What Warmer Winters Mean For Tick-Borne Disease

Winters nowadays look significantly different than they used to mere decades ago. Many areas that used to be home to the harshest winter weather now see milder temperatures, less snow, and more rain. These changes are mainly due to the effects of climate change on the globe.

Milder temperatures are making their way to areas where snow and cold are usually present. In areas where snowfall is unlikely, cold snaps are occurring. Climate change is complicated, and scientists are still trying to predict and understand how it’s causing these extreme weather changes.

While it’s true that these global changes can lead to harsher winters with more intense blizzards, the opposite is true for many areas in the northern part of the country. The states that border Canada are often predisposed to cold winters and heavy snow. However, in recent years, those areas have been experiencing record-breaking warmer temperatures because the atmosphere is heating up.

Climate change affects all life on earth – including tick populations. But how does climate change affect ticks and the spread of the diseases they carry? Let’s investigate what warmer winters mean for tick-borne disease.

Image by Matt Heaton on Unsplash: How do you get Lyme disease in the winter?

How does weather affect tick populations?

Ticks depend primarily on the weather to get through their life cycle. Ticks lay their eggs during the spring, and those eggs hatch during the winter months. The newly born ticks then progress into the larva stage when spring and summer roll around again. They reach adulthood in the fall and winter months. During this life cycle, ticks go through many stages. However, during each stage of life, ticks must feed off the blood of a host to survive.

Ticks tend to be most active during the warmer months between March and May and August to November. This weather gives them a prime opportunity to thrive in the wooded areas they live in. When the cold months return, ticks must hide under brush, snow, or other debris to stay warm enough to survive. That is why it’s much more difficult for them to feed during those months.

When the weather remains warm enough for ticks to survive and feed for the better part of the year, not only are they more able to spread disease, they are also more likely to multiply faster. More prolonged bouts of warm weather allow more ticks to lay eggs, and a boom in tick populations is born from those eggs the following spring.

Can ticks survive high temperatures?

Ticks thrive best in temperatures of 70–90 degrees. However, temperatures higher than that do not necessarily kill ticks. They can survive in higher temperatures, but often hide away in cooler areas under the brush so they do not overheat. Humidity also affects tick survival; if humidity is below 80% for too long, ticks are likely to die quickly from dehydration.

Ticks also have an uncanny ability to survive in colder temperatures as well – especially if they are infected with Lyme disease. One study examined the survivability of ticks in cold weather and found that infected ticks are more likely to make it through colder winters than their non-diseased counterparts. Ticks carrying the bacteria are also more motivated to find a host than those who do not carry Lyme disease.

Image by Robin Lyon on Unsplash: How does temperature affect Lyme disease?

The effects of climate change on ticks and tick-borne diseases

As the globe heats up, so does the climate in all areas of the world. This can cause disastrous effects such as flooding, heat waves, and other extreme weather events. Regarding ticks and tick-borne diseases, climate change can cause populations to grow. When that happens, the chances of tick-borne diseases spreading becomes higher.

In the last two decades, one of the most well-known tick-borne diseases, Lyme disease, has spread significantly. Nearly three times more cases are reported now than in the 1990s, and it is considered the most common zoonotic disease in North America. This is primarily due to climate change and how weather patterns have shifted in the last few decades.

When winters become milder, ticks can feed more often, and the animals they choose are more likely to roam. This allows ticks to latch onto a deer or other host, hitch a ride to another area of the country, and lay their eggs in the new location. As the geographical area ticks can survive in grows, so does their ability to spread disease.

Climate change has also caused unpredictable weather to occur throughout the year. For example, the winter months often see temperatures ranging from highly mild to cold in a matter of days. If a tick feels that the weather is warming, it will climb out of its hiding spot and try to find food.

Changing weather patterns are no joke when it comes to tick populations. Due to the fact that Lyme disease and other tick-borne diseases such as Colorado tick fever, Rocky Mountain spotted fever, and the Heartland virus can cause debilitating effects on human health, the changes in tick populations because of climate change need to be monitored closely to avoid a public health crisis.

Featured image by Oziel Gómez on Unsplash

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