Actinobacillosis - Cattle

Also known as:

Wooden tongue

Fibrous Stroma - Cut Surface of actinobacillosis affected tongue (Courtesy of Alun Williams (RVC))

==Description==

An infectious disease caused by the gram-negative coccobacilli Actinobacillus lignieresii. Characterised by inflammation of the soft tissues of the head especially the tongue and pharangeal lymph nodes of cattle and sheep. The Causal agent is widespread in the environment and part of the normal flora of the gastrointestinal mucosa. It gains access to the tongue via small abrasions. It can be a progressive disease of low virulence but high persistence so the animal may stop eating and eventually die if not treated.

Signalment

Occurs in cattle and sheep of all ages but particularly seen in young beef breeds particularly sucklers on poor forage.

Diagnosis

A diagnosis can often be made on history and clinical signs. Additionally, Pus from the abscesses may contain microcolonies interspersed with clublike pieces of calciuk phosphate which will give the appearance of sulphur granules.

Clinical Signs

Often begins like foot and mouth disease. Animals are dull, have difficulty masticating, are inappetent and salivate profusely. The tongue is inflammed, hard swollen and painful with small areas of ulceration along its sides. Often the tongue is described like a lump of wood hence the name, especially the dorsal part of the posterior 2/3rds. In contrast to foot and mouth cases are nearly always sporadic.

Occasionally generalised infections occur and the bacteria cmay affect soft tissue anywhere in the gastrointestinal tract. Additionally a cutaneous form of the disease has been reported where ulcers and nodules are present in the subcutaneous tissue containing yellow-green pus.

Pathogenesis

• Very similar to Mandibular Osteomyelitis ("lumpy jaw").

Pathology

'Sulpher body' of Actinobacillosis (Courtesy of Alun Williams (RVC))

• If cut into tongue, substance of tongue changed to fibrous stroma with raised red nodules. (2-3mm across).
• This lesion is a pyogenic granuloma with central sulphur body.
• Can spread from tongue to other tissues e.g. retropharyngeal lymph nodes and palate.
• This type of lesion is caused by the host response to the pathogen, rather than directly a pathogen effect.

• Small granulomatous lesions containing 'sulfa granules' of large numbers of gram-negative rods