ARTIFICIAL TRANSMISSION OF BOLO DISEASE IN WOOLLED SHEEP AND ATTEMPTED CHARACTERIZATION OF THE CAUSATIVE UNCLASSIFIED CORYNEBACTERIUM SP

Bacterial isolated (n = 38) previously cultured from sheep with Bolo d isease were compared bacteriologically with known Corynebacterium spp. and Actinomyces spp. The isolates did not conform to any previously d escribed species but closely resembled C. pseudodiptheriticum and C. u realyticum. More comprehensive tests are needed to classify this Coryn ebacterium sp. Bacterial cultures of this unclassified Corynebacterium sp. were used artificially to induce Bolo disease in Dohne Merino she ep (n = 20). Ten sheep were kept at Middelburg in the Cape Midlands (N orthern Cape) under arid conditions and another 10 at Queenstown in th e 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) Corynebacter ium 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 e xperiment. Corynebacterium sp. established itself on 81 out of 171 ino culation sites of the remaining sheep and caused typical lesions of Bo lo disease, clinically and pathologically. Bolo disease lesions develo ped slowly over 175 days at Middleburg and 287 days at Queenstown. Wea ther conditions were unfavourable to the development of fleece-rot and mycotic dermatitis. No difference was seen in lesion development betw een rams and ewes or between sheep with 5 months; wool growth and thos e 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).