A new study has found that cases of meat allergies caused by an insect bite appear to be increasing in the United States.

The study reported that a large number of cases in which people had strong allergic reactions were linked to a specific meat allergy. The allergy – which is caused by tick bites - is linked to alpha-gal, a complex sugar found in red meat. Alpha-gal is not found in humans, but is common in red meats like pork and beef.

The study was based on patients treated at a single health center in Memphis, Tennessee. Results were reported in the scientific journal the Annals of Allergy, Asthma and Immunology.

Researchers studied patients who suffered from an intense allergic reaction known as anaphylaxis. Anaphylaxis is the most severe kind of allergic reaction. People suffering from anaphylaxis can experience a series of reactions, some of which can be life-threatening. The condition can result from allergies caused by food, drugs, insect bites or other things.

Over a 10-year period, the researchers evaluated 218 cases of anaphylaxis in patients from age 9 to 78 years old. Before the new study, doctors could not identify the cause of anaphylaxis in about 60 percent of patients. They noticed, however, a big drop after examining the new results.

The researchers identified 85 cases, or 39 percent, of anaphylaxis as having a specific cause. Of these, 28 cases, or 33 percent, were found to be linked to alpha-gal. This was a higher percentage than any other cause.

Researchers identified another 57 cases, or 26 percent, of anaphylaxis, but they were less sure about the probable cause.

Overall, the meat allergy was the most commonly identified cause of anaphylaxis in a total of 142 cases.

There are no exact figures for how many Americans developed tick-related meat allergies, which have also been discovered in other countries. But results from several U.S. studies show that up to 5,000 people developed the alpha-gal red meat allergy.

Jay Lieberman is a doctor at the University of Tennessee Health Science Center who helped lead the study. He told Reuters that even though the new findings are important, he does not want the news to cause fear or "hysteria" among the public.

"The vast majority of people with a history of tick bites are not going to develop this allergy to meat and will continue to eat meat with no problem," Lieberman said. He added that even among those found to carry the alpha-gal molecule, only a small number will actually show symptoms.

But Lieberman's team does hope the new study will inform doctors and patients that the meat allergy could be the cause of unexplained anaphylaxis. Many would not make this connection because the tick-related allergy is a fairly recent discovery.

I'm Bryan Lynn.

Bryan Lynn wrote this story for VOA Learning English, based on reports from VOA News, Reuters and other sources. Hai Do was the editor.