Artificial transmission of Bolo disease in woolled sheep and attempted characterisation of the causative unclassified Corynebacterium sp.
Bacterial isolates (n = 38) previously cultured from sheep with Bolo disease were compared bacteriologically with known Corynebacterium spp. and Actinomyces spp. The isolates did not conform to any previously described species but closely resembled C. pseudodiptheriticum and C. urealyticum. More comprehensive tests are needed to classify this Corynebacterium sp. Bacterial cultures of this unclassified Corynebacterium sp. were used artificially to induce Bolo disease in Dohne Merino sheep (n = 20). Ten sheep were kept at Middelburg in the Cape Midlands (Northern Cape) under arid conditions and another 10 at Queenstown in the Eastern Cape in a more humid climate. Two suspensions containing 2.8 x 10(5) Corynebacterium sp. (inoculum A) and 2.8 x 10(9) Corynebacterium sp. (inoculum B) respectively were used to infect each sheep on 9 different sites on the skin. One sheep died during the course of the experiment. Corynebacterium sp. established itself on 81 out of 171 inoculation sites of the remaining sheep and caused typical lesions of Bolo disease, clinically and pathologically. Bolo disease lesions developed slowly over 175 days at Middelburg and 287 days at Queenstown. Weather conditions were unfavourable to the development of fleece-rot and mycotic dermatitis. No difference was seen in lesion development between rams and ewes or between sheep with 5 months' wool growth and those which were shorn before inoculation. More lesions developed with the higher concentration of inoculum B (49 sites positive) as compared to inoculum A (32 sites positive).
Joubert
J P
JP
Veterinary Laboratory, Kroonstad, Republic of South Africa.
Henton
M M
MM
Whitehead
C J
CJ
Kellerman
G E
GE
D000190:Actinomyces / Q000145:classification; D000818:Animals; D003352:Corynebacterium / Q000145:classification*; D003354:Corynebacterium Infections / Q000382:microbiology / Q000635:transmission / Q000662:veterinary*; D005260:Female; D008297:Male; D008685:Meteorological Concepts; D012621:Seasons; D012756:Sheep; D012757:Sheep Diseases / Q000382:microbiology / Q000635:transmission*; D012874:Skin Diseases, Infectious / Q000382:microbiology / Q000635:transmission / Q000662:veterinary*; D013019:South Africa; D014935:Wool