One benefit of living in the developed world is access to clean soil and water, which means the absence of parasites if everything is running smoothly. Children in developing countries like Tanzania, however, aren’t so lucky. The Centers for Disease Control and Prevention estimate that one billion people worldwide suffered from worm infections in 2002.
Ascaris lumbricoides, or hookworm, and Trichuris trichiura, or whipworm, eggs can enter the body if a person eats or drinks contaminated food or water. They cause disruption in the gastrointestinal tract and infections.
For children, an infection can impact more than just day-to-day life. For some, it can severely stunt growth.
“Children infected are physically, nutritionally, and cognitively impaired,” said Benjamin Speich, a researcher at the Swiss Tropical and Public Health Institute. “This means they…grow slower, have difficulties [paying] attention in school, and with higher infection intensities they might suffer from anemia.”
Currently, the World Health Organization (WHO) recommends annual de-worming treatments for children and at-risk groups. But in the face of whipworm, these treatments aren’t enough. A better course, Speich's research shows, is oxantel pamoate, a drug more commonly used by veterinarians.
Scientists from the Swiss institute have found that oxantel pamoate combined with the standard treatment, Albendazole, rids 31 percent of children of worm infections and decreases eggs in children’s stools by 96 percent after just one treatment.
For researchers, these findings were not surprising—the drug has been a known treatment for whipworm since the 1970s. And after testing it thoroughly in the lab, researchers found that it performed much better than the standard drugs like mebendazole.
“We therefore hoped that these promising results would also be observed in humans,” said study author Jennifer Keiser, Ph.D., an assistant professor of medical parasitology and infection biology at the Swiss Tropical and Public Health Institute.
Researchers collected data from 458 children ages 6 to 14 on Pemba Island in Tanzania, of whom 450 were infected with whipworm, 443 with hookworm, and 293 with A. lumbricoides. Children were given a 20 mg dose of oxantel pamoate per kilogram of body weight, plus 400 mg of albendazole on consecutive days.
Researchers found that the cure rate for whipworm was significantly higher with the combined treatment than with mebendazole—nearly three times higher. Unfortunately, oxantel pamoate did not effectively treat the other two types of parasite infection.
Keiser and her team are not the first to suggest that oxantel pamoate is a good supplement to the current standard of care. “[A] number of small-scale studies in the 1970s showed that oxantel pamoate is also a safe and effective way of tackling whipworm infections in humans,” Speich said. Getting the drug for people however, turned out to be harder than they expected.
“Access...to it is extremely difficult,” Keiser said. Researchers tried to reach out to veterinary companies that produce the drug, but some of the companies did not want to provide it.
“We solved [the] problem with colleagues from the pharmaceutical department at the University of Basel, who produced tablets for us,” Keiser said.
Before oxantel pamoate is readily available for more than just animals, safety and dosing studies will need to be conducted to find a fixed dose that works no matter how much a patient weighs. That will be crucial for mass drug administration programs, Speich said.
Garnering the support of the WHO will also be crucial, Keiser said, because they choose first-line treatments for worm infections.