Outbreaks of pleuritis and peritonitis in calves associated with Pasteurella multocida capsular type B strain

Abstract

Abstract

CASE HISTORY: Three dairy calf-rearing properties experienced high mortality in calves during 2008 and 2009. Affected calves were aged 13–18 weeks (Farm I), 6 months (Farm II), and 2–11 weeks (Farm III), and the mortality rate was 22/175 (13%), 5/80 (6%), and 60/900 (7%), respectively.

CLINICAL AND LABORATORY FINDINGS: Affected calves rapidly became moribund, were in respiratory distress, and had a fever (40–41°C). Post-mortem examination of nine calves revealed fibrinopurulent pleuritis, pericarditis, and peritonitis. This was confirmed histopathologically on tissues from three calves, one from each farm; aggregates of small Gram-negative coccobacilli were evident on Gram stain. Pasteurella multocida was cultured from tissues from affected calves on the three farms, and PCR of DNA extracted from tissue samples amplified cap-sular type B-specific DNA. Multi-locus sequence typing (MLST) demonstrated that all capsular type B isolates belonged to the same sequence type (ST), ST62, but did not belong to serotype B:2, the only B serotype classified as causing haemorrhagic septicaemia by the Office International des Épizooties (OIE).

DIAGNOSIS: Pleuritis and peritonitis due to infection with P. multocida capsular type B strain.

CLINICAL RELEVANCE: Haemorrhagic septicaemia was excluded as a cause of disease from the three farms, however P. multocida was the primary agent in the affected calves. It is possible the agent has been present in New Zealand for some time but not reported, as there had been no transfer of animals between affected farms. Emergence of the syndrome could potentially be a result of factors other than just the presence of the organism, such as changing management. The syndrome described may be of increasing importance in the future.

Key Words:

• Pasteurella multocida
• capsular type B
• calves
• bovine
• cattle
• pneumonia
• pleuritis
• peritonitis
• septicaemia
• haemorrhagic septicaemia

Acknowledgements

The authors would like to thank laboratory staff and other members of the Incursion Investigation team at the IDC for their contribution to this investigation; the referring veterinarians Jen Clo-sey, Megan Reidie, Corissa Miller, and Rick Nortje; to the owners of the affected herds/farms who graciously complied with every request from the IDC; and to Wendy McDonald and Ciaran Luke McFadden who provided comments on the manuscript. All funding for the project was provided as a part of normal foreign animal disease investigation carried out by the IDC.

Notes

¹ R Turner, Meteorology and Remote Sensing, National Institute of Water and Atmospheric Research, Wellington, New Zealand

² LH McIntyre, MAF Biosecurity New Zealand, Wellington, New Zealand