Wednesday, April 29, 2009

"Swine Flu"--What's In A Name?

Updates Below

Once again the New York Times has written thoughtfully about a subject--but I got there first! (Or at least we seem to have published at about the same time.) On the subject of the very name "swine flu" for this outbreak, see Keith Bradsher's piece "The Naming of Swine Flu, a Curious Matter." In it, he makes most of the same points I made yesterday about choosing to call this human-pig influenza "swine flu," though includes one or two howlers for comic effect. "An Israeli deputy health minister — an ultra-Orthodox Jew — said his country would do the same [i.e. call it "Mexcian Flu"], to keep Jews from having to say the word 'swine,'" he wrote. Then he deadpanned, "however, his call seemed to have been largely ignored." Points for humor, Keith!

Just for review: influenza's habitat--its "breeding grounds," let's call it--are both humans and various birds and mammals. To call this one specifically swine flu may be a somewhat clinically convenient shorthand, but it's not particularly accurate. The virus is coated in two proteins, called "H" and "N." There are sixteen "H" and nine "N" subtypes. Thus, lots and lots of combinations. Not all of these combinations are able to infect humans, much less cause harm or death. Since 1968, the major strains affecting humans have been the H1N1 and H3N2 strains (before that were H1N1 and H2N2 strains, the latter appearing to have dropped from circulation for the time being). These strains change from year to year, so one year's predominant H1N1 strain may be different enough from another year's circulating strain that a previous vaccine may not be protective; this is very different from viruses like measles or polio, which provides essentially lifelong protection with one shot (plus identical boosters). Anyway, some of these strains are more likely to reproduce in the bird population, some in the porcine population, and some in the simian population (that's us). And because of the special quirks of the influenza virus, individual copies can "trade" H and N subtypes, creating recombinant strains that may be more or less transmissible, and more or less lethal than their "parents." Sometimes this is referred to as the "mixing vessel" phenomenon when people talk about the swine, but it's no less likely that humans or birds are mixing vessels; the virus is passed back and forth between species in an continuous cycle of recombination, a constant tinkering with infectiousness. (For the sake of completeness, I am keeping this subject as simple as possible and not discussing Influenza B and C, which are separate types. The subtypes above all refer to Influenza A.)

The all-time biggie is the influenza strain that caused the 1918 pandemic and likely killed tens of millions of people worldwide. This was an H1N1 subtype, and is often called the "Spanish flu" because it supposedly originated in Spain (though this is dubious, but more anon). The "avian influenza" that has kept WHO officials up late at night over the past several years is a more unusual H5N1 subtype, which is quite lethal, killing roughly 50% of those infected, but appears thus far not to be particularly talented at spreading from human to human. For those who don't know much about the 1918 influenza pandemic, for a couple of bucks I highly recommend Gina Kolata's Flu, and though I have not read it I am told that John Barry's thicker tome The Great Influenza is good reading as well. The Cliff's Notes version is that the 1918 flu pandemic was really really bad. At least in my opinion it ranks only second to the bubonic plague outbreak of 1346-9 (the so-called "Black Death") in terms of catastrophic impact on human life, though smallpox was no fun either, especially for the aboriginal populations following contact with European settlers during the 15th-18th centuries.

In terms of nomenclature, scientists in general try to name viruses after their point of origin. Since influenza already has a name (see here for its etymology), the pandemics are named after theoretically originating points: the Spanish Flu of 1918, the "Asian Flu" of 1957, and the "Hong Kong Flu" of 1968 are the most notable. Needless to say, in a fast-moving pandemic--and influenza specializes in creating fast-moving pandemics--the point of origin may not necessarily be where the disease is first detected, so it's an open question as to the reliability of this strategy. Don't believe me? Check out this post which might indicate the virus originated in, yes, Ohio.

In general, locals aren't precisely thrilled when their village or region is used to name a deadly microbe, and that holds particularly true when those places are peopled by groups traditionally marginalized by past European or American governments. No doubt the people in the Yambuku region of Zaire, after enduring centuries of enslavement, famine, and plunder by the west must not have been pleased when scientists chose to name one of the most lethal viruses known to man after the Congo tributary by whose shores many make their home. We are all familiar with that little tributary's name these days, for what more scary virus could there be than Ebola? One of the ironic twists to this practice is that Ebola's close relative, that other filovirus, was not detected until 1967 when there was an outbreak among 31 Germans who worked with African-imported monkeys, and thus the hemorrhagic fever Marburg came to be dubbed.

