DefinePK

Abstract

Bovine demodicosis was surveyed in five States of the Sudan during vaccination campaigns and in abattoirs. Among the total number of cattle surveyed (48,000), 16,608 cattle had skin lesions of demodectic mange. Among those infected, 8,012 cattle (48.2%) had simultaneous skin and meibomian gland demodicosis. Meibomian gland demodicosis was characterized by lacrimation, hyperaemia and congestion of the mucous membranes, and in extreme cases, by purulent exudation, swelling and closure of the eyelids. Both eyelids showed 2-4 purulent nodules of 3-4 mm in diameter each, arranged in a linear fashion. Demodex ghanensis and primary pathogenic bacteria (Moraxella bovis and Staphylococcus aureus) were isolated from the infected material expressed from meibomian gland lesions. The histopathological changes seen were compatible with cell-mediated immunity. The destruction caused by the mites and associated bacteria resulted in typical granulomatous reaction. The central core of infection in the glandular acini composed of mites, bacteria and purulent exudate was infiltrated by neutrophils and a few eosinophils; surrounded by lymphocytes, plasma cells, macrophages, epithelioid, giant cells and proliferation of connective tissue.