OBJECTIVE: To identify the species of bats involved in maintaining the rabies cycle; to investigate the distribution of the rabies virus in the tissues and organs of bats and the time taken for mortality among inoculated mice. METHODS: From April 2002 to November 2003, bats from municipalities in the State of São Paulo were screened for the presence of the rabies virus, by means of direct immunofluorescence. The virus distribution in the bats was evaluated by inoculating mice and N2A […]

The behavior of a human S. mansoni strain was studied in infected, outbred mice. A comparative study was carried out to evaluate the effects of the infection in inbred mice, employing human and wild rodent strains of S. mansoni. The use of inbred mice was advantageous in that it allowed greater uniformity in the results as well as greater penetration of surrounding areas through the caudal tegmentum.

Swiss mice were infected with 100 cercariae of the Belo Horizonte strain of Schistosoma mansoni and were sacrificed weekly during eight weeks following of infection. The levels of serum protein totals in these animals did not differ from those presented by the control animals. However, serum albumin levels that were determined by rocket immunoelectrophoresis were lower during the 5th, 6th, and 7th weeks of infection. The pattern determined by crosed immunoelectrophoresis revealed alterations in serum components with mobility in the […]

The study of the behaviour of T. cruzi strains in animals as in human beings, runs into great difficulties when the attempt is made to relate the morphology of this parasite to its biological behaviour. The thin forms are able to penetrate vertebrate cells faster than the broad forms. So, faced with the biological complexity of the T. cruzi strains and substrains it was decided to investigate the behaviour of its blood forms obtained from normal mice as biological filters. […]

By means of comparative studies of the infection of mice with T. cruzi using intraperitoneal and subcutaneous inoculation, it was concluded that more uniform and virulent infections are obtained after subcutaneous inoculation. This is due to an immediate cellular response, when intraperitoneal inoculations are used. With the aim of making comparative studies as between the two methods of inoculation, the intraperitoneal using two, morfologically distinct, strains of T. cruzi: Y with predominance of thin forms and Bolivia with predominance of […]

Mansoni schistosomiasis was studied in mice fed on a low protein diet. Four groups of the Swiss breed Mus musculus were used in an experiment with two factors, each with two levels: 1-non-infected, normal diet; 2 – infected, normal diet ; 3 – non-infected, low protein diet; 4 – infected, low protein diet. The mice were killed for observation at age 90 days, after 60 days of infection, for those infected. It was found that the worms suffered the effects […]

The infection of several opossums Didelphis albiventris, male, female and young, by oral means by feeding them either on infected triatomines or on mice experimentally infected by Tripanosoma cruzi, is studied. After feeding uncontaminated opossums on carcasses or living specimens of baby mice, infected with the Bolivian strain of T.cruzi, a 60.0% infection index was obtained on xenodiagnoses. On the other hand, after feeding uncontaminated opossums on infected triatomines, an 83.3% index was obtained on xenodiagnoses. These results indicate that […]

Conventional swiss mice were innoculated intragastrically (IG) and intravenously (IV) with Yersinia enterocolitica serotypes 0:3, 0:8 and 0:9 and with Yersinia enterocolitica like strains. A control animal group was not innoculated. The period that strains remained in the cecal content after the IG and IV challenge was determined. After IG and IV innoculation, Yersinia enterocolitica serotypes 0:3, 0:8 and 0:9, considered adapted to man, were isolated from the cecal content for a longer period than those considered nonadapted.

Considering that gentian violet is effective in the prevention of transfusion-acquired Chagas’ disease and possibly toxoplasmosis, it is decided to carry out an experimental assay on the acitvity of this dye in the prevention of post-transfusion malaria. Mice infected with Plasmodium berghei were studied with regard to parasitemia, mortality and histopathologic changes. Gentian violet added to blood in 1/1.000 and 1/4.000 concentrations turned out to be effective in abolishing infectivity after storage for 24 hours at 4°C. Thus is opened […]

The viability of Schistosoma mansoni miracidia in host molluscs, obtained from two origins is examined: from eggs eliminated with feces of the definitive hosts and liver granuloma eggs. The effect of the origin of the miracidia on the number of cercariae and on the time of cercariae elimination was investigated. The prepatent period of cercariae elimination, snail survival after infection and the sex of the eliminated cercariae were also observed. The following results were obtained: a) snails infected with miracidia […]