Abstract

Pasteurellosis, also known as fowl cholera, is a highly contagious and economically significant bacterial disease of poultry, particularly chickens. This report presents a case of Pasteurella spp. infection in a commercial layer chicken farm in Osun State, Nigeria. A flock of 7,500 ISA Brown pullets bought at 14 weeks developed acute mortality (73 dead within a week) and reduced egg production approximately ten weeks (24 weeks old) after being introduced to the farm. Post-mortem examinations, bacteriological analyses, and antibiotic sensitivity tests identified Pasteurella spp. as the primary pathogen. Abnormalities in the birds included a congested liver, cloudy air sacs, pale combs with dry shanks, peritonitis, haemorrhage at the proventriculo-gizzard junction, and egg retention. Bacteriological analysis showed heavy growth of Pasteurella spp. from pooled organ samples (liver, heart, spleen, lungs, and tracheal swabs). Antibiotic sensitivity test revealed that the organism was very sensitive to streptomycin, neomycin, intermediate sensitivity to enrofloxacin, gentamicin and colistin and resistant to tylosin, ciprofloxacin, and amoxicillin. The outbreak was successfully managed through antibiotic therapy based on antibiotic sensitivity test (Penprovit, a combination of penicillin, streptomycin and vitamins by Kepro, Holland) was administered at 100 g/150 L of drinking water for 7 days, combined with improved and enforced farm biosecurity, with full recovery of flock productivity three weeks after the treatment. This case highlighted the importance of incorporating fowl cholera into the flock’s health program as a preventative measure, routine antimicrobial susceptibility testing (AST) to inform rational antibiotic use and biosecurity protocols on farms to be regularly reviewed and strictly enforced.

Key words: Antibiotic resistance, Biosecurity, ISA Brown, Layers, Nigeria, Pasteurella spp., Poultry health