Donut the dog has always been a bit of a lemon. “She hates kids. She hates other dogs. She hates physical activity,” says Julia Gilden. Gilden adopted the 80-pound Bearded Collie seven years ago. All the things people love about dogs? Donut didn’t really have many of those attributes. But she was sweet and goofy and, for the most part, pretty healthy.
All that changed in 2015. Donut developed a series of health problems so perplexing and expensive that Gilden, a cellular immunologist, began pondering a radical DIY solution. “How dumb is it,” she asked her Facebook friends, “to consider giving her a brief helminth infection?” In other words, should she deliberately infect her dog with parasitic worms?
Donut’s troubles began when Gilden had a baby. The dog became increasingly anxious and withdrawn, so at the recommendation of a dog behaviorist, Gilden tried Prozac. The pill seemed to help the dog’s demeanor, but it didn’t do much for her stomach. Donut started barfing. The vet thought the problem might be stomach acid, so Gilden gave her a second pill, the heartburn medication Prilosec. At first, it seemed like the drug might be working. But a couple of weeks later, Donut got sick again in a most spectacular way.
The incident occurred while Gilden was on vacation with her family. When the dog sitter called, her husband picked up. She heard him say, “I’m so sorry. I’m so sorry. I’m so sorry.” Donut had vomited into the dog sitter’s mouth while she was asleep. Gilden, horrified, booked another vet appointment.
No one was sure what had caused the sudden illness. Maybe the Prilosec? Or something Donut picked up at the dog park? To cover all the bases, the vet prescribed a bland diet, an anti-parasitic, a strong antibiotic, and a probiotic. And the cocktail seemed to help, at least for a while. But Donut’s gastrointestinal distress returned. Maybe, the vet said, she has a food allergy. So Gilden put her on a special allergen-free diet. Again Donut seemed more or less cured.
Last fall, however, Donut began to itch with unprecedented ferocity. Under her front legs, Gilden could see raw patches. This time Gilden left the vet with a prescription for Apoquel, a new state-of-the-art drug for itchy dogs. Each pill cost $2.75, but the effect was nearly instantaneous. “It was like a light switch. One dose and she completely stopped itching,” Gilden says. (Fun fact: the drug is approved for dogs, but it also does wonders for Andean bears with alopecia.)
Unfortunately, the effect didn’t last. A couple of months after starting the medication, Donut was itching again. That’s when Gilden, desperate, remembered her work with helminths.
When Gilden was still an undergraduate, she took a job in the helminth immunology lab at the National Institutes of Health. A physician who worked there would talk about Peace Corps volunteers who get worms when they’re abroad, and then seem to be cured of their allergies. “That’s the fundamental question of this lab,” she remembers him saying. “What’s the deal with that?”
Scientists have been pondering the relationship between parasites and allergies for decades. Some believe that the rise in allergic disease in developed countries can be explained by increased hygiene. The idea, called the hygiene hypothesis, is that less exposure to parasites and other microbes leads to overactive immune systems. If so, it’s possible that exposing people to parasites might provide some relief. And there is ample evidence to show that helminths can modify the immune system.
So Gilden looked into ordering worms for her dog. Wormswell.com sells 25 hookworms for $200 in bitcoins. That dose is “large enough to provide potential benefit whilst also being small enough to avoid any serious discomfort,” according to the web site. (Presumably they’re talking about humans, not dogs).
Whether this DIY fix would work, however, is an open question. A number of clinical trials are trying to provide answers— for humans anyway—but only a few have been completed and published. And when Gilden delved into the literature, she found that most of those had failed. “I’m thinking my idea was not good,” she says.
But there’s another worry too. Hookworms can penetrate human skin, so walking barefoot over infested soil is enough to contract them. If Donut were pooping hookworms, she might contaminate the yard and pass the parasite on to Gilden’s daughter. “How would I explain that to the pediatrician?” she wonders.
“I’m not sure what I’m going to try next,” Gilden says. One friend suggested feeding Donut foods she has never encountered before, like kangaroo. Gilden doesn’t want to be the kind of person who does increasingly crazy things for her dog (like Ira Glass and his quest for ever weirder meats to feed his pit bull). But she also doesn’t want Donut to suffer. “We love her. We have a commitment to her,” she says.
For now Gilden might shelve the hookworm idea. She recently read the latest itchy dog guidelines from the “Itchy Dog Association of America, or whatever,” and they pointed her to some new kinds of shampoo. That idea seems easy, cheap, and not at all crazy. Maybe it will even work.