In Nigeria it is a race against time to contain the deadly Ebola virus.
The first and so far only victim in the country sparked a worldwide outbreak panic after he flew from Liberia to Lagos last week.
Now the authorities are seeking to trace anyone who may have been in contact with him.
The virus which leads to death in 90 per cent of cases and is spread by contact was first reported in Guinea in February, quickly moving to neighbouring Sierra Leone and Liberia. Many airlines have now suspended flights to the region.
The top doctor treating Ebola victims in Sierra Leone died in quarantine on Tuesday. Dr Sheikh Umar Khan was hailed as a national hero by colleagues.
The World Health Organisation says the virus is the most deadly in history, and has so far claimed 672 lives in West Africa.
Chinese TV reported the first suspected case in Hong Kong, although the South China Morning Post said she later tested negative for Ebola.