For many people it would be their worst nightmare, but for some it is a reality. After being bitten by a tick, some people develop an allergy to red meat. So severe is this allergy that it can cause people to drop into potentially life-threatening anaphylaxis, where the airways constrict and your blood pressure plummets. Only very recently have doctors figured out what is going on, and according to some, the prevalence of such a reaction is worryingly on the up.
The immune reaction is not actually to the meat protein, but a sugar that is only found in non-primate mammals, meaning that it is not found in humans. Occasionally when the tick then bites a human after having fed on another mammal, the insects saliva is mixed with this sugar, so that when the body launches an immune response against the tick, there is a crossover between what the body thinks it is fighting. This means that when a person then eats red meat, and sometime even dairy products, the body can sometimes detect the sugar and launch an immune response against it.
The sugar is known officially as Galactose-alpha-1,3-galactose, or more simply alpha-gal. While there have been hints that this has been occurring for decades, it was not formally described until 2007 by Australian doctor Sheryl van Nunen, who spent years documenting the curious link between tick bites and meat allergy, which is usually incredibly rare, in and around the northern beaches of Sydney.
Those with the allergy cannot eat any red meat, including beef, lamb, pork or goat, but can eat other meats such as poultry and fish. Pavel Ilyukhin/Shutterstock