Chagas Disease in Cats

Chagas disease is caused by the single-celled protozoan parasite Trypanosoma cruzi (T. cruzi), that is common in South and Central America, but rare in the United States where it has only been detected in the southern states. The method of transmission in kissing bugs is as follows: 

• Kissing bugs carry T. cruzi larvae, which go through several life cycle stages in the bug.
• Kissing bugs bite mammals; they are called kissing bugs because they often bite the faces of their victims, although they may bite other parts of the body as well.
• The bug defecates when it bites, and when the animal or human scratches or rubs the area, feces left by the bug contaminate the bite lesion, mouth, ears, nose or eyes, allowing T. cruzi present in the kissing bug’s feces to enter the host animal.
• Once inside the mammal, the organism T. cruzi enters the host mammal’s tissues, muscles, and cells and begins reproducing.
• This causes damage to the invaded cells which then rupture, allowing T. cruzi organisms to enter the bloodstream.
• Once in the bloodstream of an infected animal, the organism can spread to other parts of the body, repeating this process and causing Chagas disease.
• They also can be taken up again by kissing bugs through bites to repeat the cycle.

In addition, the parasite T. cruzi can cross the placenta in a pregnant mammal or be passed through mother’s milk to an infected mammal’s offspring. Other methods of transmission occur when an animal eats an infected animal or by eating the infected kissing bug.

Your veterinarian will do a physical examination and specifically ask the pet owner questions about possible exposure to kissing bugs. Residence or travel to an area where infection from kissing bugs was likely to occur should be reported to your veterinarian. 

There are serological tests available to aid in the diagnosis of Chagas disease and urine and blood samples will be taken to employ these tests and also rule out other diseases. X-rays and ultrasounds may be ordered to determine the extent of heart and tissue abnormalities caused by the Chagas disease.

Chagas disease can be hard to diagnose as there are only small numbers of the parasitic organism causing it in the blood. However, a thick blood smear on a slide examined under a microscope may reveal the parasites. Another method is to take samples of lymph node cells and examine them under a microscope to reveal the presence of the parasite.

Sometimes, T. cruzi  parasites are discovered postmortem in the heart tissue of an infected animal.

A different method used to reveal the presence of T. cruzi  parasite is to feed kissing bugs the tissue of an animal that may have been infected, and then kill the bug and examine its digestive system for T. cruzi . 

There is no cure for Chagas disease and the presence of T. cruzi organisms in a host animal poses an extreme health risk to people and other animals, so euthanasia is often recommended.

There has been some success with medication used for treatment of Chagas disease (Benznidazole is one that has had some effect at disrupting the disease's progression), but resistance to the medication has occurred in many cases.

Treatment usually consists of supportive treatment for heart complications and other symptoms.