Nigeria officially ebola-free - WHO

(CNN) -- While Ebola cases keep spiraling out of control in the three West African countries, there are glimmers of hope elsewhere in the world.

Nigeria was declared Ebola-free Monday, following an announcement that Senegal is now rid of the virus.

A nurse's aide in Spain has also beaten Ebola after spending weeks hospitalized with the virus.

And the fiancee of the first person diagnosed with Ebola in the United States ends her quarantine period, meaning she almost certainly doesn't have the virus -- and isn't a risk to the Dallas community.

But more complications remain. Here's the latest on the Ebola crisis around the world:

Nigeria: Ebola is gone

Nigeria was thrust in the Ebola spotlight in July after an infected air traveler introduced the virus to the capital city of Lagos. The case spurred fears that the disease would spread across the city of 21 million and throughout Africa's most populous country.

But in the end, Nigeria confirmed 19 Ebola cases, including seven deaths.

The World Health Organization said an aggressive government response and effective contact tracing helped keep the virus in check.

"This is a spectacular success story that shows that Ebola can be contained," WHO said Monday.

"Such a story can help the many other developing countries that are deeply worried by the prospect of an imported Ebola case," WHO said. "Many wealthy countries, with outstanding health systems, may have something to learn as well."

Nigerian health officials reached 100% of known contacts in Lagos and 99.8% at the second outbreak site in Port Harcourt, WHO said.

And unlike in Guinea, Liberia and Sierra Leone -- the combined epicenter of the oubreak -- all identified contacts in Nigeria were physically monitored every day for 21 days, the agency said.

The few who tried to escape the monitoring system were tracked down and returned to finish their required monitoring period of 21 days.

For WHO to declare an Ebola outbreak over, a country must pass 42 days with active surveillance in place, supported by good diagnostic capacity, and with no new cases detected, the agency said.

The 42-day period is also twice the maximum incubation period fr Ebola.