Mammary and systemic aspergillosis in dairy sheep

Mammary aspergillosis was diagnosed in four hocks of dairy sheep, comprisin g a total of 1,750 ewes. These animals had been treated prophylactically by intramammary infusion with cloxacillin 5 months prior to lambing. Mammary aspergillosis with concomitant spread to the regional lymph nodes was prese nt in these flocks in a percentage ranging from 2% to 36.4% of treated shee p. Pathologic, bacteriologic, and mycologic studies were performed in seven of the affected ewes. Some of them also had lung, kidney, and liver involv ement. The pathologic reaction within lesions ranged from the acute to suba cute type, dominated by necrosis and vasculitis with thrombosis, to the chr onic granulomatous type, with macrophages and giant cells. The distribution of lesions and the presence of a remarkable vasculitis with fungal thrombi in the mammary gland suggested a hematogenous dissemination of the infecti on from this organ. Immunologic staining with monoclonal antibody MAb-WF-AF -1, which reacts specifically with Aspergillus hyphae, identified the causa tive agent in histologic sections of the different affected tissues. The et iologic diagnosis was further supported by the isolation of Aspergillus fum igatus in pure culture from affected tissues and from eight samples of mamm ary secretions.