Chronic Trypanosoma cruzi infection in dogs: 11 cases (1987-1996).
OBJECTIVE
To determine whether prevalence of naturally developing chronic infection with Trypanosoma cruzi in dogs in Texas changed between 1987 and 1996 and to characterize clinical aspects of the disease.


METHODS
Retrospective study.


METHODS
11 dogs with chronic infection with T cruzi.


METHODS
Number of positive serologic test results for T cruzi obtained between 1987 and 1996 were compared with the number of tests for T cruzi performed during the same period. Survival time, signalment, and clinical signs of dogs and results of thoracic radiography, electrocardiography, and echocardiography were evaluated. The Mann-Whitney test was used to assess the association between age at time of initial examination and survival time.


RESULTS
The proportion of positive test results increased, compared with the number of tests submitted, during the 9-year period. Clinical signs in affected dogs were consistent with right-sided cardiac disease. Results of thoracic radiography were nonspecific. Conduction disturbances and supraventricular and ventricular arrhythmias were evident. Echocardiographic abnormalities, including chamber enlargement and functional impairment, were detected. Dogs were characterized on the basis of survival time; group-1 dogs (n = 6) survived 0 to 5 months, and group-2 dogs (5) survived 31 to 60 months. Age at time of initial examination was associated with survival time.


CONCLUSIONS
Clinical course of disease varied. Electrocardiographic and echocardiographic changes may be detected. Clinicians should be aware of the potential for T cruzi infection in dogs with clinical signs of right-sided cardiac dysfunction and unexplained conduction disturbances and arrhythmias. Prevalence of this disease may be increasing in some regions of Texas.
Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, Texas A&M University, College Station 77843, USA.
K M
KM
Meurs
M A
MA
Anthony
M
M
Slater
M W
MW
Miller
D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D014355:Chagas Disease / Q000453:epidemiology / Q000662:veterinary*; D002908:Chronic Disease; D004283:Dog Diseases / Q000453:epidemiology*; D004285:Dogs; D004452:Echocardiography / Q000662:veterinary; D004562:Electrocardiography / Q000662:veterinary; D005260:Female; D008297:Male; D010490:Pericardial Effusion / Q000473:pathology / Q000662:veterinary; D015995:Prevalence; D013902:Radiography, Thoracic / Q000662:veterinary; D012189:Retrospective Studies; D016019:Survival Analysis; D013781:Texas / Q000453:epidemiology; D013997:Time Factors; D014349:Trypanosoma cruzi / Q000276:immunology
D000913:Antibodies, Protozoan