The lone star tick is widespread in the southeastern and eastern U.S., and is now being found as far north as Maine. A crowdsourced map is keeping track of alpha-gal allergy cases worldwide. One reason may be the explosion of the deer population on the East coast, said Dr. Thomas Platts-Mills, who heads the division of allergy and clinical immunology at the University of Virginia and who helped discover the link between the lone star tick and the allergy.