 77% of them reported no difference in mosquito infestation in their premises since 2013 and 80% of them knew about the responsibility and arrangements of PHCS of mosquito management in their premises. Only 15% had the awareness of larval source reduction strategy and 14% had implemented it. Receipt the electronic/paper edition of CNSC vector management specifications from the PHCS was very low (13%) and an official notification or bulletin for rectification mosquito-positive habitats was also very low (5%). Of the 75 responsible district departments interviewed, about half (55%) reported that they had held training courses/meetings related to CNSC vector management, the majority (96%) reported that they had not carried out independent on-site supervision of premises under their jurisdiction. No differences in larval indices were found between premises which were administrative intervened and with no administrative intervention. CONCLUSIONS: The administrative intervention of PHCS had not evidently improved mosquito management of the premises in built-up areas in Wuhan. It is a violation of the original intention of the National Patriotic Health Campaign Committee in organizing CNSC programs. To combat mosquito borne diseases, and to improve the quality of life of residents, we recommend that PHCS honestly reveals defects in urban mosquito management and seriously takes those exposed defects. The PHCS should strengthen Patriotic Health Campaign activities by strict adherence to NSC standards. Further research on sustained promotion of urban mosquito management of NSCs, which focus on effective administration, as well as on improvement of related sectors of NSC standards should be carried out.


Asunto(s)
Control de Mosquitos , Animales , China , Ciudades , Industria de la Construcción , Culicidae , Ecosistema , Humanos , Control de Mosquitos/métodos , Mosquitos Vectores , Salud Pública , Ríos , Instituciones Académicas , Encuestas y Cuestionarios , Transportes
8.
PLoS One ; 15(5): e0232481, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32421747

RESUMEN

Outbreaks of Rift Valley fever have devastating impacts on ruminants, humans, as well as on regional and national economies. Although numerous studies on the impact and outbreak of Rift Valley fever exist, relatively little is known about the role of environmental factors, especially soil, on the aestivation of the virus. This study thus selected 22 sites for study in central South Africa, known to be the recurrent epicenter of widespread Rift Valley fever outbreaks in Southern Africa. Soils were described, sampled and analyzed in detail at each site. Of all the soil variables analyzed for, only eight (cation exchange capacity, exchangeable Ca2+, exchangeable K+, exchangeable Mg2+, soluble Ca2+, medium sand, As, and Br) were statistically identified to be potential indicators of sites with reported Rift Valley fever mortalities, as reported for the 2009-2010 Rift Valley fever outbreak. Four soil characteristics (exchangeable K+, exchangeable Mg2+, medium sand, and Br) were subsequently included in a discriminant function that could potentially be used to predict sites that had reported Rift Valley fever-associated mortalities in livestock. This study therefore constitutes an initial attempt to predict sites prone to Rift Valley fever livestock mortality from soil properties and thus serves as a basis for broader research on the interaction between soil, mosquitoes and Rift Valley fever virus. Future research should include other environmental components such as vegetation, climate, and water properties as well as correlating soil properties with floodwater Aedes spp. abundance and Rift Valley fever virus prevalence.


Asunto(s)
Brotes de Enfermedades/veterinaria , Fiebre del Valle del Rift/mortalidad , Aedes/virología , Animales , Humanos , Ganado , Metales/análisis , Mosquitos Vectores/virología , Fiebre del Valle del Rift/transmisión , Fiebre del Valle del Rift/virología , Virus de la Fiebre del Valle del Rift/patogenicidad , Factores de Riesgo , Suelo/química , Sudáfrica/epidemiología , Humedales , Zoonosis/mortalidad
9.
Environ Sci Pollut Res Int ; 27(23): 29204-29217, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32430723

