Mapping Aedes aegypti indoor resting behavior reveals a preference vulnerable to householder-led vector control

Many mosquito vectors rest inside human habitations, a behavioral trait that is exploited for vector control by indoor residual spraying (IRS) of interior walls with insecticide. Although IRS and its refined version targeted IRS are very effective against Aedes aegypti, they are expensive and logistically challenging to deliver in densely populated urban areas where outbreaks of dengue and other arboviruses are the greatest challenge. In experiments in Recife, Brazil, we set out to quantify the indoor resting behavior of Ae. aegypti at a level beyond that previously reported. We found that significantly more Ae. aegypti males, unfed and fed females visited the base of walls (height 0–20 cm, corresponding to 12.3% of the total wall surface) more frequently than upper wall areas, with the difference more pronounced at higher temperatures. When the lowest 20 cm of the walls was treated with an appropriate insecticide and colored black, we recorded up to 85% cumulative mortality after 24-h exposure in the experimental room. The findings are significant because feasibly, householders could treat this small and accessible target zone manually, without the need for visits by costly IRS teams or equipment, reducing insecticide use and enabling communities to actively protect their own indoor environment

The V410L knockdown resistance mutation occurs in island and continental populations of Aedes aegypti in West and Central Africa

The extensive use of insecticides for vector control has led to the development of insecticide resistance in Aedes aegypti populations on a global scale, which has significantly compromised control actions. Insecticide resistance, and its underlying mechanisms, has been investigated in several countries, mostly in South American and Asian countries. In Africa, however, studies reporting insecticide resistance are rare and data on resistance mechanisms, notably knockdown resistance (kdr) mutations, is scarce. In this study, the recently described V410L kdr mutation is reported for the first time in old world Ae. aegypti populations, namely from Angola and Madeira island. Two additional kdr mutations, V1016I and F1534C, are also reported for the first time in populations from Angola and Cape Verde. Significant associations with the resistance phenotype were found for both V410L and V1016I individually as well as for tri-locus genotypes in the Angolan population. However, no association was found in Madeira island, probably due to the presence of a complex pattern of multiple insecticide resistance mechanisms in the local Ae. aegypti population. These results suggest that populations carrying the same kdr mutations may respond differently to the same insecticide, stressing the need for complementary studies when assessing the impact of kdr resistance mechanisms in the outcome of insecticide-based control strategies.publishersversionpublishe

Comparative Genomics of the Anopheline Glutathione S-Transferase Epsilon Cluster

Enzymes of the glutathione S-transferase (GST) family play critical roles in detoxification of xenobiotics across many taxa. While GSTs are ubiquitous both in animals and plants, the GST epsilon class (GSTE) is insect-specific and has been associated with resistance to chemical insecticides. While both Aedes aegypti and Anopheles gambiae GSTE clusters consist of eight members, only four putative orthologs are identifiable between the species, suggesting independent expansions of the class in each lineage. We used a primer walking approach, sequencing almost the entire cluster from three Anopheles species (An. stephensi, An. funestus (both Cellia subgenus) and An. plumbeus (Anopheles subgenus)) and compared the sequences to putative orthologs in An. gambiae (Cellia) in an attempt to trace the evolution of the cluster within the subfamily Anophelinae. Furthermore, we measured transcript levels from the identified GSTE loci by real time reverse transcription PCR to determine if all genes were similarly transcribed at different life stages. Among the species investigated, gene order and orientation were similar with three exceptions: (i) GSTE1 was absent in An. plumbeus; (ii) GSTE2 is duplicated in An. plumbeus and (iii) an additional transcriptionally active pseudogene (ψAsGSTE2) was found in An. stephensi. Further statistical analysis and protein modelling gave evidence for positive selection on codons of the catalytic site in GSTE5 albeit its origin seems to predate the introduction of chemical insecticides. Gene expression profiles revealed differences in expression pattern among genes at different life stages. With the exception of GSTE1, ψAsGSTE2 and GSTE2b, all Anopheles species studied share orthologs and hence we assume that GSTE expansion generally predates radiation into subgenera, though the presence of GSTE1 may also suggest a recent duplication event in the Old World Cellia subgenus, instead of a secondary loss. The modifications of the catalytic site within GSTE5 may represent adaptations to new habitats

