Histophilus somni

Diagnostic spectrum

General information

Histophilus somni (formerly Haemophilus somnus) is a gram-negative bacillus of the family Pasteurellaceae. While some strains of H. somni are commensals of the mucosa of the upper respiratory and reproductive tract in cattle, sheep and other ruminants, pathogenic strains spread systemically and can cause severe diseases such as pneumonia, thrombotic meningoencephalitis, myocarditis, septicaemia, arthritis and abortions.