U.S. monitoring of H5N1 could miss entry into USA

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U.S. efforts to monitor H5N1 could easily miss entry of the virus into

North America

Disease/Infection News Published: Thursday, 13-Dec-2007

A University of Kansas investigator closely following the spread of

the avian influenza known as H5N1 said that U.S. government monitoring

efforts easily could miss the entry of the virus into North America.

A. Townsend , University Distinguished Professor of Ecology

and Evolutionary Biology and senior curator in the Natural History

Museum and Biodiversity Research Center, directs teams of scientists

who travel from Kansas to far-flung corners of the globe to map the

spread of avian flu and other pathogens.

said the governmental scheme to detect the arrival of H5N1 in

North America - the Highly Pathogenic Avian Influenza Early Detection

System - overemphasizes testing of wild water birds in Alaska while

neglecting other possible " entry pathways " from Eurasia.

" If you take a careful look at bird migration in North America, you

probably wouldn't want to, excuse the pun, 'put all your eggs in one

basket', " said .

The KU researcher said that the Alaskan focus of the program is

sensible for monitoring a set of wild Asian birds that spend winter in

Asia and sometimes summer in Alaska. But other birds possibly carrying

the avian influenza could be overlooked.

" There's another component of birds which spend the winter in

America, " said. " They migrate north in the summer and

basically consider western Siberia to be eastern Alaska. That

component of birds migrates deep into the Americas, doesn't really

stop in Alaska at all, and would be missed by the current monitoring

plan. "

According to , a more effective system to detect the

appearance of H5N1 would track wild birds all along the Atlantic and

Pacific " flyways " of North America.

" I'm essentially suggesting that we should be considering the entire

coastal regions and that the monitoring scheme should be much more

based on hard data instead of supposition and just eyeballing the

situation, " said .

's team published initial results of its research on the

official H5N1 tracking program earlier this year in PLoS ONE , a

peer-reviewed science journal.

As of this month, government surveillance remains focused on Alaska:

According to the detection system, it sampled 11,819 wild birds in

that state, compared with 4,054 birds in California, the

second-highest state total. No highly pathogenic H5N1 virus has been

found in any of these samples.

said global efforts to track the avian flu also exaggerate

the role of wild waterfowl, such as ducks and geese.

Early research showed a higher percentage of these birds contained the

H5N1 virus, with lower rates among land birds. " But that seems to have

evolved into the idea that only water birds are the reservoir of avian

flu, " said. " As near as I can tell, there are no data behind

that. It's just that prevalances are higher. What gets forgotten is

that numbers of waterfowl are lower. So, how many bird-fulls of virus

are out there in the world flying around? It could easily be more land

birds than water birds. "

These gaps in surveillance plans could slow the response to a serious

public health risk. According to the World Health Organization, in

2007 there have been 49 human fatalities from H5N1 reported worldwide,

out of 74 confirmed cases.

" It has every possibility of turning up in North America, but it

hasn't essentially gotten in the door yet, that we know of, "

said. " These are rare events and it can take time. But I see no reason

why anybody would believe that it can't happen. If it gets to North

America, it's not going to be a terrible plague or anything. But it

increases the probability of evolving new virus strains that could

turn into something much more dangerous. "

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