At a bar in Freetown, Sierra Leone, a table of journalists wrestled with disturbing news: James Foley had been executed by ISIS. The discussion about a fallen colleague, though grim, briefly distracted them from the surrounding chaos.

It was mid-August, almost five months after Ebola had first been detected in West Africa. The number of infected was on the rise. An underdeveloped healthcare network, coupled with porous borders, hampered efforts to quarantine the sick. Already, more than 900 Sierra Leoneans had contracted the virus and over 370 had succumbed to it. The group sitting at the Freetown bar included foreign correspondents tasked with chronicling the tragedy.  

Some spent their days speeding from one hospital ward to the next, filming desperate attempts by health workers to isolate the ill. Others journeyed into rural areas, discovering villages crippled by the virus. For many of them, working in a highly fluid crisis was nothing new. They had experience covering insurgent warfare, and were familiar with the unpredictable risks that come with it—like kidnappings or suicide bombings in Iraq and Afghanistan. But this was different. The veteran reporters were covering an insurgency that was essentially invisible.

“Here’s to Foley!” Pete Muller said, holding up a glass in honor of the murdered journalist. The American photographer watched as his glass clinked those of his colleagues. Then his mind began to race. “Fuck!” he thought as he realized he had forgotten rule number one: Don’t touch other people. “What if one of us has Ebola?”

In August, Muller spent 11 days in Sierra Leone on assignment for The Washington Post. He reported mainly from the Kailahun district in the east of the country, along the border with Liberia. Muller, who lives in Nairobi, Kenya, has been assigned to some of this decade’s most violent conflict zones: Afghanistan, Somalia, the Democratic Republic of Congo, the West Bank, Mali. He lived in South Sudan for three years. Yet the unrelenting fear associated with covering the Ebola crisis, he said, is remarkable.

“There’s an inherent anxiety working in those types of conflict zones, particularly where there’s a kidnapping risk,” Muller told me. “But ... you don’t know exactly where Ebola is. That creates an awful lot of tension and you’re sort of perpetually on edge.”

War zones, despite how they may be perceived, are not completely engulfed in gunfire and explosions. They are undoubtedly risky situations, Muller said, but there are a number of ways reporters can protect themselves. Hired drivers and fixers—locals that arrange interviews—can help limit reporters’ exposure to danger, for example. While reporting on a rebellion in the DRC last November, Muller witnessed militias establish evident borders of control (man-made trenches, in some cases). These types of boundaries send signals to journalists that can direct them away from potentially hostile encounters.

But in Ebola-affected areas of West Africa, “the virus can kind of be anywhere,” Muller said.

Step in the wrong place in a hospital ward and you’re vulnerable to contaminated fluids. Simply brushing your arm against a sweaty doctor puts you at risk. A flak jacket and helmet might protect a war photographer from shrapnel, but the full-body protection suits intended to shield skin from the virus are themselves potentially lethal. Improper removal of gloves, for example, can result in infection.

To avoid being kidnapped or killed in combat zones, reporters can vary their routines by, say, changing hotels, using different taxis, and never eating at the same restaurant more than once. Evading the contagion of Ebola, however, requires that journalists act in a rigorously repetitious fashion: Take every photo from a safe distance, without any risk of human contact. Every single time.

Muller often asked nearby Doctors Without Borders officials whether it was safe to move closer for a picture. He uses only fixed lenses, and was therefore unable to zoom in on infected patients. Jerome Delay, the chief Africa photographer for the Associated Press, wrote recently that washing his hands and feet with chlorinated water “to the point of obsession” ultimately became “the norm.”

“Whatever the dynamic is that poses a threat, I’m not trying to die for a picture,” Muller said.

But the imperative of capturing images of Ebola requires photojournalists to enter health clinics in which the disease is highly contagious, and to position themselves as close to victims as safety will permit. Otherwise they can’t fully document the crisis.

“I’ve been almost killed by a car bomb and shot at by snipers and all sorts of things, and none of that compares to being just completely on edge the whole time I was out [in Sierra Leone],” Agence France-Presse photographer Carl de Souza told me.

“Whether it’s a war zone or Ebola, a photojournalist has to be in the middle of it to get the best shots,” said Geoffrey York, Africa correspondent for the Toronto-based Globe and Mail, who recently spent a week reporting in Liberia. “As a writer I can be back a little bit.”

Efforts to visually document the raw, graphic nature of death by hemorrhagic fever are not necessarily perceived as heroic in affected countries. After detailed pictures of Ebola patients, many lying motionlessly in pools of their own bodily fluids, began appearing in the press, Liberian health officials introduced new regulations on media coverage of the crisis. Journalists working in Liberia are now required to get consent from Ebola patients before taking their photos.  

De Souza initially planned to report in the border regions of Sierra Leone for two weeks. But he arrived amid talk of banning flights from West Africa. His wife was weeks away from giving birth to their first child. He feared getting stuck in the country, so he left after six stressful days of reporting. Yet the assignment shook him in surprising ways.

Whether returning from the Libyan revolution or unrest in Pakistan, de Souza had never struggled to transition back into everyday life. “I’ve never had any nightmares and never had any problems working in conflict zones,” he said. “If I need to cry, I cry. If I need to be scared, I’m scared. But I deal with it then and get it all out.”

Ebola’s three-week incubation period, however, weighed heavily on the photographer’s mind. He hesitated to kiss his wife, fearing he might be carrying the virus. He stayed out of their bedroom and slept on the couch. He checked his temperature dozens of times a day to monitor whether he was showing symptoms of Ebola. “I wasn’t happy,” he recalled.

“In a conflict zone you go out and you know you can hear the sounds of bombs and bullets,” de Souza added. “But when it’s something that’s invisible, it’s actually really, really scary.”