Double BR-OVT: a new trap model for collecting eggs and adult mosquitoes from Culex quinquefasciatus and Aedes spp.

The circulation of arboviruses throughout the world and the maintenance of lymphatic filariasis endemicity in tropical countries, combined with the lack of vaccines and specific treatments, highlight the importance of reducing the populations of mosquitoes involved in the transmission of these pathogens, Aedes aegypti and Culex quinquefasciatus. To contribute to the development of new strategies for monitoring and controlling these culicids, we evaluated the performance of the Double BR-OVT trap individually and in pairs, in the field. After 18 months, the Double BR-OVT traps captured a mean of 3.5 ± 7.4 and 1.8 ± 3.2 of Culex and Aedes/residence/cycle, respectively, in addition to 410 ± 588.3 Aedes eggs/residence/cycle. When installed in pairs, the Double BR-OVT traps collected three times more adult mosquitoes of C. quinquefasciatus (9.4 ± 8.3 Culex/ residence/bimester) and two times more Aedes spp. (3 ± 3.2 Aedes/residence/bimester) in comparison with the traps installed individually (2.6 ± 7.1 and 1.5 ± 3.2 Culex and Aedes/ residence/bimester, respectively) (p < 0.05). The Double BR-OVT trap has an exceptional advantage: it aggregates different functionalities into a single instrument, as this type of trap can concomitantly collect eggs and adult mosquitoes of C. quinquefasciatus and A. aegypti, a feature that makes it a potentially useful tool among the strategies for monitoring and controlling these mosquitoes

Evaluation of the impact of a biolarvicide based on Lysinibacillus sphaericus (Lsp) and Bacillus thuringiensis israelensis (Bti) for control of Culex quinquefasciatus e Aedes aegypti in the field

Submitted by Kamylla Nascimento ([email protected]) on 2017-11-13T11:43:30Z No. of bitstreams: 1 tese.pdf: 3071118 bytes, checksum: 27ec012383c077e3cf27688ab0277b0c (MD5)Submitted by Kamylla Nascimento ([email protected]) on 2017-11-13T13:13:48Z No. of bitstreams: 1 tese.pdf: 3071118 bytes, checksum: 27ec012383c077e3cf27688ab0277b0c (MD5)Approved for entry into archive by Kamylla Nascimento ([email protected]) on 2017-11-16T14:15:39Z (GMT) No. of bitstreams: 1 tese.pdf: 3071118 bytes, checksum: 27ec012383c077e3cf27688ab0277b0c (MD5)Made available in DSpace on 2017-11-16T14:15:39Z (GMT). No. of bitstreams: 1 tese.pdf: 3071118 bytes, checksum: 27ec012383c077e3cf27688ab0277b0c (MD5) Previous issue date: 1800Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.Produtos larvicidas à base de bactérias entomopatogênicas são seletivos e têm sido utilizados com sucesso para o controle de culicídeos e simulídeos de importância médica. Nessa perspectiva, um biolarvicida composto por cristais inseticidas de Lysinibacillus sphaericus (Lsp) e Bacillus thuringiensis svar. israelensis (Bti), VectoMax® CG, foi avaliado em relação a sua eficácia para o controle de Culex quinquefasciatus e Aedes aegypti em áreas urbanas, bem como avaliado seu impacto na suscetibilidade de C. quinquefasciatus a Lsp. O estudo foi conduzido no bairro de Água Fria, Recife-PE que já vinha tratando seus criadouros bimensalmente com larvicidas a base de Lsp (VectoLex® G) e de Bti (VectoBac® G). A região foi dividida na área 1 (A1) onde o esquema foi mantido e na área 2 (A2), onde os produtos foram substituídos pelo VectoMax®. Índices entomológicos durante o período de pré-intervenção foram analisadosa partir da densidade de adultos/formas jovens. Além da avaliação da suscetibilidade de C. quinquefasciatus a Lsp. Durante os três anos de intervenção, esses levantamentos entomológicos foram mantidos. Após o primeiro ano, houve uma redução no número de adultos de C. quinquefasciatus nas duas áreas (p=0<0,0005), atingindo uma queda de 43,83% (A1) e 61,86% (A2) comparado ao período de pré-intervenção. A suscetibilidade de C. quinquefasciatus a Lsp não apresentou perda, as razões de resistência apresentaram flutuações inferiores a 10 vezes, em ambas às áreas, na maioria das avaliações. Os alelos que conferem resistência a Lsp tiveram uma frequência de 0,057 antes da intervenção, ao longo do tratamento, a frequência na A2 foi inferior (0,069) à A1 (0,088), sugerindo que o uso do VectoMax® desfavoreceu a seleção destes alelos. Desta forma, a utilização do produto conjugado Lsp+Bti, ofereceu vantagens como um maior impacto no controle de C. quinquefaciatus, menor potencial de seleção de resistência, além de vantagens logísticas pelo uso de um único produto.Larvicidal products based on entomopathogenic bacteria are selective and have been successfully used for controlling culicidae and simulids of medical importance. From this perspective, a the effectiveness biolarvicide composed of insecticidal crystals of Lysinibacillus sphaericus (Lsp) and Bacillus thuringiensis israelensis (Bti), VectoMax® WSP, was evaluated for controlling the Culex quinquefasciatus and Aedes aegypti in urban areas, as well as its impact on the susceptibility of C. quinquefasciatus to Lsp. The study was conducted in the neighborhood of Água Fria, Recife-PE, which had been treating its breeding grounds bi-monthly with larvicides based on Lsp (VectoLex® G) and Bti (VectoBac® G). The region was divided into area 1 (A1) where the scheme was maintained and in area 2 (A2), where the products were replaced by VectoMax®. Entomological indices during the pre-intervention period were performed from the density of adults young forms. In addition the susceptibility of C. quinquefasciatus to Lsp was also evaluated. During the three years of intervention, these entomological surveys were maintained. After the first year, there was a reduction in the number of adults of C. quinquefasciatus in both areas (p = 0 <0.0005), reaching a decrease of 43.83% (A1) and 61.86% (A2) compared to the pre-intervention. The susceptibility of C. quinquefasciatus to Lsp showed no loss, the resistance ratios showed fluctuations less than 10 times, in both areas, in most evaluations. The alleles conferring resistance to Lsp had a frequency of 0.057 before the intervention, throughout the treatment, the frequency at A2 was lower (0.069) tham A1 (0.088), suggesting that the use of VectoMax® disadvantaged the selection of such alleles. In this way, the use of the Lsp + Bti conjugated product offered advantages such as greater impact on C. quinquefaciatus control, less resistance selection potential, and logistic advantages due to the use of a single product

