Scientist Infects Himself with Hookworms, For Science

Scientist voluntarily infects himself with hookworms
Dr. Jimmy Bernot being parasitised with hookworms through a gauze on the wrist.

A scientist voluntarily infected himself with 50 hookworms for a whole year; as part of a research study testing a vaccine for the parasite.

Scientists often take risks in the name of science. However, sometimes those risks may border on crazy. Take the example of Dr. David Pritchard; an immunologist-biologist at the University of Nottingham. In 2006, he made headlines for infecting himself with hookworms, all for science. Later on, he became the first to infect patients with the parasite as part of a research study exploring the parasite’s effects on allergy symptoms.

Now, Dr. Jimmy Bernot, a Postdoctoral Fellow at the Smithsonian National Museum of Natural History has taken things a step further. As part of a research study aimed at developing a vaccine against hookworm infection, the scientist voluntarily parasitized himself with 50 hookworms. He documented his journey on Twitter.

I volunteered to be vaccinated with an experimental hookworm vaccine (I was also paid). After vaccination, the vaccine (or placebo idk) was tested by infecting me with 50 hookworms (Necator americanus) that penetrated my skin from a patch of gauze I wore on my wrist for 1 hour.

Dr. Jimmy Bernot, Postdoctoral Fellow at the Smithsonian National Museum of Natural History

The Parasite That Feeds on Blood

According to the CDC, an estimated 576-740 million people globally are infected with hookworms. Infection commonly occurs from walking barefoot on soil contaminated. The hookworm larvae in the soil then penetrate human skin. Once inside, the circulatory system carries it to the lungs and then up the trachea. From there it is swallowed and ends up at its final destination that is the intestine. Here the larvae mature into adult worms. The worms can survive for 1-5 years in the intestine, feeding off the host’s blood. Luckily, the infection is treatable with anti-helminths such as albendazole or mebendazole.

Although most infections are asymptomatic, a high worm count can result in abdominal pain, diarrhea, weight loss, and anemia. Young children and older adults are affected the most. Moreover, severe itching is common at the site of penetration. Jimmy described the itch as ‘worse than poison ivy.’

Rash from the worms on Jimmy Bernot’s arm. Credits: Dr. Jimmy Bernot

The Journey of Hookworms Through Bernot’s Body

Jimmy was first injected with the experimental vaccine or placebo. Due to the study’s double-blind design, both recipient and researchers had no idea whether he received the placebo or the trial vaccine. After vaccination, he was infected with fifty hookworms through a patch of gauze, that he wore on his wrist for an hour.

As part of the clinical study, Jimmy had to document all his symptoms while a research team conducted blood tests every week to look out for any negative effects. A few weeks later, he started giving fecal samples so the team could check for worm eggs. The number of eggs helped estimate the number of worms inside Jimmy’s body. The researchers made weekly trips to Jimmy’s house for checking his vitals and collecting blood and fecal samples.

Around 6 months after living with the worms in his body, Jimmy’s participation in the study came to an end. He further received three doses of the anti-helminth, Albendazole, for 3 days.

Jimmy is still unaware whether he got the placebo or the vaccine. However, he hopes to find out once the study is unblinded. According to Jimmy, the only downside of the whole ordeal was the itchiness. But, an interesting upside he experienced was a lack of seasonal allergies. Research has shown that infection with hookworms modulates the immune system; thus, suppressing its response to allergens.


Dr. Jimmy Bernot

Cooper PJ (2004). “Intestinal worms and human allergy”. Parasite Immunol26 (11–12): 455–67. doi:10.1111/j.0141-9838.2004.00728.x


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