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Trypanosoma caninum is a new species that has been recently identified in Brazil and infects domestic dogs. To date, no accurate diagnostic assays for this parasite have been established; thus, our aim was to evaluate more than one type of PCR for the diagnosis and molecular screening of T. caninum in 229 dogs living in Rio de Janeiro state. The tests were based on the amplification and sequencing of the 18S ribosomal DNA (rDNA) gene using healthy skin fragments. Additionally, PCR amplification of the kDNA minicircles region specific to the Leishmania genus was performed. The PCR results were compared with those of culture-based analysis performed with the same specimen. Using cultures, T. caninum and Leishmania chagasi were isolated from 11 and 12 dogs, respectively, whereas the 18S rDNA PCR assay detected parasitic infection in 35 dogs. Among these, 25 dogs showed an amplification pattern similar to T. caninum and 10 showed a pattern similar to L. chagasi; these results were confirmed by sequencing analysis. The kDNA PCR analysis showed that 14 dogs were positive for Leishmania infection. Of these, 2 dogs showed negative culture results and 12 were positive for L. chagasi, including 4 with negative 18S rDNA PCR results. Thus far, culture-based testing has been the only tool used successfully for T. caninum diagnosis. Our results demonstrate that 18S rDNA PCR-based test should be a useful diagnostic tool, particularly for distinguishing between T. caninum and L. chagasi infections in areas where these 2 parasites co-exist., (Copyright © 2014 Elsevier B.V. All rights reserved.)

In 2008, in the west zone of Rio de Janeiro municipality-Brazil, the leishmaniasis control program identified 155 dogs with titers ≥ 40 by Indirect ImmunoFluorescence (IIF) on blood collected onto filter paper. The objective of this study was to describe the laboratory test findings performed in dogs euthanized by the leishmaniasis program control of Rio de Janeiro municipality. Dogs were examined, subjected to euthanasia and collection of clinical specimens. Parasite isolation was obtained in 29 animals: Leishmania chagasi was isolated in 14 dogs; Leishmania braziliensis was isolated in five dogs; Trypanosoma caninum was obtained in seven animals and one dog had mixed infection (L. braziliensis and L. chagasi). By Polymerase Chain Reaction, seventeen animals were positive in intact skin fragments. In the serological reassessment of serum samples, 28% and 22% were positive for IIF and enzyme immunoassay, respectively. Ninety-one (59%) dogs were negative for all tests performed in this study. The findings indicate that the visceral leishmaniasis control program needs to be adjusted in order to avoid non-infected dogs from being removed or permit that dogs infected with L. chagasi to remain undetected in endemic areas., (Copyright © 2011 Elsevier B.V. All rights reserved.)