As hopes fade that any of those missing since the December 26 earthquake and tsunami will be found alive, aid workers are focusing on protecting the survivors. Children are most vulnerable to a variety of risks.

As the death toll from the Indian Ocean earthquake and tsunami levels off, experts are now warning of follow-on problems, such as disease outbreaks.

Children in particular are at risk of disease. But United Nations officials also fear that trafficking gangs are targeting children left orphaned by the disaster.

Anupama Rao Singh, UNICEF regional director for East Asia and the Pacific, said Wednesday in Bangkok it is essential to protect children.

"They are vulnerable to the onset of disease; they are vulnerable to all the negative effects of drinking contaminated water, not having sanitation, not having access to health services," Ms. Singh said.

Sri Lankan children displaced by the Dec.26 tsunami

UNICEF thinks that as many as one-third of the people affected by the disaster are children.

About 150,000 are thought to have died in the quake and tsunami and thousands are missing.

With aid now flowing to most of the 12 countries hit by the disaster, relief workers can start to look beyond simply getting food and water to refugees.

Michael Diamond, regional director for aid agency Plan International has visited devastated coastal areas of Sri Lanka. He said in Bangkok that women and children appeared least able to escape the tsunami waves.

"There seemed to be many more women and children dead than men - and the old people," he said. "It looks like the women and children just weren't able to get away from the waters as fast as other people."

Indonesia says 35,000 children in Indonesia's hard-hit Aceh Province lost one or both parents to the tsunami. To prevent these children from falling into the hands of human traffickers, Indonesia has restricted the movement of children out of Aceh.

Malaysian authorities Wednesday also warned their nationals of traffickers who may attempt to sell orphaned children.

Ms. Rao Singh says special efforts are needed to care for children left on their own.

"We need to make sure that the children who have been affected are protected from various forms of exploitation - including the risk of trafficking of children," she said.

UNICEF's Ms. Rao Singh says getting traumatized children back into school is key to their long-term recovery.

"We would want to get back to children a sense of normalcy in their lives. They have been severely traumatized," she said. "They need to start recovering as soon as possible and one of the best ways of doing that is to get them back to school immediately."

For many children, like hundreds of thousands of adults, recovery will be part of a process that may take years.