Haemophilus species

Inhabit mucosal epithelium of upper respiratory and lower genital tract
Suppurative infections due to release of pro-inflammatory cytokines released from macrophages
Serofibrinous to fibrinopurative infections of lungs, body cavities and joints
Colonisation of meningeal vessels causes a thrombotic vasculitis leading to encephalitis and meningitis

Morphologically variable Gram-negative bacilli, ranging from short rods to long filaments
Facultative anaerobes
Typically oxidase positive
Depend on beta-nicotinamide adenine dinucleotide (NAD) (V factor) and/or Haemin (X fector) for growth
Heated blood agar (Chocolate Agar) required for growth of NAD-dependent strains
Haemin-dependent strains grow on Blood Agar
Do not grow on MacConkey agar

Inhabits nasopharynx of normal swine
Serotype B causes Glasser's disease in pigs
Glasser's disease
- Due to transport, environmental stresses, dietary and managemental factors
- Acute septicaemia
- Causes a polyserositis - pericarditis, peritonitis, pleurisy and meningitis - in pigs 3-10 weeks old
- Also causes suppurative bronchopneumonia, pleuritis, polyarthritis (also H. suis)
- Expressed lesions vary between animals - meningitis is most consistent, arthritis in 20% of cases
- Sporadic outbreaks in the UK
- Can be fatal in 2-5 days
- Mortality up to 50% insome outbreaks
- Chronic arthritis, meningitis and intestinal obstruction due to adhesions in surviving pigs
Fibrinous pneumonia secondary to enzootic pneumonia or virus infection e.g. swine influenza

Haemophilus sommus in Enzootic pneumonia of calves
Causes infectious thromboencephalitis in cattle 1-3 years old
Found in the USA and Europe, including UK
Causes a meningoencephalitis with fibrinous arterial thrombosis and necrosis
Causes fever, staggering and dyspnoea, progressing to somnolence, paralysis and death
Mortality can be high

Human meningitis, septicaemia, bronchopneumonia, conjunctivitis, epiglottitis, and otitis

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