RESUMEN

Aedes aegypti is the vector of important diseases like dengue, zika, chikungunya, and yellow fever. Vector control is pivotal in combating the spread of these mosquito-borne illnesses. Photoactivable larvicide curcumin obtained from Curcuma longa Linnaeus has shown high potential for Ae. aegypti larvae control. However, the toxicity of this photosensitizer (PS) might jeopardize non-target aquatic organisms. The aim of this study was to evaluate the toxicity of this PS to Daphnia magna and Danio rerio, besides assessing its mode of action through larvae biochemical and histological studies. Three PS formulations were tested: PS in ethanol+DMSO, PS in sucrose, and PS in D-mannitol. The LC50 of PS in ethanol+DMSO to D. rerio was 5.9 mg L-1, while in D. magna the solvents were extremely toxic, and LC50 was not estimated. The PS formulations in sugars were not toxic to neither of the organisms. Reactive oxygen species (ROS) were generated in D. magna exposed to 50 mg L-1 of PS in D-mannitol, and D. rerio did not elicit this kind of response. D. magna feeding rates were not affected by the PS in D-mannitol. Concerning Ae. aegypti larvae, there were changes in reduced glutathione and protein levels, while catalase activity remained stable after exposure to PS in D-mannitol and sunlight. Histological changes were observed in larvae exposed to PS in sucrose and D-mannitol, most of them irreversible and deleterious. Our results show the feasibility of this photolarvicide use in Ae. aegypti larvae control and its safety to non-target organisms. These data are crucial to this original vector control approach implementation in public health policies.


Asunto(s)
Aedes , Curcumina , Insecticidas , Infección por el Virus Zika , Virus Zika , Animales , Larva , Mosquitos Vectores
10.
PLoS One ; 15(5): e0231408, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32374725

RESUMEN

Dengue is the most important mosquito-borne viral infection disease in Sri Lanka triggering extensive economic and social burden in the country. Even after numerous source reduction programmes, more than 30,000 incidences are reporting in the country every year. The last and greatest dengue epidemic in the country was reported in July, 2017 with more than 300 dengue related deaths and the highest number of dengue incidences were reported from the District of Gampaha. There is no Dengue Virus (DENV) detection system in field specimens in the district yet and therefore the aim of the study is development of entomological surveillance approach through vector survey programmes together with molecular and phylogenetic methods to identify detection of DENV serotypes circulation in order to minimize adverse effects of imminent dengue outbreaks. Entomological surveys were conducted in five study areas in the district for 36 months and altogether, 10,616 potential breeding places were investigated and 423 were positive for immature stages of dengue vector mosquitoes. During adult collections, 2,718 dengue vector mosquitoes were collected and 4.6% (n = 124) were Aedes aegypti. While entomological indices demonstrate various correlations with meteorological variables and reported dengue incidences, the mosquito pools collected during the epidemic in 2017 were positive for DENV. The results of the phylogenetic analysis illustrated that Envelope (E) gene sequences derived from the isolated DENV belongs to the Clade Ib of Cosmopolitan genotype of the DENV serotype 2 which has been the dominant stain in South-East Asian evidencing that a recent migration of DENV strain to Sri Lanka.


Asunto(s)
Migración Animal/fisiología , Dengue/epidemiología , Epidemias , Mosquitos Vectores , Adolescente , Adulto , Aedes/virología , Anciano , Anciano de 80 o más Años , Animales , Niño , Preescolar , Dengue/virología , Virus del Dengue/genética , Brotes de Enfermedades , Epidemias/historia , Femenino , Genotipo , Historia del Siglo XXI , Humanos , Incidencia , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Mosquitos Vectores/fisiología , Mosquitos Vectores/virología , Vigilancia de la Población/métodos , Sri Lanka/epidemiología , Adulto Joven
11.
Arch Virol ; 165(7): 1715-1717, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32417973

RESUMEN

Venezuelan equine encephalitis virus (VEEV) is an important pathogen of medical and veterinary importance in the Americas. In this report, we present the complete genome sequences of five VEEV isolates obtained from pools of Culex (Melanoconion) gnomatos (4) or Culex (Melanoconion) pedroi (1) from Iquitos, Peru. Genetic and phylogenetic analyses showed that all five isolates grouped within the VEEV complex sister to VEEV IIIC and are members of subtype IIID. This is the first report of full-length genomic sequences of VEEV IIID.


