Screening of natural Wolbachia infection in mosquitoes (Diptera: Culicidae) from the Cape Verde islands

Funding Information: We are grateful to the National Institute of Public Health for the laboratory support in Cape Verde, and to technicians from the Ministry of Health for their assistance in field work. We would like to thank Prof. Paulo Almeida for providing DNA controls of Cx. pipiens and Cx. quinquefasciatus used in the species identification PCR assay. Funding Information: This work was funded by national funds through FCT—Fundação para a Ciência e Tecnologia, I.P., within the framework of the project ARBOMONITOR (PTDC/BIA-OUT/29477/2017. Aires da Moura was funded by the Ph.D. fellowship program of Camões I.P. Publisher Copyright: © 2023, The Author(s).Background: Wolbachia pipientis is an endosymbiont bacterium that induces cytoplasmic incompatibility and inhibits arboviral replication in mosquitoes. This study aimed to assess Wolbachia prevalence and genetic diversity in different mosquito species from Cape Verde. Methods: Mosquitoes were collected on six islands of Cape Verde and identified to species using morphological keys and PCR-based assays. Wolbachia was detected by amplifying a fragment of the surface protein gene (wsp). Multilocus sequence typing (MLST) was performed with five housekeeping genes (coxA, gatB, ftsZ, hcpA, and fbpA) and the wsp hypervariable region (HVR) for strain identification. Identification of wPip groups (wPip-I to wPip-V) was performed using PCR–restriction fragment length polymorphism (RFLP) assay on the ankyrin domain gene pk1. Results: Nine mosquito species were collected, including the major vectors Aedes aegypti, Anopheles arabiensis, Culex pipiens sensu stricto, and Culex quinquefasciatus. Wolbachia was only detected in Cx. pipiens s.s. (100% prevalence), Cx. quinquefasciatus (98.3%), Cx. pipiens/quinquefasciatus hybrids (100%), and Culex tigripes (100%). Based on the results of MLST and wsp hypervariable region typing, Wolbachia from the Cx. pipiens complex was assigned to sequence type 9, wPip clade, and supergroup B. PCR/RFLP analysis revealed three wPip groups in Cape Verde, namely wPip-II, wPip-III, and wPip-IV. wPip-IV was the most prevalent, while wPip-II and wPip-III were found only on Maio and Fogo islands. Wolbachia detected in Cx. tigripes belongs to supergroup B, with no attributed MLST profile, indicating a new strain of Wolbachia in this mosquito species. Conclusions: A high prevalence and diversity of Wolbachia was found in species from the Cx. pipiens complex. This diversity may be related to the mosquito's colonization history on the Cape Verde islands. To the best of our knowledge, this is the first study to detect Wolbachia in Cx. tigripes, which may provide an additional opportunity for biocontrol initiatives. publishersversionpublishe

Evaluation of Vectorial Competence of Aedes aegypti population from Santiago Island, Cape Verde, to different serotypes of Dengue virus

Made available in DSpace on 2015-11-18T13:13:40Z (GMT). No. of bitstreams: 2 153.pdf: 1182479 bytes, checksum: 572ca8cb379e9adc3ceb185ab244a3eb (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2014Fundação Oswaldo Cruz. Centro de Pesquisas Aggeu Magalhães. Recife, PE, BrasilA dengue é uma arbovirose causada pelo vírus Dengue (DENV), cujos principais vetores são os mosquitos Aedes aegypti e Aedes albopictus. A. aegypti é o único vetor de DENV em Cabo Verde, país que teve a sua primeira epidemia da dengue registrada em 2009. Contudo, pouco se sabe acerca da variação no nível de competência vetorial das populações do vetor aos diferentes sorotipos de DENV. O estudo teve como objetivo avaliar a competência vetorial de A. aegypti da ilha de Santiago, Cabo Verde, a quatro sorotipos de DENV. Para isso, os mosquitos foram alimentados artificialmente com sangue contendo diferentes sorotipos de DENV, e em seguida dissecados ao 7º, 14º e 21º dia após infecção (dpi) para verificar a presença do vírus no intestino, cabeça e glândulas salivares usando a técnica de RT-PCR. Adicionalmente, o número de cópias de RNA viral presente nas glândulas salivares foi determinado por qRT-PCR. Foram observadas altas taxas de infecção das glândulas salivares para DENV-2 e DENV-3 (65 e 75 por cento respectivamente), enquanto que para DENV-1, o RNA viral só foi detectado no intestino e cabeça, não chegando a infectar as glândulas salivares. DENV-4 não disseminou para cabeça e glândulas salivares, mantendo a infecção apenas no intestino (9 por cento). O número de cópias de RNA viral nas glândulas salivares não variou significativamente entre DENV-2 e DENV-3 e nem entre os diferentes períodos de incubação do vírus e títulos de DENV testados. Conclui-se, que a população de Aedes aegypti da ilha de Santiago, Cabo Verde, possui alta competência vetorial para as cepas de DENV-2 e DENV-3 e são pouco susceptíveis para as de DENV-1 e DENV-4. As cópias de RNA viral nas glândulas salivares mantêm-se relativamente constante por 21 dias após a infecção, o que pode potencializar a capacidade vetorial de mosquito A. aegypti e sugere alguma forma de modulação da replicação do vírus nesse órgãoDengue is an arboviral disease caused by dengue virus (DENV), for which the main vectors are the mosquitoes Aedes aegypti and Aedes albopictus. A. aegypti is the only DENV vector in Cape Verde, a country which suffered its first dengue outbreak in 2009. However, little is known about the variation in the level of vector competence of this mosquito population to the different DENV serotypes. The present study aimed to evaluate the vector competence of A. aegypti on the Island of Santiago, Cape Verde, to four DENV serotypes. For this, the mosquitoes were fed with blood containing different DENV serotypes, and then dissected at 7, 14 and 21 days post infection (dpi) to detect the virus in the midgut, head and salivary glands by RT-PCR. Additionally, copies of viral RNA present in salivary glands weredetermined by qRT-PCR. High rates of salivary gland infection were observed for DENV-2 and DENV-3 (65 and 75 %, respectively), while for DENV-1, the viral RNA was only detected in the midgut and head, but did not infect the salivary glands. DENV-4 didn´t spread to the head and salivary glands, maintaining the infection only in the midgut (9%). The number of viral RNA copies in the salivary glands did not vary significantly between DENV2 and DENV-3, nor between the different periods of incubation and the various titers of DENV tested. In conclusion, the population of Aedes aegypti on Santiago Island, Cape Verde, has high vector competence for DENV-2 and DENV-3 strains and is less susceptible to DENV-1 and DENV-4. Viral RNA copies in the salivary gland remained relatively constant for at least 21 days after infection, which may enhance the vector capacity of A. Aegypti, and suggests some form of modulation of virus replication in the salivary glands

