Parasites and Allergies

In 1973, a NIH parasitologist named Eric Ottesen discovered a high rate of worm infection on the tiny island of Mauke. He gave the islanders an anti-parasite drug. Nineteen years later, he did another survey of worm infection.

Compared with 19 years ago, Ottesen found, there was much less filarial infection on Mauke. Only 16 percent of the population harbored the microscopic worms, as opposed to 35 percent on his first visit. The reduction resulted primarily from treating the islanders with the antiparasite drug diethylcarbamazine, which Ottesen had initiated during his earlier visit. And what about allergies? There’s no question that there was a heck of a lot more allergy out there this time, says Ottesen. Nineteen years ago barely 3 percent of the people had allergies. This time it was at least 15 percent. The complaints ranged from eczema to hay fever and asthma to food allergies. What’s more, the dominant problem was one nobody had even heard of 19 years earlier: octopus allergy. It’s the number one offender, says Ottesen. People are breaking out in rashes, hives, swelling of the throat. Yet octopus is nothing new to them–they were eating it when we were there before.

Ottesen believes there is something specific to parasites that makes them protective.  I suspect this is another example of the protective effects of bacteria and bacteria-like chemicals, which I believe may come from both food and parasites. Another possibility is that the antiparasite drug killed bacteria. Nothing is said about obesity; I wonder how their diet changed over the 19 years. A switch from homemade (nonsterile) food to factory (sterile) food may be part of the problem.

5 Replies to “Parasites and Allergies”

  1. But 19 years is a long time. What about other environmental factors? Pollution? Allergies have increased around the world and I doubt that it’s related to parasites in most places.

  2. The simpler hypothesis is that diethylcarbamazine itself damages the immune system. Do we have any contrary evidence?

  3. Nathan, I don’t know of any outside evidence for or against your “simpler” hypothesis. There is plenty of outside evidence for the explanation I propose.

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