“A freckle with legs” - rise of the tick and mosquito
By: Dr. James Aw, Chief Medical Officer, OMERS
August 10, 2026
Summer is the best time to enjoy nature and the great outdoors! Yet some of us can never truly enjoy all this offers, finding themselves covered in insect bites during the season. Besides the annoyance; should you worry? Some bug bites just cause nasty local rashes and itchiness, but certain tick and mosquito bites can make humans very sick. During the summer and cottage season, it is worth educating yourself about tick-borne Lyme disease and mosquito-borne West Nile Virus (WNV). Both are becoming increasingly common and will likely continue to do so with climate change. Heat waves (prolonged insect seasons from milder winters), flooding (water reservoirs for mosquitoes), migratory birds and animals (spreading insects), and overgrown vegetation (long grasses for ticks) are some examples of optimal insect habitat conditions.
What makes human skin so attractive to bugs? It’s our smell, body heat and a bloody meal!
Humans produce unique volatile odours when skin bacteria break down our sweat components into carboxylic acids, lactic acid and ammonia. Individuals with high skin carboxylic acid levels are mosquito magnets; mosquitoes find this odour irresistible! Ticks and mosquitoes are also attracted to human breath components like carbon dioxide, acetone and nitric oxide, which draw them in. But it is the radiant heat and humidity from the skin that is a key sensor. Pregnant women attract more mosquito bites because of increased carbon dioxide production and higher body temperature during pregnancy.
Tick bites can lead to Lyme disease and other infections
Lyme disease is caused by a bacterium that is transmitted to humans from an infected tick bite (there are different versions in Eastern and Western Canada). It occurs mainly in the temperate regions of the North Hemisphere, including North America, Europe and Asia. Blacklegged tick populations are also migrating north as winters are getting milder.
Cases are rising, with the highest risk in Canada in eastern Ontario, southwestern Manitoba, southwestern Quebec, New Brunswick and Nova Scotia. The disease usually starts in May, peaks in the summer months during cottage season, but can be present late in November. The preferred tick habitat varies by species, but they tend to like forests with dense vegetation, tall grasses, leaf litter and they need an animal host (deer, mice, migratory birds and domestic pets). Other emerging co-existing tick-borne infections include anaplasmosis, babesiosis, Powassan virus, erlichiosis and rare cases of Rocky Mountain spotted fever. A rare complication of tick bites is called alpha-gal syndrome (AGS) which can cause a severe delayed allergic reaction to the consumption of red meat (beef, pork, lamb).
The classic skin finding in 70% of cases is a “bull’s eye” lesion (an expanding red circle greater than 5 centimetres with a pale centre) called erythema migrans that can occur 3-30 days after a tick bite. Other symptoms include painful joints (42%) and potentially more serious neurological (41%) and cardiac (4%) complications. Lyme is treatable with antibiotics (doxycycline) if symptomatic, but prophylactic single dose doxycycline can be given within 72 hours in high-risk areas when a black legged tick is removed from the skin. Men are more frequently affected than women and increased cases are seen in children and adults over the age of 60. LYMErix vaccine was withdrawn from the market in 2002 and new vaccines (VLA15) are in clinical development.
A freckle with legs
Ticks on skin have been described as a “freckle with legs.” The most important action is to examine the skin for ticks if you have been exposed and immediately remove any ticks with fine-tipped tweezers. Try to remove all parts of the tick with a straight up movement with proper technique. You should avoid using topical chemicals on attached ticks. Bathe or shower within 2 hours of outdoor activity if possible. Washing clothes in hot water and placing clothes in a high-heat dryer for more than 10 minutes will also remove ticks. If you are routinely outdoors, then you should perform daily skin checks focusing on the arm pit, ears, umbilicus, behind the knees, groin, waistline and scalp areas. Also perform regular skin checks on your pet cats and dogs. If you do a lot of hiking, then you should wear light-coloured, long-sleeved clothing sprayed with repellents like permethrin and DEET (20-30%) on skin. Don’t forget to reapply DEET after swimming! Other topical repellents include picaridin, IR3535, oil of lemon eucalyptus (OLE), PMD and 2-undecanone.
Mosquito bites can transmit West Nile Virus, a potentially serious neurological condition.
West Nile Virus is found in Africa (originally in Uganda in 1937), Europe, the Middle East, West Asia and North America (first case in New York in 1999). This virus is the leading cause of mosquito-borne illness in Canada (first case in 2002), with most cases in Western provinces beginning in mid-April and at their highest late in the summer. It is transmitted to humans by a mosquito (Culex species) that has fed on an infected bird (crows, ravens, jays, magpies). For most people, the infection has mild, flu-like symptoms or no symptoms (80%). However, less than 1% of those infected have severe neurological diseases (encephalitis, meningitis and rarely, paralysis). The case fatality ratio for patients with severe neuroinvasive WNV is around 10%. Individuals with a weakened immune system, over the age of 50 and with chronic diseases (cancer, diabetes, alcoholism, cardiomyopathy, chronic kidney disease) are more susceptible to WNV complications. Over 50% of patients requiring hospitalization for WNV experienced chronic fatigue, weakness, difficulty walking, memory impairment and depression. The incubation period is 2 to 14 days but may be several weeks in the immunocompromised. Individuals with unusual neurological symptoms and mosquito bites should seek medical attention for a diagnosis and supportive treatment. There is no vaccine (yet) or anti-viral treatment.
Prevention of mosquito bites is similar to tick bites in terms of long-sleeved clothing and the use of repellents. Drain standing water reservoirs like flowerpots, bird baths and buckets. Mosquito peak biting times tend to be at dawn and dusk. Mosquito netting may help. Bites that are itchy can be treated with antihistamines and topical anti-itch creams (i.e. corticosteroids).
Public health experts are monitoring other mosquito-borne viruses (Jamestown Canyon virus, Snowshoe hare virus, Eastern equine encephalitis virus, Cache Valley virus) that have been rare but linked to human neurological diseases.
Don’t be afraid of bugs. Explore nature. It’s good for you!
Not all insect bites will lead to a serious infection. It’s still relatively rare to get severe Lyme or West Nile Virus However, it makes sense to keep your outdoor property well maintained. Cut the grass, remove water basins and clear leaves. Staying active with yardwork is good for your health! Check local public health websites to assess the risk of Lyme and West Nile Virus in your area. Get into the habit of examining your skin (and your pets) for ticks and unusual rashes during the season. Learn how to properly remove a tick with tweezers. See your physician if you start to feel ill after being exposed to tick, mosquito and/or other insect bites. Apply insect repellent if spending time in high-risk areas. Please enjoy nature and have a great summer!
The information, content and material provided by OMERS Administration Corporation at each link on this page is provided for informational purposes only and is not intended to be, or to substitute for, medical advice. Always seek the advice of a qualified healthcare professional if you have any questions regarding a medical condition or treatment and do not disregard or delay seeking professional medical advice because of the content provided at any of the links on this page. OMERS AC and its affiliates and other investment entities are not responsible or liable in any manner for your use of or reliance on the above information.
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