"They were all over me," says recent parasite host Barbara Carroll, 42. "I could see them, moving beneath my skin. I could feel them."
The memory sends Carroll into shivers of disgust. She lights her fifth cigarette of the morning.
"Just look," she says, displaying a forearm pocked with scabs and fresh scars. "Look! I had worms inside me."
Hookworms, to be exact. Burrowing, biting, bloodsucking little bastards. Under magnification, they look like the thing that burst out of that guy's stomach in Alien, fangs and all. Once a hookworm invades a host body, it chews its way to the intestinal tract, where it can live for up to 15 years, munching gut tissue for nourishment. The World Health Organization estimates 700 million people carry hookworm, and 50,000 of them die each year (a badly infested host can lose a pint of blood a day). The vast majority of hookworm cases occur in developing countries, since the parasite thrives on poverty.
This offers no consolation to Carroll. Neither does knowing she almost certainly had canine hookworm, not human hookworm.
The hookworms "thought I was a dog," she says, sounding insulted.
The hookworm is a species-hopper. Hookworms carried by dogs, cats or other animals can invade humans who come into bare-flesh contact with infested animal feces.
The good news for humans infested with animal hookworms is that animal hookworms have a hard time burrowing into the guts of a human. Most of them never make it to the intestinal tract. The invaders starve to death.
The bad news is they die slowly, and they die inside you.
Animal hookworms can live for several weeks in a human body, during which time they slither aimlessly, just beneath the skin, moving a few inches per day. The hookworms leave a serpentine trail of infection in their wake, and when they finally die, they break the skin's surface, causing a circular, bloody lesion.
The medical term for this condition is "creeping eruption."
Carroll's boyfriend calls it "more like a plague from God."
"Having worms is weird," says Jim Nelms, 47, who was also infested. "It plays tricks on your mind. It gets so bad, you have to keep from hacking at yourself with a knife, trying to get them out."
Carroll and Nelms still aren't sure how this pox fell upon the house they share in a neighborhood near Desert Sky Pavilion. The couple's hobby is rock collecting, and they say they went camping several times in the weeks leading up to their simultaneous, mid-July outbreak.
"We camped beneath some bats up near Payson," says Carroll. "Maybe that was it."
Maybe. More likely, the source was the home garden Carroll and Nelms planted in their backyard in June. They say they mixed several bags of manure into the newly turned earth as fertilizer, then tended this patch of dirt and manure daily, with their bare hands, often wearing no shoes.
If there were hookworm larvae in the manure Carroll and Nelms purchased (as with a case in West Virginia four years ago), or if an infested neighborhood pet defecated in their produce patch, the couple's backyard garden became a minefield of creeping eruption.
Adult hookworms lay 1,000 eggs a day in their host's intestines. These eggs are excreted in the host's feces. Then, if the open-air environment is suitable (hookworms like it warm, wet and shady), the eggs will hatch into hookworm larvae and lie in wait for contact. When it comes, they latch on and start chewing.
The first symptom of creeping eruption is a burning rash, usually on the forearms and lower legs. When it hit Carroll and Nelms, they went to see a dermatologist, who diagnosed the rash as scabies (a tiny parasitic mite) and treated them with injections of cortisone, a steroid that is ineffective against hookworms.
"The cortisone just seemed to make them go apeshit," says Nelms.
Creeping eruption, like all forms of human hookworm infestation, is rare in the United States, and therefore often misdiagnosed. A 1993 study published in the American Journal of Tropical Medicine reported that two-thirds of creeping eruption patients treated by tropical medicine specialists in the U.S. (most of them travelers who had gone beachcombing barefoot) were misdiagnosed by at least one conventional dermatologist before receiving the correct treatment.
Carroll and Nelms say they were misdiagnosed by four in three weeks. Sifting through a jumbled stack of medical records and insurance bills she stores in a Tupperware bowl, Carroll pulls forth the evidence of each visit.
"This one said it was scabies," she says. "This one said it was a nervous rash. This one asked us if we were burning one another with cigarettes, and this one wanted to treat us with a drug they use for Tourette's Syndrome."