There is no convincing evidence that classic Lyme disease occurs in Australia, nor is there evidence that the causative bacterium, Borrelia burgdorferi, is found in Australian animals or ticks, according to a narrative review published by the Medical Journal of Australia.

Professor Peter Collignon, from the Australian National University and executive director of ACT Pathology, and his co-authors also expressed concern about increasing numbers of patient requests to be treated with antibiotics for "Lyme disease-like illnesses".

The review stated that the bacterial species that causes Lyme disease, the Borrelia burgdorferi sensu lato (B.burgdorferi s.l.) complex, has not been cultured from locally acquired cases of the disease. Additionally, Australia does not appear to have a competent tick vector for these species. Lyme disease diagnosed in this country was acquired overseas by travellers before returning to Australia.

Clouding discussions of the disease is the prevalence of false positive test results in laboratory diagnoses, further complicated by antigenic variations in the organisms used for developing these assays. The authors wrote that a twotiered test, comprising an immunoassay followed by an immunoblot to support the clinical diagnosis, remained the best way for investigating Lyme disease if there was a well founded clinical suspicion of infection.

A recent Senate inquiry raised questions about the epidemiology, diagnosis, treatment, and investigation of Lyme disease. It also focused on the stigma felt by patients with a chronic debilitating illness. Professor Collignon and his colleagues noted that focusing on patients with chronic symptoms would lead to diagnostic research, which could ultimately be beneficial for the identification of viruses and bacteria that occur in ticks, animals and people in Australia.

While there was no evidence of Lyme disease in Australia, the authors wrote that new viral or bacterial pathogens that can cause acute or chronic infections in humans may be discovered in ticks and other vectors in Australia.

Given the lack of evidence that Australia has the aetiological agent or component vector for classic Lyme disease, some patients and advocacy groups have adopted "Lyme-disease like illness" to label chronic, debilitating symptoms, often following a tick bite.

This has led to patients believing that prolonged antibiotic therapy, including intravenous antibiotics, may cure their disease. Professor Collignon and his colleagues emphasise that such treatments can present a range of hazards.

"Antibiotic resistance resulting from the unnecessary and prolonged use of broad spectrum antibiotics is a major problem," they wrote. "Until there is strong evidence from well performed clinical studies that bacteria present in Australia cause a chronic debilitating illness that responds to extended antibiotic therapy, treating patients with socalled 'Lyme disease-like illness' with prolonged intravenous or oral antibiotic therapy is both unjustifiable and unethical, and is likely to do much more harm than good."

Article: Does Lyme disease exist in Australia? Peter J Collignon, Gary D Lum and Jennifer MB Robson, Medical Journal of Australia, doi: 10.5694/mja16.00824, published 31 October 2016.