Understanding the True Threat: Richard Webby, PhD, on H5N1 Avian Flu and Its Human Impact

The Truth About Avian Flu/H5N1 (A Series)

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Reading any social media post shows an unfortunate amount of misinformation and disinformation about the avian flu, H5N1, and its variants. The spread of false information has caused the public and health care workers to be uncertain about what to believe or trust incorrect information.

To learn the truth, Infection Control Today^® (ICT^®) spoke with Richard J. Webby, PhD, a member of the St. Jude’s Research Hospital Faculty and the director of the World Health Organization (WHO) Collaborating Centre for Studies on the Ecology of Influenza in Animals and Birds. This is the first in a series from ICT.

The significance of animal influenza viruses as a pandemic threat to humans was widely recognized. In 1975, the WHO designated the influenza laboratory at St. Jude Children's Research Hospital in Memphis, Tennessee, as the Collaborating Center for Studies on the Ecology of Influenza in Animals.

ICT: What do we currently know about this version of H5N1, avian flu?

Robert J. Webby, PhD: There are currently two versions of H5N1. One is the virus circulating in cows, referred to rather unimaginatively as B3.13. This version occasionally spills into poultry, humans, and other domestic animals. The other form of the virus is D1.1, which is responsible for severe infections in Canada, some infections in poultry workers in Washington [State], and a severe case in a person in Louisiana.

There are 2 circulating forms of the virus: one primarily driven by cows and the other [one] largely driven by wild birds. From the cow perspective, we haven't changed much from where we were several weeks or even months ago; at least from a virologic perspective, that virus has remained remarkably stable in the bog population. Yes, we're still seeing spillover to humans, but there haven’t been any changes from a risk perspective.

The other version, D1.1, is a little different. It’s the new kid on the block. We're still in the early days with it, but we are monitoring it with quite a bit of interest. As I mentioned, it has caused two severe human infections, and it's still unclear where this is headed. It came down with birds that migrate from the north, spreading it south, and it's currently causing quite a bit of activity in wild bird populations.

ICT: Which version do the pigs have?

RJW: The 1 or 2 infected pigs were infected with a virus very similar to the D1.1. It was a slight nothing was D1.2. [It didn’t] spread anywhere further than that, and those pigs were in very close contact with infected birds.

ICT: How concerned should the general public and health care professionals be about increasing human exposure? Do you see any signs of it escalating into a broader threat?

RJW: For the general population right now, from an individual risk, the average person walking down the street is at no risk from this virus directly. There's the broader pandemic potential threat, of course, but I still agree that both viruses are poorly infectious for humans in their current form.

It's beneficial for the general population to be informed. I understand that viruses are present, but they don't affect animals. If you encounter something unwell, remember that it could be infected with the virus. However, there's no need to panic at this stage, especially from a healthcare provider's standpoint. It also depends somewhat on your location.

Certainly, if you're in California, there is a definite risk of people coming in infected with that bovine virus, primarily if they work in that sector. Currently, the rest of the country does not show much activity in cattle populations, and the wild bird population is at the highest risk. Fortunately, contact between susceptible people and wild birds is relatively limited. So again, it's unlikely there will be random cases; I won't say there will be no random cases, but the exposure risk remains low, and thus, the overall risk is also low.