Impact of small variations in temperature and humidity on the reproductive activity and survival of Aedes aegypti (Diptera, Culicidae)

In short space of time increase in temperature and rainfall can affect vector populations and, consequently, the diseases for them transmitted. The present study analyzed the effect of small temperature and humidity variations on the fecundity, fertility and survival of Aedes aegypti. These parameters were analyzed using individual females at temperatures ranging from 23 to 27 °C (mean 25 °C); 28 to 32 °C (mean 30 °C) and 33 to 37 °C (mean 35 ºC) associated to 60±8% and 80±6% relative humidity. Females responded to an increase in temperature by reducing egg production, oviposition time and changing oviposition patterns. At 25 ºC and 80% relative humidity, females survived two-fold more and produced 40% more eggs when compared to those kept at 35 ºC and 80% relative humidity. However, in 45% of females kept at 35 ºC and 60% relative humidity oviposition was inhibited and only 15% females laid more than 100 eggs, suggesting that the intensity of the temperature effect was influenced by humidity. Gradual reductions in egg fertility at 60% relative humidity were observed with the increase in temperature, although such effect was not found in the 80% relative humidity at 25 º C and 30 º C. These results suggest that the reduction in population densities recorded in tropical areas during seasons when temperatures reach over 35 ºC is likely to be strongly influenced by temperature and humidity, with a negative effect on several aspects of mosquito biology

Field evaluation of sticky BR-OVT traps to collect culicids eggs and adult mosquitoes inside houses

