Cell-mediated immune response to Leishmania chagasi experimental infection of BALB/c immunosuppressed mice

Leishmaniasis, a zoonosis of worldwide distribution, presents a significant impact on immunosupressed patients. This study aimed to evaluate Leishmania chagasi infection in BALB/c mice immunosuppressed with dexamethasone. Spleen cells stimulated or not with L. chagasi were cultured for cytokine quantification (IFN-gama, IL-2, IL-4 and IL-10) by sandwich ELISA. Parasite loads in the spleen and liver were determined by means of culture microtitration. Immunosuppressed groups showed statistically lower spleen weight and CD4-cell percentage in blood on the day of infection and produced Th1 and Th2 cytokines on other days of the study. The other infected groups, weather immunosupressed or not, also produced Th1 and Th2 cytokines. Parasite loads in the spleen and liver were not statistically different among the groups. It was concluded that L. chagasi infection was not affected by dexamethasone-induced immunosuppression, probably due the reversible effect of the treatment.(AU)

Leptospira spp. and Toxoplasma gondii antibodies in vampire bats (Desmodus rotundus) in Botucatu region, SP, Brazil

The destruction of natural ecosystems has caused several problems to humans and other animals; herein we investigate the close relationship among vampire bats, humans and domestic animals. Toxoplasma gondii and Leptospira spp. infections are two worldwide zoonoses that provoke serious damage to animals. To determine the prevalence of bats seropositive for toxoplasmosis and leptospirosis in the Botucatu region, 204 serum samples of vampire bats (Desmodus rotundus) were tested for T. gondii antibodies by modified agglutination test (MAT-t) and for Leptospira spp. by microscopic agglutination test (MAT-l). No animal was tested positive for T. gondii while leptospiral positivity was 7.8 percent for Pyrogenes, Shermani and Javanica serovars, with titers varying from 100 to 1,600. Thus, it was verified that D. rotundus does not play a relevant role in toxoplasmosis epidemiology. However, these bats can be important in the maintenance of Leptospira spp. in the environment.(AU)

Experimental infection with Leishmania chagasi in immunosuppressed Balb/c mice: cytokines and parasite burdens

The immune response in leishmaniasis may result in a polarization of the T lymphocyte subpopulation, altering cell phenotype and resulting in immune protection or disease exacerbation. Leishmania may persist in the body either during asymptomatic infections or after treatment, which represents high risk under immunosuppression. The objective of this study was to evaluate the effect of infection with immunosuppression by dexamethasone associated with pentoxifylline on animal weight, spleen weight, spleen and hepatic parasitic load and immunopathology, as well as the IFN-ã and IL-10 production in spleen cell culture of Balb/c mice infected with Leishmania chagasi. The infection did not cause body weight gain in animals, but both the weight and size of the spleen were increased. The immunosuppression using dexamethasone associated with pentoxifylline affected body weight gain and spleen weight and size in both infected and non-infected animals. The immunosuppression did not significantly alter the course of the splenic or hepatic parasite burden. Dexamethasone and pentoxifylline significantly affected cytokine production, but did not influence the Th1/Th2 ratio in infected animals.(AU)

Serological survey for rabies in serum samples from vampire bats (Desmodus rotundus) in Botucatu region, SP, Brazil

The chiropterans constitute 25% of the world's mammal fauna. Due to the destruction of their natural ecosystem, the vampire bats have moved from nature to artificial roosts closer to man and domestic animals. This phenomenon has happened particularly in rural areas. Rabies is a viral anthropozoonosis, 100% lethal, and vampire bats (Desmodus rotundus) represent an important role in its epidemiology. D. rotundus were captured at night with mesh nets in partnership with the Botucatu Defense Office and sent to the Zoonosis Diagnostic Service, at the School of Veterinary Medicine and Animal Husbandry, UNESP. Serum samples from 204 bats were analyzed by enzyme-linked immunosorbent assay (ELISA) and fluorescent antibody viral neutralization test (FAVN) for rabies antibody detection. The results showed 7.4% of sera with titers higher or equal to 0.5 U for rabies antibodies, which demonstrated viral flow circulation among the studied region. Data suggest a need for constant monitoring accomplished by epidemiological and sanitary measures.(AU)

Ocorrência de anticorpos anti-toxoplasma gondii e anti-leptospira spp. em suínos abatidos em três abatedouros dos estados de minas gerais e são paulo

ABSTRACT Many seroepidemiological inquiries of toxoplasmosis and leptospirosis in swine have been realized in many Brazilian states, demonstrating the importance of these diseases for swine farming, as well as the potential of this swine species as a source of infection of these diseases for man. This study aimed to establish the occurrence of antibodies anti-Toxoplasma gondii and anti-Leptospira spp. in swine slaughtered in 3 slaughterhouses, located in Minas Gerais and São Paulo states, Brazil. Two hundred sixty-two blood samples were collected from slaughtered swine, from 16 cities, and the sera samples were submitted to the modified agglutination test, to investigate antiT. gondii antibodies, and to the microscopic agglutination test, to investigate anti-Leptospira spp. antibodies. No sample was positive for T. gondii, and 2 samples reacted to Leptospira interrogans, serovar Pyrogenes (titer 100). These low occurrences of antibodies in the studied swine, for the Leptospiratest, could be due the use of the system of total confinement, allied to the hygienic-sanitary swine management and the slaughtered animals short length of stay at the farms.

RESUMO Diversos inquéritos soroepidemiológicos a respeito da toxoplasmose e leptospirose em suínos foram realizados em diferentes estados brasileiros, demonstrando a importância destas enfermidades para a suinocultura, bem como o potencial da espécie suína como fonte de infecção destas enfermidades para o homem. Este trabalho objetivou estabelecer as ocorrências de anticorpos anti-Toxoplasma gondii e anti-Leptospira spp. em suínos abatidos em três abatedouros, situados nos Estados de Minas Gerais e São Paulo. Foram colhidas 262 amostras de sangue de suínos terminados, provenientes de 16 municípios. Os soros foram submetidos ao método de Aglutinação Direta Modificada (MAD) para pesquisa de anticorpos anti-T. gondii, e à Soroaglutinação Microscópica (SAM), para anticorpos anti-Leptospira spp. Nenhuma amostra foi positiva para T. gondii e duas amostras reagiram para Leptospira interrogans, sorovar Pyrogenes (título 100). Os resultados devem ser em função do emprego do sistema de confinamento total, aliado ao manejo higiênico-sanitário na atividade suinícola e pelo pequeno período de permanência dos animais terminados nas granjas.