Excerpt from Rain on a Distant Roof: A Personal Journey Through Lyme Disease in Canada.
Copyright Vanessa Farnsworth, 2013.
In 2010, Canadian researchers decided to study Ixodes scapularis ticks collected from multiple sites stretching from Alberta to Nova Scotia in an effort to determine if the genetic diversity of Borrelia burgdorferi (Bb) might be playing a role in the accuracy (or rather the inaccuracy) of diagnostic testing in this country.
That’s when they discovered something quite unexpected.
They found relapsing tick fever borrelia and Lyme borrelia living side-by-side in the guts of some of those ticks. It was a landmark finding because it meant that for the first time proof had been found in nature that a person living in Canada could contract both illnesses from the bite of a single tick. It also meant that my diagnosis was suddenly not as improbable as it first appeared. I really could have contracted both relapsing tick fever and Lyme disease from one tick; the proof of that was sitting in government research facilities.
And not just in 2007, either.
Technically, infection with both illnesses has been possible in this country for quite some time. The ticks used in the 2010 study had been collected as far back as 2005, and who knows how many years previous to that ticks had been carrying dual infections without anybody noticing? That’s anyone’s guess. Let’s face it, unless you’re actively looking for a needle in a haystack, you have no hope of finding one. Even when you’re actively looking for one, it’s pretty hard to spot one. So the fact that the researchers found the proof in the limited sample of ticks collected from across the country is really quite extraordinary.
Yet that’s not the most interesting part of this anecdote.
The most interesting part is the species of relapsing tick fever borrelia living cheek by jowl with Bb in the guts of some of those ticks was not Borrelia hermsii, the species of relapsing tick fever that was presumed to have infected me, but rather a closely related “sister” species called Borrelia miyamotoi.
B. miyamotoi has an interesting history. It was first discovered in Japan in the mid-1990s and although it was initially thought to make its home only in that country, it has since been found in other temperate regions, including Russia, the United States and now, belatedly, Canada. Indeed, in the northeastern United States, it’s now estimated that B. miyamotoi accounts for up to 15 percent of the spirochetes carried by I. scapularis ticks. Not surprisingly, the bacterium has been found in the same white-footed mice that host Bb, firmly establishing its presence in nature in the United States.
No wonder it was found in Canadian ticks.
If Bb is moving from south to north – and it is — then why wouldn’t other forms of borrelia be doing the same? They would, that’s the point. When the ticks that carry these diseases move north, they necessarily bring with them any diseases they’re carrying.
Logic doesn’t get any simpler than that.
Initial research appears to suggest that a much lower percentage of the ticks in Canada are co-infected with Bb and B. miyamatoi than those in the United States, but keep in mind that initial research is all we have. Time will tell just how prevalent these co-infections are and also if B. miyamotoi is occurring in ticks in the absence of Bb, something that these first researchers couldn’t report on because they weren’t actually looking for B. miyamotoi at the time they discovered it. They were cataloguing different strains of Bb and, as a result, the only B. miyamotoi specimens they know about are the ones that occurred in tandem with the Bb bacterium they were targeting.
It does, however, seem likely that B. miyamotoi is occurring in ticks in the absence of Bb. It would be strange if it wasn’t.
Part of what makes B. miyamotoi so interesting is that its symptoms can span those of both Lyme disease and relapsing tick fever. There’s even some evidence to suggest that its clinical symptoms are both more diverse and more severe than those you’d expect to see in someone infected with Bb. Indeed, for some patients, a B. miyamotoi infection is a lot like having Lyme disease with the added bonus of the dramatic remitting/recurring fevers long associated with relapsing tick fever.
I’m sure you can see why the discovery of this particular species of borrelia in Canada caught my eye. It’s no longer necessary for me to have been bitten by two different ticks. I could’ve been bitten by a single tick carrying both illnesses or – more intriguingly – I could’ve been bitten by a tick carrying a single species of borrelia – possibly B. miyamotoi, possibly something else – which gave rise to the symptoms of both illnesses.
One of the interesting features of B. miyamotoi is that people who contract it often don’t develop the distinctive EM rash that public health officials insist are common in Lyme infections.
Now there’s something to contemplate.
It would go far towards explaining why I didn’t develop such a rash.
Still, the discovery of B. miyamotoi in Canada (or anywhere else, for that matter) isn’t really all that surprising. Research into borrelia bacteria is in its infancy worldwide. In the last decade, several new species have been discovered and although researchers don’t know how many more they have yet to find, the one thing they’re certain of is they will be finding more. There are lots of different types of borrelia bacteria out there and the process of cataloguing them all will span many decades to come.
It’s intriguing to think that twenty years ago, no one had ever heard of Borrelia lonestar, Borrelia theileri, or Borrelia miyamotoi, but they have all since been discovered in the guts of ticks and given names. There are also other novel borrelia species that have been discovered in recent years and are still so new that their official names have yet to be established and, in some cases, the ticks that are vectoring these species into mammals remain unknown.
No one knows at this point what role (if any) many of these species play in human infection.
Those answers are still to come.
And here’s something to contemplate: The three species of borrelia I’ve just listed above by name were all found in the guts of ixodid ticks – the hard-bodied ticks that carry Lyme disease — and yet all three are types of borrelia associated with relapsing tick fever, which is supposed to be carried by soft-bodied argasid ticks.
That’s what the textbooks say.
That’s the assumption researchers had been operating under.
These discoveries are problematic for several reasons. For one, if assumptions over which types of ticks carry which type of borrelia bacteria prove to be only partially accurate, then what other assumptions are being made by researchers that are also only partially accurate or, for that matter, not accurate at all but based on accepted reasoning that has yet to be disproven?
That answer is still on the horizon.
These discoveries also mean that there may be borrelia infections occurring in Canada for which no diagnostic tests currently exist. After all, tests have only been developed for a few species of borrelia and those tests are problematic at the best of times. Using them to detect borrelia species or even strains of Bb not previously known to exist — or worse, to identify multiple species of borrelia in a single person — is something they simply weren’t designed to do. It’ll likely be many years and require significant technological advancements before the tests that can accomplish these things are developed.
How does any of this help me?
Other than confirming that I could’ve contracted both illnesses from a single tick bite or possibly even have contracted a single bacterium whose symptoms span both illnesses, it doesn’t help a whole lot. All anyone can say for certain is that somewhere along the line I became infected with at least one form of borrelia bacteria. There’s no way for current diagnostic testing to say with any authority which form or even if the borrelia infecting me is a previously identified species or something new to science. That kind of specific diagnostic testing likely won’t exist for many years.
Possibly even decades.
And it’s questionable what use it’ll be to me once it arrives since so much time will have passed – so much time has already passed — between infection and identification.
