Kyaw Kyaw, 30, knows one thing. Nowhere is safe in the cyclone-stricken expanses of the Irrawaddy delta.

Before Cyclone Nargis overwhelmed his home village in Bogale, he and other Myanmar Red Cross volunteers had raised the alarm and evacuated people whose homes were around the river.

"We'd been warned a huge wave was coming," he said, "as well as the storm."

So in the highest part of their community they found a large building and turned it into a shelter. People streamed in and stayed dry, until winds - which may have peaked at 200 kilometres an hour - started to tear the place down.

Those inside the shelter fled again, with bricks falling down around them. That no one died, Kyaw Kyaw says, was a miracle and, as more hazards loom on his horizon, he will not rely on another one. He is among hundreds of volunteers now deployed in a scale-up of Red Cross Red Crescent preventive health efforts.

The rainy season driven by the southwest monsoon has begun to intensify, and people like Kyaw Kyaw are reporting increasing illness. Diarrhoeal disease, malaria, dengue, respiratory infections and even haemorrhagic fever continue to concern the International Federation of Red Cross and Red Crescent Societies (IFRC). While these diseases are endemic in Myanmar - and the authorities consider the reports to be normal - the threat they pose in post-cyclone conditions remains considerable.

"It would be dangerous to conclude that since no epidemic disease has occurred more than four weeks after the disaster the danger is subsiding. All our experience tells us it will not," said Mallu Oraby, a Finnish delegate with the Red Cross Red Crescent health team in the country.

"The hazards remain and, in the pouring rain that will be with us for months, every effort must be made to prevent a second wave of disaster."

The danger facing Myanmar's stricken area is the combination of disaster, disease and malnutrition, one Oraby knows well from other catastrophes. Like communicable disease, malnutrition was present before the cyclone. UNICEF estimated in 2003 that 40 per cent of Myanmar children under five were chronically malnourished. Ten per cent were acutely malnourished.

What malnutrition does is weaken natural immunity and nurture more frequent and severe infection. "The time to get excited is now," said Oraby, "not when we have an epidemic. Then it's too late. People will die of things we can prevent."

Kyaw Kyaw was in Yangon this week along with a legion of volunteers from cyclone-affected areas. Already trained in first aid and community health, they are now undergoing a one-day booster training in hygiene promotion and disease prevention.

They will form the backbone of a network of 200 first aid and health education posts being set up across the Ayeyarwady and Yangon divisions in consultation with the health authorities. Some will operate from tents - the IFRC has 60 suitable tents already available - others, where possible, from health centres and existing buildings.

The posts are part of the six-month emergency phase of a three-year IFRC programme to strengthen the Myanmar Red Cross' emergency health capacity.

As well as first aid, the posts will provide the community with health advice and education, psychosocial support and serve as a distribution points for vital hygiene goods.

"After all that has happened, we must not allow disease to follow," Kyaw Kyaw said.

Like his fellow volunteers, the man from Bogale will have one more role, as a crucial community health monitor. The posts will be well placed to spot emerging threats to public health.