Nigeria has one more confirmed Ebola case, a nurse who was treating the Liberian-American who flew into the country with the disease and died of it last month, the health minister announced Monday.

The nurse tested positive for the Ebola virus over the weekend, Health Minister Onyebuchi Chukwu told reporters in Abuja, the capital. That brings the total number of confirmed Ebola cases in Nigeria to 10, including two who have already died, the Liberian-American Patrick Sawyer and another nurse. The other eight cases are being treated in isolation in Lagos. All nine Nigerians were infected through direct contact with Sawyer, said Chukwu.

Nigerian health officials are working to prevent Ebola from spreading beyond those who had contact with Sawyer. Nigerian authorities have 177 primary and secondary contacts of Sawyer under surveillance, said Chukwu.