Rick Sacra will spend nearly four weeks working at ELWA hospital, returning with immunity to the strain of the Ebola virus that has swept west Africa

Just over four months ago, Dr Rick Sacra was lying in an isolation ward at the Liberian hospital where he worked, severely ill with Ebola.

Now, after careful treatment and weeks of recovery, the family doctor from Massachusetts is ready to go back to Liberia, where he believes he has more work to do.

“If God has loved me enough and cared for me enough to get me through Ebola, I need to give something back to him,” Sacra told the Guardian in an interview on Tuesday.

Sacra, 52, a medical missionary with the Christian organization SIM, will spend nearly four weeks working at ELWA hospital, the hospital where he contracted the disease. He will not be working in the Ebola treatment units. Rather, Sacra will work in the hospital’s maternity ward, and will treat patients with malaria and chronic health issues.

The decision to go back was an easy one, he said. As a survivor, Sacra returns with something he and only a handful of Americans have: immunity to the strain of the Ebola virus still threatening parts of west Africa.

“I’m less nervous about this trip because I know what I’m getting into a little more,” Sacra said earlier this week during a press conference at the University of Massachusetts Medical School, where he is an assistant professor. “And also because the thing I was afraid of last time, I’ve had it. And thank God, I’m through it.”

Sacra said he trusts that he is immune to the disease, but does not plan to test it. He said he will follow all safety protocols that are in place to guard health care professionals against exposure. When he returns home he will be monitored by Massachusetts health officials for 21 days, the incubation period of the Ebola virus.

His wife, Debbie, said there was never any doubt her husband would return to Liberia, where they lived for 15 years as missionaries with the Christian aid group, during a brutal civil war and the HIV/Aids epidemic.

“That’s just part of our relationship and our calling from the Lord,” Debbie said during the conference. “We know that there’s a need; we know that he has a big contribution to make. We’re happy that he’s only going for a few weeks.”

It was this same desire to serve that pulled him back to the country in early August as the epidemic was escalating. Two American aid workers, fellow missionaries with SIM, had just been flown to the US for treatment, bringing humans infected with Ebola to the US for the first time.

Fear of the virus abounded on both sides of the Atlantic, but Sacra was not put off.

The Massachusetts doctor arrived in Monrovia on 3 August, to help his colleagues reopen the hospital there, which had been temporarily closed due to the outbreak. He recalled how patients in desperate need of care collapsed in the street outside the care units as they waited for a bed to become free. Sometimes one would become free, but it would be too late.

“It was a very, very horrible situation,” he said.

He witnessed these horrors for almost four weeks, before, on 29 August, he developed the symptoms he had identified so many times in his patients, symptoms that in nearly half the cases – at the time – were a precursor to an imminent death.

“I knew I could die, of course,” Sacra said. “Honestly, I didn’t have too much concern, though. I never got to a stage when I thought to myself: ‘Today’s the day.’”

At first he wasn’t sure he’d be evacuated to the US, like his colleagues had been, and so he said he mentally prepared himself to undergo treatment in Liberia. There he was alone, without his wife and three sons who were at home in Massachusetts. But days after his diagnosis, he was flown by air ambulance and taken to the University of Nebraska Medical Center, a National Institutes of Health facility in Omaha.

At a press conference ahead of his arrival, his wife, choking back tears, told reporters: “We are indeed praying that Rick will stay longer with us so that he will continue the good work that he has been doing in Liberia, but he would want you to know that he would not be afraid to pass into eternal life with the Lord.”

Debbie Sacra’s prayers were answered; her husband recovered fully. The only lingering effect from the virus is some inflammation in his left eye, he said.

As part of his treatment, he received a blood transfusion from his colleague, Dr Kent Brantly, who had survived the disease. Sacra later donated his blood to an Ebola patient sent to the Omaha hospital.

Sacra said he wasn’t upset by the media attention his diagnosis received, and believed it was useful in shining a light on the situation in west Africa. In the months after his recovery, Sacra joined fellow Ebola survivors in urging the international community to step up its response to the outbreak, advocating for increased aid to the region and boosting the development of a vaccine.

This summer the US and other countries ramped up their aid response, though many criticized the international community for missing the window to manage the outbreak before it spiraled out of control.

To date, the Ebola outbreak has killed nearly 8,400 people in Liberia, Sierra Leone and Guinea, the most affected countries, out of an estimated 21,100 known cases, according to the latest available figures from the World Health Organization (WHO).

Though health officials still caution that there is a long way to go before the outbreak is fully eradicated, the situation in Liberia, once the heart of the epidemic, has improved dramatically.

Case incidences have plunged from a high of 300 per week in August and September to eight new cases reported in the five days leading up to 2 January, according to the WHO.

Now the country must work to rebuild its healthcare system, which was devastated by the epidemic.

“The health system is still really in shambles and will need continued support for some time to come. Liberia hasn’t even gotten back to where we were before Ebola, and that wasn’t adequate,” Sacra said, adding that he hopes to help with its reconstruction on this and future missions.

But recovery will take time, he conceded, saying that he is heartened by the gains Liberia has made in his absence. But he said for Liberia to truly begin to come back from this crippling epidemic, the virus must be wiped out completely.

Until then, he said, “Pray for west Africa.”

“We need to keep pushing and making every effort possible to eradicate Ebola. We really shouldn’t rest until we have zero cases.”