Scientists in Cambodia have said they have identified the mystery illness that has killed dozens of children in the past three months.
The Pasteur Institute in Phnom Penh, the Cambodian capital, announced on Sunday that tests indicate the unknown sickness that has led to the deaths of 64 children and hospitalisation of 66 is the Enterovirus 71.
The virus is a strain of hand, foot and mouth disease (HFMD) that is widespread in Asia, but not usually found in Cambodia.
HFMD is a human ailment caused by intestinal viruses, and not to be mistaken for foot-and-mouth disease, which only affects animals. Infected children generally suffer from high fever, rashes, respiratory and sometimes neurological problems.
In 64 of the 66 cases, the children's health deteriorated much faster than doctors expected. This is one of the reasons why the illness was difficult to identify, as the Enterovirus 71 usually does not lead to such quick deaths.
Paediatrician Beat Richner, founder of Kantha Bopha children's hospitals, was the first to raise concerns about the illness.
Richner said all the patients who died were treated in private clinics in local areas before being brought to the Kantha Bopha hospitals in the capital and the northwestern province of Siem Reap.
"They all got injections or infusions by private centres before coming to us," he said. "Some died four hours after arriving."
Out of the 66 children hospitalised, the two patients that lived were treated only by Kantha Bopha staff, suggesting that botched medical treatment may be a factor.
"All these children have encephalitis [inflammation of the brain] and in the later hours of their life they develop a severe pneumonia with a destruction of the alveoli in the lungs. That is the reason they die," Richner said.
The alveoli, or air sacs, are pockets in the lungs where the exchange of oxygen and carbon dioxide takes place.
There is no known cure for the Enterovirus, but doctors recommend good hygiene especially for young children.
The UN health body and Cambodian officials have urged parents to bring their sick children to hospital if they see any signs of any unusual illness.
There have been no cases reported outside Cambodia so far.