Spatial analysis of egg distribution and geographic changes in the spawning habitat of the Brazilian sardine Sardinella brasiliensis

This paper establishes the spawning habitat of the Brazilian sardine Sardinella brasiliensis and investigates the spatial variability of egg density and its relation with oceanographic conditions in the shelf of the south-east Brazil Bight (SBB). The spawning habitats of S. brasiliensis have been defined in terms of spatial models of egg density, temperature-salinity plots, quotient (Q) analysis and remote sensing data. Quotient curves (Q(C)) were constructed using the geographic distribution of egg density, temperature and salinity from samples collected during nine survey cruises between 1976 and 1993. The interannual sea surface temperature (SST) variability was determined using principal component analysis on the SST anomalies (SSTA) estimated from remote sensing data over the period between 1985 and 2007. The spatial pattern of egg occurrences in the SBB indicated that the largest concentration occurred between Paranagua and Sao Sebastiao. Spawning habitat expanded and contracted during the years, fluctuating around Paranagua. In January 1978 and January 1993, eggs were found nearly everywhere along the inner shelf of the SBB, while in January 1988 and 1991 spawning had contracted to their southernmost position. The SSTA maps for the spawning periods showed that in the case of habitat expansion (1993 only) anomalies over the SBB were zero or slightly negative, whereas for the contraction period anomalies were all positive. Sardinella brasiliensis is capable of exploring suitable spawning sites provided by the entrainment of the colder and less-saline South Atlantic Central Water onto the shelf by means of both coastal wind-driven (to the north-east of the SBB) and meander-induced (to the south-west of the SBB) upwelling.

Exposure of small mammals to ticks and rickettsiae in Atlantic Forest patches in the metropolitan area of Recife, North-eastern Brazil

Between December 2007 and March 2009, small mammals were captured in 6 Atlantic Forest patches in Brazil. We assessed tick-host associations and whether they differ among forest strata, sites, seasons, and host age classes or between sexes. Moreover, we assessed the exposure of animals to Rickettsia spp. In total, 432 animals were captured and 808 ticks were found on 32-9% of them. Significant differences were found among host species, collection sites, and forest strata; microhabitat preference was a strong risk factor for tick infestation. The highest tick density rates were recorded in forest fragments settled in rural areas; 91.3% of the ticks were collected from animals trapped in these forest fragments. A high prevalence (68.8%) of antibodies to Rickettsia spp. was detected among animals. This study suggests that disturbed Atlantic Forest fragments provide an environment for ticks and small mammals, which are highly exposed to rickettsiae. It also indicates that forest patches settled in rural areas are usually associated with higher small mammal diversity as well as with higher tick density rates.

Detection of hantavirus in bats from remaining rain forest in São Paulo, Brazil

Background The significant biodiversity found in Brazil is a potential for the emergence of new zoonoses. Study in some places of the world suggest of the presence to hantavirus in tissues of bats. Researches of hantavirus in wildlife, out rodents, are very scarce in Brazil. Therefore we decided to investigate in tissues of different species of wild animals captured in the same region where rodents were detected positive for this virus. The present work analyzed ninety-one animals (64 rodents, 19 opossums, and 8 bats) from a region of the Atlantic forest in Biritiba Mirin City, São Paulo State, Brazil. Lungs and kidneys were used for RNA extraction. Findings The samples were screened for evidence of hantavirus infection by SYBR-Green-based real-time RT-PCR. Sixteen samples positive were encountered among the wild rodents, bats, and opossums. The detection of hantavirus in the lungs and kidneys of three marsupial species (Micoureus paraguayanus, Monodelphis ihering, and Didelphis aurita) as well in two species of bats (Diphylla ecaudata and Anoura caudifer) is of significance because these new hosts could represent an important virus reservoirs.