Actinobacillosis - Cattle

Also known as:

Wooden tongue

Description

An infectious disease caused by the gram-negative coccobacilliActinobacillus 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 gets into the tongue via small abrasions. It can be a progressive disease - 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 be made on history and clinical signs.

Clinical

• Starts like foot and mouth disease - dull, salivating (if only one animal is unlikely to foot and mouth). - nearly always sporadic. The tongue feels like a big lump of wood especially the dorsal part of posterior 2/3rds.

This is often found in conjunction with small areas of ulceration on the side of tongue.

Pathogenesis

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

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

Pathology

Fibrous Stroma - Cut Surface of actinobacillosis affected tongue (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.

Other sites

• Occasionally can see generalised infections but more commonly spreads to local lymph nodes of alimentary tract.
• Organism can be inhaled causing actinobacillus pneumonia.
• Can affect rumen wall.
• In skin forms a neoplastic like mass in dermis.

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