Mucosal disease is a severe, sometimes fatal, form of bovine viral diarrhoea virus (BVDV). The form of BVDV that causes persistent infection in calves is the non-cytopathic form, which causes less cellular destruction and pathology to the animal. The immunity of persistently infected animals is lowered, and if the animal becomes concurrently infected with the cytopathic form of the virus then mucosal disease may result. Mucosal disease usually affects animals aged 6-18 months, and is usually rapid in onset although chronic debilitating forms can occur.
Clinical Signs
Erosions and ulcers in the mouth and intestinal tract
Erosions around the coronary band and interdigital space leading to lameness
Total anorexia and wasting
Death within 2 months in some cases
Dermatitis due to hyperkeratosis (rapid skin cell production and turnover) due to attempts to heal ulcers and erosions
Diagnosis
Presumptive based on clinical examination and history
Definitive diagnosis requires virus isolation on two occasions, three weeks apart
Treatment
Most cases are fatal, so euthanasia may be preferred
Remove persistently infected animals from the herd – sell to slaughter
Prognosis is poor