Old CW: Avoid direct contact with an Ebola patient, in the extremely unlikely event that you encounter one, and you’ll be fine. Heck, even direct contact is okay when the patient is asymptomatic.

New CW: Buy gold.

Dr. C.J. Peters, who battled a 1989 outbreak of the virus among research monkeys housed in Virginia and who later led the CDC’s most far-reaching study of Ebola’s transmissibility in humans, said he would not rule out the possibility that it spreads through the air in tight quarters…

“I see the reasons to dampen down public fears,” [Dr. Phiiip] Russell said. “But scientifically, we’re in the middle of the first experiment of multiple, serial passages of Ebola virus in man…. God knows what this virus is going to look like. I don’t.”…

CDC officials also say that asymptomatic patients cannot spread Ebola. This assumption is crucial for assessing how many people are at risk of getting the disease. Yet diagnosing a symptom can depend on subjective understandings of what constitutes a symptom, and some may not be easily recognizable. Is a person mildly fatigued because of short sleep the night before a flight — or because of the early onset of disease?

Moreover, said some public health specialists, there is no proof that a person infected — but who lacks symptoms — could not spread the virus to others.

When the Times asked the CDC for comment, a spokesman told them lab tests have uncovered no evidence that the virus is mutating in ways that would make it more dangerous to humans — so far. The spokesman also said, in response to theories that the virus might be able to travel through the air in tiny aerosolized droplets, “I’m not going to sit here and say that if a person who is highly viremic … were to sneeze or cough right in the face of somebody who wasn’t protected, that we wouldn’t have a transmission.” Is that possibly how the nurse in Spain got it? It’s hard to believe a first-world hospital, knowing how dire the risk is to staff, wouldn’t take precautions to prevent nurses from handling the fluids of an Ebola patient. But what about indirect contact, say, from an ill-timed cough while the nurse was in the patient’s presence? In fact, an experiment conducted a few years ago involving pigs infected with Ebola resulted in the pigs passing the virus to monkeys despite the lack of any direct contact. Maybe that’s because there’s something unique to pig physiology that makes it easier for them to aerosolize the virus when coughing, but there’s no way to be sure given the limited testing on Ebola. That’s the whole point of the excerpt above.

None of these questions are new to people who are following the outbreak news but it’s striking how many credible scientists like the ones quoted above are sending up these warning flares in major media outlets like the LAT. The first piece I read in this vein was this op-ed in the New York Times last month by Dr. Michael Osterholm, who claimed that doctors were privately worried that the virus might indeed evolve the capacity for airborne transmission. Osterholm’s no crank; he’s the head of the University of Minnesota’s center for infectious disease research. And his logic was straightforward: The reason you might worry more at this point about evolution in Ebola than, say, in HIV or hepatitis or other viruses that have afflicted many millions over many decades is that there’s never been a mass outbreak of Ebola in recorded history like the one we’re experiencing now. The virus simply hasn’t had much of a chance to evolve while passing from person to person. It does now, with an outcome that’s yet to be determined. Just today, the World Health Organization walked back the conventional wisdom that the virus incubates in an infected person for no more than 21 days. Turns out that a man who’s gotten the disease and survived it can still pass it through his semen for up to 70 days afterward and possibly more than 90 days. Ebola could thus continue to thrive in Africa a la HIV as a killer STD. Neo-Neocon notes something interesting too, per the bit in the excerpt about what it means to be “symptomatic”: Both Thomas Duncan, the Dallas Ebola patient, and the nurse in Spain had “slight fevers” when they first presented themselves to doctors. Fevers associated with Ebola typically run 101.5 or more. Could it be that victims with “slight fevers” are sufficiently symptomatic to pass the disease on?

In lieu of an exit question, read this new piece in WaPo by the dean of the school of public health at Mercyhurst University in Pennsylvania. With more infected people sure to try to lie their way into the U.S. to get top-notch medical treatment, he says, it’s time for a travel ban from Ebola-afflicted countries.