Natural infection of the wild canid, Cerdocyon thous, with the piroplasmid Rangelia vitalii in Brazil.

Canine rangeliosis, caused by the piroplasmid protozoon Rangelia vitalii, is currently recognized as a reemerging disease that affects domestic dogs in Brazil. In the present study, piroplasmid infection was searched in wild canids (20 Cerdocyon thous and 4 Lycalopex gymnocercus) in Brazil. Molecular analysis, based on PCR and DNA sequencing of a portion of the 18S rRNA gene, revealed that 30% (6/20) C. thous were infected by R. vitalii. Blood and bone marrow samples from one of the R. vitalii-infected C. thous were inoculated into a domestic dog, which developed clinical rangeliosis that was confirmed by molecular tests. However, the C. thous donor showed no clinical, hematological or biochemical alterations, even though its R. vitalii infection status was confirmed for at least 80 days. These observations suggest that R. vitalii is not as highly pathogenic for C. thous as it is for domestic dogs. Phylogenetic analysis inferred by the 18S rRNA gene placed R. vitalii embedded in the clade 'Babesia sensu stricto', consisting of a number of species that represent truly the genus Babesia. It is proposed that the species R. vitalii should be transferred to the genus Babesia. The present study expands our knowledge on the natural history of R. vitalii, suggesting that it might have a natural cycle involving the wild canid C. thous. Further studies are needed to confirm that C. thous is a natural reservoir of R. vitalii in Brazil.

[Ovine abortion associated with toxoplasmosis: serological, anatomo-pathological and immunohistochemistry characterization]. / Aborto em ovinos associado à toxoplasmose: caracterização sorológica, anátomo-patológica e imunoistoquímica.

Ovine toxoplasmosis is a major cause of abortion and placentitis. Lambs with congenital infection are born with encephalitis. Abortions occurred between May and August 2006 in an estate in Três Palmeiras, southern Brazil. This study aimed to assess the frequency of abortion associated with toxoplasmosis among ewes in southern Brazil using indirect hemagglutination and pathoanatomical and immunohistochemical analyses. Blood samples were collected from nine animals for indirect hemagglutination. One fetus underwent necropsy and histopathological and immunohistochemical analyses. Three samples, one of which belonged to the necropsied animals mother, were positive on the serological test. The necropsy revealed pale foci in the liver, lungs with a marbled appearance, heart with severe pallor and brain and cerebellar congestion. Fragments of all organs were collected, fixed in 10% buffered formalin, processed, and stained with hematoxylin-eosin. Microscopically, there were cysts and tachyzoites in the brain in areas of malacia with microgliosis and lymphoplasmacytic infiltration, suggesting toxoplasmic encephalitis. There was also interstitial pneumonia, centrolobular necrosis with structures compatible with tachyzoites, focal lymphocytic myocarditis and acute tubular nephrosis. The immunohistochemical test was positive for Toxoplasma gondii. The results allowed diagnosing the ovine toxoplasmosis.