Foi realizado um levantamento da infecção por Leptospira spp. em mamíferos silvestres do Pantanal sul-mato-grossense com o emprego da reação de soroaglutinação microscópica (SAM) e da reação em cadeia da polimerase (PCR). Os sorovares de maior frequência nos animais investigados foram Hardjobovis (28%), Icterohemorhagiae (12%), M-110/2006 (isolado de Cerdocyon thous; 16%), Canicola (L014 isolada de Bos taurus, 4%), Whitcombi (4%), Pomona (20%), Autumnalis (12%) e Copenhageni (M9/99 isolada de Rattus norvegicus, 4%). Das 79 amostras examinadas pela PCR, 21 (26,58%) foram positivas, com a amplificação de um fragmento de aproximadamente 331pb. Dois fragmentos amplificados obtidos de amostras de C. thous foram clonados, sequenciados e identificados como L. interrogans por análise filogenética.

A survey of Leptospira spp. in wild mammals from the southern Pantanal of Mato Grosso do Sul was performed by microscopic agglutination test (MAT) and polymerase chain reaction (PCR). The serovars most frequently found were Hardjobovis (28%), Icterohemorhagiae (12%), M110/2006 strain (isolated from Cerdocyon thous, 16%), Canicola (L014 isolated from Bos Taurus, 4%), Whitcombi (4%), Pomona (20%), Autumnalis (12%) and Copenhageni (M9/99 isolated from Rattus norvegicus, 4%). From the 79 samples tested by PCR, 21 (26.58%) were positive, resulting in the amplification fragment of approximately 331pb. Two amplified fragments from C. thous were cloned, sequenced and identified as L. interrogans by phylogenetic analysis.

The Pantanal is a South American biome characterized by extensive plains and stark environmental seasonality. Several habitats are subject to annual flooding, forcing small mammal species to aggregate in dry forest patches, which most likely influences their population dynamics and life history strategies. In order to investigate the seasonal influence on the life history traits of these small mammals, we conducted a 2-year mark-recapture study in the southeastern region of the Brazilian Pantanal (Nhecolândia) and analyzed the population dynamics of the most abundant small mammal species with the jackknife estimator. A trapping effort of 21,560 trap-nights resulted in 615 individuals in 1,171 captures (success = 5.43%). Three species of rodents - Oecomys mamorae (Thomas, 1906), Thrichomys pachyurus (Wagner, 1845), and Clyomys laticeps (Thomas, 1841) - and three species of marsupials - Gracilinanus agilis (Burmeister, 1854), Thylamys macrurus (Olfers, 1818), and Monodelphis domestica (Wagner, 1842) - were obtained. The most abundant species was O. mamorae, followed by G. agilis and T. pachyurus. Oecomys mamorae was more abundant in the wet season and presented an opportunistic reproductive strategy. Gracilianus agilis displayed increased population sizes in the dry season and synchronized, seasonal reproduction during the rainy season. Thrichomys pachyurus had a small population size, delayed response to variations in environmental conditions and higher reproductive rates in the dry season. All species revealed different life history strategies (seasonal, opportunistic or delayed response to environmental variations), coinciding with periods of higher resource availability in order to maximize survival.

Most Neotropical mammals are not easily observed in their habitats, and few studies have been conducted to compare the performance of methods designed to register their tracks. We compared the effectiveness of track registry between sand plots and two tracking methods that use artificial materials to record tracks: the sooted paper, and the plastic board methods. The latter is described here for the first time. From 2002 to 2005, we conducted two experiments in three study sites in the Pantanal region of Brazil. We compared the artificial methods with the sand plot by registering track presence/absence, the number of identifiable tracks, and the total number of tracks (identifiable and unrecognizable) in each tracking plot. Individuals avoided artificial tracking plots either by not stepping on them or by doing it fewer times than on the sand plots. The use of artificial materials to register mammal tracks resulted in underestimates that are especially relevant to short-term ecological studies. We recommend the use of the traditional sand plot method whenever possible and the development of detailed studies on the efficiency of artificial methods under a variety of environmental conditions and time lengths. Despite their relatively lower efficiency, we believe that artificial methods are useful under specific conditions and may be more efficient if used in more comprehensive sampling efforts.