June 9, 2015
As temperatures rise across the country ahead of summer, talk about ticks and the diseases they carry is also heating up.
Lyme disease, transmitted by the bite of a black-legged tick carrying the Borellia burgdorferi bacteria, is the most common vector-borne disease in North America. Untreated, the bacteria can cause serious health problems.
But misdiagnosis and misinformation about the disease can also be a problem, says Dr. David Patrick, an infectious diseases specialist, epidemiologist and director of UBC’s School of Population and Public Health.
What is Lyme disease?
It’s a bacterial infection that you get from the bite of a black-legged tick. The bacteria in ticks are extremely prevalent in the east and north east of the United States, and increasingly prevalent in Nova Scotia and Ontario. We have it here in B.C. as well, but at a very low level.
Early symptoms might include a rash at the site of the bite, headache or fatigue. Untreated, the organism can give you swollen joints, heart palpitations and nervous system disturbances.
Why have we been hearing a lot more about Lyme disease in recent years?
There are two myths contributing to this: firstly that it’s all over the place in B.C. and secondly, that so-called specialty Lyme-labs in the United States are providing accurate diagnoses of the disease.
Here in B.C. we’ve tested thousands of black-legged ticks taken off people, dogs and in the wild and we’re finding only one in 200 ticks carry the bacteria. This is a hundred times less frequent than in southern Ontario or Connecticut.
There are a lot of people genuinely ill and disabled with chronic symptoms who are justifiably annoyed about getting few answers from our health care system. Some of these folk have been diagnosed with Lyme disease through so called Lyme-specialty labs in the United States. Studies in 2014 showed conclusively that those lab tests failed to pick up Lyme disease any better than standard lab testing available in Canada.
The studies also demonstrated that as many as 50 per cent of healthy people with blood tested at these U.S. labs will be issued a false positive result. Since Lyme disease is present in far less than one per cent of tested people from
B.C. the odds that a “positive” test from such a lab is false are more than 50 to one.
Is Lyme disease hard to diagnose and treat?
It’s not hard, but people and doctors need to be on guard. Early-stage Lyme disease is a clinical diagnosis based on a tick bite, a characteristic bull’s-eye rash around the bite site and you may have other symptoms, such as fever.
Serological lab blood tests available in Canada that identify the antibodies to the bacteria are quite effective in diagnosing Lyme disease in later-stage patients.
When diagnosed properly, Lyme disease is quite treatable with a limited course of antibiotics. Most people do really well with that, but some continue to have symptoms.
What can people do to protect themselves?
Prevention is an important part, and this video produced by UBC researchers provides valuable tips for practicing tick avoidance.
What are the dangers of misdiagnosing a patient with Lyme disease?
The very real danger is that it diverts from an accurate diagnosis. There have been cases of people with cancer missed in the United States because they’ve had an alternative Lyme diagnosis. In B.C. we hear of lost vision due to delayed diagnosis of multiple sclerosis because of a false-positive Lyme diagnosis and we’ve seen death from complications of unnecessary I.V. antibiotic treatment. There is a very serious patient safety problem with these faulty tests.
What new research is being done at UBC about Lyme disease?
We’ve been working with a group of people who have been diagnosed with Lyme disease by alternative methods to see what else could be going on. We are using some next generation gene sequencing methods and looking for different organisms that could be contributing to their problems and different patterns of gene expression that might also be responsible.
These folks are sick – they have levels of disability that are similar to people with any other chronic disease but what’s also extremely interesting is that they’re quite similar to people working with chronic fatigue syndrome. The only real discernable difference is that they’ve got this test in hand from an alternative US specialty lab so I think we may be looking at a similar spectrum of illness but it’s probably not Lyme disease.