ABSTRACT
Bats are the second most diverse order of mammals and play a central role in ecosystem dynamics. They are also important reservoirs of potentially zoonotic microorganisms, of which rabies virus is the most lethal among the bat-transmitted zoonotic pathogens. Importantly, recent outbreaks of human rabies have been reported from the Brazilian Amazon. Here we present a survey of bat species and rabies virus (RABV) circulation in a bat assemblage in the Marajó region, northern Brazil. Using data from mist-net captures and bioacoustic sampling, 56 bat species were recorded along the Jacundá River basin over a 10-day expedition in November 2022. For the investigation of RABV, we used the direct fluorescent antibody test (DFAT) and the rapid fluorescent focus inhibition test (RFFIT). In total, 159 bat individuals from 22 species were investigated for RABV. Five adults of the common vampire bat, Desmodus rotundus, showed RABV-specific antibodies in serum samples. Additionally, we report on local residents with injuries caused by D. rotundus bites and the occurrence of colonies of non-hematophagous bats from different species roosting inside human residences. This scenario raises concerns about the risks of new cases of human rabies and other zoonotic diseases associated with bats in the region and highlights the need for epidemiological surveillance and mitigation measures to prevent outbreaks of emerging infectious diseases.
ABSTRACT
Its wide karyotypic variation characterizes the genus Ctenomys, and in Brazil, the genus is distributed in the country's southern, Midwest, and Northern regions. Recently, populations of Ctenomys have been found in the Midwest and northern Brazil, with two new lineages named C. sp. "xingu" and C. sp. "central". This work combines classical cytogenetic and molecular analyses to provide new chromosomal information on the boliviensis group distributed in Northern and Midwestern Brazil. This includes the validation of the karyotype of C. bicolor and C. nattereri, and the description of the karyotype of C. sp. "xingu" and C. sp. "central". We found three different karyotypes: 2n=40 for C. bicolor; 2n= 36 for C. nattereri, and specimens from a locality belonging to C. sp. "central"; 2n=34 for the lineage C. sp. "xingu" and specimens from a locality belonging to C. sp. "central". Furthermore, GTG-banding revealed homologous chromosomes between species/lineages and allowed the identification of the rearrangements that occurred, which proved the occurrence of fissions. Considering our results on the variation of 2n in the boliviensis group, we found two possibilities: the first, deduced by parsimony, is that 2n=36 appeared initially, and two fissions produced gave rise to 2n=40, and an independent fusion gave rise to 2n=34 from 2n=36; moreover, the second explanation is that all karyotypes arose independently.
