Members of the genera Haemagogus and Sabethes are the most important biological vectors of the wild yellow fever virus (WYF) in the forested areas of the Americas. The ecologies of Haemagogus janthinomys, Hg. leucocelaenus, Sabethes chloropterus, and Sa. glaucodaemon were studied in a forest of the Chapada dos Guimarães National Park, state of Mato Grosso, Brazil, to evaluate the influence of climatic factors (temperature and relative humidity [RH]) on their abundance. We also examined the association of climate with landscape structure on species distribution patterns throughout the seasons of the year. Multiple stepwise regressions showed that RH was most likely to influence the density of mosquito populations. A multidimensional scaling (MDS) was used to evaluate the effects of forest cover on the composition of mosquito populations at different radii (100-, 250-, and 1,000-m-radius buffer areas). The MDS provided 2 dimensions with values that indicated a higher similarity in the composition of culicid populations between sites 1 and 3, while site 2 was separate from the others in the ordination space. Site 2 had a much higher forest cover ratio at 100-m radius compared with sites 1 and 3. We found a possible relationship between the forest cover and the composition of the mosquito populations only in the 100-m radius. These results enabled us to infer that RH directly favored the activity of mosquito populations and that the forest cover located closest to the sampling site may influence the species composition. Since mosquito abundance was higher in the sites with lower local forest cover, forest fragmentation may be a key factor on the presence of WYF vector.

Zika virus (ZIKV) was recently introduced into the Western Hemisphere, where it is suspected to be transmitted mainly by Aedes aegypti in urban environments. ZIKV represents a public health problem as it has been implicated in congenital microcephaly in South America since 2015. Reports of ZIKV transmission in forested areas of Africa raises the possibility of its dispersal to non-human-modified environments in South America, where it is now endemic. The current study aimed to detect arboviruses in mosquitoes collected from areas with low human interference in Rio de Janeiro, Brazil. Using a sensitive pan-flavivirus RT-PCR, designed to detect the NS5 region, pools of Ae. albopictus and Haemagogus leucocelaenus, were positive for both ZIKV and yellow fever (YFV). Virus RNA was detected in pools of adult males and females reared from field-collected eggs. Findings presented here suggest natural vertical transmission and infection of ZIKV in Hg. leucocelaenus and Ae.albopitcus in Brazil.

The Atlantic Rainforest of South America is one of the major biodiversity hotspots of the world and serves as a place of residence for a wide variety of Culicidae species. Mosquito studies in the natural environment are of considerable importance because of their role in transmitting pathogens to both humans and other vertebrates. Community diversity can have significant effects on the risk of their disease transmission. The objective of this study was to understand the distribution of mosquito communities using oviposition traps in a region of the Atlantic Forest. Sampling was carried out in Bom Retiro Private Natural Reserve (RPPNBR), located in Casimiro de Abreu, Rio de Janeiro, using oviposition traps, which were set in the forest environment, from October 2015 to December 2016. The canonical correspondence analysis was used to assess the influence of the climatic variables (precipitation, maximum dew point, and direction) throughout the seasons on the population density of the mosquito species. The results showed that population density was directly influenced by climatic variables, which acted as a limiting factor for the mosquito species studied. The climatic variables that were significantly correlated with the density of the mosquito species were precipitation, maximum dew point, and direction. Haemagogus janthinomys was positively correlated with the three climatic variables, whereas Haemagogus leucocelaenus was positively correlated with precipitation and maximum dew point, and negatively correlated with direction.

Although there are many studies on the control of mosquito vectors of the yellow fever virus (YFV) in tropical forests, there are still few ecological studies regarding abiotic factors effect on these mosquitoes. Here we characterize these effects on oviposition behavior, abundance, and diversity of mosquito vectors of YFV. The study was conducted in Córrego da Luz Municipal Park, in Casimiro de Abreu, Rio de Janeiro state, Brazil, from July 2018 to December 2019. Ovitraps were placed at ground level and 3 m high. The data were tested for normality using the Shapiro–Wilk test, followed by an independent sample analysis, the Mann–Whitney test. The Shannon Diversity Index was used to evaluate the abundance of mosquitos' eggs collected at both ground level and 3 m high. We highlight the presence of Haemagogus janthinomys and Hg. leucocelaenus, primary YFV vectors in forest areas. The abundance of Hg. leucocelaenus (63%), Hg. janthinomys (75%), and Aedes terrens (58%) was higher at the height of 3 m, while Ae. albopictus (52%) was higher at ground level. Aedes albopictus was positively correlated with temperature. Culicidae monitoring is essential for assessing the YFV transmission cycle in Atlantic forest fragments.

