Lone star tick likely to be triggering red meat allergies

By Sally Robertson, B.Sc.Jun 22 2017

Experts believe that the lone star tick is responsible for the meat allergies people are developing in South-eastern states including North Carolina, Tennessee and Virginia.

The ticks are spreading up the Eastern seaboard to new locations, where they are triggering allergies after just a single mouthful of meat is eaten.

Image: Lone Star Tick (Amblyomma americanum).

Allergy expert Ronald Saff (Florida State University College of Medicine) says he is now seeing a couple of patients every week who have developed the allergy.

The bites make people allergic to the alpha-galactose or alpha-gal sugar present in mammalian meats such as beef, pork and lamb. This can cause severe symptoms including swelling, difficulty breathing, vomiting and a life-threatening anaphylactic reaction is possible.

Professor of Medicine, Robert Valet (Asthma, Sinus and Allergy Program Clinic, Vanderbilt), who is also seeing at least one new case every week, says it is unclear exactly how the allergy starts. However, the belief is that the alpha-gal sugar is contained within the tick’s gut and gets introduced to the host through the bite. “That causes the production of the allergy antibody that then cross-reacts to the meat,” he explains.

What is particularly concerning is that, unlike most food allergies, which develop within half an hour of exposure to the food, alpha-gal allergy symptoms can take many hours to manifest.

"The weird thing about [this reaction] is it can occur within three to 10 or 12 hours, so patients have no idea what prompted their allergic reactions," comments Saff. People may develop the symptoms during the night while they are sleeping and then have no idea what they could be allergic to.

Saff says that as temperatures warm, the tick is slowly going to spread northward and westward, causing even more problems than it is now.

Valet advises that people with the allergy take measures to avoid further bites, since repeated bites can increase the amount of alpha-gal antibody in the body. Carrying an EpiPen is also recommended, so that people can save themselves if they do have exposure to red meat.