Scientists have sequenced genome of the blood-sucking hookworm, an advance that could lead to better remedies against the disease-causing parasite that infects about 700 million people worldwide including India.
The parasitic worm lives in the soil and enters the body through the feet. The infection is common in parts of Africa, Asia and South America.
By feeding on victims' blood, the worms cause anemia and, in children, stunted growth and learning problems.
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Now, researchers at Washington University School of Medicine in St Louis have decoded the genome of the hookworm, Necator americanus, finding clues to how it infects and survives in humans and to aid in development of new therapies to combat hookworm disease.
"We now have a more complete picture of just how this worm invades the body, begins feeding on the blood and successfully evades the host immune defences," said senior author Makedonka Mitreva.
"This information will accelerate development of new diagnostic tools and vaccines against the infection," said Mitreva.
Necator americanus causes about 85 per cent of human hookworm infections, which are not usually fatal, researchers said.
However, in pregnant women, the worm can cause severe anemia, leading to maternal deaths and low birth weights that contribute to newborn deaths, they said.
The deworming drug albendazole typically is given as part of mass treatment programs in areas with endemic infection, but its repeated and excessive use is leading to treatment failures and drug resistance in some regions, Mitreva said.
Hookworms are common in areas of extreme poverty that lack indoor plumbing. The worm's eggs are excreted in the feces of infected individuals, contaminating the soil.
After the eggs hatch, the immature worms, called larvae, molt twice and enter the body through the feet.
The worms travel through the bloodstream to the lungs, where they are coughed up and then swallowed, making their way to the small intestine. It is there that the worms mature and begin feeding on the blood.
Decoding the worm's genome allowed the researchers to discover suites of genes that orchestrate each of these processes and to identify specific targets that may be vulnerable to vaccines or new drug treatments.
The study was published in the journal Nature Genetics.