Asunto(s)
Culex/virología , Virus de la Encefalitis Equina Venezolana/aislamiento & purificación , Encefalomielitis Equina Venezolana/virología , Genoma Viral , Mosquitos Vectores/virología , Animales , Secuencia de Bases , Virus de la Encefalitis Equina Venezolana/clasificación , Virus de la Encefalitis Equina Venezolana/genética , Encefalomielitis Equina Venezolana/transmisión , Genómica , Caballos , Perú , Filogenia
12.
Sci Total Environ ; 734: 139365, 2020 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-32464372

RESUMEN

Mosquito-borne infections often have concerted peaks, or are synchronous, across landscapes. This phenomenon might be driven by vector responses to similar environmental conditions that synchronize their abundance. While adult mosquito populations can be synchronous over spatial scales ranging from a few meters to a few kilometers, little to nothing is known about immature mosquito synchrony, including its relationship with mosquito colonization and persistence in larval habitats. Here, we present results from a 2-yearlong synchrony study in co-occurring populations of Aedes (Stegomyia) albopictus (Skuse), Aedes (Stegomyia) flavopictus Yamada and Aedes (Finlaya) japonicus japonicus (Theobald), three invasive mosquito species, along an urban altitudinal gradient in Japan. We found that Ae. albopictus was asynchronous while Ae. flavopictus and Ae. j. japonicus had synchrony that, respectively, tracked geographic and altitudinal patterns of temperature correlation. Spatially, Ae. albopictus was more persistent at hotter locations near urban land use, while Ae. j. japonicus and Ae. flavopictus increasingly persisted farther away from urban land. Temporally, Ae. albopicus and Ae. flavopictus decreased the proportion of colonized habitats following variable rainfall, while Ae. j. japonicus increased with vegetation growth and leptokurtic temperatures. Our results support the hypothesis that immature mosquito synchrony is autonomous from dispersal and driven by common environmental conditions.


Asunto(s)
Aedes , Animales , Insecticidas , Especies Introducidas , Japón , Larva , Mosquitos Vectores
13.
Environ Sci Pollut Res Int ; 27(21): 25987-26024, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32385820

RESUMEN

Mosquitoes spread several life-threatening diseases such as malaria, filaria, dengue, Japanese encephalitis, West Nile fever, chikungunya, and yellow fever and are associated with millions of deaths every year across the world. However, insecticides of synthetic origin are conventionally used for controlling various vector-borne diseases but they have various associated drawbacks like impact on non-targeted species, negative effects on the environment, and development of resistance in vector species by alteration of the target site. Plant extracts, phytochemicals, and their nanoformulations can serve as ovipositional attractants, insect growth regulators, larvicides, and repellents with least effects on the environment. Such plant-derived products exhibit broad-spectrum resistance against various mosquito species and are relatively cheaper, environmentally safer, biodegradable, easily accessible, and are non-toxic to non-targeted organisms. Therefore, in this review article, the current knowledge of phytochemical sources exhibiting larvicidal activity and their variations in response to solvents used for their extraction is underlined. Also, different methods such as physical, chemical, and biological for silver nanoparticle (AgNPs) synthesis, their mechanism of synthesis using plant extract, their potent larvicidal activity, and the possible mechanism by which these particles kill mosquito larvae are discussed. In addition, constraints related to commercialization of nanoherbal products at government and academic or research level and barriers from laboratory experiments to field trial have also been discussed. This comprehensive information can be gainfully employed for the development of herbal larvicidal formulations and nanopesticides against insecticide-resistant vector species in the near future. Graphical abstract.


Asunto(s)
Aedes , Insecticidas , Nanopartículas del Metal , Animales , Larva , Control de Mosquitos , Mosquitos Vectores , Extractos Vegetales , Hojas de la Planta , Plata
14.
PLoS Negl Trop Dis ; 14(5): e0008279, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32365059

