Geneva, December 29 (RHC)-- The World Health Organization has declared Guinea Ebola-free, an important milestone for the West African nation where the worst outbreak of the deadly virus began two years ago.

More than 2,500 people have died from Ebola in Guinea since late December 2013. The virus later spread to neighboring Sierra Leone and Liberia. Overall, more than 28,000 people were infected and 11,300 died from the disease in West Africa.

A country is declared Ebola-free after 42 days — double the 21-day incubation period for the virus — have passed since the last confirmed case. Guinea now enters a 90-day period of "heightened surveillance" to help identify any new cases quickly, the WHO said in a statement.

Sierra Leone was declared Ebola-free on November 7th. Liberia is currently toward the end of a new 42-day countdown after being twice declared free of the virus earlier this year. If no new cases develop in the next few weeks, the country could be declared Ebola-free in mid-January.

“This is the first time that all three countries – Guinea, Liberia and Sierra Leone – have stopped the original chains of transmission that were responsible for starting this devastating outbreak two years ago,” Matshidiso Moeti, WHO Regional Director for Africa, said in a statement Tuesday. “I commend the governments, communities and partners for their determination in confronting this epidemic."