By Dr. Becker
Chagas disease, or American trypanosomiasis, is caused by a one-celled parasite named Trypanosoma cruzi. Insects called kissing bugs transmit the parasite from host to host.
The disease is endemic in Central and South America where it is a significant cause of illness in humans, as well as in a number of US states, including Texas, Louisiana, Oklahoma, South Carolina, and Virginia. The parasite has also been reported in western states, including California and New Mexico, down south in Florida, Georgia, and North Carolina, and also in Maryland.
How Chagas Disease Is Transmitted
Chagas disease can only be acquired through an infection with the T. cruzi parasite. There are a number of ways a dog or cat can be exposed to the organism, including receiving a bite from an infected kissing bug, eating an infected bug, eating the poop of an infected host animal or the animal itself, or through a blood transfusion.
Small animals such as guinea pigs, rats, opossums, raccoons, and armadillos as well as cats and dogs, can serve as reservoirs for the parasite, and are able to spread the infection from animal to animal.
T. cruzi exposure generally doesn't cause the significant disease in animals that it does in people.
Symptoms of Chagas Disease
Often, animal hosts of Chagas disease, including dogs and cats, show no signs of illness.
Two forms of the disease have been observed in dogs: acute and chronic. Some dogs enter an asymptomatic period that can last months to years. During that time, however, there is a progressive quiet development of the parasite. This leads to degeneration and inflammation of the heart, which can eventually cause heart failure and death.
If the infection is severe, dogs may develop weakness, anemia, and an enlarged spleen and lymph nodes. Rarely, if large numbers of the parasite enter the heart, they can cause inflammation that leads to sudden collapse and death. Or, the parasites may cause the heart muscle to fail gradually over time.
With some infected dogs, symptoms of weakness and lack of coordination are profound. Cats may have convulsions and paralysis of the back legs.
As you can see, the symptoms of Chagas disease can be somewhat random and diverse in pets.
Diagnosing Chagas Disease
A complete physical examination, blood tests, urinalysis, serology, and an electrolyte panel will be required. Serologic tests exist for the diagnosis of Chagas disease.
X-rays may also be taken to look for heart and pulmonary abnormalities associated with the disease, and an echocardiogram may be helpful to visualize changes to the walls and chambers of the heart.
Another rather strange but effective way of diagnosing a T. cruzi infection is called xenodiagnosis. This involves keeping kissing bugs in a laboratory and feeding them blood or tissue from an animal suspected of harboring the parasite. The bugs are then killed and their digestive systems examined for the presence of the parasite.
There are several drugs that have shown limited use in improving symptoms in dogs during the acute stage of Chagas disease, but none provide a cure.
Unfortunately, even animals that receive treatment for acute symptoms often progress to the chronic form of the disease. For these pets, supportive treatment for heart complications is very important.
There are certain natural remedies that may benefit Chagas-positive patients, but they should be used under the direct supervision of a veterinarian. I have never personally treated a pet with this disease, but my holistic colleagues in South America tell me the herbs pau d'arco, turmeric, and oregano can be beneficial.
Also potentially helpful are colloidal silver, grapefruit seed extract, and thymus extract, as well as several homeopathic remedies to treat the patient's specific symptoms.
Sadly, because there is no cure for Chagas disease in pets and because it is zoonotic, meaning it can be spread to people, many veterinarians recommend euthanizing pets with this condition.
Obviously, prevention is the goal, which means ensuring your pet is never exposed to kissing bugs or host animals that could be infected with the T. cruzi parasite.
The Centers for Disease Control and Prevention (CDC) offers these precautions to prevent infestation for people living in endemic areas:1
✓ Seal cracks and gaps around windows, walls, roofs, and doors
✓ Seal holes and cracks leading to the attic, crawl spaces below the house, and to the outside
✓ Remove wood, brush, and rock piles near your house to reduce bug populations
✓ Keep your house and any outdoor pet resting areas clean, and periodically check both areas for bugs
✓ Use screens on doors and windows and repair any holes or tears
✓ Have pets sleep indoors, especially at night
✓ If possible, make sure yard lights are not close to your house (lights can attract the bugs)
I would also add that using an all-natural outdoor bug deterrent, such as cedar oil spray or cedar oil yard spray can help reduce the presence of unwanted bugs in your pet's outdoor area.