We tested two environmentally-safe products – Met52 fungal spray and TCS bait boxes – to see if these reduced the abundance of ticks. More importantly, we tested whether these products reduced the number of cases of tick-borne diseases, or encounters with ticks.
What we found
We found that the TCS bait boxes reduced the number of ticks in people’s yards by about half. We did not see a reduction in tick numbers from the Met52 fungal spray.
Most importantly, though, the incidence of tick-borne diseases in people was not affected by either the TCS boxes or the Met52 spray. People’s encounters with ticks were also not reduced by the boxes or the spray.
If you have a pet, the good news is that the incidence of tick-borne diseases in pets was lower by about half on properties that were treated with either the boxes or the spray, or both.
What it means
We do not know why we there was no difference in the incidence of tick-borne diseases in people when the number of ticks in yards was lower, but we have a few hypotheses.
It could be that having even a fairly small number of ticks in your yard is enough for you and your family members to have a risk of getting a tick-borne disease. The bait boxes and spray might not have gotten tick numbers below this level, even with our rigorous application of these products.
Another possibility is that people in our study got infected from ticks they encountered in places other than their yards or neighborhoods. If this is the case, our efforts to reduce ticks in yards might have helped pets – which often spend a lot of time in yards – more than they helped people. Unfortunately, we still don’t really know where people – or pets -- most frequently encounter ticks.
Because of our results, we think that reducing the incidence of tick-borne diseases in people might be quite difficult to achieve by managing ticks in neighborhoods or individual yards. We suspect that the best strategy going forward will be to develop vaccinations against the diseases, or against the ticks themselves.