Life Science: Our Little Tick Problem Isn't So Little Anymore

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These creepy crawly summer-time bugs are very ferocious this year. They pick up your heat and odor from feet away. They watch you as you walk down your favorite hiking trail, rushing to predict what part of the path you’ll end up on next. They climb to the tallest blade of grass, legs outstretched waiting for you to get just close enough for them to grab onto you. They can’t jump or fly, so this is their only opportunity. Then finally they latch onto you, climbing up your pants until they can find the most perfectly thin piece of skin to latch onto and call home — temporarily.

Ticks are a dangerous insect parasite. They are really good at finding hosts and that also means they’re really good at obtaining pathogens. There have been over 100 cases of tick-borne illnesses already this year just in Indiana. In fact, every year there are over 30,000 cases of Lyme disease alone reported across the U.S., officials say it’s more like 300,000, and this number is on the rise.

How do ticks become capable of spreading disease? One tick alone is annoying, sure, but not capable of making you sick. They just suck your blood for a few days and then will drop off in efforts to find a new host. It’s the hosts that cause the disease. Ticks require hosts to feed, reproduce and complete their life cycles. They tend to live in tall grass and heavily wooded areas. The adults lay the eggs in the spring and by summer the eggs have hatched into larvae and need to feed.

They find their first host, usually something small like a bird or rodent, and then they feed on them for a few days until dropping off to molt into a nymph. After molting they find a new host, feeding until they can drop off and molt into an adult. As adults, they only feed off of larger hosts, like a deer, dogs, or humans, and they rely on these hosts so that they can find a mate and reproduce. The host is absolutely essential to the life cycle of a tick it cannot molt to the next stage without a host, therefore they’re pretty determined.

Ticks can produce over 2,000 larvae. Pathogens are usually obtained early in the tick’s life cycles from a rodent or bird which means that there's a high possibility that by the adult stage when they have more of a taste for humans, they can spread those pathogens to us. This is how Lyme disease is spread or Rocky Mountain spotted fever. Other diseases such as anaplasmosis, ehrlichiosis and babesiosis, which all cause flu-like symptoms, are spread this way. Sure, these diseases depend on region but are still pretty prevalent.

Why are these monsters multiplying so much faster recently? Well, it has to do with a multitude of factors. Our deer and mice populations for one. Since humans are in the business of killing predators, being predators ourselves, there are less around to control these populations. The decrease of coyotes and wolves led to an increase in deer populations which is just that final step the ticks need to reproduce and create many more of them. If we decrease deer populations than the adult ticks will have fewer hosts and therefore would have a harder time feeding and reproducing. If we eliminate just one tick by having one less deer hanging around, its equivalent to killing several hundred nymph ticks.

A study published by the Oxford Journal of Medical Entomology found when deer populations were reduced within a community that there was a 76 percent reduction in the abundance of ticks and 80 percent reduction in the reported cases of Lyme disease. But deer populations aren't the only thing keeping the tick populations high it also has to do with our warming climate. Ticks like the warmer weather and with seasonality shifting ticks are appearing in places that were once too cold to host a population. Areas in the northern United States have grown tremendously in their tick populations over the past 13 years.

Researchers suggest that the reason ticks are able to move to new regions is that of their bird hosts. The warming climate is also changing bird migration routes and ticks just tag along for the ride. Ticks dislike weather that reaches below 40 degrees Fahrenheit, it usually kills them off but will fewer nights that reach this low temperature they are able to tough it through.  

It's important to observe these changes as ticks aren’t the only insect we should worry about in the changing climate, mosquito and flea illnesses are on the rise as well. Illnesses from these three causes have increased from around 27,000 to 96,000 since 2004 with a sharper increase every year. It is important to be aware of these changes as they will become more prevalent in the future. You can protect yourself by purchasing Environmental Protection Agency-registered insect repellent, wearing long-sleeved shirts and long pants, and checking your pets very often in the spring time through early fall. If you are unsure about whether your clothes are safe you can also put them in the dryer for a while. These little pests may be efficient in finding new hosts and climbing up pants, but they are no match against 30 minutes in the dryer.