Chagas Resource Page



This page is intended to help SWESR fosters and adopters—and anyone—learn more about the growing threat of Chagas disease and to show how SWESR is prepared to help you and your Setters respond.

The bad news is that Chagas is a growing threat in the Southern half of the country. Very soon, researchers expect Chagas disease cases to surpass the number of Heartworm cases in Texas. Researchers tell us that as many as 20 percent of shelter dogs test positive for Chagas, and the percentage is likely even higher for dogs from hunting ranches. Seventeen SWESR dogs have been diagnosed with Chagas since 2021, all rescued in Texas and Oklahoma. This was twice as many dogs as when we started testing in 2019, and for SWESR, Chagas infections now surpass Heartworm infections for our incoming dogs.

Without treatment, Chagas can be debilitating or fatal. It’s a stealthy disease that can cause acute illness and even sudden death, especially in younger dogs, even before any symptoms show themselves. In older dogs, the disease can cause chronic heart disease. And because Chagas is still not widely recognized or tested for, the symptoms and deaths it causes, are too often misdiagnosed and misunderstood.

But now for the good news. While there is still no vaccine nor an FDA approved treatment, thanks to recent advances in veterinary medicine, we are now definitely diagnosing and, as part of a clinical trial, treating this dangerous disease. SWESR understands that scientific research is dynamic and, working closely with our veterinary partners, we pledge to stay abreast of all development in treatment.

Ultimately, we are committed to testing and treating every single dog that comes to SWESR, regardless of location. We are committed to following the treatment protocol based on the most recent scientific research. At this time, we have vet clinics in Texas and Oklahoma working with us to test incoming dogs, and we are working hard to find more clinics in all states where we rescue to test and treat.

We are committed to working with the DVM community, the rescue community, and the public at large in helping advance awareness of Chagas and the resources currently available to combat it.

 We are committed to supporting our fosters and adopters every step of the way, as they learn about this disease and learn how to care for and cure dogs who have been infected.

What exactly is Chagas Disease?

If you live in Texas or the South, you’ve probably seen this bug:

It’s commonly called a Kissing Bug, but unfortunately its kiss can be fatal. That’s because these common bugs have about a 50/50 chance of carrying a nasty parasite named Trypanosoma cruzi (T. cruzi) that causes Chagas disease. Chagas invades heart muscle tissue causing severe heart arrhythmia, heart failure, and, if untreated, death.

Chagas is now endemic in Central and South America and in the southern United States, where it’s estimated to infect more than 650,000 dogs each year in Texas and millions more across Southern states. Texas A&M’s website currently identifies eleven different kinds of triatomine (kissing) bugs in the United States, with the highest numbers of the bugs found in Texas, New Mexico, and Arizona.

How is Chagas contracted in dogs?

Chagas disease can infect any mammal through the following pathways:

  1. Insect transmission through the feces of an infected kissing bug
  2. Vertically through an infected female to her young
  3. Blood transfusion
  4. Ingesting a dead infected mammalor ingesting a kissing bug

There are no cases reported ever of dog to human transmission. Dogs undergoing Chagas treatment for 2 or more weeks have no circulating parasites, and are not able to transmit the diseaseThe only way the disease could be transmitted during the two week period is through direct blood to blood contact between both dogs.

Chagas CANNOT be contracted by a dog or any mammal living in the home with an infected dog, nor can it be transmitted by an uninfected dog eating the feces of an infected dog at any time during treatment.

What are the symptoms?

There likely won’t be outwardly obvious symptoms, but an EKG is done prior to starting one of the medications as a precaution. A few dogs have shown early heart irregularities that are not life threatening and can be reversed with treatment. The first month of treatment is when the parasites are cleared from the blood stream and after that month the risk is significantly decreased. The treatment is for a full year to ensure that the parasites are gone from all tissue, not just the blood.

What is SWESR doing about Chagas? 

We are dedicating the resources it takes to take Chagas head on! SWESR was, to our best knowledge, the first Texas rescue to begin routinely testing for Chagas. From diagnostic testing to treatment to retesting, SWESR supports fosters and adopters through the whole process, providing a treatment plan for each dog according to the year-long protocol prescribed by the most expert veterinarians in the field. We supply a treatment plan for all dogs, provide the medicines and assist in getting all necessary tests done, before, during and after treatment.

What is the typical treatment protocol?

The typical treatment protocol includes the following steps: diagnostic testing, 12 months of treatment, post-treatment retesting, and annual follow-up testing. SWESR will send reminders in advance of key treatment and testing milestones. To see a quick overview of all tests and treatments associated with a Chagas diagnosis, click here.

While testing and treatment may seem confusing at first and finding clinics and labs is still a challenge, it is all going to get much easier as we move forward and as the science and our local testing capacities in Texas develop. We are excited to see more clinics coming on board in all states where SWESR rescues dogs. And we are deeply appreciative of the fosters and adopters who have already seen infected dogs through the entire process and now see them restored to health. Their experiences will lead the way for so many others.

What’s next?

SWESR is grateful to work with one of SWESR’s primary veterinary partners, Roy Madigan, DVM, as we prepare to deal with the increasing number of Chagas positive dogs coming into our rescue. Dr. Madigan is an international leader dedicated to finding the most effective tests and treatment of Chagas and is currently helping lead a clinical trial for the world’s first treatment of Chagas disease, in which SWESR and our dogs are participating.  Our hope is that at the conclusion of this important trial the treatment receives FDA approval.

SWESR is also participating in a National Chagas Registry to help determine the actual prevalence of this disease in the canine population. We are also working to help advance broader awareness of Chagas among the DVMs and veterinary clinics we work with, helping more become aware of the dangers of Chagas and to the amazing resources now available to diagnose and treat this disease.

At present, SWESR’s two primary intake clinics in Frisco, TX, and Spring Branch TX, as well as a handful of cooperating veterinarians in Texas and Oklahoma, routinely test all incoming SWESR dogs.

SWESR now uses the most accurate diagnostic test available, the ELISA test, run through the VRL laboratory in San Antonio, TX. Some DVMs may only be aware of the IFA test run through the TVMDL laboratory at Texas A&M, and SWESR will work with them to encourage the more reliable ELISA diagnostic test. SWESR now includes a diagnostic Chagas test on the vetting lists for all incoming dogs and includes a VRL order form to facilitate test processing and payment. 

In the future, we hope that testing will become far easier with more clinics and laboratories participating. We also anticipate availability sometime soon of a single annual combined test for both Heartworm and Chagas. And, of course, researchers are currently working to formulate an effective vaccine to prevent this disease. But until then, we are responding to the growing crisis of Chagas as best we can, dog by dog, case by case.

SWESR Resource Team

Dr. Roy Madigan, DVM, SWESR’s Chagas Advisory Vet, is available to talk with your Vet, as needed. He is on a mission to educate as many DVMs as possible.

Susan Dunlap provides the meds ( or at 210-865-6492)Please give at least 3 weeks advance notice when ordering more medications.

Carla Cooper coordinates SWESR’s Chagas Program with our DVM expert and keeps track of all SWESR dogs undergoing treatment. She sends reminders before treatment milestones and is always available for questions. Contact her at or at 830.837.1215