A Welsh person who is believed to have come into contact with the deadly Ebola virus "seems well" after being under surveillance for a week.
The individual is being monitored for 21 days - the maximum period that the virus can incubate before symptoms start - but has shown no symptoms so far, a Public Health Wales spokeswoman confirmed.
People cannot be tested for the virus before the development of symptoms.
The individual in Cardiff is "currently staying away from work and limiting contact with other people voluntarily" following a visit to West Africa, the spokeswoman added.
More than 160 staff will work in a UK-funded facility in Sierra Leone which is due to open in October.
UK trials of a vaccine for the Ebola virus began today - but some experts complain that the response has been a long time coming.
A Swansea doctor who took leave to treat Ebola patients in Africa, is back on the wards after three weeks in isolation.