Researchers have seriously underestimated the risk of developing red meat allergy following a tick bite.
According to new research, alpha-gal, which causes intolerance to beef and pork, is present to tick's saliva whether they recently fed or not.
The findings contradict the previous belief that humans develop red meat allergy (also known as an alpha-gal syndrome) if bitten by a tick that recently fed on deers, dogs, or other small mammals.
Alpha-gal is a carbohydrate found in the cells of many mammals, except humans. When a person develops an allergic reaction to it, usually through a tick bite, the immune system sees red meat as a threat, attacking it.
"Our original hypothesis was that humans developed the allergy after being exposed to alpha-gal through a tick that had fed on a deer, dog or other small mammal that has alpha-gal," stated Scott Commins, an associate professor of medicine and pediatrics at the University of North Carolina School of Medicine and an author of the study presented at the American Academy of Allergy, Asthma, and Immunology.
"This new data suggests that ticks can induce this immune response without requiring the mammal blood meal, which likely means the risk of each bite potentially leading to the allergy is higher than we anticipated."
Alpha-Gal In Tick Saliva
To investigate, the researchers tested the salivary gland extract of four species of ticks: Lone Star, Gulf Coast, Deer, and American Dog. Some of these ticks had previously fed on the blood of a mammal containing alpha-gal while some have not. The researchers tested the salivary gland extract in the white blood cells of people with and without the alpha-gal syndrome.
The team found that as expected, the saliva of Lone Star and Deer ticks that recently fed on blood containing alpha-gal caused an allergic reaction. However, the saliva of Lone Star and Deer ticks that did not recently feed on blood containing alpha-gal has still caused an adverse immune response.
The researchers did not see a reaction from the saliva of American Dog and Gulf Coast ticks whether they recently fed or not.
Living With Alpha-Gal Syndrome
Unfortunately, there is no known cure to an alpha-gal syndrome. People with red meat allergy can only refrain from the consumption of red meat to avoid experiencing symptoms that include runny nose, diarrhea, nausea, or hives. A more serious reaction, anaphylaxis, shuts down the body's ability to breathe.