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1.
PLoS Negl Trop Dis ; 14(9): e0008705, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32986704

RESUMO

Over the past three decades, Europe has witnessed an increased spread of invasive aedine mosquito species, most notably Aedes albopictus, a key vector of chikungunya, dengue and Zika virus. While its distribution in southern Europe is well documented, its dispersal modes across the Alps remain poorly investigated, preventing a projection of future scenarios beyond its current range in order to target mosquito control. To monitor the presence and frequency of invasive Aedes mosquitoes across and beyond the Alps we set oviposition and BG-Sentinel traps at potential points of entry with a focus on motorway service areas across Switzerland. We placed the traps from June to September and controlled them for the presence of mosquitoes every other week between 2013 and 2018. Over the six years of surveillance we identified three invasive Aedes species, including Ae. albopictus, Ae. japonicus and Ae. koreicus. Based on the frequency and distribution patterns we conclude that Ae. albopictus and Ae. koreicus are being passively spread primarily along the European route E35 from Italy to Germany, crossing the Alps, while Ae. japonicus has been expanding its range from northern Switzerland across the country most likely through active dispersal.


Assuntos
Aedes/classificação , Aedes/fisiologia , Monitoramento Epidemiológico , Mosquitos Vetores/fisiologia , Aedes/virologia , Animais , Europa (Continente) , Feminino , Espécies Introduzidas , Itália , Controle de Mosquitos/instrumentação , Oviposição/fisiologia , Suíça , Zika virus
2.
PLoS Negl Trop Dis ; 14(9): e0008657, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32997656

RESUMO

Aedes albopictus, along with Ae. aegypti, are key arbovirus vectors that have been expanding their geographic range over the last decades. In 2017, Ae. albopictus was detected for the first time at two distinct locations in Portugal. In order to understand how the Ae. albopictus populations recently introduced in Portugal are genetically related and which is their likely route of invasion, we performed an integrative cytochrome C oxidase I gene (COI)- and mitogenome-based phylogeographic analysis of mosquitoes samples collected in Portugal in 2017 and 2018 in the context of the global Ae. albopictus diversity. COI-based analysis (31 partial sequences obtained from 83 mosquitoes) revealed five haplotypes (1 to 5), with haplotype 1 (which is widely distributed in temperate areas worldwide) being detected in both locations. Haplotypes 2 and 3 were exclusively found in Southern region (Algarve), while haplotype 4 and 5 were only detected in the North of Portugal (Penafiel, Oporto region). Subsequent high discriminatory analyses based on Ae. albopictus mitogenome (17 novel sequences) not only confirmed a high degree of genetic variability within and between populations at both geographic locations (compatible with the Ae. albopictus mosquito populations circulating in Europe), but also revealed two mitogenome mutational signatures not previously reported at worldwide level. While our results generally sustain the occurrence of multiple introduction events, fine mitogenome sequence inspection further indicates a possible Ae. albopictus migration within the country, from the Northern introduction locality to the Southern region. In summary, the observed scenario of high Ae. albopictus genetic diversity in Portugal, together with the detection of mosquitoes in successive years since 2017 in Algarve and Penafiel, points that both Ae. albopictus populations seem to be already locally established, as its presence has been reported for three consecutive years, raising the public health awareness for future mosquito-borne diseases outbreaks.


Assuntos
Aedes/genética , Variação Genética , Genoma Mitocondrial/genética , Mosquitos Vetores/genética , Aedes/classificação , Aedes/virologia , Animais , Arbovirus , Complexo IV da Cadeia de Transporte de Elétrons/genética , Feminino , Haplótipos , Sequenciamento de Nucleotídeos em Larga Escala , Mosquitos Vetores/virologia , Filogeografia , Portugal , Análise de Sequência de DNA
3.
PLoS Negl Trop Dis ; 14(7): e0008408, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32692760

