The spread of disease has become a major concern in Haiti, medical experts said today, as relief groups struggled to speed up the delivery of supplies to hungry and thirsty earthquake survivors.

While a slight return to normality street vendors emerging to offer fruit and vegetables, rescue teams from around the world continued to search for survivors under the rubble of collapsed buildings. More successful rescues were being reported six days after the disaster but tens of thousands are still believed to be buried.

Medical experts said many survivors had multiple fractures and internal injuries. Medical teams at mobile hospitals that have been overwhelmed by the casualties warned of the immediate threats of tetanus and gangrene and the spread of measles, meningitis and other infections.

In Haiti, where Aids, tuberculosis and malaria are rampant, children are malnourished and hygiene is already a challenge, the quake has added potentially lethal infections, broken bones, internal injuries and other health complications.

"By any stretch of the imagination it is going to be incredibly difficult. The population in Haiti was already vulnerable and faced enormous health threats," one expert said.

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