The disease, which killed 116 Cambodians in 2006, has spread across the impoverished nation and infected 31,136 people this year, most of them in the countryside where living conditions are poor and children are vulnerable, they said. "Their parents do not have enough time to take care of them at home. They are poor, they are away from home to make a living," said Ngan Chantha, head of the country's anti-dengue programme.
More could die with the monsoon season, ideal breeding weather for the mosquitoes which carry the disease, not due to fade until the end of September, he said.
A publicity campaign against the disease, including admonitions to clean containers at home every 10 days to ensure mosquitoes cannot breed in them, has borne little fruit.
"The striking issue is villagers do not clean their containers frequently," said Duong Socheat, director of the National Malaria Centre.
The country's four-Swiss funded hospitals have appealed for $7 million to fight a disease that reached epidemic proportions in wealthy Singapore as well as striking hard in Thailand, Malaysia, Vietnam and Indonesia.
The World Bank, the World Health Organization and the Red Cross have provided pesticide to kill mosquitoes and the Asian Development Bank (ADB) gave $300,000.
Cambodia, whose health care system was devastated in 30 years of civil war, spends about $3 per person on health a year, according to the World Bank.