Morels (or abscess) disease is a non-fatal, contagious disease of sheep and goats caused by Staphylococcus aureus anaerobius. The disease is endemic in nature with high morbidity rate and frequent relapses. In 1990s, this disease caused rejection of many shipments of Sudans exported sheep with estimated losses of some millions US dollars. This initiated a research project to study the disease and to produce a protective vaccine: the outcome was the production of a vaccine with more than 96% protection. The present work represents a continuation of previous studies on this disease in the Sudan...