The practice came to a head in the US just about two decades ago, when a very deadly virus in the Four Corners area of the US infected a small number of people. A new type of hantavirus, the researchers studying it were prepared to give it the place name as per protocol, until a group of local protesters, including many Native Americans, made it clear that this was just a hair shy of engaging in racism and didn't want their community disrespected this way. As a consequence (and a compromise), this virus today literally has No Name: it is known as the Sin Nombre Virus.

Needless to say, Mexicans aren't especially eager to hear about talk of a "Mexico Flu." The potential for pre-existing biases to reinforce themselves is quite strong, particularly given US-Mexican relations over the past century and a half. Consequently it's not much of a surprise to hear the natterings of nativists in the US about closing the border (which is only what is being discussed in the polite circles of those holding such political views; the more fervent adherents, I am certain, are advocating for, um, sterner measures).

The outbreak's current popular name, "Swine Flu," sidesteps the issue of origins, but has its own issues. You may laugh at the complaints of pork producers who fear the loss of revenue from the moniker, but a mostly ignorant populace has no way of being able to sort out that eating pork poses no risk of contracting influenza. For instance: how is a layperson expected to understand that this situation is different from Mad Cow Disease, given that the English culled over four million cattle in the 1990s precisely because consumption might cause disease? So I don't blame the farmers for their distress.

My own preference at the moment is close to HHS Secretary Napolitano's, who calls it "the H1N1 virus." I'm more happy with "the H1N1 influenza strain," "the H1N1 variant," or some such. Call it what you want, until this thing dies down--the topic for my next entry--another good description is that it's one hell of a scary virus.

a. How could I have forgotten syphilis in this discussion?! Though not a virus, syphilis is a good case study in why it's not such a great idea to name diseases after their origin, and why the people from the first identified sites object to such a system. Although syphilis originated centuries ago, and thus didn't involve the modern methods of disease nomenclature, syphilis is especially apt since it is a sexually transmitted disease, and was used by proto-nationalists of every stripe to bash some foreign country. Thus in the 16th and 17th centuries (and long after), syphilis was called the "French disease" in Italy and Germany and England, the "Italian disease" in France, et cetera, with various nationalities being imputed by various other countries (a lot of which had to do with sailors, who were one of the critical amplifiers of disease).

b. Of course, not all viruses are associated with place names. HIV, the Human Immunodeficiency Virus, bears no trace of its geographical origin (else we'd call it the Somewhere In Africa Formerly Chimpanzee-Specific Immunodeficiency Virus), nor do the various Hepatitis viruses which simply bear the letters A, B, C for their designations. Both were named long before political sensibilities were a consideration. One of the viruses equivalent to this current influenza strain in terms of its scariness, the coronavirus that we call SARS (the Severe Acute Respiratory Syndrome virus), was named after its symptoms and not its origin, a province of China. There are others. That said, many viruses bear place names: Crimean-Congo Hemorrhagic Fever virus, Guanarito virus (a small town in Venezuela), Sabia virus (in Brazil), Machupo (in Argentina), Ross River and Hendra viruses (Australia), and the list goes on.

It is possible that one day there will be an international conference that will set up rules on naming of viruses and engage in a complete re-naming of current viruses in a more logical manner. For instance, the Hepatitis C virus is actually more closely related to the West Nile virus than it is to the Hepatitis A virus, and as we have seen above Ebola and Marburg are in the filovirus family, but the names are half a world apart from one another. Theoretically it would be beneficial to pound out a workable system for naming (much like they have in organic chemistry, where literally tens of thousands of molecules need to be named for patent purposes).

c. Anthony Fauci (the director of the NIH branch of infectious diseases) has also come out heavy against the name "swine flu," referring to it in an NPR piece Thursday morning as "the 2009 H1N1 influenza." I still prefer my suggestions above, but I'm in complete agreement with Dr. Fauci on the reasons to emphasize the switch.

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