Lyme Disease Cases on Near-record Pace in Maine as Tick Population Thrives


Lyme disease cases in Maine are on pace for a near-record year, according to the latest data posted by the state.

And the ticks that carry Lyme and other diseases are thriving because of the wet weather in June and July.

The Maine Centers for Disease Control and Prevention reported 753 cases through June, slightly less than the 780 cases reported during the same time period in 2022. The state ended up reporting a record 2,617 cases of Lyme disease in 2022. The previous record was 2,167 in 2019.

Tick-borne diseases are increasingly a problem in Maine, likely exacerbated by climate change. While Lyme disease is the most common, other diseases caused by the deer tick include anaplasmosis and babesiosis. The Maine CDC has reported 169 cases of anaplasmosis through June and 18 cases of babesiosis.

Lyme and other tick-borne diseases can be treated with a course of antibiotics. But many cases go undetected, especially if people are bitten by ticks in the nymphal stage, which are so tiny they can be hard to spot. Symptoms can include fatigue, joint pain, headache and fever. If untreated, the diseases can cause a range of complications.

Humid weather and rain are ideal for tick populations. So the late spring and early summer weather conditions helped ticks thrive, said Griffin Dill, integrated pest management specialist for the University of Maine Cooperative Extension’s Tick Lab. The numbers of tick bite infections could have been higher if the rainy weather did not also keep people indoors through much of last month.

“Conditions were good for deer tick activity, but people were not outdoors as much during June, so there was not as many chances for ticks to interact with humans,” Dill said.

The number of dead ticks submitted to the tick lab for identification – about 1,000 – is down 40% compared to 2022, Dill said. But submissions of deer tick nymphs, which also transmit diseases and are more commonly found on people in summertime, are up 40% this year compared to 2022, to about 700 submissions. And now that more people are out enjoying the sunnier weather, Dill said ticks are more likely to find people as hosts.

Hot and dry weather, or extremely cold temperatures when there’s no snow on the ground, can knock back tick populations. But Dill said the ground is so saturated from the abnormally heavy June rainfalls that even a prolonged dry period may not do much to tick populations this summer.

“When the weather is hot and dry, the nymphs are susceptible to drying out,” Dill said. “But with the ground saturated, the leaf litter contains high levels of moisture, which allows the ticks to quest for longer periods of time than they might have been able to otherwise.”

In August, especially later in the month, there’s a period where ticks are not seen as much, because they are in an inactive state while nymphs molt into adult ticks that will be searching for hosts this fall, he said.

Research about ticks is ongoing, and the University of Maine landed $6.2 million in federal funding to research ways to control tick populations, identify emerging tick species and expand public health efforts. Dill said the research tied to the federal money is expected to begin this fall.

To prevent ticks from attaching to you, avoid leaf litter, wear long pants and stay on paths when walking in the woods. Wear gloves when carrying firewood. Conduct tick checks if you’ve been in tick habitat.

If you do get bitten by a tick, watch for signs of a bull’s-eye rash, fatigue, joint pain, fever and chills. If caught soon after transmission, tick-borne diseases can be eradicated with a course of antibiotics. In most cases, it takes 36 to 48 hours for an attached tick to transmit Lyme disease to humans, according to the U.S. CDC.

Source: Central Maine