Via her blog Aetiology, Dr. Tara C. Smith advises us to get a grip: Ebola is already in the United States. Click through for the full post and many links. Excerpt:
It’s odd to see otherwise pretty rational folks getting nervous about the news that the American Ebola patients are being flown back to the United States for treatment. “What if Ebola gets out?” “What if it infects the doctors/pilots/nurses taking care of them?” “I don’t want Ebola in the US!”
Friends, I have news for you: Ebola is *already* in the US.
Ebola is a virus with no vaccine or cure. As such, any scientist who wants to work with the live virus needs to have biosafety level 4 facilities (the highest, most secure labs in existence–abbreviated BSL4) available to them. We have a number of those here in the United States, and people are working with many of the Ebola types here. Have you heard of any Ebola outbreaks occurring here in the US? Nope. These scientists are highly trained and very careful, just like people treating these Ebola patients and working out all the logistics of their arrival and transport will be.
Second, you might not know that we’ve already experienced patients coming into the US with deadly hemorrhagic fever infections. We’ve had more than one case of imported Lassa fever, another African hemorrhagic fever virus with a fairly high fatality rate in humans (though not rising to the level of Ebola outbreaks). One occurred in Pennsylvania; another in New York just this past April; a previous one in New Jersey a decade ago. All told, there have been at least 7 cases of Lassa fever imported into the United States–and those are just the ones we know about, who were sick enough to be hospitalized, and whose symptoms and travel history alerted doctors to take samples and contact the CDC. It’s not surprising this would show up occasionally in the US, as Lassa causes up to 300,000 infections per year in Africa.
How many secondary cases occurred from those importations? None. Like Ebola, Lassa is spread human to human via contact with blood and other body fluids. It’s not readily transmissible or easily airborne, so the risk to others in US hospitals (or on public transportation or other similar places) is quite low.
OK, you may say, but Lassa is an arenavirus, and Ebola is a filovirus–so am I comparing apples to oranges? How about, then, an imported case of Ebola’s cousin virus, Marburg? One of those was diagnosed in Colorado in 2008, in a woman who had traveled to Uganda and apparently was sickened by the virus there. Even though she wasn’t diagnosed until a full year after the infection (and then only because *she* requested that she be tested for Marburg antibodies after seeing a report of another Marburg death in a tourist who’d visited the same places she had in Uganda), no secondary cases were seen in that importation either.
And of course, who could forget the identification of a new strain of Ebola virus *within* the United States. Though the Reston virus is not harmful to humans, it certainly was concerning when it was discovered in a group of imported monkeys. So this will be far from our first tango with Ebola in this country.