DHAKA: Liberia is to be declared Ebola-free by the World Health Organization (WHO), effectively putting an end to the world's worst outbreak of the disease.

The "end of active transmission" will be declared, after 42 days without a new case in Liberia, reports the BBC.

It joins Guinea and Sierra Leone, which earned the status last year.

However, UN chief Ban Ki-moon has warned that West Africa may see flare-ups of the virus. It has killed more than 11,000 people since December 2013.

A country is considered free of human-to-human transmission once two 21-day incubation periods have passed since the last known case tested negative for a second time.

However, the end of active transmission of Ebola has been declared twice before in Liberia - only for the infection to re-emerge.

This is why the expected declaration by WHO later on Thursday will be marked with caution.

On Wednesday, Ban warned that "we can anticipate future flare-ups of Ebola in the coming year".

"But we also expect the potential and frequency of those flare-ups to decrease over time," he added.

BDST: 1244 HRS, JAN 14, 2016
RS