Identification of Zika virus vectors and implications for control

Artigo liberado em acesso aberto como parte do acordo para tornar público todos os dados produzidos sobre o vírus zika - Compartilhamento de dados em emergências de saúde pública - http://www.wellcome.ac.uk/News/Media-office/Press-releases/2016/WTP060169.htmSubmitted by Claudete Queiroz ([email protected]) on 2016-04-08T12:56:32Z No. of bitstreams: 1 Identification of Zika virus vectors and implications for control.pdf: 112950 bytes, checksum: ac59614c2522baca2a1f34aad1cf8696 (MD5)Approved for entry into archive by Claudete Queiroz ([email protected]) on 2016-04-08T13:07:38Z (GMT) No. of bitstreams: 1 Identification of Zika virus vectors and implications for control.pdf: 112950 bytes, checksum: ac59614c2522baca2a1f34aad1cf8696 (MD5)Made available in DSpace on 2016-04-08T13:07:38Z (GMT). No. of bitstreams: 1 Identification of Zika virus vectors and implications for control.pdf: 112950 bytes, checksum: ac59614c2522baca2a1f34aad1cf8696 (MD5) Previous issue date: 2016Fundação Oswaldo Cruz. Centro de Pesquisas Aggeu Magalhães. Recife, PE, Brasil.Zika virus is an emerging pathogen that has recently been causing serious epidemics around the world. Cases of Zika virus disease were reported in Micronesia in 20071 and then in French Polynesia in 2013.2 In French Polynesia, Guillain-Barré syndrome was reported for the first time in a few patients following Zika virus infection. In Brazil, Zika virus was introduced in 2014,3 and was subsequently associated with cases of microcephaly. So far, an estimated minimum of 400 000 cases of Zika virus disease have been reported in 24 states in Brazil, although the number of cases could be far higher

The Role of the Conformational Dynamics of Glutathione S-Transferase Epsilon Class on Insecticide Resistance in Anopheles gambiae

Glutathione S-transferases (GSTs) are enzymes capable of metabolizing cytotoxic compounds. The enzyme AgGSTE2, member of epsilon class GSTs (GSTE), is the most important GST conferring resistance to dichloro-diphenyl-trichloroethane (DDT) in Anopheles gambiae. We have investigated the conformational dynamics of three GSTE variants (GSTE2, GSTE2-I114T/F120L, GSTE5) from A. gambiae. Large-scale motions of helices H2 and H4 and conformational transition of the C-terminal governs the opening of the G-site and is expected to affect substrate binding and product release. This structural rearrangement places Glu116 (Glu120 in GSTE5) close of the thiol group of the tripeptide glutathione (GSH) cofactor, making this residue a candidate to act as a base in the activation of DDT. The structural rearrangement is noticeable for AgGSTE2-F120L, which has been shown to confer increased DDT-resistance. The other variants exhibit a more subtle rearrangement. These findings corroborate the hypothesis that the increase of the conformational dynamics of GST Epsilon class isoforms from A. gambiae promotes higher DDTase activity

Climate Change Influences on the Global Potential Distribution of the Mosquito Culex quinquefasciatus, Vector of West Nile Virus and Lymphatic Filariasis

Submitted by Adagilson Silva ([email protected]) on 2017-05-15T13:19:45Z No. of bitstreams: 1 27695107 2016 sam-cli.PDF: 5170317 bytes, checksum: 349e7da4c1f3736f565c0f4da8e46455 (MD5)Approved for entry into archive by Adagilson Silva ([email protected]) on 2017-05-15T13:25:36Z (GMT) No. of bitstreams: 1 27695107 2016 sam-cli.PDF: 5170317 bytes, checksum: 349e7da4c1f3736f565c0f4da8e46455 (MD5)Made available in DSpace on 2017-05-15T13:25:36Z (GMT). No. of bitstreams: 1 27695107 2016 sam-cli.PDF: 5170317 bytes, checksum: 349e7da4c1f3736f565c0f4da8e46455 (MD5) Previous issue date: 2016Ain Shams University. Faculty of Science. Entomology Department. Abbassia, Cairo, Egypt / University of Kansas. Biodiversity Institute. Lawrence, KS, United States of America.University of Khartoum. Faculty of Medical Laboratory Sciences. Department of Parasitology and Medical Entomology. Khartoum, Sudan.Ain Shams University. Faculty of Science. Entomology Department. Abbassia, Cairo, Egypt.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil.University of Kansas. Biodiversity Institute. Lawrence, KS, United States of America.Ain Shams University. Faculty of Science. Entomology Department. Abbassia, Cairo, Egypt.Rapid emergence of most vector-borne diseases (VBDs) may be associated with range expansion of vector populations. Culex quinquefasciatus Say 1823 is a potential vector of West Nile virus, Saint Louis encephalitis virus, and lymphatic filariasis. We estimated the potential distribution of Cx. quinquefasciatus under both current and future climate conditions. The present potential distribution of Cx. quinquefasciatus showed high suitability across low-latitude parts of the world, reflecting the current distribution of the species. Suitable conditions were identified also in narrow zones of North Africa and Western Europe. Model transfers to future conditions showed a potential distribution similar to that under present-day conditions, although with higher suitability in southern Australia. Highest stability with changing climate was between 30°S and 30°N. The areas present high agreement among diverse climate models as regards distributional potential in the future, but differed in anticipating potential for distribution in North and Central Africa, southern Asia, central USA, and southeastern Europe. Highest disparity in model predictions across representative concentration pathways (RCPs) was in Saudi Arabia and Europe. The model predictions allow anticipation of changing distributional potential of the species in coming decades

Identification of a major Quantitative Trait Locus determining resistance to the organophosphate temephos in the dengue vector mosquito Aedes aegypti

