What is the tick-borne disease alpha-gal and why does it cause an allergy to meat?
As more cases of the rare tick-borne disease alpha-gal are reported in the UK, what is it, and why does it cause an allergic reaction to meat in some cases?
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 it gets into the blood stream causing an immune response.
The next time you eat meat from mammals such as lamb, beef or pork the body is then triggered into believing these cause 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 blood stream, you then mount an immune response to that sugar. You have antibodies against it.
“That sugar is also found in meat, in mammal products, 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?
The symptoms of alpha-gal allergy are usually delayed, appearing three to eight hours after eating. This is unlike most other food allergies, where symptoms usually come on within minutes.
There is little research into the syndrome, especially in the UK, and reactions can be different from person to person.
They can include stomach cramps, diarrhoea, 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.
Last week the Centre for Disease Control in the US said 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.
However, sufferers have told Sky News they are facing long waits to get the right care.
Dr Gururaj Arumugakani is a consultant in Allergy and Clinical Immunology working within the NHS in Leeds. He told Sky News the waiting time for referrals for immunology specialists are “easily more than six months in most centres, and in some centres it could be anywhere between a year to two years”.
“It’s a combination of both a shortage of specialists and an increased recognition of allergies,” he said.
“Apart from traditional allergies, they also have to deal with drug allergies, and recently, there was a huge deluge of concern regarding allergies to the COVID vaccine, so that put more samples back because they had to deal with them accurately.”
What should I do?
If you think you may be allergic to alpha-gal, see your GP who can refer you to a specialist allergy clinic if needed.
They can find a clinic in your area from the British Society for Allergy and Clinical Immunology.