Cultural and immunohistochemical evaluation of bacterial agents in caprine pneumonia in Nigeria

Abstract

Goats are important protein-producing animals but pneumonia, in spite of the huge investments in small ruminant production, remains a major limitation. This study evaluates the prevalence of important bacterial pathogens associated with caprine pneumonia in Nigeria using cultural and immunohistochemical techniques. One hundred and fifty goat lungs were randomly examined from macroscopic, cultural isolation and microscopic changes using standard techniques. The common bacteria identified were formalin inactivated for bacterine and polyclonal antibody production. Immunohistochemical staining was performed against the bacteria antigens using the avidin-biotin peroxidase complex technique. The data were presented in frequencies and percentages, and compared using non-parametric statistics at α = 0.05. The pathology in the caprine lungs included broncho-interstitial pneumonia (41), interstitial pneumonia (27), and bronchopneumonia (72). Ten of the lungs were normal. Bacterial isolation yielded Mannheimia haemolytica (40%), Pasteurella multocida (20%), Escherichia coli (13%), Klebsiella pneumoniae (10%), Streptococcus sp. (8%), Baccillus sp. (5%), and Pseudomonas sp. (3%). Mannheimia haemolytica (Mh) and Pasturella multocida (Pm) were the most common isolated bacteria. The bacterial antigens were detected on the surface of respiratory bronchiolar, and alveolar epithelia, within inflammatory exudate and in cytoplasm of alveolar macrophages. One hundred twenty (80%) of the caprine lungs were positive for the Mh and Pm antigens; 47 for Mh, 59 for Pm, 14 for both, and 30 negative for either antigens. Significant differences were observed in the staining intensities of the antigens. This study validated Mannheimia haemolytica and Pasteurella multocida as most important bacterial pathogens in caprine pneumonia in Nigeria. Thus, adequate control of caprine pneumonia should consider bacterine or multivalent vaccines incorporating these important bacteria to curb morbidity and mortality of goats.

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