Submitted by Adagilson Silva ([email protected]) on 2017-09-13T17:37:01Z No. of bitstreams: 1 26576515 2015 pai-ana.oa.pdf: 602511 bytes, checksum: a3bdfb10f98627983fa539648d310799 (MD5)Approved for entry into archive by Adagilson Silva ([email protected]) on 2017-09-13T17:43:33Z (GMT) No. of bitstreams: 1 26576515 2015 pai-ana.oa.pdf: 602511 bytes, checksum: a3bdfb10f98627983fa539648d310799 (MD5)Made available in DSpace on 2017-09-13T17:43:33Z (GMT). No. of bitstreams: 1 26576515 2015 pai-ana.oa.pdf: 602511 bytes, checksum: a3bdfb10f98627983fa539648d310799 (MD5) Previous issue date: 2016-01Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, BrasilOrganophosphate insecticides (OP) have extensively been used to control mosquitoes, such as the vector Aedes aegypti. Unfortunately, OP resistance has hampered control programs worldwide. We used Quantitative Trait Locus (QTL) mapping to evaluate temephos resistance in two F1 intercross populations derived from crosses between a resistant Ae. aegypti strain (RecR) and two susceptible strains (MoyoD and Red). A single major effect QTL was identified on chromosome 2 of both segregating populations, named rtt1 (resistance to temephos 1). Bioinformatics analyses identified a cluster of carboxylesterase genes (CCE) within the rtt1 interval. qRT-PCR demonstrated that different CCEs were up-regulated in F2 resistant individuals from both crosses. However, none exceeded the 2-fold expression. Primary mechanisms for temephos resistance may vary between Ae. aegypti populations, yet also appear to support previous findings suggesting that multiple linked esterase genes may contribute to temephos resistance in the RecR strain as well as other populations

An unsettling explanation for the failure of skatole-baited ovitraps to capture Culex mosquitoes

Submitted by Kamylla Nascimento ([email protected]) on 2018-03-23T13:10:01Z No. of bitstreams: 1 PE-IAM (PREPRINT) - Ovitraps failure to capture mosquitoes .pdf: 1345690 bytes, checksum: 86bdba7a7a6069a3a716974419bdef92 (MD5)Approved for entry into archive by Kamylla Nascimento ([email protected]) on 2018-03-23T14:20:14Z (GMT) No. of bitstreams: 1 PE-IAM (PREPRINT) - Ovitraps failure to capture mosquitoes .pdf: 1345690 bytes, checksum: 86bdba7a7a6069a3a716974419bdef92 (MD5)Made available in DSpace on 2018-03-23T14:20:14Z (GMT). No. of bitstreams: 1 PE-IAM (PREPRINT) - Ovitraps failure to capture mosquitoes .pdf: 1345690 bytes, checksum: 86bdba7a7a6069a3a716974419bdef92 (MD5) Previous issue date: 2018Este trabalho foi apoiado pelo Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), sob o prêmio 407475 / 2012-5; Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco, sob premiaçãoAPQ-2141-4.00 / 12 PPSUS-FACEPE; e o Instituto Nacional de Alergia e Infecciosidade Doenças dos Institutos Nacionais de Saúde, sob o prêmio R01AI095514 e R21AI128931.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil / Universidade Federal de Pernambuco. Centro Acadêmico do Agreste. Caruaru, PE, Brasil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil.Universidade Federal de Santa Catarina. Centro de Ciências Biológicas. Departamento de Biologia Celular, Embriologia e Genética. Florianópolis, SC, Brazil.Universidade de São Paulo. Faculdade de Saúde Pública. Departamento de Epidemiologia. São Paulo, SP, Brazil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil.University of California-Davis. Department of Molecular and Cellular Biology. Davis, CA, USA.Culex mosquitoes are primarily found in temperate and tropical regions worldwide where they play a crucial role as main vectors of filarial worms and arboviruses. In Recife, a northeast city in Brazil, high densities of Culex quinquefasciatus are often found in association with human populated areas. In marked contrast to another part of the city, field tests conducted in the neighborhood of Sítio dos Pintos showed that trapping of mosquitoes in skatole-baited ovitraps did not differ significantly from captures in control (water) traps. Thus, classical and molecular taxonomic approaches were used to analyze the Culex species circulating in Sítio dos Pintos. Results obtained from both approaches agreed on the co-circulation of Culex quinquefasciatus and Culex nigripalpus in three different areas of this neighborhood. What was initially considered as an unexpected failure of this lure turned out to be a more unsettling problem, i.e., the first report in Recife of Culex nigripalpus, a vector of Venezuelan equine encephalitis virus and West Nile virus. Unplanned urbanization processes close to remnants of the Atlantic forest, such as observed in Sítio dos Pintos, may have contributed to the introduction of Cx. nigripalpus in urban areas. This article is protected by copyright. All rights reserved

Predicted future potential distribution of <i>Culex quinquefasciatus</i> under four future representative concentration pathways of climate conditions.

<p>Red areas are modeled suitable conditions; white areas are unsuitable conditions.</p

Summary of 701 <i>Culex quinquefasciatus</i> occurrences available for model calibration.

<p>Summary of 701 <i>Culex quinquefasciatus</i> occurrences available for model calibration.</p