Every year, health departments try to predict how severe tick season will be. They often count the number of deer they see. However, that might not be the best indicator. Work spanning 30 years tracked ticks, mice, deer and weather in areas with Lyme disease. It found that more deer doesn’t mean a higher risk of Lyme disease, but more acorns does.
“Studies of this depth and length are incredibly rare,” said study coauthor and co-director of the Cary Institute of Ecosystem Studies, Dr. Shannon LaDeau. “This research has followed an ecological community — including oak trees, mammals and microorganisms — examining how interactions like predation, parasitism and competition shape the system over time.”
More than 450,000 cases of Lyme disease are reported every year in the U.S. It is carried by black-legged ticks that are fed by white-tailed deer. However, researchers found that higher numbers of deer didn’t lead to more infected ticks.
The number of mice in an area is a much better way to predict how bad the next year’s tick density will be. And mice feed on acorns. So, the number of acorns in an area predicts the next year’s number of mice. That, in turn, can predict the Lyme disease risk for the next year. Look at the acorns, and you can estimate the ticks two years in advance.
While skunks, squirrels and possums all feed larval ticks the same way mice do, they don’t transmit the bacteria that cause Lyme. So tracking them isn’t as effective as tracking mice.
Extreme winters and summers did not appear to impact tick populations, as ticks can shelter in soil to avoid temperature changes. However, different species of ticks are spreading out of their original habitats and bringing their diseases with them. Lone star ticks, once only found in the Southeast, have spread north and west. They can spread alpha-gal syndrome and make infected people allergic to red meat.
Lyme disease can be treated with antibiotics. If left unchecked, it can cause harm to the joints, heart and nervous system. Some people have symptoms for years.
"On balance, these surprises have enriched our knowledge of this system, helping us to inform management of tick-borne disease risk," said lead author Richard Ostfeld.
The best way to avoid Lyme disease is to avoid tick bites. If you live in an area where Lyme disease is present, be aware. You can be bitten in your own yard or even in your home as ticks can be carried inside on clothes or pets. DEET will deter ticks, as do long-sleeve shirts and pants. You should be conscious of your risk in grassy or wooded areas. Check your body, clothing and possessions after time spent outdoors, and shower after spending time outside. If you are bitten, remove the tick as quickly as possible. Don’t wait for a medical professional to do it. Time matters, and reducing the length of a bite lowers your risk of infection. If you are bitten, talk to your doctor about whether antibiotics would be appropriate for you.
