TRYPANOSOMATIDS IN DOGS OF CHRONIC CHAGAS’ DISEASE PATIENTS FROM THE BOTUCATU REGION (SÃO PAULO STATE) EVALUATED FOR Trypanosoma cruzi and/or Trypanosoma rangeli BY ARTIFICIAL XENODIAGNOSIS, HEMOCULTURE, AND POLYMERASE CHAIN REACTION (PCR)

THESIS.S. B. Lucheis submitted this thesis for her Doctorate in Tropical Diseases at Botucatu School of Medicine, São Paulo State University, UNESP, Botucatu, São Paulo, Brasil, 2003.

Advisor: Professor Jussara Marcondes-Machado

ABSTRACT. Man has frequently altered the environment leading to triatomines, wild animals, and rodents to abandon their natural habitats and seek for food in houses and neighboring areas. Thus, they share trypanosomes with dogs, other animals, and man through water and food contamination by feces and urine or when dogs eat infected rodents. Fifty dogs of chronic Chagas’ disease patients were studied. They were from fifteen different municipalities of the central-western São Paulo State. Blood samples (8mL) were drawn from each dog for artificial xenodiagnsosis, using first-instar Dipetalogaster maximus nymphs, hemocultures at LIT medium, and Polymerase Chain Reaction (PCR) with P35/P36 primers specific for T. cruzi/T. rangeli. Results indicated that 68% of the dogs showed positive xenodiagnosis and 60% positive hemocultures. In relation to PCR results, twenty-five dogs (50%) were positive to T. cruzi and/or T. rangeli. Gender, origin, and age did not influence xenodiagnosis and PCR positivity. There was a significant association between sex and hemoculture results in which male positivity was significantly higher than female (² = 6.461; p<0.05). These results suggest that dogs from the studied areas were intensively parasitized by trypanosomatids; 50% by trypanosomes of public health interest, such as T. cruzi and T. rangeli. Although triatomines were not found in any visited houses, the results suggest that a transmission cycle may be in course with triatomine vector and synanthropic animals participating in the infection epidemiological chain. The results stress the need for further studies by repeating parasitologic tests and continuing molecular tests for identification of isolated strains.

KEY WORDS: Trypanosoma cruzi, Trypanosoma rangeli, dog, xenodiagnosis, hemoculture, trypanosomatids, epidemiology, triatomine.

CORRESPONDENCE TO: Simone Baldini Lucheis – Rua La Salle, 37 – Bairro Vila Nova Botucatu, 18602-240, Botucatu, São Paulo, Brasil. E-mail:silucheis@bol.com.br