Submitted by Ana Beatriz Oliveira ([email protected]) on 2019-04-22T13:47:56Z No. of bitstreams: 1 Field evaluation of sticky BR-OVT traps to collect cul.pdf: 1443854 bytes, checksum: faab1f0897178ecb8711ec4084c43010 (MD5)Approved for entry into archive by Ana Beatriz Oliveira ([email protected]) on 2019-04-22T13:55:30Z (GMT) No. of bitstreams: 1 Field evaluation of sticky BR-OVT traps to collect cul.pdf: 1443854 bytes, checksum: faab1f0897178ecb8711ec4084c43010 (MD5)Made available in DSpace on 2019-04-22T13:55:30Z (GMT). No. of bitstreams: 1 Field evaluation of sticky BR-OVT traps to collect cul.pdf: 1443854 bytes, checksum: faab1f0897178ecb8711ec4084c43010 (MD5) Previous issue date: 2018Fundação de Amparo à Pesquisa do Estado de Pernambuco (FACEPE), Brazil (Grant number 13/2012- PPSUS-REDE) [Programa de Pesquisa para o Sistema Único de Saúde (PPSUS-REDE)] (Research Support. APQ-2141-4.00 / 12)Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Programa de Pós-Graduação em Biociências e Biotecnologia em Saúde. Recife, 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 Rural de Pernambuco. Unidade Acadêmica de Serra Talhada. Serra Talhada, PE, Brasil.Universidade Federal Rural de Pernambuco. Unidade Acadêmica de Serra Talhada. Serra Talhada, 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.Introduction: Culex quinquefasciatus is a mosquito of importance to public health, as it represents a real and/or potential risk for the transmission of pathogens to humans, such as some arthropod-borne viruses and nematodes that cause filariasis. In Brazil, three municipalities in the Metropolitan Region of Recife (RMR) that are endemic for lymphatic filariasis conducted control actions targeting this vector. With the goal of contributing novel C. quinquefasciatus collection strategies, a sticky trap capable of collecting eggs and imprisoning mosquitoes was investigated. Methods: To evaluate the performance of the sticky BR-OVT trap, tests were carried out in the neighborhoods of Caixa d’Água and Passarinho (Olinda-PE-Brasil) between August 2011 and June 2012. Sixty traps were installed in the indoor areas of residences in the two districts. Results: During the 11-month study, 0.52 [standard deviation (SD) = 1.52] Culex egg rafts, 2.16 (SD = 4.78) C. quinquefasciatus/trap/month, and 0.55 (SD = 1.28) Aedes/trap/month were caught. Female specimens predominated the traps (59% of C. quinquefasciatus and 96% of Aedes spp.). Conclusions: The results demonstrated that the sticky BR-OVT trap is a useful tool for the collection of adult culicids of medical importance and offers an innovative way to collect C. quinquefasciatus eggs and adults in a single trap

Field evaluation of sticky BR-OVT traps to collect culicids eggs and adult mosquitoes inside houses

Abstract INTRODUCTION: Culex quinquefasciatus is a mosquito of importance to public health, as it represents a real and/or potential risk for the transmission of pathogens to humans, such as some arthropod-borne viruses and nematodes that cause filariasis. In Brazil, three municipalities in the Metropolitan Region of Recife (RMR) that are endemic for lymphatic filariasis conducted control actions targeting this vector. With the goal of contributing novel C. quinquefasciatus collection strategies, a sticky trap capable of collecting eggs and imprisoning mosquitoes was investigated. METHODS: To evaluate the performance of the sticky BR-OVT trap, tests were carried out in the neighborhoods of Caixa d’Água and Passarinho (Olinda-PE-Brasil) between August 2011 and June 2012. Sixty traps were installed in the indoor areas of residences in the two districts. RESULTS: During the 11-month study, 0.52 [standard deviation (SD) = 1.52] Culex egg rafts, 2.16 (SD = 4.78) C. quinquefasciatus/trap/month, and 0.55 (SD = 1.28) Aedes/trap/month were caught. Female specimens predominated the traps (59% of C. quinquefasciatus and 96% of Aedes spp.). CONCLUSIONS The results demonstrated that the sticky BR-OVT trap is a useful tool for the collection of adult culicids of medical importance and offers an innovative way to collect C. quinquefasciatus eggs and adults in a single trap

Fitness cost in field and laboratory Aedes aegypti populations associated with resistance to the insecticide temephos

