Opossums, Kissing Bugs Trypanosoma Cruzi And You

Ron Hines DVM PhD

Many folks call most any insects that crawl “bugs”, cockroaches, beetles, crickets, ants, etc. But none of these are true bugs or hemiptera. These specialized insects either live by sucking out plant juices or the blood of animals. As adults, all of them can fly. all of them have a long sharp, needle like mouth. That group also includes bed bugs. Bed bugs and kissing bugs are the most important of the group for pet owners. Although bed bugs prefer to bite humans, they have the ability to bite our pets as well. Thankfully, they are not know to transmit disease to pets or humans. Kissing bugs are a much more dangerous species. They are also called assassin bugs. It is not particular as to which warm blooded animal it sucks blood from. Generally it hides in the daytime and begins searching for a victim at sunset when animals are apt to be resting and not on the move. Many compounds in exhaled breath help it home in on its prey. Light also attract them. If one of the bug’s victims is already infected by the single celled (protozoa) blood parasite trypanosoma cruzi, causing Chagas disease. Chagas disease is also called American Trypanosomiasis. The victim of Chagas disease once bitten by a kissing bug could be you, your dog or less likely you cat. (read here)

I the United States among wildlife, opossums, armadillos and raccoons are the most likely to carry the Chagas disease parasite although it has also been found in rodents and rabbits. They too caught it from a kissing bug carrier. The bug itself is not harmed by that trypanosome. They have adapted to live happily together.

What Are The Signs Of A Chagas Disease Infection?

In people shortly after being bitten by a kissing bug, it is common to develop a fever, a rash at the bite site, aches and pains, headache, swollen lymph nodes and liver and spleen enlargement. With time, those signs go away. Some people then remain healthy, but other, many years after, develop serious heart arrhythmias that can lead to death. Because of the disease’s slow but continuous attack on nerves throughout the body, other possible symptoms are to many to list.

In dogs, the symptoms are similar, early in infections, signs of ill health are very non-specific. Perhaps weight loss, digestive tract issues, lack of energy, etc. Later in the disease, heart disease leads the reasons that these dogs are brought to veterinarians. Other late disease findings often include an enlarged spleen and lymph nodes, generalized weakness, diarrhea and a cough. Because all of these symptoms could have so many underlying causes, many more cases of Chagas disease in dogs are missed than discovered.

Where Is This Disease Most Likely To Be Found?

Kissing bugs love hot humid weather and dampness and hiding places. So they are common throughout the tropical countries and in the Southern, non-desert, portions of the United States and mountainous regions. The disease has been reported in dogs from Texas, Louisiana, South Carolina, Virginia, Georgia, Tennessee and Oklahoma, in that order. The Lower Rio Grande Valley of Texas, where I live, is known to be a Chagas hot spot. A 2017 study of opossums trapped by animal control departments in and around McAllen, Texas found that of 100 urban opossums trapped and sampled through the highly accurate PCR method, 15% had the parasite. Of the positive opossums, the trypanosome was not only found in their blood, body and heart muscle, it was also present in their anal glands and anal gland secretions. The Trypanosoma cruzi-positive opossums were nearly 14 times more likely to have significant heart damage when examined microscopically than the negative opossums. Two of the three kissing bugs they also caught were positive for the parasite. Detective methods have advanced so much in the last ten years. The authors write that they detected that the kissing bugs had fed on dog, human and opossum blood in the past. Read that study here.

How Would My Veterinarian Or My Physician Treat A Chagas Disease Case?

Unfortunately, there are no known medications that destroy the Chagas trypanosome parasites in the latter stages of the disease which is the stage most likely to be diagnosed. In its early (acute) stages, the drug benznidadzole is often given. The second line treatment if that fails is nifurtimox. The antifungal medications albaconazole and ravuconazole have also been suggested, but there is little evidence that they are effective. The more advanced the symptoms are, the less likely these drugs are to have positive effects. The best veterinarians have to offer is supportive care and symptom management.

How Can I Protect Myself And My Pets?

There is currently no vaccine to prevent Chagas disease in people or animals. The best advice is to minimize the chances that you or your animal are bitten by kissing bugs. That means clearing your yard of debris in which they might hide, mulch piles, wood piles, rotting lumber and brush. Free range chickens and guinea hens might also be helpful. The are known to eat ticks so kissing bugs are probably also on their menu. The problem is that birds perch high at night when the bugs would be most active.

Insecticides on your pets and around animal housing might also be quite helpful. (read here) I use a pre-diluted bedbug spray containing bifenthrin: 0.25% and imidacloprid 0.050%. Imidacloprid is an ingredient in Advantage® Defense Care®, Advantage II® and Advantage Plus®, Barrier heartworm and flea preventative and Seresto anti-flea collars, so it is quite safe. But bifenthrin can be toxic to dogs that are exposed to it in sizable amounts so I limit the bed bug spray to sidewalk and wall cracks, crannies, tool sheds, dog houses, door frames, behind washers and driers, and places where my pets are unlikely to spend time but where kissing bugs are fond to inhabit during the daytime. Permethrin is a good alternative. It is sold as a concentrate for livestock. It just is not as long lasting as bifenthrin. Rain and humidity destroy it. Permethrin is also much less likely to be toxic. For example, permethrin is the active ingredient in Nix head louse treatment for children and adults. Any insecticide that ends in thrin (cyfluthrin, cyhalothrin, cypermethirn, deltamethrin, etc.) will likely kill kissing bugs. All of these products are more toxic to cats than to dogs. Some claim that Bravecto® (fluralaner)and Nexgard® (afoxolaner) will also kill kissing bugs. But I do not know if that has been tested to be true.

Can I Catch Chagas Disease From My Dog, Cat Or The Wildlife I Might Interact With?

It would require Chagas trypanosome-contaminated blood or kissing bug faces to enter your body. That is theoretically possible but unlikely to happen if you take precautions. Perhaps through being pricked by a contaminated hypodermic needle that was left exposed after being used on an animal. Perhaps by consuming some item that was exposed to animal feces. (read here) Be cautious, be sanitary, wear gloves, wash your hands frequently. Particularly when administering injections or dealing with opossums, armadillos and raccoons.

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