Y: All packed for your trip, Don?
D: Almost. Just adding a few things to my travel first aid kit. I’ve got ibuprofen, Band-Aids, and antiseptic wipes. What else do people add to these things?
Y: Usually something for diarrhea. What’s your blood type?
D: What does that have to do with anything?
Y: It turns out people with type A blood are more likely to get sick from a specific strain of E. coli bacteria commonly seen in people living in or visiting developing countries. See, blood type groups are determined by the different sugars found on the surfaces of your red blood cells and elsewhere—people with type A blood have different sugar molecules than people with type B or O blood. Researchers found that this specific strain of E. coli secreted a protein that attached to the type A sugars found on intestinal cells of people with type A blood. This protein also sticks to the E. coli bacteria, essentially fastening the bacteria and intestinal cells together, which makes it easier for the E. coli to inject its diarrhea-causing toxins into the cell.
D: How much easier?
Y: The researchers did a study to test that: they had a hundred and six volunteers drink water laced with E. coli they isolated from a person in Bangladesh suffering from severe diarrhea. Eighty-one percent of the volunteers with type A blood developed moderate to severe diarrhea, compared to only about fifty percent with blood types B or O.D: Fifty percent odds still isn’t great. I think I’ll be better off finding a pharmacy than trying to find out my blood type. And maybe avoiding scientists offering me water, too.