Why Worry About a Bird Flu Pandemic?

“Widespread influenza is the deadliest plague in human history, and the transmission of avian influenza to human beings probably started the global pandemic of 1918, which killed 50 million people.”  (Moscona, 2004)

Quotes like this one get my attention when they are from a knowledgeable researcher.  The H5N1 influenza virus everybody’s talking about may well cause the next pandemic--or would it? Why should we worry about a pandemic now, when it took the H5N1 bird flu more than 2 years to cause illness in fewer than 200 people? H5N1 and humans go back together even farther than that. There is evidence that H5N1 has infected a few people as far back as 1992, and this virus strain still has not managed to efficiently move from person to person. So, why all the fuss now? 

Some reasons

One reason is that influenza pandemics do happen. Ten were recorded in the last 300 years. Knowledgeable people agree that there will be another pandemic for sure, and influenza researchers have already predicted the next pandemic for years. (e.g., Bartlett & Hayden, 2005)

Another reason is that H5N1 would be a likely candidate because it is a version of the influenza virus that is carried by birds across the globe. This is a virus strain to which humans in general have no immunity because they never encountered it. Recent evidence suggests that the H5N1 virus is getting more efficient at jumping from species to species among birds, to a number of other animal species, and to humans.

A third reason for concern is that if H5N1 were to cause a pandemic, it might be as bad– or worse--than the worst-ever assault by an infectious disease on humanity, the 1918 influenza. Like the H1N1 strain of 1918, the present H5N1 virus can cause very serious damage to lungs and other organs. Add to that a H5N1 death rate that is much higher than the H1N1 death rate of the 1918 pandemic. Population density has more than tripled since then and the speed of travel has increased a lot more than that.

Lots of uncertainty

Nobody has any idea when the next influenza pandemic will hit. It seems rather strange that the timing of a future influenza pandemic depends on the behavior of an extremely tiny, inanimate collection of molecules, a behavior that is blindly dictated by the chance events that lead to mutations.

Will the H5N1 virus mutate so it will jump from human to human with the same ease as does the usual H3N2 influenza virus that has been with us for so many years and that still makes so many of us miserable and kills tens of thousands of us every year? There is no guarantee that it will–or will not.

Should the H5N1 virus mutate and spread among humans with ease? Will it also remain able to cause such serious illness and kill half of those it infects? Nobody knows. Will it respond to antiviral drugs? Will we have an effective vaccine? Nobody knows for sure.

Where are we now?

According to the World Health Organization, we are presently at Stage 3, a “pandemic alert” stage, but with “no or very limited human-to-human transmission.” Especially since the bird flu outbreak in Turkey, some researchers find reasons to suggest that we may have progressed to Stage 4, with “evidence of increased human-to-human transmission.” 

Inter-pandemic phase New virus in animals, no human cases	Low risk of human cases	1
	Higher risk of human cases	2
Pandemic alert New virus causes human cases	No or very limited human-to-human transmission
	Evidence of increased human-to-human transmission	4
	Evidence of significant human-to-human transmission	5
Pandemic	Efficient and sustained human-to-human transmission	6

In any case, the bird flu outbreaks continue to smolder somewhere between Stage 3 and Stage 4 over a wide area. They may yet change to a Stage 6 raging firestorm, or they may fizzle back to Stage 2. To get a better fix on where it might be going, we need to keep watching how the H5N1 virus mutates.

References

Influenza A (H5N1): Will It Be the Next Pandemic Influenza? Are We Ready? Bartlett, J. G., Hayden, F. G., Annals of Internal Medicine 2005 Sept 20;143(6):460-462.

Oseltamivir-resistant influenza? Moscona, A., Lancet 2004 Aug 28-Sep 3:364(9436):733-734.

Comments

[Mary Jo Bergs]

Thank you for an unbiased article about the potential for an AI outbreak. It's nice to see the pertinant information without the hysteria and hype seen on all the news networks these days.

[Kim]

When this bird-flu arrives here in the us , What are the chances that we can become ill eatting chicken or any other bird after it has been cooked ? I don't want to sound like I'm some kind of dummy but we eat alot of chicken and I really don't want my family coming down wit it?

[Kim]

Your article was very informative; however, I am concerned about the safeguards that are (are not?) being put into place for the general population. Are drug stores going to stock up on vital supplies such as breathing masks, meds, etc. should a pandemic occur? How soon after a pandemic outbreak occurs will these neccessities be avaialbe? Since SARS, I have heard alot of media attention put on the avian flu. I think that very soon measures need to be taken (globally) so that people can prepare to protect themselves sooner (NOW), before an outbreak, instead of later when people will probably panic when they don't have access to supplies to protect themselves.
P.S. On OPRAH a couple of weeks ago, a scientist in the know of the bird flu mentioned that it is not a matter of IF this is going to happen, but WHEN...

[Jane Woodin]

Interesting approach to the Avian Flu situation. I would like to keep informed. As a retired Public Health nurse I know I need to keep aware of changes in the situation. Hysteria never helps but knowledge and planning are the key.

[Jen]

Out of curiosity, could there be a higher chance of contracting the Avian flu if you consume wild game? My husband and son both hunt and we routinely eat Canadian Goose and duck. Granted, we cook the meat thoroughly which is enough to kill most microbes that cause illness, but is it possible that this strain of flu could mutate enough that it could be a problem handling the game?

[Denise G.]

Are there special tests performed on all the chicken processed for human consumption so that we can be sure that the chicken bought at the supermarket is entirely safe to eat?

[jennifer]

Should I be worried about eating chicken and giving it to my daughter?

[Darlene Stovall]

We are in a direct route of migratory Canadian Geese and Sand Hills Crane going south in the spring. They fly right over our house every year. Is there any danger of their droppings being infectious?

[Dee]

It's nice to see the comments but how about the answers? I'd like to see the answers. All the questions are the same ones I have.