Reptile road-kills in Southern Brazil: Composition, hot moments and hotspots.

Understanding road-kill patterns is the first step to assess the potential effects of road mortality on wildlife populations, as well as to define the need for mitigation and support its planning. Reptiles are one of the vertebrate groups most affected by roads through vehicle collisions, both because they are intentionally killed by drivers, and due to their biological needs, such as thermoregulation, which make them more prone to collisions. We conducted monthly road surveys (33months), searching for carcasses of freshwater turtles, lizards, and snakes on a 277-km stretch of BR-101 road in Southernmost Brazil to estimate road-kill composition and magnitude and to describe the main periods and locations of road-kills. We modeled the distribution of road-kills in space according to land cover classes and local traffic volume. Considering the detection capacity of our method and carcass persistence probability, we estimated that 15,377 reptiles are road-killed per year (55reptiles/km/year). Road-kills, especially lizards and snakes, were concentrated during summer, probably due to their higher activity in this period. Road-kill hotspots were coincident among freshwater turtles, lizards, and snakes. Road-kill distribution was negatively related to pine plantations, and positively related to rice plantations and traffic volume. A cost-benefit analysis highlighted that if mitigation measures were installed at road-kill hotspots, which correspond to 21% of the road, they could have avoided up to 45% of recorded reptile fatalities, assuming a 100% mitigation effectiveness. Given the congruent patterns found for all three taxa, the same mitigation measures could be used to minimize the impacts of collision on local herpetofauna.

Risk Factors Associated with Human Visceral Leishmaniasis in an Urban Area of Bahia, Brazil.

BACKGROUND: The early diagnosis of asymptomatic, acute, and subclinical Leishmania infections remains a challenge for controlling visceral leishmaniasis (VL). Individuals with acute VL represent <1% of Leishmania infections occurring in active transmission endemic areas. In this cross-sectional study with a prospective follow-up, we explored the risk factors associated with acquisition of Leishmania infection in an area with newly identified endemic VL. MATERIALS AND METHODS: Ninety-four households were randomly selected from the study area, which included a population of 213 individuals (10% of the total population of Pé de Areia, Bahia, Brazil). Clinical and epidemiological surveys were prospectively performed to detect cases of asymptomatic infections, acute VL, and subclinical VL, using the leishmanin skin test (LST), and serological response to two Leishmania-specific antigens: rK39 and rK26. RESULTS: Within the 92 households included in the study, the prevalence of Leishmania infection in individuals detected by positive serology was 91/197 (46.2%; 95% CI: 0.3937-0.5316) and by LST was 29/114 (25.4%; 95% CI: 0.1834-0.3414). Reactivity to both antigens was detected in 64/197 individuals (32.5%; 95% CI: 0.2634-0.3931). Among 89 individuals diagnosed with leishmaniasis, we found acute VL in one (1%), subclinical VL in 20 (22.5%), and asymptomatic Leishmania infection in 68 (76.4%) subjects. Use of repellents and bed nets showed no significant protection (prevalence ratio [PR] = 1.01, p = 1.0). Interestingly, individuals residing in houses with a sand backyard had significant protection against Leishmania infection (PR = 1.24, p = 0.049) compared to those with a different type or no backyard. Moreover, the presence of cat or dog at home was also not a risk factor (dog: PR = 1.14, 95% CI: 0.80-1.64; and cat: PR = 1.19, 95% CI: 0.78-1.81). We conclude that in newly discovered areas of transmission of L. infantum infection with sylvatic reservoirs, periodic surveys may be helpful in identifying risk factors for infection and optimizing prevention guidelines.

Land use explains the distribution of threatened New World amphibians better than climate.

BACKGROUND: We evaluated the direct and indirect influence of climate, land use, phylogenetic structure, species richness and endemism on the distribution of New World threatened amphibians. METHODOLOGY/PRINCIPAL FINDINGS: We used the WWF's New World ecoregions, the WWFs amphibian distributional data and the IUCN Red List Categories to obtain the number of threatened species per ecoregion. We analyzed three different scenarios urgent, moderate, and the most inclusive scenario. Using path analysis we evaluated the direct and indirect effects of climate, type of land use, phylogenetic structure, richness and endemism on the number of threatened amphibians in New World ecoregions. In all scenarios we found strong support for direct influences of endemism, the cover of villages and species richness on the number of threatened species in each ecoregion. The proportion of wild area had indirect effects in the moderate and the most inclusive scenario. Phylogenetic composition was important in determining the species richness and endemism in each ecoregion. Climate variables had complex and indirect effects on the number of threatened species. CONCLUSION/SIGNIFICANCE: Land use has a more direct influence than climate in determining the distribution of New World threatened amphibians. Independently of the scenario analyzed, the main variables influencing the distribution of threatened amphibians were consistent, with endemism having the largest magnitude path coefficient. The importance of phylogenetic composition could indicate that some clades may be more threatened than others, and their presence increases the number of threatened species. Our results highlight the importance of man-made land transformation, which is a local variable, as a critical factor underlying the distribution of threatened amphibians at a biogeographic scale.