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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Infectious Bacterial Diseases Research » Research » Publications at this Location » Publication #217026
Title: Detection of Pathogenic Leptospira Bacteria in Pinniped Populations via PCR and Identification of a Source of Transmission for Zoonotic Leptospirosis in the Marine Environment

Author
item CAMERON, CAROLINE - UNIV. OF VICTORIA
item Zuerner, Richard
item RAVERTY, STEPHEN - BRITISH COL. MIN. OF AG
item COLEGROVE, KATHLEEN - MARINE MAMMAL CTR
item NORMAN, STEPHANIE - UNIV. OF WA
item LAMBOURN, DYANNA - WA DEPT. FISH & WILDLIFE
item JEFFRIES, STEVEN - WA DEPT. FISH & WILDLIFE
item GULLAND, FRANCES - MARINE MAMMAL CTR

Submitted to: Journal of Clinical Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/16/2008
Publication Date: 5/1/2008
Citation: Cameron, C.E., Zuerner, R.L., Raverty, S., Colegrove, K.M., Norman, S., Lambourn, D.M., Jeffries, S.J., Gulland, F.M. 2008. Detection of Pathogenic Leptospira Bacteria in Pinniped Populations via PCR and Identification of a Source of Transmission for Zoonotic Leptospirosis in the Marine Environment. Journal of Clinical Microbiology. 46(5):1728-1733.

Interpretive Summary: Leptospirosis is a ubiquitous disease with a global distribution that afflicts humans and a wide variety of domestic and wild animal species, including marine mammals. Disease outbreaks have occurred repeatedly in California sea lions off central and northern California, with hundreds of animals stranding and subsequently dying in each outbreak. Current methods for diagnosing leptospirosis among live marine mammals rely upon a combination of the microscopic agglutination test performed on sera, clinical observations and detection of serum biochemistry changes typical of renal failure. The use of modern molecular analytical techniques such as PCR is ideally suited for the detection of Leptospira infection, in that PCR technology is sensitive, specific, and widely available. PCR technology for diagnosing Leptospira infection among marine mammal populations was evaluated and compared to other conventional diagnostic methodologies. The results of this study show that PCR represents a powerful diagnostic technique and has many advantages over classic methods of diagnosis.

Technical Abstract: Leptospirosis, caused by the spirochete bacterium Leptospira, is a geographically widespread disease that affects a broad range of mammals, including marine mammals. During 2004 an outbreak of leptospirosis occurred among select pinniped populations along the West Coast of North America, with cases ranging from California to British Columbia. The objective of this study was to determine the feasibility of using polymerase chain reaction (PCR) techniques to diagnose Leptospira infection among pinniped populations in comparison with other conventional diagnostic methodologies. Our investigations demonstrated PCR is a sensitive and specific diagnostic tool for the detection of Leptospira infection in pinnipeds. Successful amplification was achieved from templates originating from a variety of sources, including freshly collected urine, urine stored at -80ºC for less than 6 months and kidney tissue (freshly collected, frozen and decomposed), as well as fecal and urine-contaminated sand collected in the vicinity of a live stranded animal. Of particular interest was the observation that PCR facilitated detection of a subgroup of putative carrier animals that exhibited positive amplification but did not exhibit overt disease symptoms. Further, the use of species-specific primer pairs allowed for speciation of infecting Leptospira species in different pinniped populations, and revealed a pattern of host specificity for Leptospira interrogans and Leptospira kirschneri.