There is only "a small window of time" for relief workers in Nepal to put in place measures to protect people from deadly disease outbreaks, a senior United Nations Children's Fund (UNICEF) official said on Saturday.
The dangers posed would be exacerbated by wet and muddy conditions brought on by the upcoming rainy season, said Rownak Khan, UNICEF's deputy representative in the country. Nepal's monsoon season normally runs from June to September.
The confirmed death toll from the 7.8 magnitude quake which devastated the densely-populated Kathmandu Valley on April 25 has risen above 6,200, with more than 14,000 injured, according to the Nepali government.
There was no number for the missing, but bodies were still being pulled from the debris of ruined buildings, and rescue workers have not been able to reach some remote areas.
"Hospitals are overflowing, water is scarce, bodies are still buried under the rubble and people are still sleeping in the open," UNICEF's Khan said in a statement. "This is a perfect breeding ground for diseases."
The earthquake last Saturday has left 3 million people needing food assistance and flattened more than 130,000 homes, meaning 24,000 people are currently staying in 13 camps in Kathmandu, UNICEF said.
Most urgently needed are medical supplies, clean water, sanitation, and shelter for those whose homes have been destroyed, Chris Tidey, a UNICEF spokesman, told the Thomson Reuters Foundation.
According to the World Health Organization (WHO), some hospitals in the worst affected areas have been completely destroyed. There is no shortage of staff, but an urgent need for medical supplies, the group said in a statement.
"We must remain vigilant in our efforts to prevent and control communicable disease outbreaks, like diarrhea," said Dr Roderico Ofrin, head of the WHO's emergency response, in a statement on Friday.
"When the monsoon rains come, it's going to be pretty nasty indeed," Chris Tidey said, warning of a second crisis later in the year if adequate provisions are not put in place.
The prevalence of diseases such as diarrhea, respiratory illnesses, measles and even cholera, which has been endemic in Nepal in recent years, "skyrocket" when people are living outdoors in heavy rains, Tidey said.
After an earthquake devastated Haiti in January 2010, killing more than a quarter of a million people, the Caribbean island nation was ravaged by diseases including cholera, which killed thousands in the years following the disaster.
A 2011 report from the U.S. Centers for Disease Control and Prevention said the Haiti cholera outbreak was likely caused by U.N. peacekeepers from Nepal discharging raw sewage near a major river used for drinking water.