Some children living in the U.S. Southeast have a rare meat allergy linked to tick bites, according to a new study. Bites from ticks, usually lone star ticks, cause the body to become allergic to a protein called alpha-gal — which also happens to be found in some mammals, including cows, pigs and sheep, the researchers said. When people who have been bitten develop this allergy, and then eat meat from these animals, they can experience hives, swelling, or more rarely, a life-threatening allergic reaction known as anaphylaxis.