RESUMO

The spread of Aedes aegypti in California and other regions of the U.S. has increased the need to understand the potential for local chains of Ae. aegypti-borne virus transmission, particularly in arid regions where the ecology of these mosquitoes is less understood. For public health and vector control programs, it is helpful to know whether variation in risk of local transmission can be attributed to socio-demographic factors that could help to target surveillance and control programs. Socio-demographic factors have been shown to influence transmission risk of dengue virus outside the U.S. by modifying biting rates and vector abundance. In regions of the U.S. where Ae. aegypti have recently invaded and where residential areas are structured differently than those in the tropics where Ae. aegypti are endemic, it is unclear how socio-demographic factors modify the abundance of Ae. aegypti populations. Understanding heterogeneities among households in Ae. aegypti abundance will provide a better understanding of local vectorial capacity and is an important component of understanding risk of local Ae. aegypti-borne virus transmission. We conducted a cross-sectional study in Los Angeles County, California during summer 2017 to understand the causes of variation in relative abundance of Ae. aegypti among households. We surveyed 161 houses, representing a wide range of incomes. Surveys consisted of systematic adult mosquito collections, inspections of households and properties, and administration of a questionnaire in English or Spanish. Adult Ae. aegypti were detected at 72% of households overall and were found indoors at 12% of households. An average of 3.1 Ae. aegypti were collected per household. Ae. aegypti abundance outdoors was higher in lower-income neighborhoods and around older households with larger outdoor areas, greater densities of containers with standing water, less frequent yard maintenance, and greater air-conditioner use. We also found that Ae. aegypti abundance indoors was higher in households that had less window and door screening, less air-conditioner usage, more potted plants indoors, more rain-exposed containers around the home, and lower neighborhood human population densities. Our results indicate that, in the areas of southern California studied, there are behavioral and socio-demographic determinants of Ae. aegypti abundance, and that low-income households could be at higher risk for exposure to Ae. aegypti biting and potentially greater risk for Zika, dengue, and chikungunya virus transmission if a local outbreak were to occur.


Assuntos
Aedes/fisiologia , Mosquitos Vetores/fisiologia , Aedes/classificação , Distribuição Animal , Animais , California , Estudos Transversais , Características da Família , Habitação , Controle de Mosquitos , Mosquitos Vetores/classificação , Densidade Demográfica
4.
PLoS One ; 15(7): e0235430, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32722672

RESUMO

Phylogeographic relationships among global collections of the mosquito Aedes aegypti were evaluated using the mitochondrial Cytochrome C Oxidase 1 (CO1) and NADH dehydrogenase subunit 4 (ND4) genes including new sequences from Sri Lanka. Phylogeographic analysis estimated that Ae. aegypti arose as a species ~614 thousand years ago (kya) in the late Pleistocene. At 545 kya an "early" East African clade arose that continued to differentiate in East Africa, and eventually gave rise to three lineages one of which is distributed throughout all tropical and subtropical regions, a second that contains Southeast Asian/Sri Lankan mosquitoes and a third that contains mostly New World mosquitoes. West African collections were not represented in this early clade. The late clade continued to differentiate throughout Africa and gave rise to a lineage that spread globally. The most recent branches of the late clade are represented by South-East Asia and India/Pakistan collections. Analysis of migration rates suggests abundant gene flow between India/Pakistan and the rest of the world with the exception of Africa.


Assuntos
Aedes/genética , DNA Mitocondrial/genética , Mitocôndrias/genética , Filogeografia , Aedes/classificação , África , África Oriental , Animais , Complexo IV da Cadeia de Transporte de Elétrons/genética , Fluxo Gênico , Genes Mitocondriais/genética , Haplótipos , Índia , Mitocôndrias/metabolismo , Paquistão , Filogenia , Sri Lanka
5.
Parasitol Res ; 119(9): 2765-2774, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32671542

