Intestinal or caecal coccidiosis caused by intracellular protozoa, belonging to the genus Eimeria (Phylum Apicomplexa) is a major cause of concern and economic losses to ht poultry industry world wide( schnitzler an Shirley, 1999),. It is estimated that the economic losses due to the disease are about US$ 450 million and due to medication are about US$100 million in the United States (Allen and Fetterer, 2002; Lillehoj et al. 2001). In countries like Pakistan where the farming is substandard, the disease becomes more serious and causes heavy economic losses; although the exact losses duet to coccidiosis in Pakistan are not known due to ht lack of statistical indices but these will be definite in million of rupees. Seven species of Eimeria are generally accepted to be the causative agent of avian coccidiosis (Long,1965). Eimeria(E) tenella and E. maxima are considered to be the most important to poultry industry from consideration of their ubiquity in broiler chicks, innate pathogenicity and immunological features(Shirlery and Bedrin, 1997). In Pakistan E.tenella is the most prevalent and pathogenic species(Dar and Rahma, 1973. The conventional methods to control the disease are by using certain coccidiostats/ coccisdiocidal drugs, but the emergence of resistant strains against the most commonly available drugs, high cost on bird production incurred due to the shift over of the medicines and sometimes the toxicity of drugs, has out dated these methods (Calnek,1990). Obviously an alternative system to control the disease is by vaccination (Davis et at.1979). Different attempts have been made on the development of vaccine(s) against coccidiosis including give (Danforht,1997), recombinant (vermeulen,1998) and subunit (Lillehoj et al.2001) vaccines, but several of the vaccine has shown promising results and reached to the status of commercialization worldwide. Innunocox®, and importee live vaccine has failed to control coccidiosis in Pakistan and may cause the disease in vaccinated birds (shaker,1997). In the preliminary studies, an experimental vaccine from sonicated inactivated sporulated oocysts was prepared in the Department of Veterinary Parasitology and was evaluated on the basis of cellular, humeral and challenge responses and gave encouraging results(Akhtar et .at 2001,a,b), but that could not be commercialized due to the unavailability of antigenic material on large scale. It was., therefore, imperative to adopt the strategies that lead to the production of antigenic material on large scale to be used in vaccine preparation. The objectives of the present project were
1Adaptation of E.tenella(local isolate) on the chicken embryo.
2Formulation of vaccine (S)from egg-adapted gametocytes.
3Evaluation of vaccine (S) on the basis of , mucosal, cellular, humoral and challenge responses.