The interesting part:

But, in recent years, researchers have also discovered that alpha-gal is in tick saliva. And, for reasons researchers still haven’t worked out, some people bitten by ticks develop a type of antibody called anti-alpha-gal IgE. This antibody may help protect people from tick bites, but it also renders them allergic to anything with alpha-gal—i.e., mammalian meat and animal products. It’s a double-edged sword that has been hypothesized to be an “allergic klendusity.”