RESUMO

Before the background of increasingly frequent outbreaks and cases of mosquito-borne diseases in various European countries, Germany recently realised the necessity of updating decade-old data on the occurrence and spatiotemporal distribution of culicid species. Starting in 2011, a mosquito monitoring programme was therefore launched with adult and immature mosquito stages being collected at numerous sites all over Germany both actively by trapping, netting, aspirating and dipping, and passively by the citizen science project 'Mueckenatlas'. Until the end of 2019, about 516,000 mosquito specimens were analysed, with 52 (probably 53) species belonging to seven genera found, including several species not reported for decades due to being extremely rare (Aedes refiki, Anopheles algeriensis, Culex martinii) or local (Culiseta alaskaensis, Cs. glaphyroptera, Cs. ochroptera). In addition to 43 (probably 44 including Cs. subochrea) out of 46 species previously described for Germany, nine species were collected that had never been documented before. These consisted of five species recently established (Ae. albopictus, Ae. japonicus, Ae. koreicus, An. petragnani, Cs. longiareolata), three species probably introduced on one single occasion only and not established (Ae. aegypti, Ae. berlandi, Ae. pulcritarsis), and a newly described cryptic species of the Anopheles maculipennis complex (An. daciae) that had probably always been present but not been differentiated from its siblings. Two species formerly listed for Germany could not be documented (Ae. cyprius, Ae. nigrinus), while presence is likely for another species (Cs. subochrea), which could not be demonstrated in the monitoring programme as it can neither morphologically nor genetically be reliably distinguished from a closely related species (Cs. annulata) in the female sex. While Cs. annulata males were collected in the present programme, this was not the case with Cs. subochrea. In summary, although some species regarded endemic could not be found during the last 9 years, the number of culicid species that must be considered firmly established in Germany has increased to 51 (assuming Cs. subochrea and Ae. nigrinus are still present) due to several newly emerged ones but also to one species (Ae. cyprius) that must be considered extinct after almost a century without documentation. Most likely, introduction and establishment of the new species are a consequence of globalisation and climate warming, as three of them are native to Asia (Ae. albopictus, Ae. japonicus, Ae. koreicus) and three (Ae. albopictus, An. petragnani, Cs. longiareolata) are relatively thermophilic. Another thermophilic species, Uranotaenia unguiculata, which had been described for southwestern Germany in 1994 and had since been found only at the very site of its first detection, was recently documented at additional localities in the northeastern part of the country. As several mosquito species found in Germany are serious pests or potential vectors of disease agents and should be kept under permanent observation or even be controlled immediately on emergence, the German mosquito monitoring programme has recently been institutionalised and perpetuated.


Assuntos
Aedes/classificação , Anopheles/classificação , Culex/classificação , Monitoramento Ambiental/métodos , Mosquitos Vetores/classificação , Ochlerotatus/classificação , Animais , Ásia , Clima , Europa (Continente) , Feminino , Alemanha , Espécies Introduzidas , Masculino
6.
PLoS Negl Trop Dis ; 14(6): e0008433, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32574163

RESUMO

Mosquitoes are of major importance to human and animal health due to their ability to transmit various pathogens. In Europe the role of mosquitoes in public health has increased with the introduction of alien Aedes mosquitoes such as the Asian tiger mosquito, Aedes albopictus; the Asian bush mosquito, Ae. japonicus; and Ae. koreicus. In Austria, Ae. japonicus has established populations in various regions of the country. Aedes albopictus is not known to overwinter in Austria, although isolated findings of eggs and adult female mosquitoes have been previously reported, especially in Tyrol. Aedes koreicus had not so far been found in Austria. Within the framework of an alien mosquito surveillance program in the Austrian province of Tyrol, ovitraps were set up weekly from May to October, 2018, at 67 sites- 17 in East Tyrol and 50 in North Tyrol. Sampling was performed at highways and at urban and rural areas. DNA obtained from mosquito eggs was barcoded using molecular techniques and sequences were analysed to species level. Eggs of alien Aedes species were found at 18 out of 67 sites (27%). Both Ae. albopictus and Ae. japonicus were documented at highways and urban areas in both East and North Tyrol. Aedes koreicus was found in East Tyrol. During this mosquito surveillance program, eggs of Ae. albopictus, Ae. japonicus, and Ae. koreicus were documented in the Austrian province of Tyrol. These findings not only show highways to be points of entry, but also point to possible establishment processes of Ae. japonicus in Tyrol. Moreover, Ae. koreicus was documented in Austria for the first time.


Assuntos
Culicidae/classificação , Culicidae/fisiologia , Monitoramento Ambiental , Aedes/classificação , Aedes/genética , Aedes/fisiologia , Animais , Áustria , Culicidae/genética , Ovos , Feminino , Mosquitos Vetores/genética , Saúde Pública , População Rural , População Urbana
7.
Mem Inst Oswaldo Cruz ; 115: e190496, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32401999

RESUMO

The geographic distribution of Aedes (Stegomyia) aegypti (L.) in South America has been expanding during the last decades. Herein we present two new distribution records that extend its southern limits towards localities with extremer environmental conditions than reported to date. San Antonio Oeste constitutes the southernmost finding for the continent (40º44'S), whereas Tandil is the infested locality with the coldest mean annual temperature in Argentina (14.17ºC). The projection of a previous distribution model for Ae. aegypti predicts these two cities as positive and suggests several other localities with suitable conditions for vector proliferation beyond its assumed distribution limits.


