Thursday, September 16, 1999 Published at 23:36 GMT 00:36 UK
Deadly new virus feared
Scientists say the outbreak was probably due to a mystery virus
The deaths of at least 34 young children in Malaysia may be due to a mystery virus which causes massive brain and heart collapse, say researchers.
The children, aged five months to seven years old, died within just five months in Sarawak.
The deaths were initially blamed on an outbreak of hand, foot and mouth disease.
But all the children who died had a fever which rapidly progressed to heart and lung failure, suggesting both their brain and heart had been affected by the virus.
A study of patients at Sibu Hospital, where 20 of the 34 children died, was unable to identify any existing virus as causing the outbreak.
Experts examined 16 cases of children who died after developing a fever, and eight children whose bodies became paralysed and floppy - one of the main symptoms of the illness - but survived.
The scientists had suspected an enterovirus - a common cause of diseases like meningitis and myocarditis, which causes pressure on the heart.
But they found that only three of the 16 children who died and none of the survivors showed traces of enteroviruses.
Two children had the enterovirus associated with hand, foot and mouth disease, a common seasonal illness in that part of Asia.
But the researchers, writing in The Lancet, believe this was not responsible for their deaths.
They say hand, foot and mouth disease does not usually progress so rapidly and does not usually affect the heart.
They say that, for those who died, myocarditis was the major cause, rather than other reasons such as brain fever.
Since only three of the children showed traces of enteroviruses, they think the myocarditis could have been caused by a type of adenovirus, which they have dubbed "agent Y".
Adenoviruses are not normally associated with life-threatening conditions. They usually only cause mild illnesses, such as colds.
They were particularly surprised to find agent Y in brain fluid as well as heart tissue.
And they believe the fact that the outbreak coincided with a seasonal hand, foot and mouth disease outbreak suggests the agent may interact with other viruses.
They conclude that scientists have only a basic knowledge of the way viruses develop in southeast Asia.
A similar outbreak took place in Taiwan in 1998 and investigations there are ongoing.