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Immunoperoxidase evaluation of pneumonic lesions induced by Pasteurella multocida in calves
M Haritani1, M Narita, H Murata
1National Institute of Animal Health, Ibaraki, Japan.
Abstract:
To evaluate the relationship between pneumonic lesions and distribution of bacteria, lungs from calves inoculated with Pasteurella multocida were examined histologically by use of immunoperoxidase technique. Pneumonic lesions fundamentally consisted of broncho-pneumonia with fibrinopurulent pleuritis. The lesions were confirmed to be associated with inoculated P multocida, using the immunoperoxidase technique. The P multocida antigen was detected not only in the bacterial clusters in the lesions, but also in the cytoplasm of infiltrating neutrophils and macrophages. Further, immunoelectron microscopy indicated that the inoculated bacteria generally were phagocytosed and digested by neutrophils.
Insights
This study investigated Pasteurella multocida in calf pneumonia, finding the bacteria within lung lesions and immune cells. Neutrophils were observed to phagocytose and digest the bacteria.
Area of Science:
- Veterinary Pathology
- Bacteriology
- Immunohistochemistry
Background:
- Bovine respiratory disease (BRD) is a significant economic concern in the cattle industry.
- Pneumonia in calves is often associated with bacterial infections, including Pasteurella multocida.
- Understanding the distribution and host-pathogen interactions of P. multocida is crucial for disease control.
Purpose of the Study:
- To elucidate the relationship between pneumonic lesions and the distribution of Pasteurella multocida in the lungs of experimentally infected calves.
- To characterize the histological features of pneumonia caused by P. multocida.
- To investigate the cellular localization of P. multocida antigens within lung tissues.
Main Methods:
- Calves were experimentally inoculated with Pasteurella multocida.
- Lung tissues were examined using histological techniques.
- Immunoperoxidase staining was employed to detect P. multocida antigen.
- Immunoelectron microscopy was utilized for ultrastructural analysis.
Main Results:
- Pneumonic lesions were characterized as broncho-pneumonia with fibrinopurulent pleuritis.
- Pasteurella multocida antigen was confirmed within the lesions using immunoperoxidase technique.
- P. multocida antigen was detected in bacterial clusters, neutrophils, and macrophages within the lesions.
- Immunoelectron microscopy revealed phagocytosis and digestion of P. multocida by neutrophils.
Conclusions:
- Pasteurella multocida is directly associated with the observed broncho-pneumonia and pleuritis in calves.
- The bacteria are found within inflammatory cells, indicating an active host immune response.
- Neutrophils play a key role in the initial clearance of P. multocida through phagocytosis and digestion.