SC Connecticut News

The Connecticut Agricultural Experiment Station (CAES) has identified the first locally acquired human case of Rickettsia parkeri rickettsiosis in Connecticut. This emerging tick-borne disease, transmitted by the Gulf Coast tick, is similar to Rocky Mountain spotted fever but with milder symptoms.

While cases have been reported in the southeastern United States, this is the first instance in the Northeast. The region already deals with various tick-borne diseases, including Lyme disease, babesiosis, anaplasmosis, Powassan virus disease, and ehrlichiosis.

The finding was published in the journal Emerging Infectious Diseases and is based on collaborative field and laboratory investigations by CAES and CDC scientists on both the tick that transmitted the disease and clinical investigations of the affected patient.

“Rising global temperatures, ecological changes, reforestation, and increases in commerce and travel are important underlying factors influencing the rate and extent of range expansion of ticks and associated pathogens," said Dr. Goudarz Molaei, PhD. He is an associate clinical professor at Yale School of Public Health and directs the CAES Passive Tick and Tick-Borne Disease Surveillance Program. "It is anticipated that warming temperatures related to climate change may lead to the continued range expansion and abundance of several tick species, increasing their importance as emerging threats to humans, domesticated animals, and wildlife."

The Gulf Coast tick is a three-host tick whose feeding stages will bite humans. Its distribution was previously restricted mainly to coastal regions bordering the Gulf of Mexico and southern Atlantic coast. However, its range has expanded northward into mid-Atlantic states like Delaware and Maryland over recent decades.

According to Molaei, Fairfield County in Connecticut reported its first established population of Gulf Coast ticks in 2021 with a 30% infection rate with R. parkeri. Additional populations were found in New York in 2022 and New Jersey in 2024 with higher infection rates. Migratory grassland birds are believed to play a crucial role in spreading these ticks to favorable environments in central and northern states.

“Because of morphological similarities between Gulf Coast ticks and American dog ticks - the principal vector of RMSF in the Northeast - these two species can be misidentified," Molaei said. "Since most tick species are associated with a unique suite of pathogens, it is important to improve regional capacity for accurate detection and identification of ticks and the pathogens they transmit in the Northeast.”

“The rapidly changing dynamics and evolving risks of tick-borne diseases across this region reinforce the need for awareness of education for tick bite prevention strategies," added Molaei. These strategies include using repellents registered with the Environmental Protection Agency (EPA) and performing regular thorough tick checks after exposure to infested areas.”