Any disease caused by bacteria of the genus Haemophilus.
a septicemic disease of cattle caused by Histophilus somni (previously called Haemophilus somnus) characterized by an acute illness with a short course and a high mortality rate. In survivors there are residual lesions, especially hemorrhagic infarcts in the brain, and synovitis, pleurisy and pneumonia. Clinical signs vary widely but predominant signs are blindness due to ophthalmitis, weakness, ataxia and recumbency. Called also thromboembolic or thrombotic meningoencephalitis.