As a rule, the bite of blood-sucking tick Ixodes holocyclus, also known as Ixodes or paralyzing mites are not dangerous to humans. But in some cases it can cause a dangerous allergic reaction to red meat, warns BBC Future columnist.
In the height of summer, the moist air growing vegetation of the Northern beaches of Sydney filled with the chirping of cicadas, the sharp scream of parrots, the Rosella and the appetizing odor of the upcoming BBQ.
But hiding in the dense Bush, tiny creature can ever be removed from the menu of the locals sausages, steaks and other meat dishes.
For Australians who like meat, this prospect intolerable, but the alternative – a severe allergic reaction known as anaphylaxis, in which Airways are narrowed, sharply lowered blood pressure and in some cases death can occur.
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Due to the bites of Ixodes ticks, Ixodes holocyclus in the Northern beaches of Sydney, more than 800 people developed a dangerous and extremely rare Allergy to mammalian meat.
Colloquially known as Ixodes holocyclus paralyzing the tick because its bite is often fatal to Pets.
Most people have no obvious discomfort from the bite of this arachnid is not observed.
But in certain cases a combination of own proteins of the tick is injected with the saliva, and certain organic compounds contained in the meat of mammals, triggers the potentially life-threatening allergic reactions.
The cases recorded also on the East coast of Australia, in some parts of the USA and in Europe, but Sydney had the dubious honor of being the hotbed of the epidemic.
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Image captionАллергия to red meat – an intolerable prospect for Sidney who loves BBQ
The history of the connection between the bite of Ixodes holocyclus and Allergy to meat sounds like a scientific detective. Even the main character of the story, Sydney allergist Cheryl van Noonan, admits that it is something from a Hollywood screenplay.
With the first patient, complained of the above symptoms, van Noonan faced 20 years ago. It was an isolated incident, and it could stay unnoticed if not for the unusual nature of the disease – Allergy to mammalian meat occurs in people rarely.
Then in the early 2000s, the Royal Northern coast hospital, where he worked van Noonan, was admitted a few patients with intolerance to red meat – and all told the same story.
“They had dinner and went to bed, then woke up in the middle of the night with a terrible attack of anaphylaxis or reaction manifested half an hour after meals. Patients could not understand, what happens to them,” Wang said Noonan.
The symptoms coincided regardless of, whether was used before the attack beef, lamb, conguration, venison or Buffalo meat.
As befit any allergist, van Noonan record detailed story of each patient and noticed that all cases are United by one thing: at some point prior to the attack, some patients developed severe local reaction to the tick bite.
Most people on the site of the bite jumps tiny itchy pimple red, but in patients Wang Noonan appeared a large hard swelling with a diameter of about 10-15 cm, surrounded by more extensive area of red rash.
Image copyrightScience Photo Library
Image captionУкус the tick Ixodes holocyclus, under certain conditions, can cause life-threatening allergic
In the next few years, according to van Noonan, the hospital was overwhelmed by a wave of appeals from people living in the Northern beaches of Sydney – in all cases, the patients complained of symptoms such as urticaria (allergic rash) and indigestion after eating red meat.
And each of them was observed in the past severe reaction to the bite of Ixodes holocyclus.
“It came to the point that now, if the patient lives in beacon hill (Sydney’s Northern suburbs) or even further North, thus complains of an anaphylactic reaction and may not accurately understand its cause, first of all, I ask the question of how he manifested a reaction to the tick bite,” Wang said Noonan.
However, not all persons bitten by Ixodes tick, subsequently, are allergic to mammalian meat. Why?
Ticks are notorious for their ability to cause the victim a life-threatening allergic reactions to contained in their saliva proteins.
In Australia particularly large number of people with serious allergies it is to the bites of Ixodes ticks – perhaps partly because his jaw is more elongated than other similar arachnids. But allergic to meat put allergists to a standstill.
Nanno Wang initially thought in the tick saliva may contain the remains of blood of the previous victims bitten by them – maybe protein Bandicoot (marsupial rat), which the human immune system can take for protein of the tick and respond accordingly.
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Image captionАмериканские scientists have found that allergies cancer patients on the drug also causes tick bite
But eventually the mystery was solved at the other end of the globe.
A group of American doctors are faced with inexplicable outbreak of severe allergic reactions to the medication used in the treatment of malignant tumors of the colon.
In 2007 it was reported that almost every fourth patient in the States of Tennessee and North Carolina, held a course of treatment with Cetuximab, showed severe allergic symptoms while in the country such symptoms were observed less than one in 100 patients.
After a long research of the problem, scientists were able to find the culprit – it turned out to galactose-alpha-1,3-galactose. This monosaccharide is present in the body of all mammals except primates (and accordingly, except for people).
Because Cetuximab was developed using cell lines (sequences) mice, it also contains alpha-galactose, and it is so hard to respond the patient’s body.
When American researchers learned about the Australian cases of Allergy to mammalian meat caused by a tick bite, they’ve got a full picture of what is happening.
Most importantly – do not crush the tick, and freeze it
In Tennessee and North Carolina found the tick Amblyomma americanum, also from the family Ixodidae. As it turned out, the habitat of this mite coincides with the geographical spread of recorded allergic reactions to Cetuximab.
Especially exciting our history makes the fact that this is the only case in which accurately set the factor that triggers the development of allergies.
For example, scientists do not know why people have allergies to cats, peanuts or eggs. The only thing we know is that at some point in the past, the combination of certain factors made the immune system react to these allergens, which most people do not cause allergies.
But in the case of Allergy to mammalian meat, developing after a tick bite, everything is clear.
“We have a full dataset, Wang said Noonan. – A provoking factor that changes the human immune system, it’s a tick”.
Now researchers have to figure out why the Allergy develops in people bitten by the Ixodes tick only once, while those mites biting repeatedly, is not affected by the disease.
The reality is not so scary, especially for those meat lovers who live in the areas of distribution of the Ixodes ticks or going on a trip in that region.
Image copyrightScience Photo Library
Image captionПри squeezing the tick releases into the bite an extra helping of saliva and stomach contents, so even the insect can be removed best by freezing
The development of an Allergy to the tick bite and the Allergy to mammalian meat, can prevent, if not to actually prevent the bite.
Part of scientific activity van Noonan in recent years has been the development of educational materials for the population on how to safely remove ticks stuck to minimize the possibility of allergic reactions.
Most importantly – do not crush the tick, and freeze it.
When compressing the calf of the tick with tweezers or scraping it from the skin it releases into the bite an extra helping of saliva and the contents of his stomach, which increases the likelihood of an allergic reaction.
Instead, experts recommend to spray the mite spray to spray on the basis of the ether – these are used to treat warts and sold in pharmacies.
Freeze the tick in this way – it will instantly die and fall off of the bite, without causing you any harm.
Van Noonan is an avid masoudi not willing to risk their habit – taking personal precautions every time you visit the Northern beaches of Sydney.
She wears special protective clothing and spraying yourself with repellent.
But at the same time van Noonan admits that he felt a kind of sympathy for the female of Ixodes tick – namely the females bite causes an allergic reaction.
“For me she is just mother, a tiny living entity, trying to raise offspring, to protect him from the cruel world and give him a chance at a happy life, says the allergist. – It just so happens that in this case it may cause trouble man”.
