Avian pox is a highly contagious poultry disease that causes significant economic losses. Mosquitoes belonging to the genus Culex (Diptera: Culicidae) have a fundamental role in disseminating Avipoxvirus (Poxviridae). This study proposes investigating the presence of Avipoxvirus (APV) DNA in Culex spp. from Rio de Janeiro to determine its frequency and perform a phylogenetic analysis based on the core like the 4b protein (p4b) gene. The detection of APVs was conducted individually on four hundred Culex spp. mosquitoes. A total of 12.23% (47/384) of the Culex spp. were positive in the PCR. Sequencing the p4b gene revealed that this study’s sequences displayed 98.8–99% identity with Fowlpoxvirus (FWPW) sequences available in GenBank. In the phylogenetic analysis, these APVs were clustered in the A1 subclade together with FWPW sequences from several countries. The evolutionary distance of the p4b gene was 0.61 ± 0.21% in rural areas and 0.38 ± 0.16% in peri-urban areas. The current investigation is the first study to report the detection of APVs in field-caught mosquitoes. Moreover, a high frequency of APV DNA was observed in Culex spp. captured in domestic areas, where backyard poultry is present. This data demonstrates the importance of implementing control measures for Culex spp. to mitigate the transmission of APVs in backyard poultry in Rio de Janeiro.

No abstract

A cross-sectional study was conducted in Colombia to recover Brucella spp. DNA from bovine whole-blood samples through probe-based real-time PCR (Probe-qPCR) and by an SNP-based assay, differentiating vaccine strains from field strains. The associated factors for the presence of Brucella-DNA were reported and evaluated using logistical regression models. A total of 656 random cows from 40 herds were selected. Template DNA was obtained based on a modified salting-out protocol. The Probe- qPCR assay using bcsp31 gene amplification showed an efficiency of 92.35%, with a slope of -3.52 reached in the standard curve. The qPCR assay detected 9.5% (n = 62/656; 95% CI: 7.3,12.0) of the animals with Brucella-DNA presence, and 62.5% (n = 25/40; 95% CI: 45.8,77.3) of the herds with Brucella-DNA presence. Using the SNP-based assay, all positive samples were identified as field Brucella strains. In the final regression model at the animal-level, five variables were associated with Brucella-DNA presence: the use of bulls for mating, recorded history of reproductive problems, pregnant cows, parlor milking, and cows belonging to farms ≤ 200 m from the main road. At the herd-level, two variables were associated with Brucella-DNA presence: recorded history of reproductive problems and bulls' use for mating. Given the fluctuant brucellosis prevalence in endemic areas, updated epidemiological studies are necessary to evaluate the disease dynamic, and if established prevention and control measures have been effective or need to be adjusted. The increase in the prevalence of brucellosis in animal reservoirs creates an important risk of transmission in humans.

No abstract

No abstract