Researchers from Washington University School of Medicine in St. Louis and Ain Shams University in Egypt found that after five years of annual mass treatments with two drugs, rates of filarial infection sharply declined in Egypt.
"The parasite's transmission efficiency is low, so the thinking is that once we get human infection rates below a critical level, remaining infections will die out without further intervention," says senior author Gary Weil, M.D., professor of medicine and of molecular microbiology at Washington University. "Our assessments suggest that the Egyptian campaign to eliminate these infections, which was implemented by the Egyptian Ministry of Population and Health, has achieved its goals in most areas of the country."
Filarial worms are nematodes closely related to the heartworm parasites that infect dogs and cats. Infections with the worms, which are spread by mosquitoes, can lead to lymphatic filariasis, a condition where the worms lodge in lymphatic vessels. This triggers inflammation that blocks the drainage normally provided by the lymphatic system and leads to massive swelling of the legs, known as elephantiasis, and genital deformities, which are called hydroceles.
"In addition to causing disability, the disfigurement created by elephantiasis is often a source of great social stigmatization," Weil notes.
Epidemiologists estimate 120 million people are infected with filarial worms in 83 tropical countries. Of those infected, approximately 40 million have clinical symptoms. As many as 1.2 billion peopl
Contact: Michael Purdy
Washington University School of Medicine