ABUJA, Nigeria - (AP) -- A Nigerian nurse who treated a man with Ebola is now dead and five others are sick with one of the world's most virulent diseases, authorities said Wednesday as the death toll rose to at least 932 people in four West African countries.

The growing number of cases in Lagos, a megacity of some 21 million people, comes as authorities acknowledge they did not treat Patrick Sawyer as an Ebola patient and isolate him for the first 24 hours after his arrival in Nigeria last month. Sawyer, a 40-year-old American of Liberian descent with a wife and three young daughters in Minnesota, was traveling on a business flight to Nigeria when he fell ill.

The death of the unidentified nurse marks the second Ebola death in Nigeria, and this worries health experts as it is the Africa's most populous country and Lagos, where the deaths occurred, one of its biggest cities.

Ben Webster, a Red Cross disaster response manager in London, said it is "critically important" that people displaying symptoms are identified quickly.

"It's impossible to say whether this specific situation could have been avoided, but there is certainly more likelihood of travelers coming from an Ebola-affected country in the region and authorities need to be aware, even if the infrastructure and situation is challenging."

In Saudi Arabia officials say a man who was being tested for the Ebola virus has died. The 40-year-old returned on Sunday from Sierra Leone, where at least 286 people have died from Ebola, and was then hospitalized in Jiddah after showing symptoms of the viral hemorrhagic fever.

Spain's Defense Ministry, meanwhile, said a medically-equipped Airbus 310 is ready to fly to Liberia to repatriate a Spanish missionary priest who has Ebola. The ministry said Wednesday that preparations for the flight are being finalized but it is not yet known what time the plane will take off.

The priest, Miguel Pajares, is one of three missionaries being kept in isolation at the San Jose de Monrovia Hospital in Liberia who have tested positive for the virus, Spain's San Juan de Dios hospital order, a Catholic humanitarian group that runs hospitals around the world, said Tuesday.

There have now been at least 1,711 cases of Ebola this year, which has no proven vaccine or treatment, according to new figures released Wednesday by the World Health Organization. More than 932 people have died in Sierra Leone, Guinea, Liberia and Nigeria as of Aug. 4, WHO said. In announcing the new deaths, WHO noted in particular that "community resistance remains high" in Liberia. Many fearful family members are refusing to bring sick relatives to isolation centers, preferring to treat them at home and pray for their survival as no proven cure or treatment exists for Ebola.

The difficulties in quarantining sick people are complicating efforts to stop Ebola's spread.

In Nigeria, the five people now infected from Sawyer would not have been contagious to their neighbors or family members until they started showing symptoms of their own, health experts say. The delay in enforcing infection control measures, though, is another setback in the battle to stamp out the worst Ebola outbreak in history.

Meanwhile, the husband of the second American aid worker recently diagnosed with Ebola says his wife is weak but showing signs of improvement.
    
The president of the aid group SIM USA says he's spoken with Nancy Writebol's husband, who says his 59-year-old wife stood when she got on the plane in Liberia that flew her to the United States.
    
Now Writebol and colleague, Dr. Kent Brantly are being treated for Ebola at an Atlanta hospital.