Calf diptheria
The disease is a serious one usually affecting calves up to 2 years of age. The lesions are confined to larynx and pharynx, and consist of well-defined areas of necrosis which are adherent to the surrounding and underlying inflamed tissue. The disease may be enzootic. Fusobacterium necrophorum is the causative organism which is a gram-negative anaerobic bacilli.

Symptoms: There is painful moist cough with respiratory dyspnoea, excessive salivation, inability to swallow food, loss of appetite and increased body temperature. The animal loses condition rapidly due to lack of nutrition and toxin liberated by the organism. Necrotic patches develop on the mucous membrane in any part of mouth and larynx. A false membrane, adherent to the parts underneath is formed; when removed it leaves deep ulcers. In some cases the condition spreads to lung and liver  where secondary necrotic lesions develop. In acute and severe cases death may occur within a week after the onset of symptoms. Death may be caused due to toxaemia and obstruction to the respiratory passage.

Diagnosis: The nature of lesions are suggestive of calf diphtheria. The disease is confirmed by examining smears after staining with Gram’s stain or methylene blue, and isolating and identifying the organism. When a rabbit is inoculated with material from a suspected case, necrotic lesion develops at the site or inoculation, and the rabbit dies in 2 to 3 weeks.

Control: Attention should be given to hygiene to avoid the predisposing factor.Rough feed should not be given. Sulphonamides and penicillin can be used for treatment of early cases.