What you need to know about a new tick-borne disease on the rise in Nova Scotia

A new tick-borne disease called anaplasmosis is on the rise in Nova Scotia. 

The disease is transferred to people through the bite of a black-legged tick, similar to Lyme disease. 

Dr. Todd Hatchette, the chief of microbiology for the central zone of Nova Scotia Health, said last year there were only a handful of cases in the province. This year, there have been 75.

"This is a large jump," Hatchette told CBC Radio's Mainstreet on Tuesday.

"Probably not totally unexpected knowing that we have seen this particular bacteria in the ticks in the last tick survey that was done in 2016, so it was just sort of a matter of time before it made the leap into humans."

Hatchette spoke with host Jeff Douglas about the emerging illness and what people need to know.

Their conversation has been edited for length and clarity.

What are the symptoms of anaplasmosis?

Well, it can actually be quite non specific. Most people present with basically a summertime influenza-like illness, so they have fevers, muscle pains, joint aches, just feeling unwell and a headache, and it can be hard to differentiate from other non-specific infections. Even COVID for that matter nowadays can present with similar features, so people need to be aware and think about it, particularly in areas that are high risk for Lyme disease, which correspond to the same areas that have the ticks that would have this particular bacteria as well.

Is there a test? How do we diagnose it if there's so much symptom overlap? 

Yeah, if people have acute symptoms, then the best way to diagnose it is using a test that's very similar to the COVID test. It detects the genetic fingerprint of the bacteria and if you do that test within the first two weeks of symptoms, it's very sensitive.

After that time, many people, the symptoms go away on their own without treatment, you can still diagnose it using serology or looking for antibodies to the bacteria much like we would do for Lyme disease.

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Is this something like Lyme where if you missed that first onset period of the disease, it can have long-term ramifications? 

Well, the vast majority of people, this is a self-limiting infection, so the symptoms will go away on their own within 30 days, but it can cause more significant problems in people who have compromised immune systems or older individuals.

In those circumstances, it can be quite serious and lead to requiring people to be admitted to hospital with problems with breathing, their kidneys, that sort of thing. So it's hard to predict who is going to do poorly with this, with this particular bacteria, and that's why we recommend treating anybody who has a positive test.

In the initial phase, if you notice that you've picked up a tick and you start to feel poorly, for a physician, how does it differentiate from Lyme early on? 

That's a great question. With Lyme disease, most people have an expanding oval rash or the bull's-eye rash that they talk about. With anaplasma, there's no real rash associated with that, so that's one clue. 

The other clue is if they're sick enough to get blood work, then you can see some features that you wouldn't see with Lyme disease. For example, people's cell counts can be low, like their platelets or their white blood cell count can be low, which is just a feature of this particular infection which wouldn't be seen with Lyme disease.

Do you know why we are seeing such an uptick? 

Well, I think there's a lot of factors. We know that the black-legged tick is here to stay. It has become entrenched in Nova Scotia and just like Lyme disease, it took some time for those infections to really start infecting humans because it takes time for the ticks to get high enough levels of the bacteria and then enough ticks to be around that people get exposed to them.

One of the things that we are doing because we've noticed an increase in the number of cases is that we've started a tick-borne disease test panel, if you will, where we will test anyone who has a Lyme disease serology request, we'll actually do an anaplasma test as well, just to see if we're missing any cases.

Is this something that could be easily misdiagnosed?

That is correct. The key is to think about it. We are sending out reminders to clinicians across the province that this is an emerging infection that people should think about and it is something they can test for in anybody who presents with sort of the flu-like illness in the summertime.

It's not to say that this is to scare people or say people shouldn't enjoy the outdoors, it's like Lyme disease in its messaging: you just have to be aware that the ticks are out there and the ticks can have these bacteria in them and take the necessary precautions to avoid tick bites or remove the tick as soon as you find it because like Lyme disease, it does take time for the bacteria to move from the gut of the tick into the human.

For doctors who are seeing this, what advice would you have for them in a clinical setting?

If they see anyone who has fevers or chills in the summertime, think about anaplasma and send in the test requesting the PCR for it. 

Is it mandatory?

There is no mandatory test and in terms of reporting, it's not a notifiable disease yet through Public Health, but that is something that is being looked at just like other tick-borne infections so that Public Health can keep better track of numbers. 

We do, in the lab, report it to Public Health as an unusual occurrence, so they ... are aware of the increased numbers of cases we have been seeing.