Abstract Background The continued use of chemical insecticides in the context of the National Program of Dengue Control in Brazil has generated a high selective pressure on the natural populations of Aedes aegypti, leading to their resistance to these compounds in the field. Fitness costs have been described as adaptive consequences of resistance. This study evaluated the biological and reproductive performance of A. aegypti strains and a field population resistant to temephos, the main larvicide used for controlling mosquitoes. Methods Comparative tests were performed with a resistant field population from the municipality of Arcoverde, Pernambuco State, Brazil, with a high rate of temephos resistance (RR = 226.6) and three isogenetic laboratory strains from the same origin (Araripina municipality, Pernambuco): RecR (RR = 283.6); RecRNEx (RR = 250.5), a strain under a process of resistance reversion; and RecRev (RR = 2.32), a reversed susceptible strain used as an experimental control. Results Our study revealed that the absence of selective pressure imposed by exposure to temephos, for five consecutive generations, led to a discrete reduction of the resistance ratio and the response of the detoxifying enzymes. Most of the 19 biological parameters were impaired in the resistant strains and field population. The analysis of the fertility life table confirmed the presence of reproductive disadvantages for the resistant individuals. Similarly, the longevity, body size, and total energetic resources were also lower for the resistant females, except for the last two parameters in the field females (Arcoverde). In contrast, the sex ratio and embryonic viability suffered no interference in all strains or population evaluated, regardless of their status of resistance to temephos. Conclusions The reproductive potential and survival of the resistant individuals were compromised. The parameters most affected were the larval development time, fecundity, net reproduction rate, and the generational doubling time. These fitness costs in the natural population and laboratory strains investigated are likely associated with maintaining the metabolic mechanism of resistance to temephos. Our results show that despite these costs, the highly temephos resistant populations can compensate for these losses and successfully overcome the control actions that are based on the use of chemical insecticides

Novel mutations associated with resistance to Bacillus sphaericus in a polymorphic region of the Culex quinquefasciatus cqm1 gene

Submitted by Kamylla Nascimento ([email protected]) on 2018-04-10T11:52:47Z No. of bitstreams: 1 Novel Mutations Associated with Resistance to Bacillus sphaericus in a.pdf: 338176 bytes, checksum: 9e301f894bd190598a46f77cc5bdebc7 (MD5)Approved for entry into archive by Kamylla Nascimento ([email protected]) on 2018-04-10T12:06:15Z (GMT) No. of bitstreams: 1 Novel Mutations Associated with Resistance to Bacillus sphaericus in a.pdf: 338176 bytes, checksum: 9e301f894bd190598a46f77cc5bdebc7 (MD5)Made available in DSpace on 2018-04-10T12:06:16Z (GMT). No. of bitstreams: 1 Novel Mutations Associated with Resistance to Bacillus sphaericus in a.pdf: 338176 bytes, checksum: 9e301f894bd190598a46f77cc5bdebc7 (MD5) Previous issue date: 2012Este trabalho foi apoiado pelo Programa Estratégico de Apoio à Pesquisa em Saúde (PAPES) da Fundação Oswaldo Cruz - FIOCRUZ, Conselho Nacional de Pesquisa (CNPq Brasil, bolsa 403488 / 2008-7 ;), Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco (FACEPE Brasil, outorga APQ 0427-2.13 / 08 ).Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, 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.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, 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.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Microbiologia. Recife, PE, Brasil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil.Bin toxin from Bacillus sphaericus acts on Culex quinquefasciatus larvae by binding to Cqm1 midgut-bound receptors, and disruption of the cqm1 gene is the major cause of resistance. The goal of this work was to screen for a laboratory-selected resistance cqm1(REC) allele in field populations in the city of Recife, Brazil, and to describe other resistance-associated polymorphisms in the cqm1 gene. The cqm1(REC) allele was detected in the four nontreated populations surveyed at frequencies from 0.001 to 0.017, and sequence analysis from these samples revealed a novel resistant allele (cqm1(REC-D16)) displaying a 16-nucletotide (nt) deletion which is distinct from the 19-nt deletion associated with cqm1(REC). Yet a third resistant allele (cqm1(REC-D25)), displaying a 25-nt deletion, was identified in samples from a treated area exposed to B. sphaericus. A comparison of the three deletion events revealed that all are located within the same 208-nt region amplified during the screening procedure. They also introduce equivalent frameshifts in the sequence and generate the same premature stop codon, leading to putative transcripts encoding truncated proteins which are unable to locate to the midgut epithelium. The populations analyzed in this study contained a variety of alleles with mutations disrupting the function of the corresponding Bin toxin receptor. Their locations reveal a hot spot that can be exploited to assess the resistance risk through DNA screening

Agarose gel electrophoresis showing: Molecular xenomonitoring by <i>WbCx</i> PCR with field samples from Fabril—São Luís.

M: 1Kb plus Ladder; 1–12: negative samples; 13: positive control from known field sample; 14: Wb–positive control; N- Negative control. (PDF)</p