Considering the widespread media coverage of the Ebola epidemic in West Africa—which has rampaged through several countries, reached Dallas (where a man belatedly diagnosed with the disease arrived from Liberia this week), and killed at least 3,000 victims—it was probably inevitable that the virus would infect an American journalist covering the catastrophe.

Thus a freelance NBC News cameraman, working in Monrovia, Liberia, with Dr. Nancy Snyderman, the network’s chief medical correspondent, and with three full-time NBC employees who have been reporting from the scene since Tuesday, has tested positive for Ebola.

“We have really worked hard to minimize our risk,” Snyderman said by phone from Liberia on Thursday night on MSNBC’s Rachel Maddow Show. “Obviously, zero risk means never coming to Liberia.”

Snyderman described the usual Ebola symptoms as “fever, followed by vomiting, achiness, and sometimes diarrhea. The deaths occur because the vomiting and diarrhea are so severe that patients basically don’t have enough fluid, and then they run into clotting problems and they die from that.”

Snyderman added: “The good news is that this young man, our colleague, was admitted to the clinic very, very early. I spoke with him today. He’s in good spirits. He’s ready to get home.”

A second U.S. network crew covering the Ebola epidemic in Monrovia consists of Dr. Richard Besser, ABC News’ chief health and medical editor and former acting director of the Centers for Disease Control and Prevention, and a cameraman, who have been roaming the streets and filming grisly scenes of Liberians suffering from the disease. According to an ABC News source, Besser and his colleague—who are taking precautions and show no signs of exposure—plan to return to the U.S. on Friday or Saturday. Meanwhile, CNN’s Nima Elbagir, who is based in Nairobi, Kenya, and reports on Africa and the Middle East, is en route to Liberia, while the cable network’s Elizabeth Cohen, David McKenzie, and Dr. Sanjay Gupta have also been reporting from the Ebola zone, said a CNN spokeswoman.

In a memo Thursday night, NBC News President Deborah Turness said the 33-year-old American cameraman, whose name was initially being withheld at the request of his family but was later identified as Ashoka Mukpo, will be airlifted to the U.S. as soon as possible for treatment.

“We are doing everything we can to get him the best care possible,” Turness wrote. “He will be flown back to the United States for treatment at a medical center that is equipped to handle Ebola patients.” Turness didn’t identify the facility or its location, though the CDC in Atlanta is expected to take a close supervisory role in the cameraman’s treatment, quarantine, and recovery.

As for Snyderman and her three colleagues, whose names were also withheld, they will be flown home on a chartered aircraft. As a precaution against exposing others, they will self-quarantine at their homes for 21 days, an NBC source said, and if they are asymptomatic for that period, they’ll know they weren’t exposed.

“We recognize that there’s a big story back home,” Snyderman said, explaining the decision to self-quarantine, “and we want to be respectful toward our colleagues and to the American public.”

Snyderman said she isn’t worried. “Because we know this isn’t a casually transmitted disease, and because none of my team has a fever, or other symptoms, we really present marginal risk. I don’t want to say zero. It’s minimal. You cannot catch Ebola from someone if that person isn’t experiencing symptoms.” According to news reports, the transmission of Ebola requires exposure to bodily fluids.

The NBC News freelancer, who has been based in Liberia for the past three years, prudently went to a clinic for testing as soon as he noticed his symptoms. He was hired Tuesday to supplement the NBC News crew as a second cameraman for Snyderman’s reports on NBC Nightly News, the Today show and MSNBC. Because of Ebola’s eight-to-10 day incubation period, it’s likely that he was exposed well before he joined the NBC crew. According to NBC’s report on the situation, he started feeling tired and achy on Wednesday—suspicious symptoms associated with the virus—and on taking a routine temperature check, discovered he was running a slight fever.

The NBC report continued: “He immediately quarantined himself and sought medical advice. On Thursday morning, the 33-year-old American went to a Medecins Sans Frontieres (MSF) treatment center to be tested for the virus. The positive result came back just under 12 hours later.”

Turness wrote in her memo: “We are also taking all possible measures to protect our employees and the general public… The rest of the crew, including Dr. Nancy, are being closely monitored and show no symptoms or warning signs. However, in an abundance of caution, we will fly them back on a private charter flight and then they will place themselves under quarantine in the United States for 21 days—which is at the most conservative end of the spectrum of medical guidance.”