Potentially deadly bacteria found in invasive tick for first time in US

As outdoor activities begin to ramp up ahead of summer, Connecticut officials announced Tuesday that they confirmed the first US case of the invasive longhorned tick carrying Ehrlichia chaffeensis, a bacteria capable of causing a potentially deadly disease.

Known as human monocytic ehrlichiosis, or HME, the disease initially causes symptoms such as sudden high fever, chills and fatigue a few weeks after an infection, according to officials with the Connecticut Agricultural Experiment Station (CAES).

Symptoms may progress to include symptoms such as nausea, confusion and, ultimately, kidney failure and respiratory complications.

HME is usually spread by the lone star tick, which is native to the US and found throughout most of the eastern, southeastern, and south-central parts of the country, the Centers for Disease Control and Prevention said.

However, the recent case of a tick carrying Ehrlichia chaffeensis, the bacteria behind HME, in Connecticut involved the longhorned tick, a tick species native to eastern Asia.

This species’ role in carrying the bacteria and spreading HME is significant because the invasive species is expected to spread throughout the eastern US, officials said.

They noted that this is due to the animal’s ability to reproduce without a male, along with its unrestrictive feeding.

“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 a number of towns in Fairfield and New Haven Counties. Additionally, individual tick specimens have been collected from New London and other counties.”

Officials warned of the species’ ability to expand their geographic range and their potential to transmit pathogens that could threaten the health of humans, pets and other animals.

They noted that the longhorned tick has been found to transmit a variety of pathogens in the US, such as those that cause Lyme disease.