Trypanosomiasis in Dogs

Acute symptoms to watch out for include:

• Depression -  your dog may seem disinterested in what is going on around him

• Lethargy - lacking energy and just wanting to sleep
• Your dog may have a fever 
• He may suffer from diarrhea
• Loss of appetite
• Enlarged liver or spleen – seen on tests or scans

• Neurologic abnormalities - he may suffer seizures

• Sudden death

With chronic symptoms, you may notice the following:

• Exercise intolerance with a reluctance to do anything active
• Increased heart rate (tachycardia)
• Abnormal heart rhythms such as skipping a beat or two
• Fluid accumulation throughout the body
• Coughing and finally death

Types

Trypanosomiasis (T.) cruzi

This is a species of parasitic euglenoid protozoan. They typically bore into tissue in another organism and feed on the blood or lymph. They are associated with heart disease in canines as the parasites attacks the heart muscle causing major damage. Infection occurs when the infected insect deposits it feces on your dog’s skin and then bite, causing an irritation and scratching. 

T. brucei

This is a species of parasitic protozoan belonging to the genus Trypanosoma.  These species invade tissue and cause tissue damage to several organs and is also known as African sleeping sickness.

If you suspect anything is wrong with your dog, it always pays to have him checked by a veterinary expert. She will check for clinical signs and will want to know of any travel history to an endemic area where your dog may have been affected by trypanosomiasis. This disease is hard to pinpoint in the very early stages. The age of the dog and supporting observations (loss of weight, lethargy, fever, loss of limb control) all play a  part in diagnosis.

Some blood test smears may show infection if the parasite is in the aparasitemic phase, or they may be seen in the lymph nodes. The gold standard for diagnosis is a combination of clinical signs and a positive serology, which is done to detect the antibodies against the parasite. Diagnosis can be based on findings of congestive cardiac insufficiency in canines as the parasite often attacks the heart muscle.

Unfortunately, treatment for this condition is not easy, as it is hard to diagnose before it becomes advanced. The drug diminazene aceturate has been shown to be effective in some cases, but not all. In the United States, it is almost impossible to obtain this drug as it is not allowed in the country. The fact that this disease does not permit a definitive cure, and remains hard to eliminate means the prognosis is not good, but if diminazene aceturate works for your dog, then it offers a reasonable quality of life although there are neurological side effects to consider. 

Another drug that is available in the United States is nifurtimox and has been used in tests, but has serious neurological and gastrointestinal side effects for your dog. This condition also weakens your dog’s heart, so your pet may need additional medication to help, but the damage that has been done may shorten your dog’s life.  You will need to talk to your veterinary caregiver and decide what is the best solution for your pet.