A rare breed of tick that can cause everything from intense itchiness and stomach cramping to difficulty breathing and even death has begun to spread around the USA. As it does, the tick is also spreading something far stranger as it goes: allergies to meat.
The lone star tick, aka the “reverse zombie" tick, makes you shy away from meat rather than crave it. One bite from the tick, in fact, and you can develop a life-threatening allergy to a sugar molecule found within red meat.
Once you've been bitten, your immune system can become triggered by the presence of galactose-alpha-1,3-galactose (alpha gal) and go into overdrive. So the next time you eat meat from a mammal that produces this sugar (e.g. pork and beef), you may find yourself breaking out in massive hives or going into anaphylactic shock (if you've been bitten that is).
The patients were all on the same drug – cetuximab – but those living in the southeast were 10 times more likely to report symptoms such as itching, swelling, and drops in blood pressure. This was quite strange, as you wouldn't expect symptoms to be so area-specific.
Platts-Mills began to work with cetuximab's distributor to investigate the blood of the symptomatic patients and find out what they had in common. It turned out to be antibodies for alpha gal – the sugar found in meat. Cetuximab is full of the sugar, as it is derived from genetically modified mice.
Eventually, Platts-Mills discovered what made the patients so sentive to alpha-gal: 80 percent of the allergic patients reported being bitten by a tick. It was the lone-star tick that had caused the allergy in the first place.
Platts-Mills has since shown that bites from the lone star tick lead to a 20-fold increase in alpha gal antibodies. Researchers are currently trying to figure out why saliva from the ticks cause the immune system to attack alpha-gal as a foreign body, but they say it's early days yet.
“There’s a lot we don’t know about the allergy,” Dave Neitzel, an epidemiologist with the Minnesota Department of Health, told the Herald Review. “It’s too early to really say anything definitive.”
Some people who get bitten by the ticks don't develop the allergy either, making the cause even more difficult to find.
“There’s something really special about this tick,” Jeff Wilson, an asthma, allergy, and immunology fellow in Platts-Mills’ group, told Wired. “Just a few bites and you can render anyone really, really allergic."
Whilst the team investigate why the tick causes a meat allergy, the only way to protect yourself against getting it is to use DEET in areas where the lone star tick dwells.