E. Tama
Laboratoire Veterinaire de Bujumbura
B.P. 227
Bujumbura, Burundi
Theileriosis is endemic in Burundi. Local Ankole (Bos indicus) cattle are naturally resistant to Theileria parva, with a calfhood mortality of less then 10%, although complications with other tick-borne diseases, endoparasites and poor nutrition make accurate diagnosis difficult. Improved cattle are much more susceptible to theileriosis and an estimated 30-40% may die each year of this disease.
Control of theileriosis and other tick-borne diseases in Burundi is achieved mainly by dipping, but this method is becoming less reliable because of the escalating cost of acaricides. Also, because of the expansion of crop agriculture, some livestock owners can no longer walk their cattle to dips. Antitheilerial drugs are used but they are expensive, not generally available and often used without proper diagnosis. Emphasizing crop agriculture, the Burundi Government wishes to increase the numbers of improved cattle (current estimate 5000) while reducing the total cattle population (now about 400000). The use of immunization is an important strategy in this programme of livestock improvement. Infection-and-treatment immunization was introduced in 1981 using a combination of three local isolates and tetracycline treatment. Later it was shown that two of the three stocks were effective against natural challenge. The immunized cattle remained productive, but different treatment regimens were necessary for different cattle types, depending on the proportion of Bos indicus in their breeding. The immunization method has been used mainly on young cattle on government farms. These immunized cattle are then distributed in the countryside. Between 1981 and 1987, 560 cattle were immunized and the total to date is 850.
The following conclusions may be drawn about the infection-and-treatment immunization programme in Burundi.
a) The immunization programme has attracted great attention; demands for its application exceed the ability of the small number of laboratory staff to provide it.b) Concern has been expressed about the disease risk that carrier (immunized) cattle may introduce to other improved stock.
c) Where dipping intervals have been extended in the western part of the country, sporadic cases of heartwater have occurred.
d) Occasional cases of blindness have been observed in immunized cattle.
