Control of tick-borne diseases or ruminants in Sri Lanka with particular reference to babesiosis and anaplasmosis

• Department of Animal Production and Health, Sri Lanka

Improvement of dairy production from cattle in the milder highlands of central Sri Lanka is hampered by the presence of two tick-borne diseases, babesiosis and anaplasmosis, caused by blood parasites Babesia and Anaplasma. Both could be controlled by immunisation. A successful control campaign would encourage farmers to increase the size of their herds.
This project aims to develop improved protective vaccines in Sri Lanka, using techniques found effective in Australia. Preliminary attempts have been made to develop better vaccines in Sri Lanka, but those currently in use are similar to types replaced in Australia 20 years ago because of their relative ineffectiveness. Although Sri Lanka has many well-trained, competent research staff, they are hampered by limited resources for research.
Australia is a world leader in the development and use of live vaccines for tick-fever parasites of cattle. The presence of experienced research workers from Australia during this project will stimulate further local research and development in Sri Lanka.
The initial stage will involve an epidemiological study to determine where and when cattle are most susceptible to babesiosis and anaplasmosis. Results will aid in the formulation of a national control strategy. Next, development of attenuated vaccines will take place, using local strains of Babesia and Anaplasma. Field and laboratory trials will test the effectiveness of these vaccines compared with other vaccines from Australia.
In the long term the Sri Lankan Government aims to develop a dairy herd comprising a mixture of Bos taurus and Bos indicus cattle adapted to local conditions. An economic study to determine the cost-effectiveness of vaccinating village livestock in areas categorised as 'high risk' in the epidemiological study will form an integral part of the project. Furthermore, effective vaccination of imported cattle will remove a major hurdle to increasing livestock productivity, and both the epidemiological and economic surveys will assist in the selection of best genotype combinations for dairy production in infected regions.
Investigators will study the role of the buffalo as a reservoir of ticks and the diseases they transmit, and they will assess the goat population to determine whether tick-borne diseases have a significant impact on these ruminants as well.
Findings in Sri Lanka may well have implications for many countries in Asia, Africa and South America, where major economic losses from ticks and tick-borne diseases presently limit many livestock development programs.