Monday, November 23, 2009

Back to the flu-ture

It's been quite some time since I've been here. I've moved cities and changed jobs, so it's taken some time to get settled. Anyway, I'm hoping to be more active over the next little while.

This pesky influenza virus that people seem to be talking about all of the time has kept me busy as well. We're finally seeing some downswings over the past two weeks, both locally here in Toronto and across North America , and hopefully, after the expected second phase of H1N1 later on in the winter and more people obtain immunity, this pandemic will slowly die down. Unfortunately, our yearly visit from plain ol' seasonal influenza is still to come, and it will be very interesting to compare mortality rates from the two viruses, just as a marker of the effectiveness of our collective panic, especially since our treatment options for plain ol' influenza are very different than big bad pandemic influenza.

Since I'm tired of pandemic strain H1N1, I'll go back to our original fear-monger, H5N1. Remember him? He's the one that everybody was worried about for years, poking his head out in various parts of the Asian land-mass, killing a few people, then going back to spend his time with chickens and other birds. This paper (see ref below), explores that exact concept in a group of poultry farmers in Vietnam, the highest-risk group of all high-risk groups for infection. In 2005, at the height of H5N1 paranoia, Vietnamese public health officials sampled the blood of chickens and/or ducks in all the farms in an endemic region near Ho Chi Minh City. Any farm with any H5N1 had its fowl culled, and, after some time, the farmers were all tested for antibodies to H5n1. Easy enough.

They found, confirming findings from other parts of the world, that fowl-to-human transmission of H5N1 is very, very rare, in that only 3 of the 500 people tested had any evidence of immunity, and those only had very low-levels, which may represent cross-reactivity to another influenza virus. We know that humans aren't easily infected with this virus, in its current form, and it would take some fairly drastic antigenic shifting for us to be affected. Nothing new, or surprising, from this study, but just more evidence that the currently circulating H5N1 virus does not easily transmit to humans, even with significant and direct exposure to the virus.

So, wash your hands, get your flu shots, live your life, and don't let the media freak you out about pandemics any time soon.



Schultsz, C., Van Dung, N., Hai, L., Quang Ha, D., Peiris, J., Lim, W., Garcia, J., Dac Tho, N., Thi Hoang Lan, N., Huu Tho, H., Xuan Thao, P., van Doorn, H., Vinh Chau, N., Farrar, J., & de Jong, M. (2009). Prevalence of Antibodies against Avian Influenza A (H5N1) Virus among Cullers and Poultry Workers in Ho Chi Minh City, 2005 PLoS ONE, 4 (11) DOI: 10.1371/journal.pone.0007948

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