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Bovine melioidosis in South-Eastern Queensland
Abstract:
Acute fatal infection with Pseudomonas pseudomallei caused pneumonia, placentitis and endometritis in a pregnant cow. Pneumonia was also present in the foetal lung. Mononuclear cell response with extensive karyorrhexis occurred in maternal and foetal lung and the same cellular pathology, but with diffuse distribution, was responsible for plaques on the endometrium. A more chronic disease with encapsulated caseous lesions in the lung, together with arthritis, occurred in a bull on the same property. Nutritional and physical stress caused by a flood were thought to be predisposing factors. An unusually wet summer with prolonged flooding apparently provided suitable environmental conditions for saprophytic growth of Ps. pseudomallei in an area far south of the region in which infection of animals with this organism commonly occur.
Insights
Pseudomonas pseudomallei caused fatal pneumonia in a pregnant cow and chronic disease in a bull. Environmental factors like flooding may promote this bacterium
Area of Science:
- Veterinary Pathology
- Bacteriology
- Environmental Microbiology
Background:
- Pseudomonas pseudomallei (Ps. pseudomallei) is an emerging zoonotic pathogen.
- Environmental factors, such as flooding, can influence the distribution and transmission of bacterial pathogens.
Observation:
- An acute, fatal infection of Pseudomonas pseudomallei occurred in a pregnant cow, leading to pneumonia, placentitis, and endometritis.
- The foetal lung also exhibited pneumonia. Maternal and foetal lungs showed a mononuclear cell response with karyorrhexis.
- The endometrium displayed similar cellular pathology, forming plaques.
- A bull on the same property developed chronic disease, including lung lesions and arthritis.
Findings:
- The study identified Ps. pseudomallei as the causative agent of severe reproductive and respiratory diseases in cattle.
- Cellular pathology, including karyorrhexis, was consistent across affected maternal and foetal tissues.
- Environmental conditions, specifically prolonged flooding, were implicated as a factor promoting bacterial growth and spread.
Implications:
- This case highlights the potential for Ps. pseudomallei to cause significant disease in livestock, even in non-endemic regions.
- Understanding environmental influences on bacterial saprophytic growth is crucial for predicting and preventing outbreaks.
- The findings underscore the importance of considering environmental factors in the epidemiology of infectious diseases in animals.