In the aftermath of the news from the past week that at least two US citizens have been infected with the Ebola virus, a very unpleasant if nagging question has appeared: can the virus spread to the US? According to NBC [6], "the Ebola virus, which has infected two U.S. humanitarian workers in Liberia, is only a short plane ride from any city on Earth. But federal health officials say it’s not a big worry for most Americans."
Maybe it should be.
Recall that last week's Ebola stunner came when not only did an Ebola patient die from the disease in the world's 4th most populous city, Nigeria's Lagos, but when he was intercepted while at the airport: how many people he may have come in contact with is anyone's guess even if the government swears they have all been quarantined.
It’s the first time this virus has moved by jet, even though public health experts love to warn that any disease is just a flight away from anywhere with an airport.
Perhaps the fact that the CDC had to go out as far as making an official statement for the record shows just how increasingly worried Americans are. According to the Centers for Disease Control, "Ebola poses little risk to the U.S. general population,” Stephan Monroe of CDC’s National Center for Emerging & Zoonotic Infectious Diseases told reporters in a conference call. It’s because you have to be in direct contact with someone who is ill to become infected.
“Transmission is through direct contact with the bodily fluids of an infected person,” Monroe said. That includes vomit, blood or diarrhea. “Individuals who are not symptomatic are not contagious,” he said.
The incubation period can last for as long as 21 days, meaning it can take 21 days for someone to develop symptoms after being in contact with an infected person. So in theory, someone could be infected and get on a plane to travel to the U.S. before he or she got sick. But the odds of this are low.
There’s no need to control travel in and out of the U.S. CDC says. It has quarantine stations in major airports and agents can forcibly isolate or quarantine people with symptoms of Ebola and other diseases such as cholera, tuberculosis, plague or bird flu.
How does the CDC hope to contain the potential threat? Apparently so far the first and only line of defense is... interrogation? Careful questioning can usually rule out a disease such as Ebola. In this case, it would be asking people if they’ve been to West Africa in recent weeks or in close contact with someone who had been and who was ill. One wonders how honest potential carriers would be if they knew the rest of their short lives could be spent under CDC quarantine.
"U.S. health experts pulled this off with MERS -- the Middle East Respiratory Syndrome virus, which was carried into the country twice by travelers, both of whom recovered fully without infecting anybody else."
And another denial:
“The likelihood of this spreading out of West Africa is very low,” Monroe said. While it’s possible someone ill could get on a plane, they couldn’t spread the virus to someone who just happened to be sitting nearby. “It is very unlikely they would be able to spread disease to their fellow passengers,” Monroe said. CDC worries more about airborne viruses such as measles, which can spread silently.
And even more attempts to contain any possible panic:
“People are not infectious prior to becoming symptomatic,” he stressed. And once in the U.S., doctors should isolate a patient quickly. “We are fairly confident that the standard of care in the U.S. would prevent much of the transmission of the virus were to show up here,” Monroe said.
“We do not anticipate this will spread in the US if an infected person is hospitalized here but we are taking action now by alerting healthcare workers in the US and reminding them how to isolate and test suspected patients while following strict infection control procedures.” CDC Director Dr. Tom Frieden added in a statement.
The CDC is correct about the infectious phase. The problem is that while Ebola symptoms are quite glaring, such as fever, throwing up, and general pain, only about half of all Ebola cases show the bleeding that so frightened people, and that’s only in very advanced cases. The rest of the symptoms can be confused for your garden variety flu.
Still, despite all assurances, the CDC has issued a “level 2” alert, which cautions people in the affected region to avoid contact with anyone who seems infected. CDC also issued a health alert, a reminder to doctors in the U.S. "Ebola virus disease poses little risk to the U.S. general population at this time. However, U.S. healthcare workers are advised to be alert for signs and symptoms of Ebola virus disease in patients with compatible illness who have a recent (within 21 days) travel history to countries where the outbreak is occurring, and should consider isolation of those patients meeting these criteria, pending diagnostic testing," it reads.
Bloomberg has some more details on the potential spread of the disease which has so far managed to spread beyond Africa only once, but as Bloomberg notes, "that doesn’t mean it can’t happen now, infectious disease experts warn."
The symptoms appear from two days to three weeks after infection, meaning it’s possible for an infected person who doesn’t feel ill to board a plane, said Ben Neuman, a virologist at the University of Reading in the U.K. Since Ebola in its earliest stages can resemble nothing more than flu, no one else would know either, he said.
The symptoms appear from two days to three weeks after infection, meaning it’s possible for an infected person who doesn’t feel ill to board a plane, said Ben Neuman, a virologist at the University of Reading in the U.K. Since Ebola in its earliest stages can resemble nothing more than flu, no one else would know either, he said.
“One person per plane load would have something that you would possibly call flu-like symptoms,” Neuman said in a telephone interview. “Do you want to detain all those people coming into your airport? Do you have the manpower to do that, and send them all for testing? It’s expensive, and difficult.”
The question of trans-continent infection became more key this week after Patrick Sawyer, a Liberian government worker who took a July 20 flight to Lagos, Nigeria, died from Ebola five days later. His death gave Africa’s most populous nation its first case, a frightening hint at how global air travel may enable the spread of disease.
“We’ve known it’s a risk ever since the beginning of the Ebola outbreak, and now it’s finally happened,” Neuman said. “He could have gone anywhere on this flight.”
The 1994 case:
Fruit bats are thought to be the natural host of Ebola virus, according to the WHO. Monkeys, chimpanzees, gorillas, porcupines and forest antelope can also be infected, and human outbreaks can begin when people eat the meat of infected animals, according to the WHO.
The only case in which an Ebola victim was known to be taken out of Africa by aircraft came in 1994, when a 34-year-old Swiss zoologist became infected with the virus while performing an autopsy on a chimpanzee in Ivory Coast.
Eight days later, she developed chills, then diarrhea, an all-body rash, temporary memory loss and was flown to Switzerland by air ambulance for treatment, accompanied by health workers wearing masks, gloves and gowns. She recovered without infecting anyone else.
The Ebola outbreak is expected to go on for some time and will be difficult to stop as it can easily “re-ignite” from even one case, the CDC’s Monroe said. Even if there are no new cases, it would be 42 days before health workers would be sure the outbreak was over.
But the biggest smoking gun, and perhaps the reason why 2014 may be the new 1994, is this:
wife & children of a Texas doc working in Liberia w/ Ebola patients, returned to America last week, days b4 Brantly -came down w/ Ebola WTF?
— Robert Passarella (@robpas) July 28, 2014 [7]