Additional file 1 of Screening of natural Wolbachia infection in mosquitoes (Diptera: Culicidae) from the Cape Verde islands

Additional file 1: Table S1. Primer sequences used for molecular identification of mosquito species collected in Cape Verde islands. Table S2. Primers used for PCR detection of Wolbachia and genotyping of wPip I–V groups by PCR-RFLP. Table S3. Primers used for Wolbachia MLST loci and wsp hypervariable region amplification and sequence analysis

Additional file 2 of Screening of natural Wolbachia infection in mosquitoes (Diptera: Culicidae) from the Cape Verde islands

Additional file 2: Table S4. Mosquito species collected on each island and tested for Wolbachia using wsp

Susceptibility profile of Aedes aegypti from Santiago Island, Cabo Verde, to insecticides

Submitted by Adagilson Silva ([email protected]) on 2017-09-21T12:23:32Z No. of bitstreams: 1 26307496 2015 roc-sus.oa.wo.pdf.ed.pdf: 857693 bytes, checksum: 88721db53d43c2d2f2e41e119ad1315a (MD5)Approved for entry into archive by Adagilson Silva ([email protected]) on 2017-09-21T12:52:03Z (GMT) No. of bitstreams: 1 26307496 2015 roc-sus.oa.wo.pdf.ed.pdf: 857693 bytes, checksum: 88721db53d43c2d2f2e41e119ad1315a (MD5)Made available in DSpace on 2017-09-21T12:52:03Z (GMT). No. of bitstreams: 1 26307496 2015 roc-sus.oa.wo.pdf.ed.pdf: 857693 bytes, checksum: 88721db53d43c2d2f2e41e119ad1315a (MD5) Previous issue date: 2015-12Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, BrasilIn 2009, Cabo Verde diagnosed the first dengue cases, with 21,137 cases reported and Aedes aegypti was identified as the vector. Since the outbreak, chemical insecticides and source reduction were used to control the mosquito population. This study aimed to assess the susceptibility of A. aegypti populations from Santiago, Cabo Verde to insecticides and identify the mechanisms of resistance. Samples of A. aegypti eggs were obtained at two different time periods (2012 and 2014), using ovitraps in different locations in Santiago Island to establish the parental population. F1 larvae were exposed to different concentrations of insecticides (Bacillus thuringiensis var israelensis (Bti), diflubenzuron and temephos) to estimate the lethal concentrations (LC90) and calculate the respective rate of resistance (RR90). Semi-field tests using temephos-ABATE(®) were performed to evaluate the persistence of the product. Bottle tests using female mosquitoes were carried out to determine the susceptibility to the adulticides malathion, cypermethrin and deltamethrin. Biochemical and molecular tests were performed to investigate the presence of metabolic resistance mechanisms, associated with the enzymes glutathione S-transferases (GSTs), esterases and mixed-function oxidases (MFO) and to detect mutations or alterations in the sodium channel and acetylcholinesterase genes. A. aegypti mosquitoes from Santiago exhibited resistance to deltamethrin, cypermethrin (mortality<80%) and temephos (RR90=4.4) but susceptibility to malathion (mortality≥98%), Bti and diflubenzuron. The low level of resistance to temephos did not affect the effectiveness of Abate(®). The enzymatic analysis conducted in 2012 revealed slight changes in the activities of GST (25%), MFO (18%), α-esterase (19%) and β-esterase (17%), but no significant changes in 2014. Target site resistance mutations were not detected. Our results suggest that the A. aegypti population from Santiago is resistant to two major insecticides used for vector control, deltamethrin and temephos. To our knowledge, this is the first report of temephos resistance in an African A. aegypti population. The low level of temephos resistance was maintained from 2012-2014, which suggested the imposition of selective pressure, although it was not possible to identify the resistance mechanisms involved. These data show that the potential failures in the local mosquito control program are not associated with insecticide resistance

Knowledge, attitudes and practices about malaria in Cabo Verde: a country in the pre-elimination context

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