As summer approaches and outdoor activities increase, officials in Connecticut have reported the first U.S. case of the invasive longhorned tick carrying Ehrlichia chaffeensis, a bacteria that can cause a potentially fatal disease. The disease, known as human monocytic ehrlichiosis (HME), initially presents with symptoms such as sudden high fever, chills, and fatigue a few weeks after infection, according to the Connecticut Agricultural Experiment Station (CAES).
The progression of HME can lead to more severe symptoms, including nausea, confusion, kidney failure, and respiratory complications. Typically, HME is spread by the lone star tick, a species native to the U.S. and prevalent in most of the eastern, southeastern, and south-central parts of the country, according to the Centers for Disease Control and Prevention.
However, the recent Connecticut case involved the longhorned tick, a species native to eastern Asia. This tick’s role in carrying the bacteria and spreading HME is significant because the invasive species is expected to spread throughout the eastern U.S. This is due to the tick’s ability to reproduce without a male and its unrestricted feeding habits.
“The first fully engorged human-parasitizing longhorned tick specimen was recorded by the CAES in 2018 from Fairfield, Connecticut, and the first populations of the tick were reported from this county in 2020,” said Dr. Goudarz Molaei, director of the CAES Passive Tick and Tick-Borne Disease Surveillance Program.
Since then, populations of longhorned ticks have expanded into several towns in Fairfield and New Haven Counties. Individual tick specimens have also been collected from New London and other counties. Officials have expressed concern about the species’ ability to expand their geographic range and their potential to transmit pathogens that could pose a threat to the health of humans, pets, and other animals.
The longhorned tick has been found to transmit a variety of pathogens in the U.S., including those that cause Lyme disease.