Detection of Salmonella spp. in wild and domestic birds in an anthropized ecotone between the Cerrado and the Amazon Forest in Brazil.

Emergence of zoonotic infectious diseases represent one of the main threats to people worldwide. To properly understand and prevent zoonoses is fundamental to study their epidemiology and the possibility of spillover events, especially for commercially intensive domestic animals and humans. Here, we studied 210 wild birds from the "Ipucas" region, which consists of fragments of the Amazon Forest interspersed with fragments of the "Cerrado" that is subject to seasonal flooding and 75 domestic birds from neighboring poultry farming. Then, we molecularly diagnosed Salmonella and Chlamydia from wild birds and poultry. Among the wild birds, four were diagnosed with Chlamydia psittaci and 23 with Salmonella spp., while we detected 15 poultry infected by Salmonella spp. and no poultry with C. psittaci. We highlighted the common infections of wild and domestic birds in an anthropologically modified environment and potential spillover of Salmonella pathogens among wild and livestock birds. Those infections can harm the health of native and domestic species.

Migration and season explain tick prevalence in Brazilian birds.

Neotropical birds are mostly parasitized by immature ticks and act as reservoir hosts of tick-borne pathogens of medical and veterinary interest. Hence, determining the factors that enable ticks to encounter these highly mobile hosts and increase the potential for tick dispersal throughout migratory flyways are important for understanding tick-borne disease transmission. We used 9682 individual birds from 572 species surveyed across Brazil and Bayesian models to disentangle possible avian host traits and climatic drivers of infestation probabilities, accounting for avian host phylogenetic relationships and spatiotemporal factors that may influence tick prevalence. Our models revealed that the probability of an individual bird being infested with tick larvae and nymphs was lower in partial migrant hosts and during the wet season. Notably, infestation probability increased in areas with a higher proportion of partial migrant birds. Other avian ecological traits known to influence tick prevalence (foraging habitat and body mass) and environmental condition that might constrain tick abundance (annual precipitation and minimum temperature) did not explain infestation probability. Our findings suggest that migratory flyways harbouring a greater abundance of migrant bird hosts also harbour a higher prevalence of immature ticks with potential to enhance the local transmission of tick-borne pathogens and spread across regions.