Histophilus ovis and Haemophilus somnus are closely related organisms sometimes associated with the following conditions:

Sheep

Epididymitis; gangrenous mastitis; abortion; septicaemia, polyarthritis and abscessation in lambs; pneumonia and nephritis.

Cattle (in Australia)

Purulent vaginitis and endometritis; pneumonia, fibrinopurulent leptomeningitis and ependymitis.

(Overseas septicaemia, thromboembolic meningoencephalitis, polyarthritis, tendonitis, and less commonly, mastitis).

Diagnosis

Clinical findings and pathology, including histopathology. Isolation of H ovis / H somnus from affected tissues.

NB.
The organism may be a commensal, carried in the urogenital or upper respiratory tract of normal animals.

Specimens required

1. Samples of affected tissues and swabs in Amies charcoal transport medium for bacteriology.

   e.g. milk and affected gland (mastitis), liver, lung, kidney, spleen (septicaemia), whole affected joint unopened (arthritis) or synovial fluid and synovial membrane (arthritis), vaginal/uterine swabs and exudate (reproductive), affected epididymis (epididymitis), whole aborted foetus and membranes (abortion), brain (CNS), abscess swab and/or abscess content (abscessation), lung (pneumonia).

2. Portions of affected tissues fixed in buffered formalin for histopathology.