VIROLOGICAL AND SEROLOGICAL DIAGNOSIS OF RABIES IN BATS FROM AN URBAN AREA IN THE BRAZILIAN AMAZON

The outbreaks of rabies in humans transmitted by Desmodus rotundus in 2004 and 2005, in the northeast of the Brazilian State of Para, eastern Amazon basin, made this a priority area for studies on this zoonosis. Given this, the present study provides data on this phenomenon in an urban context, in order to assess the possible circulation of the classic rabies virus (RABV) among bat species in Capanema, a town in the Amazon basin. Bats were collected, in 2011, with mist nets during the wet and dry seasons. Samples of brain tissue and blood were collected for virological and serological survey, respectively. None of the 153 brain tissue samples analyzed tested positive for RABV infection, but 50.34% (95% CI: 45.67-55.01%) of the serum samples analyzed were seropositive. Artibeus planirostris was the most common species, with a high percentage of seropositive individuals (52.46%, 95% CI: 52.31 52.60%). Statistically, equal proportions of seropositive results were obtained in the rainy and dry seasons (c² = 0.057, d.f. = 1, p = 0.88). Significantly higher proportions of males (55.96%, 95% CI: 48.96-62.96%) and adults (52.37%, 95% CI: 47.35-57.39%) were seropositive. While none of the brain tissue samples tested positive for infection, the high proportion of seropositive specimens indicates that RABV may be widespread in this urban area.

Bat fauna of the Cerrado savanna of eastern Maranhão, Brazil, with new species occurrences

Abstract In Brazil, 179 bat species have been recorded to date, representing 68 genera and nine families. Few data are available on the bat fauna of the state of Maranhão, so the present study was based on a survey of the bat fauna of the Inhamum Municipal Environmental Protection Area (APA Inhamum) in the Cerrado savanna of the eastern extreme of the state. This inventory provides new records of bat species for the state of Maranhão and the Cerrado biome. A total of 31 species (four families) were collected, representing 39% of the bat species known to occur in Maranhão and 28.71% of the species described for the Cerrado. The family Phyllostomidae was the most diverse, with 23 species (74.20% of the total), and also the most abundant, with 86.09% of the specimens collected. The Molossidae (four species) was the second most diverse, followed by the Vespertilionidae (three species) and the Emballonuridae (one species). Carollia perspicillata was the most abundant species (28%).The records of Artibeus fimbriatus and Platyrrhinus fusciventris are the first for the Cerrado and were also recorded in Maranhão for the first time. The cumulative species curve did not reach an asymptote. The species Dermanura gnoma, Lasiurus blossevillii, Lasiurus ega, Micronycteris schmidtorum, Molossops temminckii, Platyrrhinus cf. recifinus, Phylloderma stenops and Trachops cirrhosus, were also recorded in Maranhão for the first time demonstrating the value of for mammal inventories and emphasizing the need for further surveys in this poorly-known region.

Phylogeography of the dark fruit-eating bat Artibeus obscurus in the Brazilian Amazon

Artibeus obscurus (Mammalia: Chiroptera) is endemic to South America, being found in at least 18 Brazilian states. Recent studies revealed that different populations of this genus present distinct phylogeographic patterns; however, very little is known on the population genetics structure of A. obscurus in the Amazon rainforest. Here, using a fragment (1010bp) of the mitochondrial gene cytochrome b from 87 samples, we investigated patterns of genetic divergence among populations of A. obscurus from different locations in the Brazilian Amazon rainforest and compared them with other Brazilian and South American regions. Analysis of molecular variance (AMOVA), fixation index (Fst) analysis, and phylogeographic patterns showed divergence between two major monophyletic groups, each one corresponding to a geographic region associated with the Atlantic and Amazon forest biomes. The Atlantic forest clusters formed a monophyletic group with a high bootstrap support and a fragmented distribution that follows the pattern predicted by the Refuge Theory. On the other hand, a different scenario was observed for the Amazon forest, where no fragmentation was identified. The AMOVA results revealed a significant geographic heterogeneity in the distribution of genetic variation, with 70% found within populations across the studied populations (Fst values ranging from 0.05864 to 0.09673; φST = 0.55). The intrapopulational analysis revealed that one population (Bragança) showed significant evidence of population expansion, with the formation of 2 distinct phylogroups, suggesting the occurrence of a subspecies or at least a different population in this region. These results also suggest considerable heterogeneity for A. obscurus in the Amazon region.

Rabies in humans and non-human in the state of Pará, Brazilian Amazon

We evaluate the relationship of positive cases of rabies with the continuing expansion of livestock production, and analyse the trends of this zoonosis in human population in the state of Pará, Brazilian Amazon. The distribution of rabies cases was recorded between 1999 and 2004. Of 148 cases of rabies, 21% were in humans and 79% in non-human mammals. The rapid growth in livestock numbers seems to be associated with the increase of positive cases in bovine livestock transmitted by vampire bats. This idea is supported by positive and significant relationship of both events in time (p < 0.01), but failed when spatial distribution among regions of the state was considered. However, rabies cases tend to occur toward the northeastern of the state of Pará, where rabies cases are proportionally five times greater than other mesoregions, suggesting that increased livestock production may influence the increase of this zoonosis.