Maine is in the peak season for young deer ticks and the diseases they transmit to people.
The past two years broke records for Lyme disease case numbers in Maine and saw rising rates in people older than 65. In the first six months of 2024, 976 Lyme cases were reported by the Maine Center for Disease Control and Prevention.
June and July are considered the highest-risk times for Lyme disease, when the deer ticks are in their young nymph stage, according to MaineHealth’s Institute for Research. About the size of a poppy seed, the nymphs are harder to detect than the adult ticks that will drive case numbers up in the fall.
Lyme disease is caused by two different types of bacteria that deer ticks carry. A bite from an infected tick often causes a bulls-eye shaped rash and fever, fatigue and soreness early on. The disease is treatable with antibiotics if caught early, but can cause long-term health problems like arthritis, neurological issues and heart problems.
It remains the most prevalent tick-borne disease in the state. A record-breaking 2,943 Lyme cases were reported last year. But the Maine CDC also tracks cases of common deer tick-carried diseases Anaplasmosis, which numbered 391 as of July 1, and Babesiosis, which totaled 39.
Anaplasmosis is caused by a bacterium that infects white blood cells, causing symptoms a week or two later that include headaches, chills, nausea and muscle pain. It can be treated with antibiotics but is fatal in rare cases, according to the MaineHealth’s Institute for Research.
Babesiosis results from parasites infecting red blood cells, causing symptoms later on that include fever, chills, headaches and anemia. It can be treated with prescription medications.
All of these diseases are likely increasing as deer tick populations spread and grow in size, meaning more of the hard-to-detect young nymphs carrying disease.
The highest case rates of these three diseases combined are in Knox and Lincoln counties this year, where more than 200 cases have been reported per 100,000 people. Waldo and Hancock counties have the next highest rates.
When it comes to Lyme disease specifically, Knox County stands alone as the state hotspot so far.
Individual Lyme disease case numbers, not adjusted by population, are highest in York, Cumberland, Knox and Hancock counties with between 100 and 110 cases each.
Lyme cases have been concentrated along the coast for the past 15 years, according to CDC data.
People 65 years and older have the highest rates of all three diseases, and that rate has increased sharply in the past few years.
In 2020, nearly 125 cases were reported per 100,000 people in that age group. It had more than doubled to 325 per 100,000 just two years later in 2022, the last year for which data is available.
The next highest rates that year were in 5-14 year-olds and the 45-64 age bracket, which both landed around 190 cases per 100,000.
The tick testing lab at the University of Maine Cooperative Extension, which tests submitted ticks for disease, has received 1,700 samples so far this year. That’s less than the 2,000 received at this point last year, lab coordinator Griffin Dill said, but in line with previous years.
Despite hot temperatures, ticks are still active, he said, and people should do tick checks and protect themselves.
Two different vaccines for Lyme disease are in clinical research trials. MaineHealth’s Pen Bay Medical Center in Rockport is part of the trials for one of those vaccines through Pfizer, which could be available in two or three years if approved by federal regulators.
