They burrow into your skin, crawl up your windpipe and end up living in your small intestine. But some people are happily hosting hookworms for research into whether they might improve a raft of medical conditions.

Ten minutes after gauze is applied to his arm, Christian Williams feels an unusual pinching sensation.

“I didn’t feel them again for another month or so,” Williams says.

The “them” he’s referring to are hookworms trapped under the gauze, and the mild rash he is left with marks the beginning of an epic journey for the 30 larvae the Malaghan Institute has infected him with.

One school of thought is that there might be an infection sweet-spot, where just the right number of hookworms hanging out in your small intestine, cruising for sex and sucking your blood, might be an infection with benefits for both host and hookworms. Hit this balance and the relationship might be more symbiotic than parasitic.

It’s not mentioned in the article, but I believe this study is being carried out in NZ because it’s run by the Malaghan Institute, based in Wellington.