Sandy Bauers, For The Inquirer
Posted:
Thursday, June 11, 2015, 1:08 AM
The small shorebird - a ruddy turnstone - was not happy.
Moments ago, it had been feasting on horseshoe crab eggs along the waterline of Delaware Bay near Villas, N.J. But now, University of Georgia researcher Deb Carter had a gentle but inescapable grip on the bird, and her colleague Clara Kienzle was sticking a cotton swab down its throat.
Next, they swabbed the bird's other end and then jabbed a slim needle into a vein to draw blood before releasing it.
Their goal: to see if this healthy bird was carrying a flu virus.
Shorebirds, it turns out, are a major reservoir for the influenza virus. This article is from wwwphilly.comEvery flu virus known to infect humans has its origins in the wild bird population, primarily shorebirds and ducks.
And for shorebirds, nowhere do scientists find as many influenza viruses, or as high an infection rate, as they do on Delaware Bay.
Learning more about these viruses now will help scientists be better prepared if the viruses one day leap into other species.
The viruses may, for instance, jump into commercially valuable livestock - as is happening now in Midwest poultry, forcing the slaughter of millions of birds and causing egg prices nationwide to skyrocket.
On Wednesday, the Pennsylvania House Agriculture and Rural Affairs Committee heard testimony that the state should prepare for the outbreak here.
Ultimately, the viruses found in shorebirds may even jump into humans, causing anything from small effects to pandemics such as the 2009 outbreak. As many as 90 million people were sickened and thousands died.
Back in the lab, about 2,000 samples taken during a few weeks in May, when migrating shorebirds were passing through the bay, are being analyzed and frozen until needed for future research, possibly even the development of a vaccine.
Scientists think Delaware Bay's importance to this work may have something to do with so many birds coming in from so many places - all over South America - to just a few beaches. There, they congregate in huge flocks, mingling with resident gulls and other birds, making the transmission of viruses from one species to another all the more likely.
"Just that mixing allows a little explosion," said David Stallknecht, a professor in the University of Georgia's Southeast Cooperative Wildlife Disease Study, who has been coming to the bay since the late 1990s.
Researchers taking 400 samples on the Georgia-Florida coast may recover just 10 viruses, he said. On Delaware Bay, it's routine to recover 10 times that in the same number of samples.
"I have to think there's some marvel going on here," said Scott Krauss, a researcher from Tennessee who has been studying viruses in shorebirds for years.
The first to discover the importance of the bay were researchers from St. Jude Children's Research Hospital in Memphis, where Krauss is laboratory operations manager in one of the nation's Centers of Excellence in Influenza Research and Surveillance.
But the roots of that research go back to 1957, when a flu pandemic arose and no one knew where the virus came from, said Robert G. Webster, a St. Jude emeritus professor who specializes in the ecology and origin of influenza viruses.
One day, as he and a colleague were walking along a beach in Australia, they found lots of dead birds. They knew that in South Africa an influenza was killing terns, so they decided to check birds on the Great Barrier Reef, where the same species as the dead birds they saw nested. Sure enough, samples from the birds showed influenza viruses similar to those in humans. It was the beginning of a new era of influenza virus research.
Eventually, Webster moved to Memphis and later focused on Delaware Bay after learning that a Johns Hopkins researcher had found flu viruses in gulls that frequented a Baltimore landfill. He and other researchers started going to the bay in 1985 and have returned every year since to gather samples.
In 2006, St. Jude researchers completed the first large-scale study of bird flu virus genomes, leading to DNA sequences for 2,196 genes.
When birds leave for the summer, does the virus - or its virulence - fade away?
It seems to. In the fall, shorebirds heading south from the Arctic, where they have nested, do not show the same level of infection. It fits with one theory that the reason some birds have such a long-distance migration is that passing through different climates will help them shed parasites and pathogens.
But just last year, a virus that was detected on Delaware Bay in May showed up in a shorebird that fall in South America.
"So the viruses move, apparently, from South America to North America and back again," Krauss said. "But something happens at Delaware Bay that starts a massive cycle of infection."
A big question this year is whether the lab results will show that the deadly avian flu virus in the Midwest - found in the nation's three other major flyways, or migratory routes used by wild birds - has spread to the bay, signaling major concerns for poultry operations in Pennsylvania, New Jersey, and the Delmarva peninsula.
On June 2, the Centers for Disease Control and Prevention officially notified public health workers of the potential for human infection.
Stallknecht said he didn't expect to see it. It hasn't been found in shorebirds or gulls, and the birds on Delaware Bay come from the south, not the west. But because it is so deadly, they'll be watching closely as they do their lab work.
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