https://www.cidrap.umn.edu/tick-bor...ies-bites-2-more-types-ticks-red-meat-allergy
Research ties bites from 2 more types of ticks to red meat allergy
Mary Van Beusekom, MS
Today at 2:40 p.m.
Tick-borne Disease
AGS is an immunoglobulin E (IgE)-mediated allergy to galactose-α-1,3-galactose (alpha-gal), a disaccharide (sugar) found in most nonprimate mammalian meat. It can cause gastrointestinal (GI) symptoms, malaise, and anaphylaxis. In the United States, AGS is usually associated with bites from the lone star tick (Amblyomma americanum).
The US Centers for Disease Control and Prevention (CDC) estimates that AGS affects up to 450,000 Americans.
45-year-old woman in Maine
For the first study, a team led by CDC researchers investigated a patient in Maine showing AGS symptoms 9 days after a black-legged tick (Ixodes scapularis) bite in May 2022. They also collected surveillance data from 57 confirmed or suspected cases of AGS, including this case.
The case involved a 45-year-old woman who removed a black-legged tick from her left bicep after returning from a walk on a wooded path in York County. Three days later, the bite area became inflamed and itchy and featured an enlarged red circumference.
Nine days after the bite, she had GI symptoms 2.5 hours after eating roasted rabbit and having an alcoholic drink. Symptoms such as delayed-onset abdominal pain and malaise continued for 2 weeks after she ate red meat, and she sought care 20 days post-bite after experiencing a severe bout of vomiting and diarrhea after eating beef.
Blood tests revealed a serum alpha-gal–specific IgE level above the upper limit of detection, and the woman's clinician recommended avoiding beef, lamb, and pork.
Outside of the lone star tick range
In the 2 months after the bite, the patient found another black-legged tick and an American dog tick (Dermacentor variabilis), or wood tick. Eating bacon at 3 months and steak 7 months after her first symptoms led to delayed heartburn. Ten months after the initial symptoms, the patient tolerated a steak dinner and roast beef sandwich and started eating red meat again.
After increasing AGS surveillance, the Maine CDC received positive alpha-gal–specific IgE laboratory reports on 57 Maine residents in 12 counties from November 2014 to October 2023. The average age of patients was 57 years, 61% were men, and 74% lived in coastal areas.
The Maine CDC confirmed AGS in 23 of the 57 case-patients after interviewing healthcare providers or patients and reviewing medical records. Review of the 23 patients' medical records revealed evidence of an allergy to meat or alpha-gal–containing products.
Of 12 patients interviewed, 11 reported having at least one recent bite from a lone star, black-legged, or other tick.
"US health and public health professionals should be aware of AGS outside the established lone star tick range," the authors wrote. "Further exploration is necessary regarding the role of I. scapularis ticks in AGS and factors driving AGS onset in patients residing outside the established lone star tick range."
61-year-old woman in Washington
In Washington state, a Kaiser Permanente Seattle–led team detailed a case of alpha-gal syndrome in a state resident bitten by a western black-legged (Ixodes pacificus) tick.
A 61-year-old woman who worked as a wildlife biologist reported diffuse urticaria (hives) and lip swelling to a nurse, who advised her to take the antihistamines ranitidine and diphenhydramine. Her symptoms resolved within 24 hours.
A month later, the woman called 911 after experiencing itching in her groin, urticaria on her back, and rapid-onset tongue swelling and difficulty speaking. After noting wheezing, low blood pressure, and a high heart rate, paramedics administered epinephrine for anaphylaxis. Her condition improved slightly, but within several minutes, paramedics documented worsening tongue swelling, throat tightness, and tunnel vision.
Public health practitioners across the United States should continue efforts focused on tick bite prevention, healthcare provider education, and improved tick and tickborne disease surveillance.
The woman received a second dose of epinephrine, and after her symptoms worsened in the ambulance, she also received the corticosteroid methylprednisolone and an epinephrine nebulizer. Her symptoms improved in the emergency department (ED), and she was released home with prescriptions for prednisone, the antihistamines famotidine and diphenhydramine, and an epinephrine autoinjector.
Later, the patient remembered that she had walked her dog in a wooded area the month before and experienced itching on her back. She found a non-engorged tick embedded in her left shoulder, which had likely been there for about 12 hours.
After she removed parts of the tick, the bite area subsequently became painful and red. The same day, she sought care at an ED, where the mouthparts were removed and doxycycline was prescribed.
Establishing tie between AGS, Ixodes ticks
The woman visited an allergist, who detected elevated alpha-gal IgE levels, diagnosed AGS, told her to avoid eating mammalian meat, and cautioned her about consuming milk and gelatin. She then avoided meat and gelatin and had no further allergic episodes, and within 6 months, her alpha-gal IgE level had fallen markedly.
The patient reported two more bites with I pacificus ticks in April 2020 and March 2022, after which she experienced similar itchy reactions at the bite site, as well as elevated alpha-gal IgE levels. "Had the patient not switched to a vegetarian diet, clinical experience suggests that the rise in IgE titer might have increased her chances of having an allergic reaction after red meat consumption," the researchers wrote.
"Additional work will be needed to determine a possible link between I. pacificus or other Ixodes spp. ticks and AGS in the United States," they concluded. "Public health practitioners across the United States should continue efforts focused on tick bite prevention, healthcare provider education, and improved tick and tickborne disease surveillance."
