Introduction
The corynebacterium are small, Gram-positive, pleomorphic rod bacteria that occur in a characteristic filamentous, angular, palisade arrangement often located intracellularly. They are non-motile, aerobic, fermentative, non-spore forming.C. pseudotuberculosis is a facultative intracellular parasite that has been implicated in the diseases caseous lymphadenitis in sheep and goats, ulcerative lymphangitis in horses and formation of abscesses in many other animal species. Infections of man have also been recorded in farm workers and vets exposed to infected animals usually manifesting as lymphadenitis.
The prevalence of infection in adult animals can be very high with figures of 50-80% in some countries often quoted. It is of special concern in areas where intensive husbandry is practised.
Normal Habitat:
The ecology of the organism and source of natural infection are not well documented or understood, however C. pseudotuberculosis is known to be present and able to survive in the environment following contamination by infected animals. Low temperatures and damp conditions prolong survival time. Environmental contamination is therefore considered the most important factor in the spread of this organism. C. pseudotuberculosis has been shown to be able to survive for prolonged periods (>6 mths) in contaminated environments and has been isolated from feed, feeders, fences, shears and sheep dips, plus dust and soil samples from around stock handling areas.The main source of infection and potential spread of the organism is via the rupture of affected lymph nodes and abscesses with the discharge of thick caseous pus containing millions of organisms into the environment.
References:
Batey, R G - Pathogenesis of caseous lymphadenitis in sheep and goats, Australian Vet Journal, Vol 63, No 9, Sept 1986.
Lloyd, S: Caseous lymphadenitis in sheep and goats, In Practice, Jan 1994.
Caseous lymphadenitis in sheep and goats in N.Z, Surveillance 15, 8 June, 1988.
Miers, K C and Ley, W B:Corynebacterium pseudotuberculosis Infection in the Horse; Journal of American Veterinary Medical Association, Vol 177, No3, Aug 1980.
Welsh, R D: Corynebacterium pseudotuberculosis in the Horse, Equine Practice, Vol 12, No 2, Feb 1990.*Disclaimer - This report was written by a student participaring in a microbiology course at the Missouri University of Science and Technology. The accuracy of the contents of this report is not guaranteed and it is recommended that you seek additional sources of information to verify the contents.
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