The lone star tick, an aggressive human biter, is rapidly expanding its range and population in Fairfield and New Haven counties, according to the Connecticut Agricultural Experiment Station.

The tick, officially known as Amblyomma americanum, has the potential to alter the dynamics of a myriad of existing and emerging tick-borne diseases in the state and throughout the Northeast, the state’s scientists said.

Previously limited to the southeastern U.S., lone star ticks have been detected in areas of the northeastern U.S. with no previous record of activity including Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New York, and Rhode Island. Established populations of this tick species have now been documented across most of southern New Jersey, Long Island, Fairfield and New Haven counties, coastal Rhode Island, and on Cape Cod and the Islands.

According to Dr. Goudarz Molaei, a research scientist who also directs the state’s Tick Surveillance and Testing Program, the number of lone star ticks submitted to the CAES Tick Testing Laboratory increased by 58 percent from the period of 1996-2006 to 2007-2017, mainly from Fairfield County.

Established populations of lone star ticks were discovered in Fairfield and New Haven counties in 2018 and 2019, respectively, and further establishment in New Haven County was documented this year on June 17.

As an aggressive biter with highly irritating bites, the lone star tick has been associated with several human diseases and medical conditions, including tularemia, ehrlichiosis, rickettsiosis, Heartland virus disease, southern tick-associated rash illness, red meat allergy and likely the newly identified Bourbon virus disease.

“Rising global temperatures, ecologic changes, reforestation, and increases in commerce and travel are important underlying factors influencing the rate and extent of range expansion for ticks and associated disease-causing pathogens,” Dr. Molaei said.

“It is anticipated that warming temperatures associated with climate change may lead to the continued geographic range expansion and abundance of the lone star tick, increasing its importance as an emerging threat to humans, domesticated animals and wildlife,” he added.

Depending on weather conditions, adult lone star ticks are usually active from mid-March to late June, nymphs from mid-May to late July and larvae from July to September. It is important for people and health practitioners to develop a heightened awareness of the health risks associated with emergent tick vectors such as the lone star tick and their potential for changing the dynamics of tick-borne diseases in Connecticut and throughout the northeastern United States.

Detailed information about the CAES Tick Testing Laboratory, personal protection measures, tick control measures, and tick-associated diseases can be found at ct.gov/CAES.