Cross-immunity studies between Cowdria ruminantium isolates from the savanna and forest vegetational zones of Nigeria

摘要

Two Cowdria ruminantium isolates obtained from savanna and forest vegetational zones of Nigeria were used in immunity and cross-immunity studies in local savanna brown goats. The experiments involved primary infection of the animals divided into twogroups of four animals per group with either of the isolates followed by secondary homologous and tertiary heterologous challenges, three weeks apart. Lack of clinical reactions to homologous and heterologous challenges was used to confirm immunity and cross-immunity respectively. It was observed that both isolates conferred homologous immunity on the infected animals. However, while the animals immune to the savanna isolate were protected against challenges by the forest isolate, the latter failed to protect all the animals, immune to it, against the more pathogenic savanna isolate.