The Washington Post recently reported on hookworms burrowing into a teenager's skin during a trip to Florida. The teenager had spent a lot of time outdoors and within days of returning home, he had a red, itchy rash covering his entire backside. The symptoms were a telltale sign of certain type of hookworm, a parasite that can infect both animals and humans.
According to the Centers for Disease Control and Prevention (CDC), hookworms are spread through the feces of animals or humans who have the parasite, and people can get them by simply walking barefoot on sand or soil that has been contaminated.
Bobbi Pritt, M.D., Director of the Clinical Parasitology Lab and Co-Director of Vector-Borne Diseases Lab Services in Mayo Clinic’s Department of Lab Medicine and Pathology, commented on the two main types of hookworm: human hookworms and animal, or zoonotic, hookworms.
Dr. Pritt said, "Both kinds can be transmitted to people, and it happens in a similar way—animals or humans infected with the parasite defecate into sand or soil and, because their feces carry the parasite's eggs, the ground then becomes contaminated. Once in the ground, the eggs hatch into larvae, or immature hookworms, and when people come into contact with them, they can penetrate the skin."
When human hookworms penetrate a person's skin, they migrate into the bloodstream and take up residence in the gut. "However, animal hookworms cannot adapt to the human body, so the larvae usually never make it into the person's intestines," Dr. Pritt said. "Instead, the larvae, which are microscopic, roam around in the person's skin—causing those red, squiggly marks—trying, but unable, to mature or to reproduce. Eventually the larvae die."