Chagas Disease is caused by a protosoan parasite, Trypanosoma cruzi, which can cause heart disease and other sever health concerns in dogs. The parasite zoonotic, meaning that it can be transmitted to humans.
Transmission and Contraction
T. cruzi is trasmitted through the bite of the reduviid insect, commonly known as the kissing bug or assassin bug. Dogs can also contract the parasite by eating infected tissue of certain wild animals--primarily raccoons and opssums--or via contaminated blood transfusions. In the United States, Chagas disease is found mostly in the southern half of the country, especially Texas, although it has been diagnosed in California, Virginia and Maryland as well. The disease is also a concern in South and Central American, where it is more likely to be transmitted to humans.
The T. cruzi parasite can sprea throughout the body through the blood, potentially causing symptoms shortly after contraction. However, some dogs enter an asymptomatic latency period, which can last for months or even years. Although symptoms don't appear during this time, the parasite spreads and develops, eventually causing heart failure. Aside from the latency stage of the condition, Chagas disease is categorized in two phases: acute and chronic. The acute phase usually occurs in younger dogs, and is characterized by symptoms like lethargy, diarrhea, swollen lymph nodes and fever. Chronic Chagas disease is representated by lethargy, possible fainting, increased heart rate and congestive heart failure. Sudden death is possible if the disease progresses to this stage.
In addition to a full laboratory work-up, serology tests will be administered if a dog is uspected of Chagas disease. These tests measure the body's antibody response to the parasite. In addition, X-rays and echocardiogram scans can show abnormalities of the heart muscle that may be associated with T. cruzi infestation.
TreatmentUnfortunately, there is no cure for Chagas disease. Treatment is symptomatic in nature, and focuses on responding to heart failure and heart arrhythmias. Even dogs who do receive treatment may progress to the chronic phase of the condition, and death is the most likely outcome. At this time, studies to develop viable drug treatments for Chagas disease are ongoing.