Chagas Disease (Kissing Bug Disease) in Dogs

Chagas disease is a medical emergency; it is a life-threatening condition that can affect all mammals, including humans. Currently, there is no vaccine, and treatment options are limited and not always effective.

Animals living in and those that have traveled to endemic areas should be screened for the disease if infection is suspected. The only way to increase the patient's chances of survival is prompt treatment in the early stages of the condition to reduce damage to the heart.

If treatment is delayed or the condition is left untreated, congestive heart failure develops. Many animals die as a result of cardiac failure or undergo euthanization due to the zoonotic nature of the condition.

While chagas disease is most commonly found in Latin America, a number of cases have been reported in the southern United States.

Chagas disease symptoms are nonspecific and may vary from case to case, with some patients exhibiting minor clinical signs prior to death. The condition is divided into three stages, acute, latent, and chronic.

Acute phase: The acute phase of the disease can occur anywhere between five to forty days from infection. In the first stage, animals may result in asymptomatic or present only mild, frequently overlooked symptoms.

Latent phase: After the first acute phase, the infection enters its latent stage, generally lasting between one and four months. During this time, the patients do not present any symptoms. Some animals may die suddenly during the latent phase.

Chronic phase: If the condition is not identified and treated within the first two phases, the infection becomes chronic. The Trypanosoma cruzi parasites in the animal's body enter the heart tissue where they replicate. The chronic phase is characterized by the onset of severe symptoms.

Chagas disease is caused by the Trypanosoma cruzi parasite. T. cruzi cannot spread from mammal to mammal, as it requires an intermediate host to spread, the Triatominae bug, commonly known as the kissing bug.

Dogs become infected as the result of the following:

• An infected Triatominae bug feeding on their blood and depositing feces in the bite wound
• Eating infected Triatominae bugs, usually while grooming
• As the result of a blood transfusion from an infected donor

Once the parasite enters the animal's bloodstream, it multiplies and causes severe damage to the heart, liver, and other organs. While mammal-to-mammal transmission cannot occur, pregnant dogs can transmit the disease to their puppies via the placenta or infected breast milk.

Most cases of Chagas disease are diagnosed during the third phase of the condition, as most animals do not present severe symptoms before the onset of heart failure. If the infection is suspected, the animal will undergo the following diagnostics:

• Physical examination
• Testing for the parasite or antibodies against the parasite
• Blood smear analysis
• Bloodwork
• Diagnostic imaging such as X-rays or ultrasound
• Electrocardiogram

Currently, there is no definitive treatment for Chagas disease. Once diagnosed, treatment options depend on the phase of the infection.

Animals diagnosed early have been treated with a variety of different anti-parasitic medications, with varying levels of success. Even animals treated during the acute or latent phase can progress to the third stage of the infection as medication does not clinically cure the condition. Once the disease enters its chronic phase, no treatment is available, and euthanasia is the only option. Animals that develop heart failure may benefit from supportive therapies designed to improve cardiac function, however the success of these treatments is often minimal.

Prognosis for Chagas disease varies from guarded to extremely poor depending on the stage of the infection. Animals diagnosed during the acute phase of the infection and treated early have the highest chance of survival; nonetheless, due to the absence of definitive treatment, even if properly treated, patients can develop chronic Chagas disease.

Chronically affected patients have an extremely low chance of survival and die. Due to the zoonotic potential of the disease, affected animals are often euthanized.

Due to the infectious nature of the disease, the lack of an available vaccine and the absence of effective treatment options, prevention is paramount. Strategies include:

• Insect control: plastering walls, frequently cleaning the house, and using insecticide spays are useful methods in controlling Triatominae bugs
• Deltamethrin collars can reduce the risk of triatominae bugs feeding on the animal's blood.
• Frequently washing and disinfecting animals' bedding and living area.

Chagas disease is more common in animals living in endemic regions, especially in Latin America. Cases of Chagas disease infections have been found in the southern United States.

Animals living in rural and low-income areas are more likely to become infected.

• Trypanosomiasis
• Chagas disease
• American trypanosomiasis
• Kissing bug disease
• Triatomine bug disease