Tick that makes you allergic to meat is spreading across US

Disease ecologist points to warmer climate as cause of Lone Star tick’s eastward expansion

A female Lone Str tick (Lisa Zins/CC BY 2.0)

A tick that causes people to become allergic to meat is spreading across the United States, according to a report, with cases in places such as New York and New Jersey.

Known as the Lone Star tick for the single white dot on the back of females, the arachnid is known to transmit a molecule (called alpha-gal) normally found in mammals they have fed on to people they bite.

That infection causes a person’s immune system to attack the alpha-gal molecules found in non-primate mammals such as cows and pigs, despite the meat being safe.

In some circumstances, an allergic reaction can be triggered even when the amount of meat is small, a Scientific American report found last month, with a person’s antibodies trying to fight off the alpha-gal.

While the Lone Star tick has been known to live in places such as the American south and southeast, the ticks are now being found on the upper Eastern Seaboard in New York and New Jersey and in parts of the Midwest, the US Centres for Disease Control and Prevention (CDC) says.

Richard S Ostfeld, a disease ecologist and a distinguished senior scientist at the Cary Institute of Ecosystem Studies, told Scientific American “the ticks do appear to be spreading” beyond their normal home – and climate change could be to blame.

Researchers believe the tick’s suitable habitat is growing as climate warming continues, with the disease ecologist saying: “There are studies that suggest that, as the climate continues to warm, the geographic range of the Lone Star tick will not expand, although most studies suggest that it will.”

Mr Ostfeld also pointed to a lack of nationwide surveillance in the US of Lone Star ticks as another reason for the apparent spread., and said that has prevented authorities from mapping “where they are and how quickly they’re moving.”

According to the CDC, the allergic reaction trigged by meat consumption following a Lone Star tick bite can begin anywhere between two to six hours after ingesting alpha-gal, although it can vary from person to person.

Symptoms of Alpha-gal syndrome (AGS) including swelling, inflammation and tingling all over the body, as well as life threatening reactions such as seizures. Most cases have however gone undiagnosed for long periods of time before a person is found to have AGS.

Kristina Carlson, who told Scientific American she started experiencing aching joints and stomach bleeding following a hike trip in North Carolina, was later found to have been bitten by a Lone Star tick and had AGS.

“I cut all the hoofed animal products,” she said, “and the rash, the infection, the joint [pain], the inflammation all went away.”

There is currently no known cure for AGS, limiting those diagnosed to a mainly plant-based diet.