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The Chikungunya virus (CHIKV) presents global health challenges, with Brazil experiencing outbreaks since its introduction in 2014. In 2023, following a CHIKV outbreak in Minas Gerais (MG), social media was used to optimize an entomological survey aimed at identifying vectors and viral lineages and assessing insecticide resistance. Following Instagram posts, residents with suspected CHIKV infection were able to schedule mosquito aspirations. In total, 421 mosquitoes (165 Aedes aegypti and 256 Culex quinquefasciatus) were captured from 40 households in Salinas city (MG) and tested for the Dengue, Zika, and Chikungunya viruses through RT-qPCR. Twelve of 57 pools (10 Ae. aegypti and two Cx. quinquefasciatus) tested positive for CHIKV RNA. Viral RNA was also detected in the heads of nine Ae. aegypti, indicating viral dissemination but not in Cx. quinquefasciatus. Genome sequencing yielded the first near-complete genome from the 2023 outbreak, unveiling that the CHIKV strain belonged to the East/Central/South African (ECSA) genotype. Additionally, genetic analyses revealed high frequencies of kdr alleles, including in CHIKV-infected mosquitoes, suggesting resistance to pyrethroid insecticides in this Ae. aegypti population. Social media was important for guiding mosquito-capture efforts in CHIKV transmission hotspots, thus optimizing the opportunity for viral detection. These findings emphasize the urgent need for innovative vector studies and control strategies, as well as interdisciplinary approaches in public health interventions.
RESUMO
Arboviruses cause millions of infections each year; however, only limited options are available for treatment and pharmacological prevention. Mosquitoes are among the most important vectors for the transmission of several pathogens to humans. Despite advances, the sampling, viral detection, and control methods for these insects remain ineffective. Challenges arise with the increase in mosquito populations due to climate change, insecticide resistance, and human interference affecting natural habitats, which contribute to the increasing difficulty in controlling the spread of arboviruses. Therefore, prioritizing arbovirus surveillance is essential for effective epidemic preparedness. In this review, we offer a concise historical account of the discovery and monitoring of arboviruses in mosquitoes, from mosquito capture to viral detection. We then analyzed the advantages and limitations of these traditional methods. Furthermore, we investigated the potential of emerging technologies to address these limitations, including the implementation of next-generation sequencing, paper-based devices, spectroscopic detectors, and synthetic biosensors. We also provide perspectives on recurring issues and areas of interest such as insect-specific viruses.
Assuntos
Infecções por Arbovirus , Arbovírus , Culicidae , Animais , Humanos , Mosquitos VetoresRESUMO
BACKGROUND In Brazil, the yellow fever virus (YFV) is maintained in a sylvatic cycle involving wild mosquitoes and non-human primates (NHPs). The virus is endemic to the Amazon region; however, waves of epidemic expansion reaching other Brazilian states sporadically occur, eventually causing spillovers to humans. OBJECTIVES To report a surveillance effort that led to the first confirmation of YFV in NHPs in the state of Minas Gerais (MG), Southeast region, in 2021. METHODS A surveillance network was created, encompassing the technology of smartphone applications and coordinated actions of several research institutions and health services to monitor and investigate NHP epizootics. FINDINGS When alerts were spread through the network, samples from NHPs were collected and YFV infection confirmed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and genome sequencing at an interval of only 10 days. Near-complete genomes were generated using the Nanopore MinION sequencer. Phylogenetic analysis indicated that viral genomes were related to the South American genotype I, clustering with a genome detected in the Amazon region (state of Pará) in 2017, named YFVPA/MG sub-lineage. Fast YFV confirmation potentialised vaccination campaigns. MAIN CONCLUSIONS A new YFV introduction was detected in MG 6 years after the beginning of the major outbreak reported in the state (2015-2018). The YFV strain was not related to the sub-lineages previously reported in MG. No human cases have been reported, suggesting the importance of coordinated surveillance of NHPs using available technologies and supporting laboratories to ensure a quick response and implementation of contingency measures to avoid YFV spillover to humans.
