Friday, September 13, 2013
Yet Another Reason to Avoid Ticks
In Vermont, ticks have a bad reputation. The most recent data suggests that Vermont has the second highest incidence of Lyme disease in the country only lagging behind Delaware. It turns out that Vermonters (at least those living in the southern part of the state) may have to worry about yet another complication of tick bites: red meat allergy.
As reported in The Wall Street Journal (Health Journal: June 14, 2013), this odd allergy is on the rise. The culprit is not Ixodes scapularis but Amblyomma americanum, the Lone Star Tick. Some individuals bitten by the tick develop allergy to different meat products. Unlike allergies associated with bee stings, the symptoms tend to develop hours after ingestion of the food – and weeks and months after the tick bite. While symptoms range from vomiting, diarrhea, and abdominal cramps to hives and shortness of breath, no deaths have been reported. Given the interval between the tick bite and the food ingestion, making a connection between the two can be difficult. Patients often report the symptoms initially follow ingestion of a specific meat product, but then may follow ingestion of other meats as well.
The association between tick bites and red meat allergy was found by chance when studying cancer patients with an allergy to a specific monoclonal antibody, cetuximab. Further research showed that patients with IgE antibody to the mammalian oligosaccharide epitope, galactose-alpha-1,3-galactose (alpha-gal) could develop either immediate anaphylaxis to intravenous cetuximab or delayed onset anaphylaxis three to six hours after ingestion of meats. The presumed reason for the delay in symptoms following meat ingestion is that alpha-gal is concentrated in fat and it takes time for the fat to break down. Only patients in the distribution of the Lone Star Tick had the antibody to alpha-gal.
Unfortunately, the Lone Star Tick continues to expand its habitat, so more people may be at risk. As for me, this is yet another reason to wear long-sleeved clothing while hiking, and using plenty of repellents or insecticides while outside.
*This filler excerpt can be found in the September 2013 Pediatrics print journal p. 546, or online here.