5 research outputs found
Diversity of mosquitoes (Diptera: Culicidae) collected in different types of larvitraps in an Amazon rural settlement.
Anthropogenic environments provide favorable conditions for some species, which is especially true of mosquitoes that present eclecticism at the moment of choice for the site of oviposition. In the present study, the diversity of mosquitoes was assessed by providing plastic containers, bamboo internodes, and tires in a forest, the forest edge, and peridomicile environments in a rural settlement area. Eighteen sampling points were chosen, delimited by a buffer of 200 m, placed in three environments: forest, forest edge, and peridomicile. In each environment, larvitraps were installed, separated by a minimum distance of 7 m and 1 m from the ground. A total of 10,131 immature mosquitoes of 20 species were collected. The most abundant species was Culex urichii (29.5%), followed by Trichoprosopon digitatum (27.1%), and Cx. (Melanoconion) spp. (10.4%). There was a difference in the composition of immature mosquito populations between larvitraps (p < 0.0005), and the plastic container hosted a greater diversity of species, whereas tires presented a greater abundance of individuals. The forest, forest edge, and peridomicile environments were also different with regard to diversity of immature mosquito populations (p < 0.0010). The forest edge was the environment with the greatest diversity of species, followed by the peridomicile and forest environments. In the forest and peridomicile, plastic container larvitraps had the greatest diversity, whereas the forest edge tire presented the largest number of individuals. Further, tire larvitraps collected the largest number of individuals in all environments. Ten species associated with the bamboo internode and tire were identified. The preference of species for artificial larvitraps, such as the plastic container and tire, even in wild environments was noted. These artificial objects may represent a risk factor for the population living in this region, as all vector species found in the study were present in plastic containers and tires
Description of three new species of frog–biting midges (Diptera: Corethrellidae) from the Central Brazilian Amazon
Three species of Corethrella Coquillett, 1902 from the state of Amazonas, Brazil are described as new to science based on female adult specimens. Corethrella cabocla Feijó, Belchior, Marialva & Pessoa sp. nov. possesses four large setae on the frons between the ventromedial area of ommatidia, a wide clypeus with 1–4 setae, a wing with the apex of R2 basal to the apex of M2 and with a midlength band, and with the abdomen entirely dark brown. Corethrella ielemdei Feijó, Ramires, Lima & Pessoa sp. nov. possesses an elongated coronal suture, four large setae on the frons between the ventromedial area of ommatidia, a clypeus squarish with 42–43 setae, a wing with the apex of R2 basal to the apex of M1 and with a midlength band and dark scales on the basal and subbasal areas of the anterior margin, legs with dark scales, and with the abdomen entirely dark brown. Corethrella menini Feijó, Picelli, Ríos-Velásquez & Pessoa sp. nov. possesses wings with the apex of R2 basal to the apex of M2 and a midlength band, with darker basal scales along all veins, basal band dark scales on C, Sc, R, M, and Cu and the abdomen entirely dark brown. With the addition of the new species, the numbers of frog-biting midges described in the Amazon basin, Brazil and in Neotropical region are now 31, 49 and 80 species, respectively
Distribution and diversity of mosquitoes and Oropouche-like virus infection rates in an Amazonian rural settlement.
Mosquito diversity and disease transmission are influenced by landscape modifications, i.e., vectors and pathogens previously found only in forests are now found close to human environments due to anthropic changes. This study determined the diversity and distribution of mosquitoes in forest environments in order to analyze the potential vectors of Amazonian forest arboviruses. Mosquitoes were collected by 1) vertical stratification from forest canopy and ground areas using Hooper Pugedo (HP) light traps and human attraction and 2) horizontal stratification using HP light traps in peridomicile, forest edge, and forest environments near the Rio Pardo rural settlement, Amazonas, Brazil. A total of 3,750 mosquitoes were collected, representing 46 species. 3,139 individuals representing 46 species were sampled by vertical stratification. Both the Shannon-Weaver diversity index (H') and equitability (J') were higher in the canopy than on the ground. 611 individuals representing 13 species were sampled by horizontal stratification. H' decreased in the following order: forest edge > forest > peridomicile, and J' was greater at the forest edge and smaller in the peridomicile environment. Moreover, H' was higher for the human attraction collection method than the HP traps. A total of 671 pools were analyzed by RT-qPCR; three species were positive for Oropouche-like viruses (Ochlerotatus serratus, Psorophora cingulata, and Haemagogus tropicalis) and the minimum infection rate was 0.8%. The composition of mosquito species did not differ significantly between anthropic and forest environments in Rio Pardo. Some mosquito species, due to their abundance, dispersion in the three environments, and record of natural infection, were hypothesized to participate in the arbovirus transmission cycle in this Amazonian rural settlement
First evidence of Zika virus venereal transmission in Aedes aegypti mosquitoes
<div><p> BACKGROUND Aedes aegypti is considered the main Zika virus (ZIKV) vector, and is thought to be responsible for the 2015-2016 outbreak in Brazil. Zika positive Ae. aegypti males collected in the field suggest that vertical and/or venereal transmission of ZIKV may occur. OBJECTIVES In this study, we aimed to demonstrate that venereal transmission of ZIKV by Ae. aegypti can occur under laboratory conditions. METHODS Ae. aegypti collected in the city of Manaus, confirmed as negative for Zika, Dengue and Chikungunya virus by reverse transcription real-time polymerase chain reaction (RT-qPCR) (AaM3V- strain), were reared under laboratory conditions and used for the experiments. The ZIKV used in this study was isolated from a patient presenting with symptoms; ZIKV was confirmed by RT-qPCR. Experiment 1: virgin male mosquitoes of AaM3V- strain were intrathoracically inoculated with a ZIKV suspension; four days after injection, they were transferred to a cage containing virgin females of AaM3V- strain and left to copulate for five days. Experiment 2: virgin female mosquitoes of AaM3V- strain were orally infected with a ZIKV suspension by blood feeding membrane assay; nine days after blood feeding, they were placed in cages with Ae. aegypti AaM3V- virgin males and left to copulate for four days. After copulation, all mosquitoes were individually evaluated for viral infection by RT-qPCR. FINDINGS The mean infection rate in Experiment 1 and Experiment 2 was 45% and 35%, respectively. In both experiments, cycle threshold values ranged from 13 to 35, indicating the presence of viral genomes. MAIN CONCLUSION Ae. aegypti males intrathoracically inoculated with a ZIKV suspension are infected and can transmit the virus to uninfected females by mating. Moreover, Ae. aegypti females orally infected with a ZIKV suspension can transmit the virus to uninfected males by copulation. This study shows that ZIKV infection of Ae. aegypti mosquitoes occurs not only during blood feeding, but also during copulation.</p></div