Assuntos
Aedes/classificação , Mosquitos Vetores/classificação , Distribuição Animal , Animais , Argentina , Feminino , Masculino , Densidade Demográfica
8.
Mem Inst Oswaldo Cruz ; 115: e190437, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32428083

RESUMO

BACKGROUND Aedes aegypti and Aedes albopictus are the most important arbovirus vectors in the world. OBJECTIVES This study aimed to investigate and compare the infestation pattern of these species in a neighbourhood of Recife, Brazil, endemic for arboviruses in 2005 (T1) and 2013 (T2). METHODS Infestation, distribution and relative abundance of these sympatric species were recorded by egg collection using a network of 59 sentinel ovitraps (s-ovt) at fixed sampling stations for 12 months in T1 and T2. FINDINGS A permanent occupation pattern was detected which was characterised by the presence of egg-laying females of one or both species with a high ovitrap positivity index (94.3 to 100%) throughout both years analysed. In terms of abundance, the total of eggs collected was lower (p < 0.005) in T2 (146,153) than in T1 (281,103), although ovitraps still displayed a high index of positivity. The spatial distribution showed the presence of both species in 65.1% of the 148 s-ovt assessed, while a smaller number of traps exclusively contained Ae. aegypti (22%) or Ae. albopictus (13.2%) eggs. MAIN CONCLUSIONS Our comparative analysis demonstrated the robustness of the spatial occupation and permanence of Ae. aegypti and Ae. albopictus populations in this endemic urban area.


Assuntos
Aedes/classificação , Mosquitos Vetores/classificação , Aedes/fisiologia , Distribuição Animal , Animais , Infecções por Arbovirus/epidemiologia , Infecções por Arbovirus/transmissão , Brasil/epidemiologia , Doenças Endêmicas , Feminino , Masculino , Mosquitos Vetores/fisiologia , Oviposição , Densidade Demográfica , Estações do Ano
9.
BMC Infect Dis ; 20(1): 371, 2020 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-32448116

RESUMO

BACKGROUND: Zika virus (ZIKV, genus Flavivirus, family Flaviviridae) is transmitted mainly by Aedes mosquitoes. This virus has become an emerging concern of global public health with recent epidemics associated to neurological complications in the pacific and America. ZIKV is the most frequently amplified arbovirus in southeastern Senegal. However, this virus and its adult vectors are undetectable during the dry season. The aim of this study was to investigate how ZIKV and its vectors are maintained locally during the dry season. METHODS: Soil, sand, and detritus contained in 1339 potential breeding sites (tree holes, rock holes, fruit husks, discarded containers, used tires) were collected in forest, savannah, barren and village land covers and flooded for eggs hatching. The emerging larvae were reared to adult, identified, and blood fed for F1 production. The F0 and F1 adults were identified and tested for ZIKV by Reverse Transcriptase-Real time Polymerase Chain Reaction. RESULTS: A total of 1016 specimens, including 13 Aedes species, emerged in samples collected in the land covers and breeding sites investigated. Ae. aegypti was the dominant species representing 56.6% of this fauna with a high plasticity. Ae. furcifer and Ae. luteocephalus were found in forest tree holes, Ae. taylori in forest and village tree holes, Ae. vittatus in rock holes. ZIKV was detected from 4 out of the 82 mosquito pools tested. Positive pools included Ae. bromeliae (2 pools), Ae. unilineatus (1 pool), and Ae. vittatus (1 pool), indicating that the virus is maintained in these Aedes eggs during the dry season. CONCLUSION: Our investigation identified breeding sites types and land cover classes where several ZIKV vectors are maintained, and their maintenance rates during the dry season in southeastern Senegal. The maintenance of the virus in these vectors in nature could explain its early amplification at the start of the rainy season in this area.


Assuntos
Aedes/virologia , Secas , Mosquitos Vetores/fisiologia , Estações do Ano , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/transmissão , Zika virus/genética , Aedes/classificação , Aedes/fisiologia , Animais , Arbovirus/genética , Feminino , Florestas , Larva , Masculino , RNA Viral/genética , Chuva , Reprodução , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Areia/virologia , Senegal/epidemiologia , Microbiologia do Solo , Árvores/virologia , Infecção por Zika virus/virologia
10.
PLoS Negl Trop Dis ; 14(5): e0008279, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32365059

RESUMO

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.


