Bacteria link with disease ‘still realm of supposition’


Peter Irwin says the research will go on for several years to come.
Peter Irwin says the research will go on for several years to come.

IT is plausible that Australian ticks harbour bacteria that cause Lyme disease-like symptoms.

That is the conclusion of Murdoch University researcher Peter Irwin, who has spent the past three years scouring the nation’s ticks for any sign of Borrelia burgdorferi, the bacterium associated with Lyme disease in America and Europe.

While Dr Irwin’s search for that particular bacterium has proved fruitless, his team of researchers have uncovered bacteria with a similar genetic makeup to Borrelia burgdorferi.

“Lyme disease is caused by one particular type of bacteria and we have found no evidence of that type of bacterium in any of the Australian ticks that we have tested,” he said.

“However, we have found many other bacteria and it is certainly plausible that some of them cause people to get ill.

“We can even go so far as to think it is likely because some bacteria we have found is very close to bacteria discovered overseas that is linked to Lyme disease.”

While conceding an as-yet undefined tick-borne disease may be present in Australia, Dr Irwin cautioned that until further research and clinical testing was conducted any possible link remained “in the realm of supposition”.

“This is where it begins to get murky. The multi-million dollar question is whether or not those bacteria can cause illness in people in Australia,” he said.

Dr Irwin said he was working with doctors to develop studies that would ascertain whether the bacteria his team had found in ticks was also present in people.

“It is quite complicated research to conduct but that is where the work has to go. I think over the next five or so years, a lot more work will occur in this area as people begin picking up on our results,” he said.

Results of overseas tests can confuse

Murdoch University researchers, in conjunction with colleagues at the University of Sydney and Curtin University, have now tested between 600 and 700 ticks for the Lyme disease-causing bacterium Borrelia burgdorferi.

While that represents just a tiny fraction of the billions of ticks present in Australia, lead researcher Peter Irwin believes the sample is an accurate cross-section of the entire population.

“The second study we conducted was only looking at ticks taken off people, some of those people ill with what they believed to be a Lyme disease-like illness,” Dr Irwin said.

“We tested 460 of those ticks and if the Lyme disease bactierum really was present in Australia that is the group we thought we would find it in.”

Dr Irwin also took aim at American and European labs that often returned positive results for Lyme disease from blood samples sent overseas by desperate Australians.

“Part of the problem is that in order to test for a disease you need to what to test for,” he said.

“In America or Europe you get tested for Lyme disease because you know that it exists there.

“The problem here in Australia is that people are being tested for Lyme disease by North American or European tests and some of them come back positive.

“The question is does that mean you have Lyme disease, or is the test actually reacting to some other organism that is similar but not Lyme disease.

“No accredited lab in Australia has ever found it in people who have never travelled overseas so some people getting these tests done overseas are unfortunately being led to believe they have Lyme disease when they quite probably do not.”