Khalid Rodwan, Abdulkhalig Babiker, Sulieman El Sanousi:
Studies on Vaccination Trials Against Morel's Disease and Monitoring of Transfer of Passive Immunity from Dams to Lambs


University of Khartoum, Faculty of Veterinary Medicine, Sudan

This becomes the first report of vaccination against Morel's disease (sheep abscess disease) in the world. A trial of formaline killed bacterin of S. aureus subsp. anaerobius to protect young lambs against sheep abscess disease (Morel's disease) was carried out. Vaccination reduced the incidence of infection by approximately 65% and the size of abscess was markedly reduced in lambs which acquired infection in spite of vaccination. Another trial using a formalinised killed whole culture, capsular antigen and toxoid produced 96.4% protection was tried. Two doses of this vaccine prepared (the first dose was 1.0 ml and the second 0.5 ml) given two weeks a part, and then challenged one months latter with 1200 organisms (three times the minimum abscess causing dose). This protection has been achieved both in experimental studies and field experiments against Morel's disease. The vaccine gave protective responses detected by prevention of abscess formation in challenged lambs. Monitoring of Passive Immunity Transfer from pregnant vaccinated ewes (against Morel's disease) to their lambs The passive immunity transfer from pregnant ewes to their lambs was monitored from birth to seventh months of age in those born from vaccinated ewes against Morel's disease and others born from non-vaccinated ewes. The vaccination of ewes before lambing provided passive protection to lambs during the first 20 weeks of age. Usually the site reaction after vaccination appears first as oedematous area that enlarges and reaches the maximum site reaction; then hardened and start to regress till disappear, leaving no scar and forming no abscess. The vaccination against Morel's disease did not cause abortion nor it affected the conception rate.

Keywords: Abscess, lambs, sheep, Staphylococcus, vaccination


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Contact Address: Khalid Rodwan, University of Khartoum, Faculty of Veterinary Medicine13314 Khartoum, Sudan, e-mail:
Andreas Deininger, September 2004