Field study on buffaloe oedematous skin disease in Assiut Governorate: a model study.

摘要

As the buffalo oedematous skin disease (OSD) became an endemic disease in Egypt, the present investigation aimed at a field study in a localized district. Through a village clinic, 44 buffalo cows suffering from OSD were included in the study during May-August 2006. The disease was observed in two clinical forms, oedematous (95.5%) and nodular (4.5%), while the ulcerative form was not recorded. Anterior parts of the body were mostly affected (79.5%). Corynebacterium pseudotuberculosis was the causative agent of the disease. It was isolated from aspirated exudates as a single infection from 32 (80.0%) and as a mixed infection with Staphylococcus epidermidis from 3 (7.5%) animals. 24 (68.6%) of these isolates showed nitrate reduction positive reactions (serotype I), while the other 11 strains (31.4%) were nitrate reduction negative (serotype II). Both serotypes were recovered from adult Hippobosca equina flies. Strains of serotype I were isolated from either pupae or laboratory developed flies. The present study proved the sole role of H. equina in disease transmission. C. pseudotuberculosis was isolated from the external body surface, internal body content of flies, pupae and the second generation. Failure of isolation from blood sucking lice confirmed that the endosymbiotic nature of C. pseudotuberculosis was limited to H. equina. Antibiogram of the isolated bacteria revealed their 100% sensitivity 100% for tobramycin, gentamicin and ciprofloxacin, followed by oxytetracycline (84%). All bacterial isolates showed resistance against penicillin, ampicillin and cloxacillin. Treatment regimen based on antibiotic and antihistaminic administration and ectoparasitic eradication achieved a recovery rate of 97.72%.