By Robyn Dixon for the LA Times.

More than two years after the Ebola virus erupted in a small Guinean village and tore across West African borders, killing more than 11,000 people and infecting more than 28,500, the continent was declared free of the virus Thursday.

The World Health Organization, however, warned of likely new outbreaks in the three West African countries worst hit by the disease.

Thursday marked 42 days since the last known Liberian patients, the father and brother of a 15-year-old boy who died of Ebola, were discharged from hospital. Neighboring Sierra Leone was declared free of the virus Nov. 7, and Guinea was declared Ebola free Dec. 29.