Health officials in several countries across South East Asia are on alert over a deadly virus that has killed more 50 young children and which the authorities fear could spread further. This week, officials in Cambodia closed all its kindergartens and primary schools to try and prevent the spread of hand, foot and mouth disease, caused by the Enterovirus 71 (EV-71), that has killed at least 55 children in the country since April. On Thursday, Thai officials took similar steps, closing more than 100 primary and secondary schools, a number of them in Bangkok, in an effort to halt the spread of the virus. In Thailand, while there have not yet been any deaths as a result of the disease, up to 14,000 cases of people being infected by a strain of the virus have reportedly been detected. The disease has killed at least 17 people in China and a number in Vietnam have also died, according to reports. The sharpest focus on the virus has been in Cambodia, where the World Health Organisation says 55 children are known to have died since the spring. Most were younger than three years old and died within 24 hours of being admitted to hospital. Timothy O’Leary, a regional spokesman for the WHO, based in Manila in the Philippines, said on Friday there was no vaccine against the virus and that his organisation was stressing the need for good hygiene to prevent its spread. He said ensuring people washed their hands, was perhaps the single most useful safeguard. “The WHO has been working with the ministry of health in Cambodia to identify the cause of what had been an unidentified disease,” he said yesterday. “It’s an infectious disease that spreads from person to person. The best way to stop it is good hygiene.” Officials in Phnom Penh who took the decision to close schools on Wednesday, a move that will affect many tens of thousands of people, said schools had been due to close for the summer holidays at the end of August.