Senegalese border police check papers after an aircraft carrying U.N. humanitarian personnel landed near Dakar on Sept. 27. (Seyl Lou/AFP/Getty Images)

The World Health Organization said on Friday that the Ebola outbreak in Senegal is officially over.

Senegal's first and only confirmed Ebola patient traveled to the country by road from Guinea in August, bringing the virus with him. Officials confirmed his Ebola diagnosis on Aug. 29. But samples from this index patient tested negative for Ebola on Sept. 5, "indicating that he had recovered from Ebola virus disease," the WHO said in a news release.

By Sept. 18, the patient was fully recovered and returned to Guinea.

According to the WHO, Senegal officials kept track of 74 close contacts of the patient -- people who were at risk of contracting Ebola themselves. None of those contacts showed symptoms or tested positive for the disease.

The global health organization praised the country's efforts as "a good example of what to do when faced with an imported case of Ebola."

The deadliest Ebola outbreak in history is centered in Guinea, Liberia and Sierra Leone, where the virus has killed nearly 4,500 people. Senegal was one of four additional countries with Ebola cases.

There were 20 confirmed cases of Ebola in Nigeria, all connected to a Liberian American traveler who flew into Lagos on July 20. Assuming there are no new cases there between now and then, the WHO is prepared to declare Nigeria Ebola-free on Monday.

The other two countries are Spain and the United States, both of which currently have active cases of Ebola. A Spanish health-care worker contracted the disease from a missionary who was repatriated to Madrid for treatment after falling ill in West Africa.

And in the United States, two nurses caught Ebola in Texas while treating Thomas Eric Duncan, the Liberian man who became the first person diagnosed with the illness in the country.

Although the maximum incubation period for the Ebola virus is 21 days, the WHO waits until 42 days have passed since the last instance of a possible high-risk exposure before declaring an outbreak over. The country must also demonstrate active surveillance of all contacts for that period, with no new cases detected.

In congratulating Senegal on ending the outbreak, the WHO cautioned that the country isn't totally in the clear, saying: "Senegal's geographical position makes the country vulnerable to additional imported cases of Ebola virus disease. It continues to remain vigilant for any suspected cases by strict compliance with WHO guidelines."