Work for bird flu researchers is a day at the `icky' beach

It was a glorious day for field work on the shores of the Delaware Bay. The late afternoon sun cast a warm glow over the gently sloping beach. The receding tide revealed a smattering of shells. The dune grasses rustled in the breeze. The beach vines were in bloom. And the bird droppings were fresh and plentiful.

“Here's one,” said Pamela McKenzie, a researcher at St. Jude Children's Research Hospital in Memphis, Tennessee, pointing a gloved finger at one tiny white splotch and then another. “There's one, there's one, there's one.”

For the next two hours, McKenzie and her colleagues crept along the shore, scooping up avian excrement. Their goal: to stay a step ahead of bird flu, a group of avian-adapted viruses that experts have long worried could evolve to spread easily among humans and potentially set off the next pandemic.

Every spring, this part of southern New Jersey becomes a bird flu hot spot. Shorebirds winging their way north alight on local beaches to rest and refuel, excreting virus along the way. And every year for the past four decades, scientists from St. Jude have flown into town to pick up after them.

The work requires patience — waiting for the movements of the birds and the movements of the tides to align — keen eyes and resilient knees, sturdy enough to withstand hours of shuffling and squatting along the sometimes rugged shorelines. “They're not nice, sandy beaches,” said Lisa Kercher, a member of the St. Jude team. “They're thick, muddy, icky beaches that are full of bird poop.”

But these dropping-covered shores are helping scientists learn more about how bird flu evolves, how it behaves in the wild and what it might take for these bird viruses to become a global public health threat. These scientific questions, which have driven the St. Jude team for decades, have become even more urgent as the United States grapples with its largest bird flu outbreak in history, caused by a new, highly pathogenic version of a virus known as H5N1.

In June, the southern New Jersey shore fills up with vacationing families, their colorful beach umbrellas sprouting up across the sand.

But in May, the beaches belong to the birds. Hundreds of thousands of migrating shorebirds and gulls make pit stops here en route to their summer breeding grounds, some arriving, bedraggled and depleted, after dayslong journeys from South America. “They're in a desperate need to replenish their weight,” said Lawrence Niles, a wildlife biologist who leads local shorebird conservation projects through his company, Wildlife Restoration Projects.

Fortunately, the birds arrive just as hordes of horseshoe crabs are hauling themselves up onto shore, laying eggs by the thousands. The birds might spend two weeks gorging on the gelatinous green eggs, “almost doubling their body weight,” Niles said. During that time, they blanket the beaches, mingle with local birds and give each other the flu.

Wild water birds — including ducks, gulls and shorebirds — are the natural reservoirs for influenza A viruses, which come in a variety of subtypes. Generally, wild birds carry relatively benign versions of these viruses, which pose little immediate threat to birds or people. But flu viruses can change quickly, accumulating new mutations and swapping genetic material. These changes can, and sometimes do, turn a hohum virus into a lethal one, like the version of H5N1 that is currently circulating.

Over the years, the St. Jude team has found it in 12% of their samples, on average, though that figure has climbed as high as 33%.