ABUJA, Aug. 20 -- A Nigerian doctor who have treated an Ebola patient died Tuesday in southwestern Nigeria's state of Lagos, local authorities said.

The doctor, identified as Ameyo Stella Adadevoh, a senior consultant endocrinologist, died in an isolation facility at the Yaba Mainland General Hospital in Lagos, minister of health Onyebuchi Chukwu said in a statement.

Medical sources said she had suffered infection while treating Liberian-American Patrick Sawyer, adding that she had been in coma before her death on Tuesday.

"Two other patients currently under treatment in the isolation wards are stable and are being taken care of," Chukwu said in a statement made available to Xinhua, noting all of the fatalities so far recorded were people who had close contact with Sawyer.

According to the official, the deceased doctor was one of the primary contacts of the index Ebola Virus Disease case. The doctor's death sums up the total number of Ebola fatalities in Nigeria to five.

The first was the death of Sawyer on July 25.

A nurse who had attended to the Liberian died on Aug. 5. Jatto Asihu Abdulqudir, a 36-year-old staff of the Economic Community of West African States was killed by the virus last Tuesday. Another nurse also died of Ebola on Aug. 14.

At least 177 persons are under surveillance in the West African country, the government said.

Earlier this month, Nigerian president Goodluck Jonathan declared a national emergency, saying a sum of 1.9 billion naira (11.6 million U.S. dollars) would be released to prevent further spread of the epidemic.

Ebola spreads through body fluids and has killed over 1,200 people in West African countries.