RANGOON - The United Nations plans to launch a massive anti-dengue campaign this week in cyclone-hit areas of Burma where mosquitoes that carry the disease have become a major concern, an official said Monday.

More than 1,700 volunteers will fan out across 22 priority areas in Rangoon, Burma's biggest city, and the harder-hit Irrawaddy delta applying larvicide, a pesticide that kills the mosquito larva, to water containers and other areas where mosquitoes are likely to breed, said Leonard Ortega, the World Health Organization's dengue expert in Yangon.

WHO and UNICEF are handling the operation with local aid groups.

"It is a major concern not just because this is dengue season, but because of the displacement of the population, the destruction of houses and because people are more exposed to mosquitoes,'' Ortega said.

The U.N. estimates a total of 2.4 million people were affected by the May 2-3 cyclone and warns that more than 1 million of those still need help, mostly in hard-to-reach spots in the Irrawaddy delta. The cyclone killed more than 78,000 people and left another 56,000 missing.

"We fear that there will be more cases this year. That's why we're embarking on a massive larviciding to contain mosquitoes and reduce transmission,'' Ortega said.

So far this year, the number of cases is roughly in line with previous years, Ortega said. There were 781 cases of dengue fever reported in Yangon as of June 10, and 481 cases reported in the delta through the end of May.

The first phase of the operation requires 44 tons of larvicide to be applied over roughly a 10-day period, Ortega said, adding that a second phase of 44 tons might be carried out six weeks later in the same areas.

So far, only 1.5 tons of larvicide have arrived in Myanmar with another 5 tons waiting to be delivered from neighbouring Thailand, he said. The remainder is in the process of being bought.

The WHO hopes to start the operation Tuesday in Rangoon and continue later in the week in the delta if supplies of larvicide are available, Ortega said.

State-run media and volunteers from the Burma Red Cross and other organizations are informing the public about the campaign and advising home owners to dispose of old tires, bottles, tin cans and other objects where water can collect and become breeding grounds for mosquitoes.

The Burma Times on Monday said children should dress in long pants, long-sleeved shirts, wear mosquito repellent and sleep under mosquito nets. The paper also asked people to keep water tanks covered and avoid stagnant water in flower pots.

The WHO has also provided the government with 200 fogging machines to spray pesticide in areas where dengue cases have been reported, Ortega said, noting that fogging only kills adult mosquitoes but does not destroy the larva.