Assuntos
Aedes/classificação , Aedes/genética , Genótipo , Mosquitos Vetores/classificação , Mosquitos Vetores/genética , Aedes/crescimento & desenvolvimento , Distribuição Animal , Animais , Cidades , Genética Populacional , Técnicas de Genotipagem , Repetições de Microssatélites , Mosquitos Vetores/crescimento & desenvolvimento , Filipinas , Análise Espacial
11.
PLoS Negl Trop Dis ; 14(4): e0008209, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32310960

RESUMO

Dengue, a vector-borne disease spread by Aedes mosquitoes, is a global threat. In the absence of an efficacious dengue vaccine, vector control is the key intervention tool in Singapore. A good understanding of vector habitats is essential to formulate operational strategies. We examined the distribution, long-term trend and seasonality of Aedes data collected during regulatory inspections in residences and public areas from 2008 to 2017. We also studied the seasonality of climate factors to understand their influence on the detection of Aedes-positive containers. The most frequently reported Aedes-positive containers were domestic containers, drains, discarded receptacles, ornamental containers, flower pot plates/trays, plants, gully traps, canvas/plastic sheet, bins, ground puddle, inspection chambers and roof tops/gutters. We found more Ae. aegypti and Ae. albopictus-positive containers per inspection in residences and public areas, respectively. The seasonality of Ae. aegypti-positive containers in residences and public areas coincided with that of mean temperature. However, the seasonality of Ae. albopictus-positive containers lagged by one month compared to that of mean temperature. Our study demonstrates the seasonal fluctuations of Aedes-positive containers in an urban environment. Understanding the distribution and seasonality of Aedes breeding helps to facilitate resource planning and community awareness to moderate dengue transmission.


Assuntos
Aedes/crescimento & desenvolvimento , Aedes/virologia , Distribuição Animal , Meio Ambiente , Estações do Ano , Aedes/classificação , Animais , Dengue/transmissão , Vírus da Dengue/isolamento & purificação , Vírus da Dengue/fisiologia , Habitação , Larva/virologia , Mosquitos Vetores/virologia , Pupa/virologia , Singapura
12.
PLoS One ; 15(4): e0232192, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32343725

RESUMO

The introduction of exotic disease vectors into a new habitat can drastically change the local epidemiological situation. During 2012-2015, larvae and an adult of the yellow-fever mosquito, Aedes aegypti, were captured alive at two international airports serving the Greater Tokyo Area, Japan. Because this species does not naturally distribute in this country, those mosquitoes were considered to be introduced from overseas via air-transportation. To infer the places of origin of those mosquitoes, we genotyped the 12 microsatellite loci for which the most comprehensive population genetic reference is currently available. Although clustering by Bayesian and multivariate methods both suggested that all those mosquitoes captured at the airports in Japan belonged to the Asia/Pacific populations, they were not clustered into a single cluster. Moreover, there was variation in mitochondrial cytochrome oxidase I gene (CoxI) haplotypes among mosquitoes collected in different incidents of discovery which indicated the existence of multiple maternal origins. We conclude there is little evidence to support the overwintering of Ae. aegypti at the airports; nevertheless, special attention is still needed to prevent the invasion of this prominent arbovirus vector.


Assuntos
Aedes/genética , Aeroportos , Mosquitos Vetores/genética , Aedes/classificação , Aedes/virologia , Animais , Infecções por Arbovirus/transmissão , Infecções por Arbovirus/virologia , Arbovirus/isolamento & purificação , Arbovirus/patogenicidade , Teorema de Bayes , Ecossistema , Complexo IV da Cadeia de Transporte de Elétrons/genética , Genes de Insetos , Genes Mitocondriais , Variação Genética , Genética Populacional , Genótipo , Haplótipos , Humanos , Proteínas de Insetos/genética , Repetições de Microssatélites , Mosquitos Vetores/classificação , Mosquitos Vetores/virologia , Tóquio
13.
Rev Soc Bras Med Trop ; 53: e20190504, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32267458

RESUMO

INTRODUCTION: The study of the landscape ecology, biological microhabitat, and epidemiological implications for the distribution of the main vectors Aedes aegypti and Aedes albopictus contribute to the prevention and control actions regarding the diseases they transmit. METHODS: This study sought to assess data on positive properties of the vector control program activities from 1998 to 2010. An entomological survey was also carried out on a sample of buildings collecting larvae and pupae from containers between October and April (spring / summer) from 2002 to 2005. We assessed the physico-chemical data of the water in 20% of positive containers. The vegetation and urbanization were assessed with the aid of satellite images and microenvironments were classified as urbanized, woods, and shrubs. The data were analyzed using statistical and geoprocessing software. RESULTS: Ae. aegypti and Ae. albopictus colonized all types of microhabitats and microenvironments, predominantly in the urbanized area, in isolation and in coexistence. The microhabitat of Ae. aegypti showed a temperature gradient greater than that of Ae. albopictus, and there was an association with urbanized areas for the first species and wooded areas for the last species. CONCLUSIONS: Landscape ecology and intra-urban differences favor different microclimates, which contribute to the coexistence of species in the urban environment in an area close to the forest, raising the risk of other arbovirus infections in urban areas. The ecological niche should be considered for Ae. albopictus. Entomological and virologic monitoring are suggested as arbovirus surveillance actions in urban infested centers near preserved forests.


