Reported Lyme disease cases remain low in Hamilton
Hamilton Health Services says there has been only one reported local case of Lyme disease this year where the person was bitten by a tick in the city.
Two other cases involved Hamiltonians whose Lyme disease was “travel associated,” meaning the disease was acquired while visiting another jurisdiction.
The figures come after health services warned in the spring that black-legged ticks — the kind that can carry the disease bacterium — have established a home here and Hamilton had been deemed an “estimated risk area for Lyme disease.”
Connie DeBenedet, manager of vector-borne diseases with the city, says physicians must report Lyme disease cases to health services. And it’s not clear whether they’re not following through or cases don’t exist.
“Maybe we take a little credit in getting the message out that people should take the precautions such as staying on trails and avoiding grassy areas and using DEET products or wearing light-coloured clothes,” she said.
There are likely situations where doctors feel they are uncertain whether their patients have the disease and they are waiting for a clearer diagnosis before reporting the case, DeBenedet acknowledged.
As well, she said, the spread in Hamilton of black-legged ticks, those with the Lyme bacterium and human cases of the disease are still at an early stage. We could see much higher numbers in the future, as has been the case elsewhere in Ontario.
Hamilton public health also does testing to get an idea of black-legged ticks in the community and the percentage of them that have the bacterium.
To get Lyme disease, the tick has to be both black-legged and carrying the bacterium.
In Hamilton this year, 530 ticks were collected. Of those, 82 were black-legged ticks with eight having the bacterium.
That compares to 2017, when 817 ticks were collected with 44 black-legged ones. None had the bacterium. In 2017, there were four human cases reported in Hamilton. The year 2015 had the highest number with 11.
“This evidence clearly shows we are seeing more black-legged ticks with some of them having the bacterium,” DeBenedet said. “We were right in following the criteria to call ourselves an estimated risk area for Lyme disease.”
However, Ellen Hohs, of Lyme Ontario, an advocate group for Lyme disease awareness and research, says it’s far more prevalent than health department numbers suggest.
“The problem is patients are not meeting the case definition and we know that you don’t need to meet the case definition to be infected with the disease.
“We get 10-15 emails a day from people looking for help because they have all these symptoms. Doctors can’t figure out what is going on with them so they are coming to us.”
The Haldimand-Norfolk Health Unit has reported its first human case of the disease in 2018. To date, the unit has collected 72 black-legged ticks (also known as deer ticks) in Haldimand and Norfolk counties. Of those, 24 tested positive for the bacterium.