STUDIES ON THEILERIIDAE (SPOROZOA) IN TANZANIA .10. LARGE-SCALE FIELD TRIAL ON IMMUNIZATION AGAINST CATTLE THEILERIOSIS

  • 1 January 1977
    • journal article
    • research article
    • Vol. 28  (4) , 499-506
Abstract
Cattle (50) immunized by an infection and treatment method with 3 strains of T. parva (Muguga, Kiambu 5 and Serengeti transformed), together with 19 controls, were exposed to natural tick infestation in Tanzania, in a site where a continuous influx of infected ticks from different regions of the country may be expected to occur. Exposure lasted for 2 mo. monitoring continued for 3 more weeks after exposure ended. All 19 controls contracted East Coast Fever [ECF] and died. Of the 50 immunized animals 40 survived the whole period of monitoring; 10 died of other causes, none of ECF. This method of immunization can be routinely applied to protect valuable animals at risk. An attempt to immunize against pathogenic T. mutans by injecting blood containing piroplasms of a strain of low pathogenicity, showed that this method may protect against high parasitemias caused by natural tick-borne infections and may be useful in eliminating the confusing factor of T. mutans in future trials on ECF.