C.P. Otim
Animal Health Research Centre
P.O. Box 24
Entebbe, Uganda
Uganda is a land-locked country of 240000 sq. km lying on the equator. It borders Sudan to the north, Kenya to the east, Tanzania and Rwanda to the south and Zaire to the west. About one-seventh of the country is covered by water. In the south of the country there are two rainy seasons, one in April/May and the other in September/November. In the northern parts of the country there is one long rainy season lasting about five months, usually from May to September. The northeastern part of Karamoja District is arid, having less than 510 mm of rainfall annually. Rainfall in the rest of the country ranges between 1015 and 1525 mm.
About 80% of households depend mainly on agriculture, livestock or fishing for their income. Crop cultivation is by far the most important source of income (55%), followed by mixed farming (20%). Only 5% of the households depend principally on livestock. The cattle population at the end of 1987 was estimated at 3.91 million, the majority of which are indigenous breeds grazed communally.
Tick-borne diseases are the most widespread diseases of cattle and theileriosis is one of the most economically important. The major species of Theileria in Uganda are T. parva parva and T. mutans. The presence of T. p. lawrencei is assumed, particularly in areas adjacent to game parks and reserves. Theileria velifera is known to occur but it causes no disease. Theileriosis caused by T. p. parva, East Coast fever (ECF), is a major killer of cattle and is an important constraint to improving production and productivity of the livestock industry. East Coast fever is enzootic throughout Uganda except in the drier open plains of the Karamoja region. Its distribution coincides with that of the tick vector Rhipicephalus appendiculatus. However, ECF epizootics occur from time to time in Karamoja during periods of unusual vector abundance because the majority of cattle lack immunity.
East Coast fever is regarded as one of the most serious causes of economic loss in Uganda, although accurate data on the incidence, case fatality and seasonal occurrence of the disease is lacking. Estimates of losses in indigenous cattle range between 20% and 40% of the calf crop. The mortality in Ugandan breeds of cattle due to ECF recorded during the period 1941-1964 at Serere Government Research Station was between 11% and 16%. A study recently concluded among indigenous herds not subjected to tick control at Kigungu, Entebbe, showed that 23% of the calves aged between 2 and 6 months died of ECF.
In a survey of 15226 cattle kept under different management systems and representing all areas of the country, 21% had antibodies to T. parva, 65% had antibodies to T. mutans and 45% had Theileria piroplasms detected in blood smears. Examination of blood and lymph node smears submitted to the Animal Health Research Centre, at Entebbe, showed that 30.8% in 1985, 15.1% in 1986, 27.3% in 1987 and 29.9% in 1988 had Theileria parasites. Recorded cases of ECF deaths were 10010 in 1986; these occurred in 18 of the country's 33 districts.
The main method used in Uganda to control tick-borne diseases of cattle, particularly ECF, is intensive tick control with acaricides. Of the 1890 dips, 284 sprays and other types of acaricide application recorded in the country, less than 60% are functional. This problem is compounded by the escalating cost of acaricides and the development of tick resistance to the acaricides. Tick-borne diseases continue to be a major source of cattle losses and a hinderance to the improvement of the livestock industry.
