New data show anti-parasite drugs are effective in combating mortality, anemia and malnutrition in pregnant women and young children suffering from intestinal worms, the World Health Organization (WHO) said on Thursday.

In a statement issued after experts from 12 affected countries took part in two-day talks, the WHO called for treatment to be stepped up, especially in less developed countries.

Some 2 billion people worldwide suffer from parasitic infections, which cause malnutrition, organ damage and in severe cases, bladder cancer, according to the United Nations agency.

But due to safety concerns, anti-parasite drugs were not widely recommended for young children or for pregnant women until 2002 when a WHO expert committee gave the go-ahead for pregnant women and babies over 12 months old.

Nepal reported a major study showing significant improvement in maternal health and a 41 percent drop in infant mortality after treatment for parasites, it said. In Sierra Leone, deworming medicine lowered anemia in pregnant women.

“We are overwhelmed by this evidence,” said Lorenzo Savioli, coordinator of the WHO’s parasite control program. “We knew there would be benefits from expanding deworming treatment, but we never imagined the impact would exceed even our most optimistic expectations,” he said.

Only 65 million school-age children around the world get anti-parasite drugs, but the WHO aims to get 650 million children on the treatment by the year 2010, according to Savioli, who put the annual cost at just $200 million.

“Drugs are not the issue - it costs two cents a tablet,” Savioli told Reuters. “It’s setting up a system that is sustainable. This is not a one-off intervention, it has to be linked to vaccine campaigns and distributions in schools,” he said.

Sub-Saharan Africa is the hardest-hit region, but Uganda has been a model for battling parasitic infections through a partnership with donors including Microsoft boss Bill Gates’s foundation, Savioli said.

The WHO was in negotiations with Johnson & Johnson for private sector support of the global initiative, he added.