This is a sporadic infection of the tongue caused by Actinobacillus lignieresii, a bacterium normally resident in the mouth. Mucosal abrasion or injuries to the tongue allow bacteria to establish infection. Cases may be more likely to occur in dry periods or when feeding coarse or prickly feed. The tongue becomes progressively disabled by swelling and fibrosis, and affected animals suffer weight loss due to difficulty eating and drinking.
Early cases may inadvertently enter the export process.
Affected animals may show weight loss, drooling, tongue-lolling, chewing movements, protrusion of the tongue and bottle jaw. Finding a thick, hard, dry tongue, is diagnostic. Differential diagnoses include oral foreign bodies such as a bone or stick; broken teeth or jaw; or grass seed abscess affecting lymph nodes of the throat. At necropsy, the tongue contains numerous pussy yellow granules.
Laboratory confirmation requires a smear of pus from deep within the lesion for microbiology, and from dead animals, a section of tongue in buffered formalin for histology.
A course of systemic antibiotics (procaine penicillin or oxytetracycline) will usually eliminate the infection. In advanced cases there may be irreversible fibrosis of the tongue and these animals will not regain normal tongue function.
The unpredictable and infrequent occurrence on farm or feedlot does not warrant special control measures. Awareness of the condition and systems for early detection are therefore important.