Kissing Bugs and Chagas Disease in Dogs

Chagas disease is a protozoal infection transmitted by the “kissing bug.” It is a zoonotic infection, meaning it can infect both humans and animals. Chagas disease in dogs and humans can vary in severity, ranging from asymptomatic infection to fatal disease. 

Historically, Chagas disease was seen primarily in Central and South America. Sporadic cases occurred in the United States, but the parasite was not considered widespread. In September of 2025, however, a publication by the Centers for Disease Control and Prevention argued that Chagas disease should be recategorized as endemic to the U.S. (1). This means Chagas disease is now continuously present and circulating in the U.S.

As Chagas disease becomes more common, it is important to understand the impact this disease can have on both dogs and humans. 

What Is Chagas Disease in Dogs?

Chagas disease, also known as American trypanosomiasis, was first discovered in 1909. It is caused by a protozoan, Trypanosoma cruzi. This parasite can infect all species of mammals, but it tends to primarily affect humans and dogs. Common wildlife reservoirs include coyotes, raccoons, and opossum. 

Chagas in dogs causes a variety of clinical signs, ranging from asymptomatic to sudden death. In most cases, Chagas disease is not diagnosed until the late stages of infection. 

Causes of Chagas Disease in Dogs

Chagas disease is spread by triatomes, also known as “kissing bugs.” These insects are found throughout the Southern United States.

How is Chagas disease transmitted? When kissing bugs feed on an infected animal, they ingest T. cruzi found in the infected animal’s bloodstream. Once ingested, T. cruzi reproduces inside the kissing bug’s intestines. The infectious stage of T. cruzi is then shed in the feces. Humans and dogs typically become infected when an open wound (such as a kissing bug bite) is contaminated with infected feces. They can also become infected by ingesting a kissing bug or its feces.  

Chagas disease is most common in South America and Central America. It is also found in Mexico and throughout much of the United States, though it is most common in the Southern states. In Texas, for example, 55 percent of tested kissing bugs are infected with T. cruzi (2). Chagas disease is expanding its range over time, likely due to a combination of climate change and other factors (3).

Chagas disease is most common in dogs living in kennel or shelter environments. Kennels can attract kissing bugs, allowing for increased transmission. A dirty kennel environment can also increase the likelihood of dogs coming in contact with kissing bugs or their feces. 

Chagas Disease in Dogs Symptoms

Signs of Chagas disease in dogs can vary significantly, depending on the phase of infection. Clinical signs tend to progress and vary over time. Some dogs become very ill, while others stay mostly asymptomatic. 

Chagas disease symptoms in dogs may include: 

• Asymptomatic infection
• Fever
• Lethargy
• Decreased appetite
• Vomiting
• Diarrhea
• Enlarged lymph nodes, liver, or spleen
• Neurologic signs (e.g., seizures)
• Congestive heart failure
• Generalized weakness
• Sudden death

Phases and Forms of Chagas Disease

Chagas disease in dogs is typically divided into three phases: acute, latent, and chronic. The acute phase occurs immediately after infection. Next, infection enters a latent (asymptomatic) phase. Signs of chronic infection develop months or even years after the first exposure.  

In the acute phase, some dogs are entirely asymptomatic. If clinical signs of illness do occur, they typically include non-specific signs like fever, decreased appetite, lethargy, vomiting, and/or diarrhea. Your veterinarian may not even suspect Chagas disease, because the signs of acute Chagas disease correspond to many other signs of illnesses. Specific signs that may point to Chagas disease include heart inflammation, neurologic signs (uncommon), and enlarged lymph nodes, liver, and/or spleen. This acute phase of infection typically lasts approximately one month. 

After the acute phase of infection, a latent phase occurs. This phase is asymptomatic. The latent, asymptomatic phase of infection may last months to years. Some dogs stay in the latent phase for the rest of their life. In other dogs, however, damage caused by the parasite accumulates and causes signs of chronic infection. 

