Trypanosoma cruzi : blood parasitism kinetics and their correlation with heart parasitism intensity during long-term infection of Beagle dogs

• Published in: Memórias do Instituto Oswaldo Cruz 2008-09, Vol.103 (6), p.528-534
• Main Authors: Veloso, Vanja M, Guedes, Paulo MM, Andrade, Isabel M, Caldas, Ivo S, Martins, Helen R, Carneiro, Cláudia M, Machado-Coelho, George LL, de Lana, Marta, Galvão, Lúcia MC, Bahia, Maria T, Chiari, Egler
• Format: Article
• Language: English
• Subjects: Acute Disease; Animals; Beagle dogs; blood and tissue PCR; blood culture; Chagas Cardiomyopathy - parasitology; Chagas Cardiomyopathy - pathology; Chronic Disease; Disease Models, Animal; Dogs; Female; Fibrosis - parasitology; Fibrosis - pathology; Inflammation - parasitology; Inflammation - pathology; Male; parasitemia; Parasitemia - parasitology; Parasitemia - pathology; PARASITOLOGY; Polymerase Chain Reaction; TROPICAL MEDICINE; Trypanosoma cruzi; Trypanosoma cruzi - Beagle dogs - parasitemia - blood culture - blood and tissue PCR; Trypanosoma cruzi - classification; Trypanosoma cruzi - pathogenicity
• ISSN: 1678-8060; 0074-0276; 1678-8060; 0074-0276
• DOI: 10.1590/S0074-02762008000600003

The goals of the present study were to evaluate the kinetics of blood parasitism by examination of fresh blood, blood culture (BC) and PCR assays and their correlation with heart parasitism during two years of infection in Beagle dogs inoculated with the Be-78, Y and ABC Trypanosoma cruzi strains. Our results showed that the parasite or its kDNA is easily detected during the acute phase in all infected animals. On the other hand, a reduced number of positive tests were verified during the chronic phase of the infection. The frequency of positive tests was correlated with T. cruzi strain. The percentage of positive BC and blood PCR performed in samples from animals inoculated with Be-78 and ABC strains were similar and significantly larger in relation to animals infected with the Y strain.Comparison of the positivity of PCR tests performed using blood and heart tissue samples obtained two years after infection showed two different patterns associated with the inoculated T. cruzi strain: (1) high PCR positivity for both blood and tissue was observed in animals infected with Be-78 or ABC strains; (2) lower and higher PCR positivity for the blood and tissue, respectively, was detected in animals infected with Y strains. These data suggest that the sensitivity of BC and blood PCR was T. cruzi strain dependent and, in contrast, the heart tissue PCR revealed higher sensitivity regardless of the parasite stock.