Virological Surveillance of Aedes aegypti Vectors Identifies All Four Dengue Serotypes in a Hyperendemic Region

Dengue virus (DENV) 1-4 is the etiological agent of dengue, the most important viral infection transmitted by Aedes spp mosquitoes to humans. Our goal was to identify the circulating DENV in Aedes aegypti collected in an area of Brazil where all four DENV serotypes had already been detected in humans, understand the epidemiology better, and to test the vector as a virological surveillance tool. Twenty-eight larvae pools and 174 females of Aedes aegypti were screened by reverse transcriptase quantitative polymerase chain reaction and semi-nested PCR assays. PCR products were sequenced, and phylogenetic analyses were performed. Nine larvae pools (32.1%) were positive for DENV, four (44.4%) with DENV-3, and five (55.6%) with more than one serotype. Fifteen females (8.6%) were positive for any DENV serotype. DENV-1 isolates belong to genotype V, DENV-2 to American-Asian genotype, DENV-3 to genotypes I and III, and DENV-4 to genotypes I and II. We demonstrate for the first time the co-circulation of all four DENV serotypes in larvae pools and adult Aedes aegypti in a hyperendemic area. This scenario represents a challenge for disease control and reinforces the importance of virological surveillance in the vector as a tool for predicting circulating DENV serotypes in humans.

Characterization of animal sporotrichosis in a highly urbanized area

An epidemiological characterization of animal sporotrichosis was carried out between 2017 and 2018, in a highly urbanized area in Brazil, including outcomes and the spatial distribution of the cases according to the health vulnerability index (HVI) of the study territory. One hundred and sixty-five cats and four dogs suspected of sporotrichosis were identified by a surveillance and control program previously implemented in the study area. One hundred and five of these animals (62.1 %) were considered positive for Sporothrix spp., of which 103 were cats and two were dogs. Cases predominated among male cats (53.4 %), although gender did not present a statistically significant association (p > 0.05) with sporotrichosis cases. Considering the positive cats, 55.4 % were not neutered and free access to the street was reported as a habit for 86.4 % of them. Roaming free in the streets increased the chance of infection by 2.54 times. We observed a high frequency of euthanasia or death (48.8 %) among 86 infected cats available to be included in the follow-up stage of the study, even when they were treated (46.5 %) and a low cure rate (31 %). The disease spread, unrelated to the HVI in the territory. Data produced suggested that avoiding access to the street seems to have greater importance to sporotrichosis control in cats than neutering and reinforces the importance of health education, especially in relation to responsible feline ownership. The free offer of diagnosis and treatment also should be taken into consideration as important measures to control the disease.