Healio
Healio
April 29, 2009
3 min read
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It has arrived

Benjamin Franklin once said, "An ounce of prevention was worth a pound of cure." Although it may not be possible to prevent an influenza pandemic, readiness efforts will pay its dividents now. Or at least that is what we all hope.

The WHO has declared a phase-5 pandemic alert level.

It is not the so-feared avian H5N1 virus. It is a reassortant A/H1N1 swine influenza virus, which contains gene segments from the Eurasian swine, the North American swine, avian and human influenza viruses.

Fifty cases of swine influenza (14 pediatric) were recently reviewed in the literature (Clin Infect Dis. 2007;44:1084), but little was revealed regarding the epidemiology of this virus. We are learning more now in hours than what we did in years.

The first swine flu viruses were recognized in pigs in 1918, but it was not until 1930 that these viruses were isolated. The most common swine influenza belongs to the A/H1N1 subtype. Reports of swine A/H3N2 and H1N2 strains exist.

Why pigs? Influenzally speaking, pigs are “mixing vessels.”

Avian influenza viruses bind to cells using receptor molecules with an alpha-2,3 linkage between sialic acid and galactose, whereas human influenza viruses bind receptors with an alpha-2,6 sialic acid-galactose linkage. Pigs carry both hemagglutinin receptors at their tracheal epithelial cells, rendering susceptible to both viruses.

I leave you two references: Animal influenza epidemiology, by Ducatez, Webster and Webby (2008); and The emergence of novel swine influenza viruses in North America, by Olsen (2002). In addition, the Journal of Infectious Diseases published in a February 2008 supplement, “Avian and Pandemic Influenza.”

Why flu? As you know, the virus undergoes evolutionary antigenic drift (seasonal) and antigenic shift (pandemic). The virus genetic material is composed by eight RNA segments. That is why if more than one flu virus infects the same cell, new reassortant strains can arise.

Do pigs get sick? Sure they do. They are following this epidemic closer than us. They develop either respiratory disease, characterized by fever, lethargy, cough, dyspnea or porcine respiratory disease complex, a polymicrobial infection. If your ex tells you that you are a pig, you are in deep trouble.

Six things you should do

  1. Stay calm. Don’t run around like a chicken without a head, you might get an avian flu too. Besides, the virus is spreading all over the world, and there is no reason for alarm. Well, actually, there is.
  2. Don’t hang around sick people. Unless you are a doctor, of course.
  3. If you get sick, do not go to work. Unless you are a doctor and there are people sicker than you. And, of course, you are not one of the 13 million unemployed Americans.
  4. If you cough or sneeze, do cover your face with a tissue, mask or arm. Do you really need the CDC to come and tell you that?
  5. Wash or rub your hands before and after. You will prevent the spread of the swine flu virus, the pigs will thank you for that, and we will continue to enjoy good bacon and wet ribs.
  6. Above all, stay informed. I suggest the following resources:

Your leadership will be expected in your hospitals and institutions. It is time to be prepared. The flu has come, and we should all be ready to protect our children and ourselves. Stay safe.