Assuntos
Aedes/fisiologia , Ecossistema , Mosquitos Vetores/fisiologia , Aedes/classificação , Distribuição Animal , Animais , Infecções por Arbovirus/transmissão , Brasil , Mosquitos Vetores/classificação , Densidade Demográfica , Estações do Ano , Análise Espacial , População Urbana
14.
Parasit Vectors ; 13(1): 161, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32238178

RESUMO

BACKGROUND: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) biotyping is an innovative strategy, applied successfully for the identification of numerous arthropod families including mosquitoes. The effective mosquito identification using this emerging tool was demonstrated possible at different steps of their life-cycle, including eggs, immature and adult stages. Unfortunately, for species identification by MS, the euthanasia of the mosquito specimen is required. METHODS: To avoid mosquito euthanasia, the present study assessed whether aedine mosquitoes could be identified by MALDI-TOF MS biotyping, using their respective exuviae. In this way, exuviae from the fourth-instar and pupal stages of Aedes albopictus and Aedes aegypti were submitted to MALDI-TOF MS analysis. RESULTS: Reproducible and specific MS spectra according to aedine species and stage of exuviae were observed which were objectified by cluster analyses, composite correlation index (CCI) tool and principal components analysis (PCA). The query of our reference MS spectra database (DB) upgraded with MS spectra of exuviae from fourth-instar larvae and pupae of both Aedes species revealed that 100% of the samples were correctly classified at the species and stage levels. Among them, 93.8% (135/144) of the MS profiles reached the threshold log score value (LSV > 1.8) for reliable identification. CONCLUSIONS: The extension of reference MS spectra DB to exuviae from fourth-instar and pupal stages made now possible the identification of mosquitoes throughout their life-cycle at aquatic and aerial stages. The exuviae presenting the advantage to avoid specimen euthanasia, allowing to perform complementary analysis on alive mosquitoes.


Assuntos
Aedes/classificação , Proteínas de Insetos/genética , Aedes/química , Animais , Análise por Conglomerados , Proteínas de Insetos/química , Larva/química , Larva/classificação , Pupa/química , Pupa/classificação , Especificidade da Espécie , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
15.
PLoS Negl Trop Dis ; 14(3): e0008163, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32203510

RESUMO

Zika virus (ZIKV) is a Flavivirus (Flaviviridae) transmitted to humans mainly by the bite of an infected Aedes mosquitoes. Aedes aegypti is the primary epidemic vector of ZIKV and Ae. albopictus, the secondary one. However, the epidemiological role of both Aedes species in Central Africa where Ae. albopictus was recently introduced is poorly characterized. Field-collected strains of Ae. aegypti and Ae. albopictus from different ecological settings in Central Africa were experimentally infected with a ZIKV strain isolated in West Africa. Mosquitoes were analysed at 14- and 21-days post-exposure. Both Ae. aegypti and Ae. albopictus were able to transmit ZIKV but with higher overall transmission efficiency for Ae. aegypti (57.9%) compared to Ae. albopictus (41.5%). In addition, disseminated infection and transmission rates for both Ae. aegypti and Ae. albopictus varied significantly according to the location where they were sampled from. We conclude that both Ae. aegypti and Ae. albopictus are able to transmit ZIKV and may intervene as active Zika vectors in Central Africa. These findings could contribute to a better understanding of the epidemiological transmission of ZIKV in Central Africa and develop suitable strategy to prevent major ZIKV outbreaks in this region.