RESUMEN

Dengue is a highly endemic disease in Southeast Asia and is transmitted primarily by the mosquito, Aedes aegypti. The National Capital Region (NCR) of the Philippines, or Metropolitan Manila, is a highly urbanized area that is greatly affected by this arboviral disease. Urbanization has been shown to increase the dispersal of this mosquito vector. For this reason, we conducted a fine-scale population genetic study of Ae. aegypti in this region. We collected adult Ae. aegypti mosquitoes (n = 526 individuals) within the region (n = 21 study areas) and characterized the present population structure and the genetic relatedness among mosquito populations. We genotyped 11 microsatellite loci from all sampled mosquito individuals and analyzed their genetic diversity, differentiation and structure. The results revealed low genetic differentiation across mosquito populations which suggest high gene flow and/or weak genetic drift among mosquito populations. Bayesian analysis indicated multiple genetic structures (K = 3-6), with no clear genetically distinct population structures. This result implies the passive or long-distance dispersal capability nature Ae. aegypti possibly through human-mediated transportation. The constructed dendrogram in this study describes the potential passive dispersal patterns across Metropolitan Manila. Furthermore, spatial autocorrelation analysis showed the limited and active dispersal capability (<1km) of the mosquito vector. Our findings are consistent with previous studies that investigated the genetic structure and dual (active and passive) dispersal capability of Ae. aegypti in a fine-scale highly urbanized area.


Asunto(s)
Aedes/clasificación , Aedes/genética , Genotipo , Mosquitos Vectores/clasificación , Mosquitos Vectores/genética , Aedes/crecimiento & desarrollo , Distribución Animal , Animales , Ciudades , Genética de Población , Técnicas de Genotipaje , Repeticiones de Microsatélite , Mosquitos Vectores/crecimiento & desarrollo , Filipinas , Análisis Espacial
15.
PLoS Negl Trop Dis ; 14(5): e0008320, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32392224

RESUMEN

BACKGROUND: The global spread of Aedes albopictus has exposed new geographical areas to the risk of dengue and chikungunya virus transmission. Several autochthonous transmission events have occurred in recent decades in Southern Europe and many indicators suggest that it will become more frequent in this region in the future. Environmental, socioeconomic and climatic factors are generally considered to trigger the emergence of these viruses. Accordingly, a greater knowledge of the determinants of this emergence in a European context is necessary to develop adapted surveillance and control strategies, and public health interventions. METHODOLOGY/PRINCIPAL FINDINGS: Using French surveillance data collected from between 2010 and 2018 in areas of Southern France where Ae. albopictus is already established, we assessed factors associated with the autochthonous transmission of dengue and chikungunya. Cases leading to autochthonous transmission were compared with those without subsequent transmission using binomial regression. We identified a long reporting delay (≥ 21 days) of imported cases to local health authorities as the main driver for autochthonous transmission of dengue and chikungunya in Southern France. The presence of wooded areas around the cases' place of residence and the accumulation of heat during the season also increased the risk of autochthonous arbovirus transmission. CONCLUSIONS: Our findings could inform policy-makers when developing strategies to the emerging threats of dengue and chikungunya in Southern Europe and can be extrapolated in this area to other viruses such as Zika and yellow fever, which share the same vector. Furthermore, our results allow a more accurate characterization of the environments most at risk, and highlight the importance of implementing surveillance systems which ensure the timely reporting and of imported cases and swift interventions.


Asunto(s)
Aedes/crecimiento & desarrollo , Fiebre Chikungunya/transmisión , Dengue/transmisión , Transmisión de Enfermedad Infecciosa , Mosquitos Vectores/crecimiento & desarrollo , Animales , Fiebre Chikungunya/epidemiología , Dengue/epidemiología , Femenino , Francia/epidemiología , Humanos , Masculino
16.
PLoS Negl Trop Dis ; 14(5): e0008250, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32401756

RESUMEN

BACKGROUND: The French overseas Territory of the Wallis and Futuna Islands has been affected by several dengue epidemics. Aedes polynesiensis is the main mosquito vector described in this territory. Other Aedes species have been reported, but recent entomological data are missing to infer the presence of other potential arbovirus vectors and to assess the entomological risk factors for transmission of arboviral diseases. METHODOLOGY/ PRINCIPAL FINDINGS: An entomological prospective study was conducted on the three main islands of the territory to determine the presence and distribution of Aedes spp. Larvae, pupae and adult mosquitoes were collected from 54 sampling points in different environments, with a final sampling of 3747 immature stages and 606 adults. The main identified breeding sites were described. Ae. polynesiensis was found in every sampled site in peridomestic and wild habitats. Ae. aegypti was only found on the island of Wallis in peridomestic environments with a limited distribution. Two other Aedes species endemic to the Pacific were recorded, Aedes oceanicus and Aedes futunae. To evaluate the ability of local Ae. polynesiensis to transmit the chikungunya virus (CHIKV), two field populations were analyzed for vector competence using experimental oral exposure of females to CHIKV and infection, dissemination and transmission assays. Results showed that both populations of Ae. polynesiensis were competent for CHIKV (30% at 7 days post-infection). CONCLUSIONS/SIGNIFICANCE: This study showed the ubiquitous distribution and abundance of Ae. polynesiensis on the three islands and demonstrated that local populations were able to transmit CHIKV. Combined with the presence and expansion of Ae. aegypti on the main island of Wallis, these data highlight the risk of transmission of arboviral diseases in the territory of Wallis and Futuna and provide relevant information for entomological surveillance and vector control programs.