RESUMO
BACKGROUND In Brazil, the Yellow Fever virus (YFV) is endemic in the Amazon, from where it eventually expands into epidemic waves. Coastal south-eastern (SE) Brazil, which has been a YFV-free region for eight decades, has reported a severe sylvatic outbreak since 2016. The virus spread from the north toward the south of the Rio de Janeiro (RJ) state, causing 307 human cases with 105 deaths during the 2016-2017 and 2017-2018 transmission seasons. It is unclear, however, whether the YFV would persist in the coastal Atlantic Forest of RJ during subsequent transmission seasons. OBJECTIVES To conduct a real-time surveillance and assess the potential persistence of YFV in the coastal Atlantic Forest of RJ during the 2018-2019 transmission season. METHODS We combined epizootic surveillance with fast diagnostic and molecular, phylogenetic, and evolutionary analyses. FINDINGS Using this integrative strategy, we detected the first evidence of YFV re-emergence in the third transmission season (2018-2019) in a dying howler monkey from the central region of the RJ state. The YFV detected in 2019 has the molecular signature associated with the current SE YFV outbreak and exhibited a close phylogenetic relationship with the YFV lineage that circulated in the same Atlantic Forest fragment during the past seasons. This lineage circulated along the coastal side of the Serra do Mar mountain chain, and its evolution seems to be mainly driven by genetic drift. The potential bridge vector Aedes albopictus was found probing on the recently dead howler monkey in the forest edge, very close to urban areas. MAIN CONCLUSIONS Collectively, our data revealed that YFV transmission persisted at the same Atlantic Forest area for at least three consecutive transmission seasons without the need of new introductions. Our real-time surveillance strategy permitted health authorities to take preventive actions within 48 h after the detection of the sick non-human primate. The local virus persistence and the proximity of the epizootic forest to urban areas reinforces the concern with regards to the risk of re-urbanisation and seasonal re-emergence of YFV, stressing the need for continuous effective surveillance and high vaccination coverage in the SE region, particularly in RJ, an important tourist location.
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Febre Amarela/terapia , Sistemas de Transporte de Aminoácidos , Mosquitos Vetores/patogenicidade , Alouatta , FilogeografiaRESUMO
Despite the importance of the mosquito
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Animais , Feminino , Aedes/anatomia & histologia , Cruzamento , Comportamento Animal/fisiologia , Insetos Vetores/fisiologia , Oviposição/fisiologiaRESUMO
The mosquito Aedes aegypti (Diptera: Culicidae) is the main vector of human arborvirus in Brazil.Oviposition behavior is important for the survival and dispersal of A. aegypti. The objective of this studywas to evaluate the oviposition behavior and its relationship to meteorological factors. Twenty ovitrapswere installed in two neighborhoods in the urban area of the city of Salinas, MG, southeastern Brazil.The traps were inspected weekly for the presence of eggs in the water and on the paddle. Simultaneously,regional weather data were analyzed. The results showed the Ovitrap Positivity Index (OPI) variedgreatly, from 0 to 90 percent, between the weeks and boroughs sampled, demonstrating the vectors greatpopulation fluctuation. Among the analyzed climatic factors, rainfall strongly influenced oviposition,followed by relative air humidity. The number of eggs found on the paddle was significantly higher thanin the water (p<0.05). However, a significant increase of eggs in the water was noticed when the relativehumidity dropped below 40 percent. This seems to be an important behavior to maintain the population inperiods of drought. Through the low number of eggs (<30) found in 56 percent of positive traps, we concludedthat skip-oviposition behavior occurred, contributing to the prevalence of mosquitoes during thesampled period. It is concluded that the occurrence of water oviposition may be higher than described inthe literature, and should be studied due to its evolutionary and epidemiological importance...
O mosquito Aedes aegypti é o principal vetor de arborvírus humanos no Brasil. O comportamentode oviposição é importante para a sobrevivência e dispersão do A. aegypti. O objetivo deste trabalho foi avaliar estes comportamentos e sua relação com fatores climáticos. Instalaram-se vintearmadilhas ovitrampa em dois bairros de Salinas-MG. Todas foram inspecionadas semanalmentepara contagem e identificação dos ovos presentes na água e na palheta. Paralelamente, analisaram-sedados meteorológicos da região. Os resultados mostraram que o Índice de Positividade deOvitrampa (IPO) variou muito (0 por cento a 90 por cento) entre as semanas/bairros amostrados, o que demonstraa grande flutuabilidade populacional do vetor. Dentre os fatores climáticos analisados, o que maisintensamente influenciou a oviposição foi a precipitação, seguida da umidade relativa. O númerode ovos encontrados na palheta foi significativamente maior que na água (p<0,05). Entretanto,observou-se aumento significativo de ovos na água quando a umidade relativa esteve abaixo de 40 por cento.Este parece ser um dado importante para a manutenção das populações em períodos de seca. O baixonúmero de ovos (<30) encontrados em 56 por cento das armadilhas positivas demonstrou a ocorrência docomportamento de skip-oviposition que pareceu contribuir para a prevalência do mosquito em todoo período amostrado. Concluiu-se que a ocorrência de oviposição na água pode ser maior do que odescrito na literatura e deve ser investigada em virtude de sua importância evolutiva e epidemiológica...