Acta Vet. Brno 2006, 75: 247-250

Fatal Actinobacillosis in a Dairy Buffalo

G. Muhammad, M. Saqib, M. Athar

Department of Veterinary Clinical Medicine and Surgery, Faculty of Veterinary Science, University of Agriculture, Faisalabad, Pakistan

Received August 23, 2005
Accepted March 16, 2006

The present report describes a case of fatal actinobacillosis in a dairy buffalo (Bubalus bubalis). Clinical signs included a large multilobular, firm abscess located caudo-ventral to the right ear base, submandiblar and prescapular lymphadenopathy, fever and dyspnoea. Haemogram revealed an accelerated erythrocyte sedimentation rate and erythropenia. Provisional diagnosis of actinobacillosis was confirmed by the demonstration of a Gram-negative pleomorphic organism in pus, microscopic examination of a compression preparation of a sulphur granule as well as growth of the organism on blood agar. Intraperitoneal inoculation of pus in guinea pigs was fatal at around 48 hours post-injection. The LD50 of the Actinobacillus lignieresii isolate in mice was 104 colony forming unit per milliliter of Hank's balanced salt solution. The animal died 12 hours after the initiation of surgical drainage of the abscess and administration of iodide, antibiotics and steroids. Necropsy findings included interlobular pneumonia, pulmonary abscessation and mediastinal lympadenopathy that were ascribed to metastatic spread of the organisms to the lungs which probably led to the death of the animal. This case report appears to be the first documentation of fatal actinobacillosis in the dairy buffalo.