Background Continuous vector surveillance and sustainable interventions are mandatory in order to prevent anopheline proliferation (or spread to new areas) and interrupt malaria transmission. Anopheline abundance and richness were evaluated in urban and peri-urban malaria foci at a medium-sized city in the Brazilian Amazon, comparing the protected human landing catch technique (PHLC) and alternative sampling methods over different seasonal periods. Additional information was assessed for female feeding behaviour and faunal composition. Methods Anophelines were sampled bimonthly in four urban and peri-urban sites in the city of Porto Velho, state of Rondônia, Brazil. The average number of captured mosquitoes was compared between an PHLC (gold standard), a tent trap (Gazetrap), and a barrier screen by means of generalized linear mixed models (GLMM), which also included season and environment (peri-urban/urban) as predictors. Results Overall, 2962 Anopheles individuals belonging to 12 species and one complex were caught; Anopheles darlingi represented 86% of the individuals. More mosquitoes were captured in the peri-urban setting, and the urban setting was more diverse. The model estimates that significantly more anophelines were collected by PHLC than by the Screen method, and Gazetrap captured fewer individuals. However, the Screen technique yielded more blood-engorged females. The peak hours of biting activity were from 6 to 7 p.m. in urban areas and from 7 to 8 p.m. in peri-urban areas. Conclusions Although peri-urban settings presented a greater abundance of anophelines, Shannon and Simpson diversities were higher in urban sites. Each technique proved to be useful, depending on the purpose: PHLC was more effective in capturing the highest anopheline densities, Gazetrap caught the greatest number of species, and the barrier screen technique captured more engorged individuals. There was no seasonal effect on Anopheles assemblage structure; however, a more diverse fauna was caught in the transitional season. Biting activity was more intense from 6 to 8 p.m., with a predominance of An. darlingi.

The presence and establishment of Culicidae in urban areas increase the transmissibility of tropical diseases, since some species can participate as vectors of pathogens. Thus, this study aimed to evaluate the indoor and outdoor abundance of immature and adult populations of Culicidae at the urban area of Porto Velho, Rondônia. Mosquitoes were captured using electric aspirators and ovitraps in September and December 2018 in 27 households spread over nine neighborhoods. A total of 2,342 specimens were collected, distributed among five species, of which Culex quinquefasciatus (Say, 1823), Aedes aegypti (Linnaeus, 1762) and Aedes albopictus (Skuse, 1894) were the most abundant. Considering the sum total obtained by both techniques, more mosquitoes were captured indoors than outdoors. However, the GLM estimates for the ovitrap technique showed that immature Ae. aegypti, Ae. albopictus and Cx. quinquefasciatus were significantly more abundant in the outdoors, on average. The opposite result was observed for electrical aspiration, in which Ae. aegypti and Cx. quinquefasciatus adults were more abundant indoors. The average number of winged Ae. albopictus showed no significant difference between indoors and outdoors. Our findings corroborate the data on the abundance and incidence of these three species in other regions of Brazil, highlighting the need for continuous surveillance due to their importance in disease transmission to humans. We also demonstrated that the ovitrap is a sensitive device to monitor Cx. quinquefasciatus larvae and wild species that occasionally frequent urban areas, and thus can be used for surveillance, especially when there are budgetary constraints. Therefore, we emphasize that the combination of techniques, in addition to identifying which species and which stage of development are more frequent inside and outside households, also allows for the implementation of specific and integrated control measures.

Culex spp. mosquitoes have idiosyncratic characteristics and its low variability makes difficult their identification. The aim of our study was to analyze the 5' region of the cytochrome oxidase subunit I gene (coI) for the taxonomic identification of Culex species which were previously morphotyped and diagnosed in Culex and Melanoconion subgenera at the field conditions. Ten specimen sequences were analyzed by the Automatic Barcode Gap Discovery (ABGD). All sequences showed 94-99% identity when compared to other Culex species sequences available from GenBank. Five initial partitions supported 80-88 species groups. Among them, eight sets contained the specimens of the present study. Of the 10 mosquito sequences, five did not form any consistent cluster, and the remaining showed some consistency in the taxonomic diagnosis at the field conditions. Our results suggest that some coI gene sequences of specimens may belong to species of the subgenus Melanoconion, whose 5' coI sequence is unknown or unpublished in GenBank. Palavras-chave: ABGD, coI gene, HP trap, Neighbor-Joining method, Taxonomic Diagnosis. ResumoOs mosquitos Culex spp. apresentam características idiossincráticas e sua baixa variabilidade dificulta sua identificação. O objetivo do nosso estudo foi analisar a região 5 'do gene da subunidade I do citocromo oxidase (coI) para a identificação taxonômica de espécies de Culex que foram previamente diagnosticadas em subgêneros Culex e Melanoconion em condições de campo. Dez sequências de espécimes foram analisadas pelo Automatic Barcode Gap Discovery (ABGD). Todas as sequências apresentaram 94-99% de identidade quando comparadas com outras sequências de espécies de Culex disponíveis no GenBank. Cinco partições iniciais suportaram 80-88 grupos de espécies. Entre eles, oito conjuntos continham os espécimes do presente estudo. Das 10 sequências de mosquitos, cinco não formaram nenhum cluster consistente, e as demais apresentaram alguma consistência no diagnóstico taxonômico nas condições de campo. Nossos resultados sugerem que algumas sequências do gene coI de espécimes podem pertencer a espécies do subgênero Melanoconion, cuja sequência 5' coI é desconhecida ou inédita no GenBank.

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Mosquitoes are vectors of many pathogens, including viruses, protozoans, and helminths, spreading these pathogens to humans as well as to wild and domestic animals. As the identification of species and the biological characterization of mosquito vectors are cornerstones for understanding patterns of disease transmission, and the design of control strategies, we conducted a literature review on the current use of noninvasive and nondestructive techniques for pathogen detection in mosquitoes, highlighting the importance of their taxonomic status and systematics, and some gaps in the knowledge of their vectorial capacity. Here, we summarized the alternative techniques for pathogen detection in mosquitoes based on both laboratory and field studies. Parasite infection and dissemination by mosquitoes can also be obtained via analyses of saliva- and excreta-based techniques or of the whole mosquito body, using a near-infrared spectrometry (NIRS) approach. Further research should be encouraged to seek strategies for detecting target pathogens while preserving mosquito morphology, especially in biodiversity hotspot regions, thus enabling the discovery of cryptic or new species, and the determination of more accurate taxonomic, parasitological, and epidemiological patterns.