Files
Abstract
Histomonas meleagridis is an anaerobic protozoan and the causative agent of blackhead disease in gallinaceous birds. Blackhead was previously controlled with nitroimidazoles, this compound has since been deregistered and currently no approved treatment exists. A killed vaccine and experimental feed additives were tested in turkeys for possible efficacy and control of H. meleagridis. A vaccine was prepared with killed H. meleagridis cells and administrated subcutaneously with Freunds incomplete adjuvant. After challenge there was no indication that vaccination offered any protection. In the second study ZnSO4 and CuSO4 previously shown in vitro to have antihistomonal activity, were tested to determine if metals protect against a H. meleagridis direct challenge or decrease lateral transmission in turkeys. The addition of neither ZnSO4 nor CuSO4 protected against blackhead or reduced lateral transmission in turkeys. Under the conditions of this work inactivated vaccines and ZnSO4 and CuSO4 used alone did not offer protection against blackhead in turkeys.