Practical use of vaccines for the control of coccidiosis in the chicken

Immunological control is recognised as the only major practical alternative to chemotherapy for the control of coccidiosis. Initial hopes that it woul d be possible to develop a genetically engineered vaccine against Eimeria s pecies have not yet been realised, and there is therefore renewed interest in the development and application of vaccines based upon live parasites. R ecognition that existing drugs are not as effective as in the past, that fe w new drugs are currently under investigation, and that the inclusion of dr ugs in the feed may be restricted in the future has focused attention on th e need for new vaccines. Although considerable research has been undertaken on the basic mechanisms involved in the acquisition of immunity, very litt le attention has been given to the practical aspects of vaccination. In ord er for an anticoccidial drug: to be successful, it is necessary to generate considerable information on efficacy and safety. With few exceptions, litt le information is available to support the use of coccidiosis vaccines. Hop efully, the introduction of new vaccines and improved application methods w ill encourage manufacturers to generate more information concerning their p roducts. In future, coccidiosis should be controlled by adopting an integra ted approach where drugs and vaccines are both used to prevent this disease . In addition to immunisation, a possible advantage to the application of c ertain vaccines is that their use could repopulate a poultry house with dru g-sensitive organisms. Theoretical rotation programmes, in which the use of drugs is alternated with that of vaccines, are described.