Chagas Disease in Dogs

Chagas disease in dogs is the result of infection by Trypanosoma cruzi, a protozoan parasite. This disease can spread from dogs to humans, and is considered a serious illness when it occurs in humans. Here's what you should know about Chagas disease, its spread, symptoms and treatment.

Chagas Disease Explained

Chagas disease is an infection caused by T. cruzi, a one-celled, parasitic microorganism. It's spreads through kissing bugs. The kissing bugs bite an infected host, and then T. cruzi develops within the bug's body. When the kissing bug bites again, it also defecates on its host. The kissing bug's fecal matter is infected with T. cruzi, and the T. cruzi parasites can enter the kissing bug's host through open wounds, like cuts or scrapes, or through orifices, like the eyes and mouth.

Once T. cruzi has infected a host, it begins to reproduce inside the cells of the host's muscles. This leads to cell rupture. Ruptured cells release the T. cruzi protozoa then enter the infected host's bloodstream, where they can be further spread by the kissing bug's bite.

The bite of the kissing bug is a common means of transmission, but animals may also catch this infection if they eat smaller infected hosts, or if they eat the infected kissing bugs themselves.

Symptoms of Chagas Disease in Dogs

If your dog is infected with Chagas disease, he may never display any symptoms of that infection. When symptoms appear, however, they usually include:

  • Anemia
  • Weakness
  • Lack of coordination
  • Enlargement of lymph nodes
  • Enlargement of the spleen
  • Fever

T. cruzi can infect your dog's heart, causing rapid inflammation and sudden death, or slow heart failure and death. 

Diagnosing and Treating Chagas Disease in Dogs

Chagas disease can be difficult to diagnose definitively, because there usually aren't very many T. cruzi parasites in the infected animal's blood stream at any given point. Your vet may need a blood sample and a sample of lymphatic tissue for biopsy. Your vet may diagnose the infection via xenodiagnosis, a procedure in which requires feeding your dog's blood to a kissing bug and then dissecting the kissing bug to look for immature T. cruzi protozoa in its digestive tract.

Chagas disease in dogs cannot be cured. The disease is dangerous to humans, and can cause fever, lethargy and enlargement of the spleen and lymph nodes. Children most often develop a life-threatening, acute form of the infection, which damages the heart and brain. Adults usually develop a chronic form of Chagas disease, which causes digestive and heart problems, usually 10 to 20 years after the initial infection.

Because there is no cure for Chagas disease and it can be life-threatening to humans, most vets recommend that dogs with Chagas disease be put down in order to prevent outbreaks of the disease among humans. Chagas disease is most common in Central and South America, but it appears infrequently in the southern regions of the United States. The best way to prevent Chagas disease is to rid your environment of kissing bugs.