What is the tick-borne disease alpha-gal and why does it cause an allergy to meat?
More cases of alpha-gal are being reported in the UK. Alpha-gal can cause anaphylaxis in sufferers when they eat meat such as beef, pork, or lamb.
Whilst it is rare more cases of the tick-borne disease are being reported in the UK.
A small number of ticks can be infected with bacteria or viruses, and they can pass these on to humans when they attach themselves.
The most common disease this causes in the UK is Lyme disease with up to 4,000 cases in England and Wales each year, however, ticks carrying tick-borne encephalitis have been found in the UK, and they can also cause alpha-gal syndrome.
Anaphylaxis UK says that alpha-gal causes an unusual type of food allergy caused by the transfer of a type of carbohydrate found in the muscles of mammals which the ticks feed on.
When you are bitten by a tick which carries this molecule, the molecule enters the bloodstream and can cause an immune response. The next time you eat meat such as lamb, beef, or pork the body response is triggered believing this causes a threat.
‘Risk of biting common all year round’
Professor Richard Wall from the University of Bristol explained: “The ticks have got this alpha-gal sugar in their saliva when they feed they inject that into your bloodstream, and you then mount an immune response to that sugar. You have antibodies against it.
That sugar is also found in meats such as lamb, beef, or pork, you then have an immune response against that particular compound.
“In previous years we didn’t see them bite in the winter, it’d be a spring peak of tick biting, then there’d be no biting in the summer, and then a smaller peak in the autumn, but now with the changing climate we’re seeing them certainly biting all winter and we’re seeing a gradual change in seasonal patterns. So, the risk of biting is now fairly common all season round.”
What are the symptoms?
Alpha-gal allergy symptoms are usually delayed, appearing three to eight hours after eating. This is unlike most other food allergies, where symptoms usually come on within minutes, and reactions can be different from person to person.
They can include stomach cramps, diarrhea, hives, and shortness of breath that could trigger fatal anaphylaxis, a potentially life-threatening reaction involving multiple organ systems, which may need urgent medical care.
The US Centre for Disease Control has stated that the number of Americans suffering from the allergy is increasing and has impacted up to 450,000 people; specialist immunology consultants in the UK say the number here is much lower.
