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January 19, 2014

Researchers Map Genetic Sequence of Parasitic Worm

by Jessica Berman

An estimated one to two billion people around the world are infected with soil parasites known as helminthes. Researchers have drawn the genetic blueprint for the hookworm, the most common source of soil-borne parasitic infection in humans. The hookworm’s genetic sequence could lead to better treatments and prevention strategies.
 
An estimated 700 million people in sub-Saharan Africa, China, Southeast Asia and Indonesia are thought to be infected with hookworms.
 
These parasites, about a centimeter in length, live in the soil and enter the body through the skin on the soles of bare feet, according to Makedonka Mitreva, assistant director of the Genome Institute at Washington University in St. Louis, Missouri. She says children are at highest risk:
 
“Especially kids are exposed a lot to infected soil and that’s why the level of infection is really high,” says Mitreva.
 
After they have entered the body, hookworms live in the small intestine and feed on blood.  Infection causes anemia and malnutrition, which can impair cognitive development and stunt children’s growth. Hookworm infection can cause severe illness and even death in pregnant women.
 
Because the symptoms are so similar to those of other diseases, Mitreva says hookworm infections are frequently overlooked or misdiagnosed.
 
Mitreva and colleagues mapped the DNA sequence of the hookworm, identifying genes that are responsible for the hookworm's infection of humans and other warm-blooded animals, genes involved in blood feeding and the helminthes’ life cycle, as well as potential new drug targets.
 
The problem now, says Mitreva, is there are no vaccines and the helminthes are starting to become resistant to existing drugs. But, she adds, the genetic blueprint should make it easier to develop better weapons against the soil parasite.
 
“So this genomic-based drug target discovery, vaccine target discovery or, you know, tools for diagnosis are possible when you have the genomic information,” says Mitreva.
 
The DNA sequence of the hookworm parasite is described in the journal Nature Genetics.