Actinomyces hyovaginalis-associated lymphadenitis in a Nubian goat.

A 6-year-old Nubian goat with a history of progressive weight loss and cough was presented for necropsy. The goat tested negative for antibodies to caseous lymphadenitis and caprine arthritis and encephalitis by hemagglutination inhibition assay and enzyme-linked immunosorbent assay, respectively. Postmortem examination revealed marked enlargement and, with histopathology, a fibrinopurulent necrotizing lymphadenitis of a tracheobronchial lymph node, with an appearance similar to that reported in cases of caseous lymphadenitis. An organism characterized by molecular methods as Actinomyces hyovaginalis was isolated together with Staphylococcus spp. and Streptococcus spp. from the lesion. No Corynebacterium pseudotuberculosis was recovered. To the authors' knowledge, this is the first isolation of A. hyovaginalis from a goat. Although the exact contribution of A. hyovaginalis to the lesion remains to be established, this case demonstrates that A. hyovaginalis should be considered in cases of caseous lymphadenitis-type lesions, especially when C. pseudotuberculosis has been excluded.