Asunto(s)
Aedes/crecimiento & desarrollo , Fiebre Chikungunya/transmisión , Transmisión de Enfermedad Infecciosa , Ecosistema , Mosquitos Vectores/crecimiento & desarrollo , Animales , Femenino , Polinesia , Estudios Prospectivos , Medición de Riesgo , Encuestas y Cuestionarios
17.
PLoS Negl Trop Dis ; 14(5): e0008303, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32407315

RESUMEN

In New Caledonia (NC), Aedes aegypti is the only proven vector of dengue virus (DENV), which is the most prevalent arbovirosis in NC. Since World War II, the four DENV serotypes have circulated regularly in NC. The epidemiological profile, however, has evolved over the last ten years, with the persistence of DENV-1 circulation and the co-circulation of several DENV serotypes. The current study evaluated the ability of Ae. aegypti from NC to transmit four DENV serotypes (and two DENV-1 genotypes) isolated during recent outbreaks in NC. An Ae. aegypti F1 generation was twice independently orally challenged with each DENV strain (107 FFU/ml). Infection, dissemination and transmission rates and transmission efficiency were measured at day 7 and 14 post-exposure, as well as the quantity of infectious virus particles. Mosquito infection was observed as early as 7 days post-infection. Infection rates between 18 and 58% were measured for all DENV serotypes/genotypes tested. Although dissemination rates ranged from 78 to 100%, transmission efficiencies were low, with values not exceeding 21% at 14 days post-infection for all DENV strains. This study shows that NC Ae. aegypti are moderately competent for DENV in laboratory conditions. In link with epidemiological data, these results suggest implication of other factors in the sustained circulation of DENV-1 in New Caledonia.


Asunto(s)
Aedes/virología , Virus del Dengue/aislamiento & purificación , Dengue/transmisión , Mosquitos Vectores/virología , Animales , Dengue/epidemiología , Virus del Dengue/clasificación , Brotes de Enfermedades , Transmisión de Enfermedad Infecciosa , Femenino , Genotipo , Humanos , Nueva Caledonia/epidemiología , Serogrupo
18.
BMC Infect Dis ; 20(1): 333, 2020 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-32393183

RESUMEN

BACKGROUND: Malaria is a life threating vector borne disease caused by different Plasmodium parasites. Metema and Armachiho are two of the top five malaria endemic areas among the districts of Amhara region in Ethiopia. Transmission pattern is seasonal and migrant laborers who visit these areas for employment in mechanized agriculture are highly affected. The aim of this study was to investigate seasonal abundance, abdominal status and parity rate of An.gambiae s.l in Metema-Armachiho lowlands, Northwest Ethiopia. METHOD: A 1 year longitudinal entomological study was conducted in Metema-Armachiho lowlands from June 2016-May 2017. Mosquitoes were collected using CDC-light traps in indoor and outdoor sites for four consecutive days in each month. A total of eight standard battery operated CDC-light traps were used to collect mosquitoes. Female mosquitoes were classed as unfed, fed or gravid under a dissecting microscope. The ovaries of all unfed An.gambiae s.l mosquitoes were examined for evidence of parity. Data were entered and analyzed using SPSS-20 software. Chi-square test was applied to show significant difference between variables. P-value< 0.05 was taken as statistically significant. RESULTS: Of the total 1253 mosquitoes collected, 713 (552 female, 161 male) were culex and 540 (501 female, 39 male) were An.gambiae s.l. About 50.9% were collected in June-August 2016, 21.7% in September-November 2016, 12.0% in December 2016-February 2017 and 15.4% in March to May 2017. Of the total, 57.2 and 42.8% of the An.gambiae s.l were collected from indoor and outdoor sites respectively. Of the total females collected, 76.8% were unfed; of which 69.4% were parous. Significantly higher number of female An.gambiae s.l were collected in indoor and there was significant difference in abdominal status of An.gambiae s.l mosquitoes collected in different season (P < 0.05). CONCLUSIONS: Highest number of An.gambiae s.l was observed from June-August followed by September-November. The parity rate of An.gambiae s.l was high and there was significant difference in abdominal status of An.gambiae s.l collected in different season.


