BEIJING (AP) -- An outbreak of Japanese encephalitis in southern China has killed at least 18 children, prompting the government to launch an emergency vaccination program, health officials and state media said Friday.

At least 211 people have contracted encephalitis in Guangdong province, where rice paddies provide a breeding ground for mosquitos that carry the disease, newspapers reported.

The disease, which causes the brain to swell, usually strikes southern China every summer, between May and July. It is untreatable and is usually fatal in 30 percent of cases, according to the World Health Organization.

The WHO is monitoring the outbreak, but doesn't consider it to be out of control, said a spokesman for the U.N. agency in Beijing.

"This is a seasonal occurrence," said spokesman Bob Dietz. "If the numbers are accurate, you have a death rate of about 10 percent, which is actually low."

Cases have been reported in areas throughout Guangdong, including seven in the provincial capital of Guangzhou, China's southern business center.

Many are children of migrant workers, who often aren't covered by the government health program, which includes vaccinations for encephalitis, the newspaper Xin Kuai News said.

"Some parents want to save money or time," the newspaper said. "Others simply don't know anything about the disease" and fail to get necessary shots.

It said the government had launched an emergency program that has vaccinated 100,000 children in the past week.

Encephalitis kills nearly 10,000 people each year in Asia, most of them children, and infects 40,000. Many survivors suffer permanent nerve damage.

A Guangdong Health Department official who would give only his surname, Wu, said 211 cases had been reported by Wednesday. He wouldn't give newer figures, saying Chinese regulations only require epidemic statistics to be updated once a month.

"This isn't like SARS," he said, referring to the outbreak of severe acute respiratory syndrome that prompted hard-hit Guangdong and other Chinese regions to issue daily bulletins on deaths and new cases.

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