Contagious Bovine Pleuropneumonia (CBPP) Post- Vaccinal Complication in Ethiopia

In Ethiopia, immunization of cattle against contagious bovine pleuropneumonia (CBPP) has been practiced for the last 4 decades using vaccines prepared from streptomycin-resistant vaccine seed strain. Recently, a vaccine strain denominated T1/44 has been introduced to Ethiopia to prepare vaccine for filed use. A total of 296,248 cattle were vaccinated with vaccine produced from this seed strain in 3 different zones of Ethiopia. Post-vaccinal reaction affected the vaccinated animals with an overall attack rate of 1.02% (95% confidence interval, 1.0192−1.024) while the mortality and case-fatality rates were found to be 0.17% and 16.5%, respectively. The occurrence of the reaction was found to be significantly higher in Western Wellega zone (P < 0.001) than in the other 2 zones. Site of inoculation was shown to be the main predisposing factor in all 3 zones considered. The post-vaccinal reaction caused substantial economic loss and moral demotion to the resource-poor, livestock-owning community. Strict adherence to precautions and guidelines needs to be adopted in order to reduce the likely loss following mass vaccination. Intern J Appl Res Vet Med • Vol. 3, No. 4, 2005 344 For instance, Laval reported that CBPP incurs a cost of more than ETB 205.6 million per annum in Ethiopia. Contagious bovine pleuropneumonia had been eradicated from the U.S.A, Australia, and most European countries through implementation of policy of restriction of animal movement. It remains endemic in African countries where effective vaccination policy seems the only realistic method of choice for control of CBPP. In Ethiopia, vaccination against CBPP has been carried out since 1964. Initially, broth culture-based vaccine prepared from KH3-J vaccine strain of Mmm-sc was used extensively during the years 1964−1968. In the later years (since 1969), a more stable freeze-dried vaccine prepared from the same strain was used. A need arose during the 1970’s PARC (Pan African Rinderpest Campaign) program to combine CBPP and rinderpest vaccines in an attempt to eradicate rinderpest and possibly control CBPP. Hence, a streptomycin-resistant variant of KH3-J, KH3 J-SR, came into use until 1988 when it was replaced by T1-SR, that is, streptomycin-resistant vaccine strain T1 of the causative mycoplasma. In 1996, a streptomycin sensitive but more immunogenic variant of the vaccine strain T1 (denominated T1/44) was recommended by the Food and Agriculture Organization as the only vaccine strain of choice; T1-SR was constrained by lower potency and efficacy. N o CBPP vaccination campaign had been followed by post-vaccinal reaction in Ethiopia before introduction of T1/44 as the seed strain. However, immunization of animals with vaccine prepared from T1/44 has caused post-vaccinal complication in different regions. The objective of this paper was, therefore, to investigate the reaction and its impact on the livestock owners. MATERIALS AND METHODS Study Areas The study was undertaken in 3 zones where vaccination with T1/44 has been carried out, namely Borana, South Omo and Western Wellega. In Borana zone, the vaccination was given in 4 districts. The mean annual temperature varies from 19 ̊ C to 25 ̊ C with moderate seasonal variation. The mean annual rainfall ranges from 250−700 mm with bimodal distribution. Pastoral livestock production is the main means of livestock for hundreds of thousands of individuals in B o r a n a . In Western Wellega zone, the vaccination was given in 2 districts. The area is characterized by humid and tropical climate with average annual rainfall of 2200 mm. The altitude range of the zone is 1000−2 0 0 0 m above sea level with mean annual temperature ranging from 12 ̊ C to 28 ̊ C. Sedentary mixed crop-livestock farming is the dominant economic activity encountered