Chronic Chagas disease typically affects the heart. Signs may include congestive heart failure and generalized weakness. Sudden death may also occur.

Humans experience a similar disease course. Most human infections (70-80 percent) remain asymptomatic. However, when symptomatic infections occur, they also involve an acute phase, a latent phase, and a chronic phase. The chronic phase of Chagas disease in humans is typically associated with heart problems, digestive problems, and neurologic disease (such as seizures). 

Diagnosing Chagas Disease in Dogs

There are several different ways to diagnose Chagas disease. The best test depends on a dog’s stage of infection. 

During the acute phase of infection, microscopic T. cruzi parasites are typically visible in the blood. Your veterinarian or veterinary technician will make a blood smear, examine it under a microscope, and make a diagnosis. Less commonly, veterinarians may perform PCR testing to look for T. cruzi in the blood. 

In the chronic phase of infection, T. cruzi is not easy to find. Therefore, veterinarians must send a blood test for Chagas disease to an outside laboratory. Antibodies to T. cruzi in the blood show that the dog has been exposed to Chagas disease. False positives may occur, so multiple tests may be needed to confirm the diagnosis. 

Your veterinarian may also perform other testing, such as x-rays. Imaging can be used to diagnose the effects of Chagas disease, such as congestive heart failure or enlargement of the heart, liver, and/or spleen.

Chagas Disease Treatment and Management for Dogs

If your dog has been diagnosed with Chagas disease, you may be asking yourself, “is Chagas disease treatable?” Treatment options for Chagas disease are limited and not well-researched. Treatment in the acute phase of infection would probably be the most helpful, but most cases are not diagnosed until the dog is in the chronic phase of disease. In chronic Chagas disease, dogs are already experiencing changes to their heart; treatment at this phase is not always able to reverse these changes. 

Veterinarians typically treat T. cruzi with benznidazole or nifurtimox. These are anti-protozoal drugs designed to kill T. cruzi. Dogs may also be treated with a variety of heart medications to control the cardiac effects of Chagas disease. A pacemaker may be recommended for dogs with significant heart rhythm disturbances. 

Chagas Disease in Dogs Life Expectancy

The life expectancy for a dog with Chagas disease varies, depending on the severity of disease. Dogs with severe disease may survive for less than a year, while dogs with mild or asymptomatic disease may survive for several years. 

Cost to Treat

The cost of treatment can vary significantly. Some dogs are asymptomatically infected, and they may not require any treatment. In severe cases, treatment may cost several thousand dollars. Your veterinarian will be able to provide you with expected treatment costs after figuring out what treatment your dog needs. 

How to Prevent Chagas Disease in Dogs

While it is impossible to eliminate the risk of Chagas disease (unless you move to an area where the parasite is not present!), there are steps you can take to reduce your dog’s risk:

• Keep kissing bugs out of your home. Use screens in open doors and windows and ensure that the screens are free of holes. Plug gaps around doors, windows, and baseboards.
• Clean the area under and around your home. Remove brush, wood piles, and trash to make your yard less attractive for wildlife and kissing bugs. 
• Turn off outside lights at night. Kissing bugs are attracted to light. 
• Work with a pest control company to control kissing bugs on your property.

Unfortunately, there is currently no vaccine available for Chagas disease.

References

1. Chagas Disease, an Endemic Disease in the United States. U.S.  Centers for Disease Control and Prevention. Emerging Infectious Diseases. Vol. 31, No. 9. Sept. 2025. Accessed online https://wwwnc.cdc.gov/eid/article/31/9/24-1700_article
2. Kissing Bugs and Chagas Disease in the United States. Texas A&M University. Accessed online https://kissingbug.tamu.edu/
3. Climate change and Trypanosoma cruzi transmission in North and central America. Forsyth, Colin et al. The Lancet Microbe, Volume 5, Issue 10, 100946