American Trypanosomiasis Parasitic Infection in Dogs
Chagas disease is an illness caused by the protozoan parasite Trypanosoma cruzi, which may infect dogs in several ways, including through blood exposure to the feces of “kissing bugs,” the ingestion of infected kissing-bugs, kissing-bug feces or prey (e.g., rodents), or congenitally from a mother to her offspring.
Once the parasites enter the cells in a dog’s body (often the heart muscle), they multiply and eventually rupture the infected cells. This is why Chagas disease is commonly associated with heart disease in dogs.
Chagas disease is endemic in South and Central America, but it is also found in the United States, typically in in Texas, Louisiana, Oklahoma, South Carolina, and Virginia. But the disease’s range is expanding as our climate warms.
Symptoms and Types of Chagas Disease
Two forms of Chagas disease are observed in dogs: acute and chronic. Some dogs experience an extended asymptomatic period between the two forms, which can last for months to years.
- Loss of appetite
- Swollen lymph nodes
- Enlarged liver or spleen
- Neurologic abnormalities (e.g., seizures)
- Sudden death
These symptoms may not be noticed by owners because they often resolve without treatment.
- Exercise intolerance
- Increased heart rate (tachycardia)
- Abnormal heart rhythms
- Fluid accumulation throughout the body
Causes of Chagas Disease
Although Chagas disease can only be acquired through an infection with the T. cruzi parasite, there are a variety of ways a dog may come in contact with the organism. Illness may occur when a vector—a kissing bug (Triatominae)—bites the dog on the skin or on a mucous membrane (such as the lips) and leaves infected feces in the wound. It can also occur when a dog eats an infected prey animal (e.g., rodent) or ingests the feces from a kissing bug. The parasite can also be passed from a mother to her offspring.