Abscess Disease in Pastoral and Feedlot Sheep in The Sudan

Abstract

Morel's disease caused by Staphylococcus aureus subsp. anaerobius and caseous lymphadenitis caused by Corynebacterium pseudotuberculosis are important diseases of sheep in the Sudan. Both diseases cause significant economic losses due to rejection of affected animals at veterinary quarantines and condemnation of carcasses of sheep in abattoirs. Surveys were conducted for abscesses in 2000 pastoral sheep, 2100 breeder sheep, 8600 sheep kept for fattening, and 12694 sheep in other collection areas including sheep markets, export quarantine and its vicinity. Mean morbidity was 16.7%, with significantly higher morbidity (p<0.0005) sheep kept for fattening compared to unfattened (breeder and pastoral) sheep. A strong association (Phi Coefficient = 0.278) was found between the fattening of sheep and the incidence of abscesses. Two local sheep ecotypes (Hamari and Kabbashi) were susceptible to the disease with mean incidence of 50% and 33.9%, respectively. Other local sheep ecotypes (Wateesh, Dubasi, Zaghawi and Baladi) had low incidence of abscesses (0.7, 1.9, 4.8 and 8.8%, respectively). Bacteria isolated from affected lymph nodes of sheep with clinical abscesses (N=217) were 65.95% for S. aureus anaerobius, 19.8% for C. pseudotuberculosis, 5.1% mixture of both bacteria and 6.5% for other staphylococci. The results of this investigation expand on the existing knowledge on Morel's disease and are useful in the design of control programmes of the disease in the Sudan.