Tick and Canadian Winters
With all the talk of weather bombs and polar vortices, it’s easy to assume the subzero temperatures of winter will kill ticks and wipe out their thriving populations. Ticks are most certainly susceptible to prolonged freezing temperatures, but what sounds like a simple solution to this increasing threat may not actually do the trick.
Ticks are busy well into late fall, first seeking their final pre-winter blood meal, and then securing a suitable protective habitat to get them through to spring. Some ticks won’t bother to hibernate, and instead will survive frigid winters on the literal backs (or ears, scalps, groins, etc.) of hosts mammals. However, when temperatures drop significantly most ticks will have already found refuge in moist layers of leaf litter or other organic ground cover.
Ground temperatures are typically warmer than the air in winter. Scientists propose that when warmer earth is combined with layers of leaf litter, snowfall just adds another layer of insulation, making sure ticks are able to survive air temperatures that would typically kill them if otherwise unprotected.
In addition, antifreeze proteins (I. scapularis antifreeze glycoproteins, or IAFGP), are present in certain tick species, including the blacklegged tick, further helping to protect them from freezing to death. Interestingly, these proteins can be enhanced by certain pathogens, making some infected ticks particularly cold hardy.
If winter arrived with sudden onset but sustained subzero temperatures, in areas with little to no organic ground cover or snow, then yes, many exposed ticks would likely die. But if has winter waltzed in and laid out a lovely layer of the white stuff, ticks will easily survive what we’d consider the ‘coldest winter yet.’
It is extremely important to remember that ticks can and will emerge any time temperatures rise above approximately 4C or 39-45F, whether winter is over or not.They won’t emerge to bask in the sun, they’ll be on the hunt for blood.
One more thing to be aware of, tick borne diseases acquired in the winter may prove harder to diagnose as the symptoms of these illnesses so closely mimic those of the colds and flus typically caught at this time of year. Please don’t let your guard down. Keep up with your tick checks and make sure you and your pets are tick free before you come back in from the cold.