Assuntos
Aedes/virologia , Mosquitos Vetores/virologia , Infecção por Zika virus/virologia , Zika virus/isolamento & purificação , Aedes/classificação , África Central , Animais , Suscetibilidade a Doenças , Feminino , Mapeamento Geográfico , Mosquitos Vetores/classificação , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/transmissão
16.
PLoS Negl Trop Dis ; 14(3): e0008130, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32130209

RESUMO

BACKGROUND: Yellow fever, dengue, chikungunya and Zika viruses are responsible for considerable morbidity and mortality in humans. Aedes aegypti and Aedes albopictus are the most important mosquito vectors involved in their transmission. Accurate identification of these species is essential for the implementation of control programs to limit arbovirus transmission, during suspected detections at ports of first entry, to delimit incursions or during presence/absence surveillance programs in regions vulnerable to invasion. We developed and evaluated simple and rapid colorimetric isothermal tests to detect these two mosquito species based on loop-mediated isothermal amplification (LAMP) targeting the ribosomal RNA internal transcribed spacer 1 (ITS1). METHODOLOGY/PRINCIPAL FINDINGS: Samples were prepared by homogenizing and heating at 99 oC for 10 min before an aliquot was added to the LAMP reaction. After 40 min incubation at 65 oC, a colour change indicated a positive result. The tests were 100% sensitive and species-specific, and demonstrated a limit of detection comparable with PCR-based detection (TaqMan chemistry). The LAMP assays were able to detect target species for various life stages tested (adult, 1st instar larva, 4th instar larva and pupa), and body components, such as legs, wings and pupal exuviae. Importantly, the LAMP assays could detect Ae. aegypti DNA in mosquitoes stored in Biogents Sentinel traps deployed in the field for 14 d. A single 1st instar Ae. aegypti larva could also be detected in a pool of 1,000 non-target 1st instar Aedes notoscriptus, thus expediting processing of ovitrap collections obtained during presence/absence surveys. A simple syringe-sponge protocol facilitated the concentration and collection of larvae from the ovitrap water post-hatch. CONCLUSIONS/SIGNIFICANCE: We describe the development of LAMP assays for species identification and demonstrate their direct application for surveillance in different field contexts. The LAMP assays described herein are useful adjuncts to laboratory diagnostic testing or could be employed as standalone tests. Their speed, ease-of-use, low cost and need for minimal equipment and training make the LAMP assays ideal for adoption in low-resource settings without the need to access diagnostic laboratory services.


Assuntos
Aedes/classificação , Aedes/crescimento & desenvolvimento , Colorimetria/métodos , Entomologia/métodos , Técnicas de Diagnóstico Molecular/métodos , Mosquitos Vetores/classificação , Mosquitos Vetores/crescimento & desenvolvimento , Técnicas de Amplificação de Ácido Nucleico/métodos , Aedes/genética , Animais , DNA Espaçador Ribossômico/genética , Feminino , Mosquitos Vetores/genética , Sensibilidade e Especificidade
17.
Parasitol Res ; 119(3): 841-845, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32036439

RESUMO

Currently, five invasive Aedes mosquito species are of concern in Europe according to the European Centre for Disease Prevention and Control: Aedes aegypti, Ae. albopictus, Ae. atropalpus, Ae. japonicus, and Ae. koreicus. Among these, only Ae. albopictus was reported to occur in Romania, in Bucharest. The aim of this study was to update the knowledge on the distribution of this invasive mosquito species in Romania, by investigating new potential locations. Monitoring of Ae. albopictus was carried out between May 2017 and October 2018. Three types of traps (CDC-Gravid Traps, CDC miniature Light Traps, ovitraps) were placed in 53 localities in 13 counties at sites suitable for container-breeding mosquitoes. Collected adult mosquitoes were counted and identified according to morphological criteria. Larvae were found present in domestic containers and rain catch basins. Aedes albopictus adults and eggs were collected in 10 localities in eight counties across Romania. Our study confirms nine new localities and seven counties where Ae. albopictus became established in Romania, highlighting the need for surveillance to further assess the species' distribution and abundance, as well as the pathogen transmission risk related to that vector species.


Assuntos
Aedes/fisiologia , Espécies Introduzidas/estatística & dados numéricos , Mosquitos Vetores/fisiologia , Aedes/classificação , Distribuição Animal , Animais , Larva/classificação , Larva/fisiologia , Mosquitos Vetores/classificação , Óvulo/classificação , Óvulo/fisiologia , Romênia
18.
Acta Trop ; 205: 105390, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32044285

RESUMO

The southeastern region of Brazil has recently experienced the largest yellow fever disease outbreak in decades. Since July 2016 epizootic events were reported in São Paulo state's north region, where 787 Culicidae were captured as part of public health surveillance efforts and tested using real-time quantitative PCR. One Aedes scapularis pool collected in November 2016 in an agriculture area in Urupês city tested positive for YFV-RNA. Using a validated multiplex PCR approach we were able to recover a complete virus genome sequence from this pool. Phylogenetic analysis of the novel strain and publicly available data indicates that the belongs to the South American genotype 1 clade circulating in Sao Paulo state and is basal to the recent outbreak clade in southeast Brazil. Our findings highlight the need of additional studies, including vector competence studies, to disentangle the role of Aedes scapularis in yellow fever transmission in the Americas.


