Experimental Chagas' disease in dogs

Abstract

This paper describes the development of experimental Chagas' disease in 64 out-bred young dogs. Twenty-nine animals were inoculated with the Be-62 and 35 with Be-78 Trypanosoma cruzi strains. Twenty-six were infected with blood trypomastigotes by different inoculation routes and 38 with metacyclic trypomastigotes from the vector via the conjunctival route. Twenty of the 26 dogs infected with blood trypomastigotes were autopsied during the acute phase. Eleven died spontaneously and nine were sacrificed. Six remained alive until they died suddenly (two) or were autopsied. (four). Twelve of the 38 dogs infected with metacyclic trypomastigotes evolved naturally to the chronic phase and remained alive for 24-48 months. The parasitemia, clinical aspects and serology (IgM and IgG) as well as electrocardiogram, hemogram and heart anatomo-histopathologic patterns of acute and chronic cardiac forms of Chagas' disease as seen in human infections, were reproduced. The most important finding is the reproducibility of diffuse fibrosing chronic chagasic cardiopathy in all dogs infected with Be-78 T. cruzi strain autopsied between the 90th and 864th days of infection. Thus, the dog can be considered as a suitable experimental model to study Chagas' disease according to the requisites of the Word Health Organization (1984). Furthermore the animal is easily obtained and easy to handle and maintain in experimental laboratory conditions.

A study of experimental reinfection by Trypanosoma cruzi in dogs.

“…Our cardiac findings, similar to those of Andrade and An-drade, 14 Andrade, 39 and Lopes and others, 40 differ from those reported by Pellegrino 26 and Lana and others, 15,42 who found diffuse fibrous cardiopathy and cardiac insufficiency in some infected dogs. However, Lana and others 15,42 worked with dogs of a different breed and another strain of the parasite and also inoculated a larger number of animals than were used in our study.…”

“…Several studies have investigated this aspect [2][3][4][5][6][7][8][9][10][11][12] without being able to resolve this question. The dog has been extensively used as an experimental model in the study of Chagas' disease, [13][14][15] since it has characteristic aspects of the infection in humans.…”

Morphometry of submucous and myenteric esophagic plexus of dogs experimentally reinfected with Trypanosoma cruzi

“…Although it is known that dogs can develop the acute stage (Andrade 1984, Lana et al 1992, the cardiac (Lana et al 1988(Lana et al , 1992 and indeterminate (Lopes et al 1980, Machado et al 2001 forms of the chronic stage of the Chagas disease, showing clinical, morphological and electrocardiographic aspects similar to those observed in human, little is known about the digestive form of the infection in this animal. Few experimental anatomo-pathological studies refer to the esophageal or intestinal dilation.…”

Trypanosoma cruzi high infectivity in vitro is related to cardiac lesions during long-term infection in Beagledogs

“…Besides IgA antibody levels decreased (15 weeks after infection) earlier than the IgM isotype (20 weeks after infection). Since IgM antibodies have been detected for longer periods in patients (Ouaissi et al 1991) and in the canine model during the initial chronic phase of the infection (Lana et al 1992), we suggest here that the association of IgA and IgM antibody levels are certainly useful specific markers for the acute chagasic infection. As expected IgG isotype levels were higher during the chronic phase.…”

“…Until today, the pathogenesis of the chronic phase is not fully understood, in part by the difficulty in finding the ideal animal model and by the lack of correlation between the host immune response and heart damage. Since chronic canine chagasic cardiomyopathy has been shown to resemble the human disease (Lana & Chiari 1986, Lana et al 1992 we decided to investigate the correlation between the production of different immunoglobulins isotypes and pathogenesis of Chagas disease.…”