AMHERST, Mass. – Stephen Rich, microbiologist and professor at University of Massachusetts, Amherst, and his team were sampling ticks in a backyard in Maine when they came across something unusual: rabbit ticks.

Rabbit ticks, so named because the adult ticks primarily feed on rabbits, are not uncommon to Maine, but they’re typically not found in backyards, Rich explained. This is because rabbit ticks are more likely to be found in rabbit habitats, whereas black legged ticks or dog ticks are more likely to be found in backyards. Black legged ticks and dog ticks are just as happy to feed on humans as they are dogs or deer.

Rich and his team were sampling backyards for Project Is Tick Control Helping (ITCH), a five-year program that began in 2023 with the goals of identifying landscape features that predict tick density, evaluating the effectiveness of pesticides for tick control, investigating how people perceive the risk of tick-borne diseases, and property characteristics of tick habitats. As part of the project, ticks collected in backyards were sent to laboratories to determine what bacteria the ticks were infected with.

When the rabbit ticks were tested, a unique strain of Rickettsia was discovered. Rich said the strain was a novel find for the region.

Rickettsia is a genus or group of bacteria found in ticks as well as other insects such as lice, fleas and mites. The species of Rickettsia, Rickettsia sp. ME2023, that Rich and other Project ITCH researchers discovered is related to the group of pathogens that can cause severe illness in humans and other animals.

For example, Rickettsia rickettsii causes Rocky Mountain Spotted Fever, the most common and deadly spotted fever rickettsiosis in the U.S. Symptoms include rash, severe headache, and fever, and the illness can be treated with antibiotics. Spotted fevers, and other tickborne diseases, can affect humans and animals.

Although Rocky Mountain Spotted Fever is the most common spotted fever rickettsiosis, there are only about 6,000 cases of the illness in the U.S. each year, according to the Cleveland Clinic. In contrast, over 89,000 cases of Lyme Disease were reported in 2023 according to the Centers for Disease Control and Prevention.

Rich cautioned against becoming overly concerned about the new discovery.

“The headline is that this is not a big alarm bell. It’s an interesting discovery, but at this point it’s probably a relatively low risk thing,” he said. “There’s a potential that this (new strain of bacteria) could cause one of these terrible diseases in people, but a lot of things would have to happen first. First of all, we’d have to know if it’s more widespread than just this one pocket in Maine. Secondly, you’d have to have an interesting circumstance for the bacteria to pass on, because rabbit ticks don’t really feed on people. We’d have to have a rabbit get infected by a rabbit tick, then have a deer tick or a black legged tick feed on that rabbit and then feed on a person.”

While that series of events is not impossible, Rich emphasized that they are all relatively low frequency events. Still, he added that it’s possible this newly discovered strain could be responsible for reported cases of spotted fever around the country, although it’s not possible to go back in time and identify the strain that caused illness in humans. Moving forward, the team hopes to develop a survey with rabbit hunters to collect and sample rabbits for Rickettsia sp. ME2023.

Even if the newly identified strain of Rickettsia isn’t a huge concern for transferring illness, there are plenty of other tickborne pathogens and diseases to be aware of this spring and summer season. Rich said people should be aware of Alpha-gal Syndrome.

“Alpha-gal is a sugar that comes from the tick bite, gets into the human patient, and actually leads to an allergy, an allergic response, to alpha-gal sugar, which is present in all red meat. What ends up happening is people get bitten by a tick and they develop a food allergy against red meat,” he said. “The symptoms can range from having an upset stomach from eating meat to very extreme cases where people use a shampoo that has an animal byproduct and having anaphylactic shock. It can sometimes last for months and months, and sometimes years and years, and other times it can be self-resolving.”

There are over two dozen pathogens associated with ticks that can infect livestock, companion animals and people. The best prevention is being vigilant in protecting yourself from tick bites. Rich said the best thing people can do is wear permethrin-treated clothing. Permethrin is an insecticide that is toxic to ticks and has very low toxicity for people. Several companies sell sprays, and clothing that has been pre-treated. Repellents containing DEET or picaridin are also useful, although they need to be reapplied very often to be effective.

Rich added that one of the main causes related to the increase of ticks in more places is the proliferation of white-tailed deer. Many of the ticks that transmit pathogens feed and breed on white-tailed deer. Because it’s unlikely that hunter pressure will rebound to the levels needed to drastically reduce the deer population, some researchers are investigating oral vaccines to be delivered to deer that would kill ticks.