Assuntos
Aedes/virologia , Mosquitos Vetores/virologia , Febre Amarela/transmissão , Vírus da Febre Amarela/genética , Aedes/classificação , Animais , Brasil/epidemiologia , Genoma Viral , Humanos , Filogenia , Reação em Cadeia da Polimerase em Tempo Real , Febre Amarela/epidemiologia
19.
Parasit Vectors ; 13(1): 91, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-32075683

RESUMO

BACKGROUND: The international movement of used tyres is a major factor responsible for global introductions of Aedes invasive mosquitoes (AIMs) (Diptera: Culicidae) that are major disease vectors (e.g. dengue, Zika, chikungunya and yellow fever). Surveillance methods are restricted by expense, availability and efficiency to detect all life stages. Currently, no tested method exists to screen imported used tyres for eggs in diapause, the life stage most at risk from accidental introduction. Here we test the efficiency of adhesive tape as an affordable and readily available material to screen tyres for eggs, testing its effect on hatch rate, larval development, DNA amplification and structural damage on the egg surface. RESULTS: We demonstrated that the properties of adhesive tape can influence pick up of dormant eggs attached to dry surfaces. Tapes with high levels of adhesion, such as duct tape, removed eggs with high levels of efficiency (97% ± 3.14). Egg numbers collected from cleaned used tyres were found to explain larval hatch rate success well, particularly in subsequent larval to adult emergence experiments. The strength of this relationship decreased when we tested dirty tyres. Damage to the exochorion was observed following scanning electron microscopy (SEM), possibly resulting in the high variance in the observed model. We found that five days was the optimal time for eggs to remain on all tested tapes for maximum return on hatch rate success. Tape type did not inhibit amplification of DNA of eggs from three, five or ten days of exposure. Using this DNA, genotyping of AIMs was possible using species-specific markers. CONCLUSIONS: We demonstrated for the first time that adhesive tapes are effective at removing AIM eggs from tyres. We propose that this method could be a standardised tool for surveillance to provide public health authorities and researchers with an additional method to screen tyre cargo. We provide a screening protocol for this purpose. This method has a global applicability and in turn can lead to increased predictability of introductions and improve screening methods at high risk entry points.


Assuntos
Aedes/fisiologia , Controle de Mosquitos/métodos , Adesivos/economia , Aedes/classificação , Aedes/genética , Animais , Espécies Introduzidas/economia , Espécies Introduzidas/estatística & dados numéricos , Controle de Mosquitos/economia , Controle de Mosquitos/instrumentação , Mosquitos Vetores/classificação , Mosquitos Vetores/fisiologia , Óvulo/classificação , Óvulo/fisiologia
20.
Emerg Microbes Infect ; 9(1): 67-77, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31894724

RESUMO

Rapid and significant range expansion of both Zika virus (ZIKV) and its Aedes vector species has resulted in ZIKV being declared a global health threat. Mean temperatures are projected to increase globally, likely resulting in alterations of the transmission potential of mosquito-borne pathogens. To understand the effect of diurnal temperature range on the vectorial capacity of Ae. aegypti and Ae. albopictus for ZIKV, longevity, blood-feeding and vector competence were assessed at two temperature regimes following feeding on infectious blood meals. Higher temperatures resulted in decreased longevity of Ae. aegypti [Log-rank test, χ2, df 35.66, 5, P < 0.001] and a decrease in blood-feeding rates of Ae. albopictus [Fisher's exact test, P < 0.001]. Temperature had a population and species-specific impact on ZIKV infection rates. Overall, Ae. albopictus reared at the lowest temperature regime demonstrated the highest vectorial capacity (0.53) and the highest transmission efficiency (57%). Increased temperature decreased vectorial capacity across groups yet more significant effects were measured with Ae. aegypti relative to Ae. albopictus. The results of this study suggest that future increases in temperature in the Americas could significantly impact vector competence, blood-feeding and longevity, and potentially decrease the overall vectorial capacity of Aedes mosquitoes in the Americas.


Assuntos
Aedes/virologia , Mudança Climática , Mosquitos Vetores/virologia , Infecção por Zika virus/transmissão , Aedes/classificação , Animais , Sangue , Comportamento Alimentar , Feminino , Florida , México , Mosquitos Vetores/fisiologia , New York , Temperatura
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