Did you know that the period of highest risk for tick (order Ixodida) bites in Ontario is typically between May and July when nymphs (immature ticks) emerge? However, ticks can remain active as long as the temperature stays above freezing, extending their activity well into the fall and posing a risk to individuals such as deer hunters and nature lovers. Ticks feed on the blood of animals and humans, and have the potential to transmit diseases, including Lyme disease, which is the most common illness resulting from tick bites in the province.
Photo credit: Bipin Dinsha
As human settlements expand into natural areas, the interaction between suburban areas and the habitats of deer and other animals increases. Ticks favor areas with tall grass, bushes, and leaf litter as these environments provide opportunities for them to climb onto passing hosts. They can be found in wooded areas, forests, meadows, and even urban parks. While ticks can be found throughout Ontario, certain regions like eastern Ontario and parts of the Niagara Peninsula have a higher prevalence of ticks. It's worth noting that ticks are not only carried by ground-dwelling animals but also by songbirds such as robins, which can deposit infected ticks in urban yards while searching for worms in lawns. Additionally, pets like dogs and cats can inadvertently bring infected ticks into homes.
The primary tick species found in Ontario are the Black-legged Tick (Ixodes scapularis) and the American Dog Tick (Dermacentor variabilis). The Black-legged Tick is the main carrier of Lyme disease in Ontario. Lyme disease is caused by a bacterial infection from the spirochete bacterium Borrelia burgdorferi. Infected Black-legged Ticks (the only known tick species to carry this pathogen) transmit this disease to humans through their bites. Symptoms of Lyme disease may include a characteristic bullseye rash (erythema migrans), fatigue, fever, headache, muscle and joint aches, and swollen lymph nodes. If left untreated, it can lead to more severe symptoms affecting the joints, heart, and nervous system.
Interestingly, only about one-third of individuals diagnosed with Lyme disease recall being bitten by a tick. Did you know that estimates of the presence of a rash in Lyme patients vary widely, ranging from as low as 27% to as high as 80%? In one study, the characteristic bullseye rash was present in only 20% of cases.
Transmission rates of Lyme disease increase with the duration of tick attachment, although there is no definitive cutoff for a safe period. The notion that transmission requires 24 to 72 hours may have stemmed from the belief that the tick needs to regurgitate its stomach contents into the wound. However, it is now known that Borrelia, the bacterium causing Lyme disease, is present in the Ticks salivary gland, suggesting that transmission can occur rapidly. A 2015 review article summarizes animal studies demonstrating infection within 72 hours, and there are case reports of infection occurring within 6 hours or less in humans. Additionally, determining the duration of attachment is challenging, especially with the tiny, younger stages of ticks, as their bites are often painless and can go unnoticed. Other tick-borne infections, such as Anaplasma, can also be transmitted within a few hours of tick attachment.
Multiple studies have indicated that the two-tiered test for Lyme disease (ELISA followed by a Western blot) has a high rate of false negatives.   This occurs because the test measures our immune response to the bacteria and Borrelia is adept at disguising itself and altering its outer surface proteins to evade detection.
To prevent ticks and reduce the risk of tick bites, here are some recommended preventive measures:
Wear appropriate clothing: When spending time in tick-prone areas, wear long-sleeved shirts, long pants, and closed-toe shoes. Tuck your pants into your socks or boots to create a barrier and prevent ticks from crawling up your legs.
Use insect repellents: Apply insect repellents containing DEET (N, N-Diethyl-meta-toluamide) or picaridin to exposed skin and clothing. Follow the instructions on the product label for proper application. Consider using permethrin-treated clothing, which repels and kills ticks.
Conduct regular tick checks: After spending time outdoors, thoroughly check your body, clothing, and pets for ticks. Pay close attention to areas such as the scalp, neck, armpits, groin, and behind the ears. Promptly remove any attached ticks using fine-tipped tweezers or a tick-key, while making sure to get the whole tick body out including the head.
Create a tick-safe yard: Keep your yard well-maintained by mowing the grass regularly, clearing leaf litter, and trimming shrubs and bushes. Consider creating a barrier between wooded areas and your yard using gravel or wood chips to help reduce tick migration (this will not help though, with other wildlife or pets bringing them to your yard as mentioned above).
Protect your pets: Use tick preventive products recommended by your veterinarian to protect your pets from ticks. Regularly check your pets for ticks, especially after they have been in tick-infested areas.
Be cautious in tick-prone areas: If you are in an area known for high tick populations, take extra precautions. Avoid tall grasses, brushy areas, and leaf piles. Stick to the center of trails when hiking or walking in wooded areas.
Shower after outdoor activities: Take a shower as soon as possible after coming indoors to wash off any unattached ticks. This can help remove ticks that are crawling on your body.
- Consider landscaping modifications: If you live in a tick-prone area, you can make modifications to your landscaping to reduce tick habitats. This may include creating a border of gravel or wood chips between wooded areas and your yard, removing leaf litter, and trimming tree branches to allow more sunlight into your yard.
*It's important to note that even with these preventive measures, it is still possible to encounter ticks. If you develop any symptoms after a tick bite or have concerns about tick exposure, consult a healthcare professional for appropriate diagnosis and treatment.
What can you do Within Your Gardens?
While there are NO plants that can completely eliminate ticks, some plants are believed to have properties that may help deter them. Here are a few examples:
Rosemary: The strong scent of rosemary is said to repel ticks. Plant rosemary in your garden or place potted rosemary near outdoor seating areas to help discourage ticks.
Lavender: The aromatic scent of lavender is known to repel ticks. Plant lavender in your garden or use lavender essential oil on clothing or as a natural tick repellent.
Mint: The strong smell of mint is thought to deter ticks. Plant mint around your yard, patio, or outdoor areas to help discourage ticks.
Garlic: Some people believe that consuming garlic can make your body less attractive to ticks. While more research is needed to validate this claim, including garlic in your diet may offer some potential benefits.
- Lemongrass: The scent of lemongrass is known to repel ticks. Plant lemongrass in your garden or use lemongrass essential oil on clothing or as a natural tick repellent.
*It's important to note that relying solely on plants for tick prevention may not provide complete protection. It is still essential to use other preventive measures such as wearing appropriate clothing, using insect repellents, conducting regular tick checks, and maintaining a tick-safe yard.
When using plants as a tick deterrent, you can crush the leaves to release their natural oils, which may enhance their effectiveness. You can also make homemade tick repellent sprays using essential oils extracted from these plants. However, it's important to dilute essential oils properly and conduct a patch test on a small area of your skin to check for any adverse reactions before applying them more broadly.
Remember that while these plants may help to some extent, it's still crucial to take comprehensive preventive measures and consult healthcare professionals or entomologists for more specific advice on tick control in your region.
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