Washington: Parasitic worms are known for infecting over a billion people worldwide and kill or sicken many every year. But they may be useful in treating lung disease and healing wounds, according to a new study.

The research, published in the journal Nature Medicine, found that the worms trigger key elements of the immune system responsible for mending damaged tissues and reducing inflammation.

These live worms could be used someday in a controlled setting to treat serious lung injury caused by respiratory infections, such as pneumonia, said lead study author William Gause of New Jersey Medical School in Newark.

Gause and his colleagues studied a worm in rodents called Nippostrongylus brasiliensis, similar to a specific hookworm that infects over 700 million humans every year.
They found that both the worms enter the host's body when skin, often on the feet, comes in contact with worm larvae in feces-contaminated mud or water, LiveScience reported.

The larvae travel through the circulatory system to the lungs; burrow out through windpipe; get swallowed down the esophagus; and then make their way through the stomach to the small intestines, where they mature into worms and propagate furiously, producing millions of eggs.

The worse damage from the worms is to the lungs. But the researchers found the immune system proteins called cytokines that help to oust intestinal worms in mouse lungs and also initiate a cascade of healing.

They do so by mobilising various elements of the immune system to reduce inflammation and clear infectious debris while stimulating so-called growth-factor steroids and other proteins simultaneously to mend the damaged lung tissue.

That action is called a Th2 response that involves immune system white blood cells called Type 2 helper T cells. The key findings are that the Th2 response has secondary, potent acute wound-healing effects and that worms can trigger it.

Gause said that what occurs in mice from N brasiliensis perhaps occurs in humans from parasitic worms. If so, these worms could be more effective than some drugs at triggering the immune response to cure the body from within, he said.

"This orchestrated enhanced wound-healing response, which includes control of harmful inflammation and direct mediation of wound repair, may have evolved in the host to mitigate harmful effects of the considerable acute tissue damage these large multicellular parasites can cause as they migrate through essential organs," Gause said.

"In this regard, these parasites or parasite products may potentially be used to treat acute lung injury."

The use of helminths, or parasitic worms, to treat immune disorders is called helminthic therapy, and it is not new.

Several studies are currently using live worms to treat several inflammatory diseases and autoimmune disorders such as Crohn's disease. Gause's work adds a new twist to helminthic therapy, moving it into the realm of wound healing and tissue repair.

(Agencies)