Infecção por trypanosoma cruzi em um cão domiciliado da área urbana do município de castanhal, estado do Pará, Brasil

Trypanosoma cruzi, the etiologic agent of Chagas disease, is endemic in the Americas (VASOO & PRITT, 2013). After adapting to the domestic and peridomestic environments, the blood-sucking triatomine, a flagellate, became capable of infecting domestic and wild animals, and humans, as well. Therefore, the aim of this study is to report a case of T. cruzi infection in a dog, which occurred in the urban area of Castanhal, PA. In May 2013, a four-month old Rottweiler bitch died on the way to the Veterinary Hospital of the UFPA (Universidade Federal do Para). According to the owner, the animal clinical symptoms were fatigue, tremors and seizures during sleep, as well as oral and nasal bleeding. Discrete pale areas in the myocardium in both ventricles; diffuse reddening of the lungs and liver; and linear hemorrhages in the serosa of the stomach were observed at necropsy. Histopathological analysis showed an acute multifocal coalescing lymphoplasmacytic myocarditis, associated with moderate number of nests of amastigotes typical of T. cruzi. Lungs and heart presented severe congestion, in addition to follicular hyperplasia in the spleen and lymph nodes. The presence and severity of cardiac lesions associated mainly to changes in the lungs and liver led to acute heart failure, left and right (ZACHARY & MCGAVIN, 2007). The brief clinical evolution of the disease is justified by all these changes together, which are often described in acute Chagas disease (PAVARINI et al., 2009). Still, the diffuse myocarditis with moderate nests of amastigotes suggests an oral infection due to high parasite load at the time of infection (QUIJANO-HERNANDEZ et al., 2012). The data show occurrence of Chagas disease in urban Castanhal and demonstrate the need for additional studies particularly related to the presence of infected vectors in the dog habitat since this disease is of great importance to public health.