Research ties bites from 2 more types of ticks to red meat allergy
Mary Van Beusekom, MS
Today at 2:40 p.m.
Tick-borne Disease
Two Emerging Infectious Diseases studies link bites from black-legged (deer) and western black-legged ticks to potentially life-threatening alpha-gal syndrome (AGS), or red meat allergy.AGS is an immunoglobulin E (IgE)-mediated allergy to galactose-α-1,3-galactose (alpha-gal), a disaccharide (sugar) found in most nonprimate mammalian meat. It can cause gastrointestinal (GI) symptoms, malaise, and anaphylaxis. In the United States, AGS is usually associated with bites from the lone star tick (Amblyomma americanum).
The US Centers for Disease Control and Prevention (CDC) estimates that AGS affects up to 450,000 Americans.
45-year-old woman in Maine
For the first study, a team led by CDC researchers investigated a patient in Maine showing AGS symptoms 9 days after a black-legged tick (Ixodes scapularis) bite in May 2022. They also collected surveillance data from 57 confirmed or suspected cases of AGS, including this case.
The case involved a 45-year-old woman who removed a black-legged tick from her left bicep after returning from a walk on a wooded path in York County. Three days later, the bite area became inflamed and itchy and featured an enlarged red circumference.
Nine days after the bite, she had GI symptoms 2.5 hours after eating roasted rabbit and having an alcoholic drink. Symptoms such as delayed-onset abdominal pain and malaise continued for 2 weeks after she ate red meat, and she sought care 20 days post-bite after experiencing a severe bout of vomiting and diarrhea after eating beef.
Blood tests revealed a serum alpha-gal–specific IgE level above the upper limit of detection, and the woman's clinician recommended avoiding beef, lamb, and pork.
Outside of the lone star tick range
In the 2 months after the bite, the patient found another black-legged tick and an American dog tick (Dermacentor variabilis), or wood tick. Eating bacon at 3 months and steak 7 months after her first symptoms led to delayed heartburn. Ten months after the initial symptoms, the patient tolerated a steak dinner and roast beef sandwich and started eating red meat again.
US health and public health professionals should be aware of AGS outside the established lone star tick range.
After increasing AGS surveillance, the Maine CDC received positive alpha-gal–specific IgE laboratory reports on 57 Maine residents in 12 counties from November 2014 to October 2023. The average age of patients was 57 years, 61% were men, and 74% lived in coastal areas.
The Maine CDC confirmed AGS in 23 of the 57 case-patients after interviewing healthcare providers or patients and reviewing medical records. Review of the 23 patients' medical records revealed evidence of an allergy to meat or alpha-gal–containing products.
Of 12 patients interviewed, 11 reported having at least one recent bite from a lone star, black-legged, or other tick.
"US health and public health professionals should be aware of AGS outside the established lone star tick range," the authors wrote. "Further exploration is necessary regarding the role of I. scapularis ticks in AGS and factors driving AGS onset in patients residing outside the established lone star tick range."
61-year-old woman in Washington
In Washington state, a Kaiser Permanente Seattle–led team detailed a case of alpha-gal syndrome in a state resident bitten by a western black-legged (Ixodes pacificus) tick.
A 61-year-old woman who worked as a wildlife biologist reported diffuse urticaria (hives) and lip swelling to a nurse, who advised her to take the antihistamines ranitidine and diphenhydramine. Her symptoms resolved within 24 hours.
A month later, the woman called 911 after experiencing itching in her groin, urticaria on her back, and rapid-onset tongue swelling and difficulty speaking. After noting wheezing, low blood pressure, and a high heart rate, paramedics administered epinephrine for anaphylaxis. Her condition improved slightly, but within several minutes, paramedics documented worsening tongue swelling, throat tightness, and tunnel vision.
Public health practitioners across the United States should continue efforts focused on tick bite prevention, healthcare provider education, and improved tick and tickborne disease surveillance.
The woman received a second dose of epinephrine, and after her symptoms worsened in the ambulance, she also received the corticosteroid methylprednisolone and an epinephrine nebulizer. Her symptoms improved in the emergency department (ED), and she was released home with prescriptions for prednisone, the antihistamines famotidine and diphenhydramine, and an epinephrine autoinjector.
Later, the patient remembered that she had walked her dog in a wooded area the month before and experienced itching on her back. She found a non-engorged tick embedded in her left shoulder, which had likely been there for about 12 hours.
After she removed parts of the tick, the bite area subsequently became painful and red. The same day, she sought care at an ED, where the mouthparts were removed and doxycycline was prescribed.
Establishing tie between AGS, Ixodes ticks
The woman visited an allergist, who detected elevated alpha-gal IgE levels, diagnosed AGS, told her to avoid eating mammalian meat, and cautioned her about consuming milk and gelatin. She then avoided meat and gelatin and had no further allergic episodes, and within 6 months, her alpha-gal IgE level had fallen markedly.
The patient reported two more bites with I pacificus ticks in April 2020 and March 2022, after which she experienced similar itchy reactions at the bite site, as well as elevated alpha-gal IgE levels. "Had the patient not switched to a vegetarian diet, clinical experience suggests that the rise in IgE titer might have increased her chances of having an allergic reaction after red meat consumption," the researchers wrote.
"Additional work will be needed to determine a possible link between I. pacificus or other Ixodes spp. ticks and AGS in the United States," they concluded. "Public health practitioners across the United States should continue efforts focused on tick bite prevention, healthcare provider education, and improved tick and tickborne disease surveillance."