An American missionary doctor in Liberia who was not treating Ebola patients has tested positive for the virus, SIM USA confirmed.

The unidentified doctor was treating obstetrics patients at SIM’s ELWA hospital in Monrovia, the organization said in a news release.

The doctor was treating patients in the main hospital, which is separate from ELWA’s Ebola isolation unit. It is not yet known how he contracted the virus.

“My heart was deeply saddened but my faith was not shaken when I learned another of our missionary doctors contracted Ebola,” Bruce Johnson, president of SIM USA, said in a statement. “As a global mission, we are surrounding our missionary with prayer, as well as our Liberian SIM/ELQA colleagues, who continue fighting the Ebola epidemic in Liberia.”

The patient was immediately isolated and placed in the ELWA Ebola unit, where he is said to be doing well and to be in good spirits, according to the news release.