Living bamboo stalks are one of the most specialized habitats for mosquito oviposition and immature development. Most of the mosquito species that breed in these habitats are sylvatic, and some are of importance for public health as possible vectors of pathogens. Perforated internodes are a very specialized environment due to the difficulty of access. Furthermore, due to their relatively simple fauna, they represent a valuable model for ecological studies that may be applicable to more complex environments. This study aims to assess the mosquito bionomics of species raised in bamboo internodes. Therefore, the diversity of mosquito species and the influence of abiotic variables (pH and temperature) on the distribution of mosquitoes that breed in this habitat were analyzed. The study area is a fragment of Atlantic Forest within the Association of da Armada (ATA) in Nova Iguaçu, state of Rio de Janeiro, Brazil. Immature mosquitoes were sampled with suction tubes (mouth aspirators) between August 2017 and July 2018. A total of 3,170 larvae were collected in 5 bamboo plants, each with 8 stalks perforated. Of these, 688 larvae reached the adult stage, representing 10 genera and 19 species. The most common species were Culex neglectus (43%), Trichoprosopon digitatum (22%), Culex iridescens (8%), Sabethes identicus (7%), and Orthopodomyia albicosta (7%). The richness of the immatures collected in the ATA was 19 species, with a diversity of 1.10 and Shannon evenness of 0.57. A diverse composition of Culicidae in bamboo stalks was found, although dominance was low.

The mosquito-borne yellow fever virus (YFV) is the cause of a zoonotic disease, with both sylvatic and urban cycles. Some mosquito species have been associated directly with transmission of the virus in South America, although the importance given to each species varies depending on the bibliography, geographical location, or year of publication. For Argentina, few publications have assessed the involvement of mosquito species, especially those included in the sylvatic cycle. Therefore, the goal of our paper was to gather all the information available in South America and categorize all mosquito species potentially involved in the YFV transmission cycle in Argentina according to incriminating vector criteria. Based on three main characteristics (‘Hosts’, ‘Mosquito vector’, and ‘YF outbreak’), we generated scales of importance by species, one exclusively for Argentina and another for all of South America, Sabethes albiprivus Theobald, 1903 was the most important species in Argentina; whereas the most important species in South America were Haemagogus janthinomys Dyar 1921, Hg. leucocelaenus Dyar and Shannon, 1924, and Sa. chloropterus Von Humboldt, 1819. Our review highlights the lack of research that evaluates the importance of these species for YFV transmission in Argentina, while serving as a starting point to establish priorities for research on the bionomics and vector status of these species.

The present study aims to analyze the effectiveness of ovitraps in the capture of Hg leucocelaenus eggs and evaluate the influence of the dry and rainy seasons on their abundance and hatching rates. The eggs were collected in the Atlantic Forest of State of Rio de Janeiro, Brazil, an area in which the yellow fever virus is known to circulate. We distributed 15 ovitraps in three sampling points, with five ovitraps per point. We distributed 15 ovitraps in three sampling points on trees within a forested area, which were sequentially numbered, monitored, and replaced every two weeks from October 2016 to April 2018. There was a high dominance of Hg. leucocelaenus eggs (98.4%) and a variation in egg hatching rates between the wet and dry seasons. These rates were 1.5 times higher in the rainy season than in the dry season. The rainy season also showed a greater abundance of eggs and higher values of ovitrap positivity and egg density indexes in the installed ovitraps. The abundances of Hg. leucocelaenus eggs were positively correlated with mean monthly temperature and air humidity but not significantly correlated with accumulated precipitation. These results, as well as their implications for the possible use of ovitraps to monitor vector mosquitoes of yellow fever in the study region, are discussed.

In order to assess the influence of climatic variations in temperature, relative humidity, and rainfall upon the population density of Psorophora albigenu (Peryassú, 1908) in its natural habitat, samplings were carried out at different times of the year in Mato Grosso, Brazil. Mosquitoes were captured with the use of suction tubes and Shannon traps during 2 different periods of the day and 1 at night.