THERAPEUTIC MANAGEMENT OF TRYPANOSOMIASIS IN DOGS
Trypanosomosis is a haemoprotozoan disease entity caused by various members of Trypanosoma sp. affecting different species of domestic and wild animals like horses, mule, donkey, camel, cattle, buffaloes, sheep, goat, dogs, pig, elephant, deer, foxes, tiger and jackals with chief clinical signs of high intermittent fever, anaemia, loss of weight, oedema of dependent parts, nervous symptoms, abortion and is responsible for major production losses (Barr et al.1991). The disease is transmitted by biting flies particularly Tsetse, Tabanus, Stomaxys, Culicoidesetc (Green 2006). Severity of canine Trypanosomosis ranges from acute, subacute to chronic. In dogs an acute and fatal type is commonly seen and death possibly occurs in 2 – 4 weeks (Soulsby 1982). Lakshmi Prasad et al. (2015) reported prevalence of 2.28 % in male, 2.40% in female dogs and highest prevalence in young dogs of less than 2 years of age. Clinical signs are characterized by weight loss, progressive weakness, anorexia, anaemia, intermittent fever, conjunctivitis, swelling of limbs, enlarged superficial lymph nodes and corneal opacity which are characteristic findings in chronic Trypanosomosis (Thirunavukkarasu et al.2004). There are a number of effective trypanosomacidal agents for dogs including suramin, quinapyramine and diminazene but single dose of diminazene aceturate is effective in eliminating the natural Trypanosomosis infection in canine (Rani and Suresh 2007).
Trypanosomiasis is a zoonotic disease caused by protozoans of the genus Trypanosoma that typically inhabit tropical and subtropical climates. Trypanosoma evansi infects only animals and causes a disease known as “surra”. Infected dogs present primarily with lymphadenopathy, malaise, weight loss, hyperthermia and anemia. Conjunctivitis, blepharitis and uveitis have also been described.
Symptoms of 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.
- 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.
Causes of Trypanosomiasis in Dogs
- The cause of disease comes from the bite of the tsetse fly which is carrying the trypanosomes, they act a biological vector (carrier of the parasite or disease)
- If an infected tsetse fly bites your dog, the parasites are transmitted in the saliva to the wound
- The insect also deposits infected feces on your pet’s skin and combined with the bite it aggravates the bite site causing irritation and scratching which only makes it worse by spreading the irritant around and pushing it into the open skin
- Trypanosomes can also be spread by other various biting flies, for example, the horse flies (Tabanidae)
- Mechanical vectors can include surgical instruments, needles, and syringes that have been contaminated with infected matter or flies landing on them
Diagnosis of Trypanosomiasis in Dogs
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.
Treatment of Trypanosomiasis in Dogs
Treatment of dog is carried out with diminazene aceturate at dose rate of 3.5 mg/kg body weight intramuscularly (Rani and Suresh, 2007). Injection of Berenil RTU (Diaminazine Aceturate, Intervet) is administered followed by administration of tablet Doxypet (Doxycyclin, Savavet) @ 5 mg/kg bid per orally. Supportive treatment like hepatic protectant, tablet Hepa20 O.D. and syrup Immulyte @ 5 ml bid for platelet boost up is also given. To reduce the nervous sign, neurobion forte one tablet is given once a day, for seven days. The dog may be recovered clinically, within a week of time.
The clinical signs and symptoms along with the microscopic examination of Trypanosoma organism through peripheral blood smear may be suggested the case of Trypanosomosis. However, it is difficult to distinguish the species of Trypanosoma. So there is need of serological and molecular tests for the diagnosis of species of Trypanosoma. Moreover, it can also be concluded that single dose of diminazene aceturate @ 3.5 mg/ Kg body weight had been successful in treating the dog with Trypanosomosis (Ramesh et al. 2016).
Compiled & Shared by- This paper is a compilation of groupwork provided by the
Team, LITD (Livestock Institute of Training & Development)
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