Asunto(s)
Anopheles/parasitología , Malaria/epidemiología , Malaria/transmisión , Mosquitos Vectores/parasitología , Paridad , Estaciones del Año , Animales , Entomología/métodos , Etiopía/epidemiología , Femenino , Humanos , Estudios Longitudinales , Malaria/parasitología , Masculino , Plasmodium , Embarazo
19.
Artículo en Inglés | MEDLINE | ID: mdl-32418511

RESUMEN

Introduction: Ross River virus (RRV) disease is Australia's most common arthropod-borne disease which has an important impact on population health and productivity. The aim of this study was to identify the spatial and temporal distribution of RRV notifications during 2000-2013 in South Australia (SA). Methods: The epidemiologic patterns of RRV notifications in SA from January 2000 to December 2013 were examined at a statistical local area (SLA) level. Spatial-temporal analyses were conducted using patient-reported place of exposure to characterise the recurrence of RRV infection stratified by age and sex. Results: During the study period, a total of 3,687 RRV disease notifications were recorded in the state with state-wide mean annual rates of 16.8 cases per 100,000 persons and a 1:1.32 male:female ratio. The SLAs reporting cases of RRV disease exhibited spatial and temporal variation. Notified cases of RRV disease occurred more frequently in summer and autumn. A geographic expansion was observed of the area within which RRV cases occur. The comparison of age- and sex-standardised incidence rates, calculated by place of residence and patient-reported place of exposure, highlights the importance of using the latter to accurately display geospatial disease trends over time. Areas with the largest proportion of visitor cases and having the highest risk were mostly along the River Murray, which provides many vector mosquito habitats. Conclusion: Although public health interventions should be considered in all SLAs where RRV occurs, we suggest that priority should be given to the Riverland areas identified as highest risk.


Asunto(s)
Infecciones por Alphavirus/epidemiología , Virus del Río Ross , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Infecciones por Alphavirus/virología , Niño , Preescolar , Notificación de Enfermedades , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Mosquitos Vectores , Estaciones del Año , Australia del Sur/epidemiología , Análisis Espacio-Temporal , Adulto Joven
20.
Arch Virol ; 165(8): 1769-1776, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32440701

RESUMEN

South Texas has experienced local transmission of Zika virus and of other mosquito-borne viruses such as chikungunya virus and dengue virus in the last decades. Using a mosquito surveillance program in the Lower Rio Grande Valley (LRGV) and San Antonio, TX, from 2016 to 2018, we detected the presence of an insect-specific virus, cell fusing agent virus (CFAV), in the Aedes aegypti mosquito population. We tested 6,326 females and 1,249 males from the LRGV and 659 females from San Antonio for CFAV by RT-PCR using specific primers. Infection rates varied from 0 to 261 per 1,000 mosquitoes in the LRGV and 115 to 208 per 1,000 in San Antonio depending on the month of collection. Infection rates per 1,000 individuals appeared higher in females collected from BG Sentinel 2 traps compared to Autocidal Gravid Ovitraps, but the ratio of the percentage of infected pools did not differ by trap type. The natural viral load in individual males ranged from 1.25 x 102 to 5.50 x 106 RNA copies and in unfed females from 5.42 x 103 to 8.70 x 106 RNA copies. Gravid females were found to harbor fewer viral particles than males and unfed females.


Asunto(s)
Aedes/virología , Flavivirus/genética , Animales , Femenino , Virus de Insectos/genética , Masculino , Mosquitos Vectores/genética , ARN Viral/genética , Texas , Carga Viral/genética
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