The importance of dogs and cats in the epidemiology of Chagas disease
Rojas, A.; Sotelo, J.M.; Villarroel, F.; Contreras, M.del.C.
Boletin Chileno de Parasitologia 28(1): 42-43
1973
ISSN/ISBN: 0365-9402 PMID: 4206279 Document Number: 57921
An account is given of an investigation of the importance of dogs and cats in the epidemiology of Chagas' disease in the province of Santiago, Chile. By xenodiagnosis with batches of 5 third-instar nymphs of Triatoma infestans (Klug) allowed to feed for 30 min, 8 of 86 dogs examined and 1 of 27 cats were found to be naturally infected with Trypanosoma cruzi. The infected animals were examined by xenodiagnosis on 270 occasions over a period of 6 months, and 68.5% of the tests were positive. The cat and one of the dogs were taken to the laboratory and tested with totals of 256 and 300 third-instar nymphs, respectively. The proportion of positive nymphs rose from 23.4% after 30 days to 28.9% after 60 days and 30.5% after 90 days. There was no further rise after 120 days. There were no significant differences in positive rates between nymphs fed on the dog and those fed on the cat. The positive rates were similar to those in two series of bugs applied to a patient with a chronic infection and high and persistent parasitaemia. The volumes of blood ingested by the nymphs from dog, cat and man were similar. These results show that dogs and cats are natural reservoirs of T. cruzi and that xenodiagnosis would detect only 68.5% of infected animals.