Epidemiology and Infection

Research Article

Lyme disease: a search for a causative agent in ticks in south–eastern Australia

R. C. Russella1, S. L. Doggetta1, R. Munroa2, J. Ellisa3, D. Averya1, C. Hunta4 and D. Dickesona5

a1 Department of Medical Entomology, Centre for Infectious Diseases and Microbiology, University of Sydney and Westmead Hospital, ICPMR, Westmead Hospital, Westmead NSW 2145, Australia

a2 Department of Microbiology, Liverpool Hospital, Liverpool NSW 2170, Australia

a3 Department of Microbiology, University of Technology Sydney, Gore Hill NSW 2065, Australia

a4 Department of Parasitology, Centre for Infectious Diseases and Microbiology, University of Sydney and Westmead Hospital, ICPMR, Westmead Hospital, Westmead NSW 2145, Australia

a5 Department of Clinical Microbiology, Centre for Infectious Diseases and Microbiology, University of Sydney and Westmead Hospital, ICPMR, Westmead Hospital, Westmead NSW 2145, Australia

Abstract

Attempts were made to identify the causative organism of Lyme disease in Australia from possible tick vectors.

Ticks were collected in coastal areas of New South Wales, Australia, from localities associated with putative human infections. The ticks were dissected; a portion of the gut contents was examined for spirochaetes by microscopy, the remaining portion inoculated into culture media. The detection of spirochaetes in culture was performed using microscopy, and immunochemical and molecular (PCR) techniques. Additionally, whole ticks were tested with PCR for spirochaetes.

From 1990 to 1992, approximately 12000 ticks were processed for spirochaetes. No evidence of Borrelia burgdorferi or any other spirochaete was recovered from or detected in likely tick vectors. Some spirochaete–like objects detected in the cultures were shown to be artifacts, probably aggregates of bacterial flagellae.

There is no definitive evidence for the existence in Australia of B. burgdorferi the causative agent of true Lyme disease, or for any other tick–borne spirochaete that may be responsible for a local syndrome being reported as Lyme disease.

(Accepted October 03 1993)

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