The announcement that a case of Ebola virus has been diagnosed in a Dallas hospital sent a chill through the medical, public health, and basic citizen communities. I know my jaw surely dropped as far as it has dropped since 2001, when the word of the first anthrax case in New York appeared in my email. As the details have begun to emerge, many people are wondering the same thing: Will this happen in my city?
The answer is quite clear: Maybe.
The facts are straightforward, at least in the version that the Centers for Disease Control and Prevention laid out: A man of uncertain age flew from Liberia, where the disease remains uncontrolled, to Dallas to visit family. When checked for illness on departure, he had no fever. Upon landing in Texas on September 20, he was fine. Within four days, though, he began to feel ill—sufficiently so that he sought medical attention on September 26. That evaluation apparently failed to provide clues to the diagnosis, but two days later his symptoms had progressed enough that he again sought medical attention and this time was hospitalized, placed immediately into isolation, and diagnosed on September 30.
The timeline as presented raises countless questions. First: Was he contagious when boarding the plane and are his plane-mates therefore at risk? Surely not—the most compelling epidemiological fact in the entire tragic seven month outbreak has been the story of Patrick Sawyer, the Minnesotan who after traveling from Liberia to Nigeria, developed symptoms of overwhelming Ebola and died soon thereafter. Although few details have been revealed, none of those who traveled with Sawyer developed the disease despite the fact that he, unlike the Dallas case, was ill with the infection while traveling. And it is axiomatic (and hopefully true) that a person is contagious only when they are sick, not when they are brewing the infection.
Second: What about others? Surely others in Texas were exposed and are at risk—specifically those the new case spent time with from September 26, when he first felt ill, until September 28, when he was hospitalized and placed promptly into isolation. Here is where the CDC’s calm and forceful “Nothing to See Here” message cracks a bit around the edges. Dr. Thomas Frieden, who has led the CDC admirably throughout the Obama years, stressed in his press conference Tuesday that Ebola could and would be controlled by hewing to the basic principles of infection control: isolation and contact tracing of anyone suspected of contact. With this approach, people with exposure are placed into quarantine and, if sick, into isolation. This method works for TB, for cholera, for rabid animals—for just about everything.
But what about Ebola? The Dallas case is breaking some of our ironclad assumptions. The CDC has a well-considered algorithm that places those returning from the three endemic West Africa countries—Sierra Leone, Guinea, and Liberia—into a measure of extra vigilance if and only if the person has had exposure to a known case of Ebola. Per the press conference, the Dallas case had no such exposure. He was not a health-care worker treating patients, nor was he from a family battling active disease. Of course, more facts may emerge that contradict today’s story—but today’s facts, if they hold up, mean that yesterday’s assumptions are no longer correct. Liberia may indeed be enough of a hotbed of Ebola that anyone arriving from the area will need to be considered for extra vigilance.
More disturbing, though, is this: Infections follow basic rules. That’s what informs the confidence of public health experts. TB, for example, is spread when I inhale the exhaled breath of a person with active disease. Cholera and typhoid fever are transmitted when I ingest contaminated food or drink. And blood-borne infections like HIV, hepatitis B, and Ebola are spread after contacting infected blood or having sex with an infected person.
But even according to these basic rules, Ebola is slightly different in a way that remains obscure. HIV is not spread easily: The per-sexual exposure with an infected person is on the order of 1 in 100; a needlestick with blood from an infection person sustained by a health-care worker transmits infection in only 300 exposures. Hepatitis B plays by the same rules, though the rates of transmission are about 10 times more frequent. In other words, the likelihood of catching HIV or hepatitis B from an infected person, even with a blood or sexual exposure, is quite low.
Exposures to Ebola, however, seem to leave no room for error. Although we lack carefully performed studies, Kent Brantly, the physician who developed the disease and was airlifted to Atlanta, seemed to have no gross exposure to the disease, though he worked on an Ebola ward. Ditto for Nancy Writebol the other American flown back in that dramatic first wave. According to reports, they were mighty careful at every step, but just not careful enough.
In contrast, it is said that absolutely no one working for Médecins sans Frontières, or Doctors Without Borders, has come down with Ebola, though they have been and are working cheek by jowl with the same patients, presumably because they are perfectly and methodically garbed and attentive 100 percent of the time, not 99 percent. So Frieden’s message to America surely is correct—we are 1,001 disasters away from an alarming national outbreak; our health-care systems are indeed quite sturdy.
But his message to those caring for the Dallas patient both in his home and now in the hospital needs a bit of punching up. For once, all those rules about assuring that masks fit and gloves (two pairs) are snug and gowns are tied and all the rest are deadly serious, as is the mechanical sequence of doffing the disposable garb, then washing hands carefully. This time, even in the freewheeling city of Dallas, the rules must be followed carefully, as if one’s life depended on it—because when dealing with Ebola, it does.
