The father of an eight-year-old boy who died from encephalitis on Sunday has questioned whether an oversight by doctors at the Prince of Wales Hospital led to his son's death. Lau Wai-lun, a Sha Tin district councillor, said his only son, Ted Lau, had shown symptoms of encephalitis on June 15, when he was admitted to the hospital, and on the following day, but that doctors did not take action until he had a seizure. "My son vomited on the day he was admitted to the hospital. The following morning, at about 9am, the paediatrician was unable to wake him up," Lau said. "But the doctor just told me he was sleepy and that they would keep him under observation." Lau said his son had a seizure at 2pm on June 16 and was transferred to the hospital's intensive care unit that night. "That's a five-hour delay. In hindsight, could my son have been saved if they [had taken] action earlier?" Lau asked. He added that vomiting and lethargy are symptoms of encephalitis, an acute inflammatory disease of the brain. The hospital has confirmed that the boy had tested positive for encephalitis, but that it took a long time to reach that diagnosis. He was in hospital for 15 days. A Centre for Health Protection spokesman said on Monday that the bacteria Mycoplasma pneumoniae - which can be spread in airborne droplets following a cough or sneeze - was found in the boy's windpipe. In rare cases, the bacteria can cause encephalitis. "I hope that the hospital can give us an explanation. It's important to avoid a repeat of this tragedy," Lau said, adding he would request a meeting with hospital management. He said the Health Department contacted him yesterday for more details about his son's case. Paediatrician Dr Tse Hung-hing, who is president of the Hong Kong Medical Association, said there was no specific treatment for encephalitis and the symptoms can be similar to those of other diseases. "I wonder how much difference it would have made [if encephalitis was detected earlier]," Tse said, adding that the cause of encephalitis could not be identified in most cases. University of Hong Kong microbiologist Dr Ho Pak-leung said the doctors could have been working on various diagnoses and trying different medications on the boy while he was in their care, and that the bacteria was not found until it was too late. He added that a lack of access to fast testing facilities may have delayed the diagnosis. But a spokeswoman for the hospital denied there was any delay, saying a rapid test was carried out - although she did not specify when it was done.