Trypanosomiasis
Disease Name:Trypanosomiasis
Species affected:Bovine, equine,
About disease:
“Surra” or trypanosomosis caused by Trypanosoma evansi is the most widely distributed
pathogenic mechanically transmitted vector borne haemoprotozoan disease of domestic livestock
and wild animals in India. The disease is transmitted mechanically through the bite of flies of
species Tabanus, Haematopota, Lyperosa and Stomoxys. Trypanosomiasis causes serious
economic losses in cattle from anemia, loss of condition, and emaciation. This chronic infection
often ends in the death of the animal. Because trypanosomes are transmitted by tsetse flies and
other vectors, trypanosomiasis is difficult to control.
Animals affected:
T. evansi has a wide host range. Surra affects mainly camels and horses but buffaloes and cattle
are also affected. Other species that develop severe disease include donkeys, mules, deer, llamas,
dogs, cats, cattle and buffalo. Sheep, goats, pigs and elephants may occasional develop mild or
chronic disease.
Cause:
Trypanosoma evansi
Symptoms:
In cattle and buffalo the disease occurs as peracute, acute, subacute or chronic form.
In acute form animal is dull, show staggering gait, staring wide-open eyes, encircling
movement, pyrexia and death occurs within 6 to 12 hours.
In peracute form neural signs can be confused with anthrax, neural form of ketosis and
tumor or cyst or abcess in brain.
In subacute and chronic forms, along with other signs emaciation and corneal opacity
occurs.
Control and Management:
Following measures can be adapted for the control of Trypanosomiasis:
1. Use of chemoprophylactic (suramin, quinapyramine methyl sulphate and chloride) drugs
before the onset of rainy season. This will protect the susceptible animals during the high-risk
period.
2. Sick animals must be given immediate attention and proper treatment. This helps in spreading
of disease and reduces the risk of infection and development of carrier status.
3. Trypanocides must be selected keeping in mind the problem of drug resistance in the area.
4. In view of reports of immunosuppression caused by trypanosomes, thereby interference with
vaccination programme, the animals must be treated for surra, before adopting any vaccination
programme.
5. Mass campaign for eradication of Tabanus and other biting flies by spraying insecticides. It
has limited value under Indian conditions.
6. Need for diagnostic centers all over the country.
7. Search for new chemotherapeutic agents.
8. Herbal medicines must be investigated for the treatment of surra.
9. Regular disease surveillance and monitoring in apparently healthy animals.
10. Treatment and control against other diseases, deworming and vitamin supplements.
Vaccines:
No vaccines are available
Meteorological Occurrence:
The monsoon and post monsoon seasons are most prevalent for propagation of disease due to the
preponderance of tabanid flies. However, cases of surra are encountered throughout the year. Surra has
been detected in animals of arid and semi-arid regions of countries with warm and temperate climate. The
incidence of surra is higher in north and northwestern parts as compared to eastern and southern parts of
India.