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SUSSEX: Del. officials monitor ducks for avian flu
By Molly Murray
The News Journal
REHOBOTH BEACH ? Delaware?s largest population of canvasback ducks spends the winter in an unlikely place ? Silver Lake in Rehoboth Beach.
There isn?t a marsh here but the birds, a flock of about 300, keep returning year after year to this safe haven amid the swank oceanfront homes and private gazebos that line the lake.
For state wildlife officials, the resting area has become a perfect laboratory ? to band and track the movements of these ducks and to study the population for Avian Influenza.
The canvasbacks are one of seven species of migratory birds that will be tested for the virus in Delaware this year.
?We have bird flu all the time,? said Jack Gelb Jr., chairman of the University of Delaware?s Animal and Food Science Department and Director of the Avian Biosciences Center. But what scientists and researchers have seen in the wild bird population hasn?t caused concern.
Still, scientists and government officials worry that some strains from the wild could infect Delaware?s economically vital poultry industry. They also say a more potent strain of a specific bird flu could come to North America and make people seriously ill.
After years of monitoring, researchers throughout the county have found lots of bird influenza strains in the wild population but none is the potentially lethal, highly pathogenic variety that has been blamed for more than 100 human deaths in Asia.
In 2004, two poultry flocks in Delaware were destroyed after birds became infected with an H7N2 version of bird flu. That virus was tracked back to live bird markets and not to the wild bird population.
As part of an early warning system, scientists throughout the country have sampled thousands of birds in key migratory flyways looking for signs of the disease.
Last year alone, more than 2,000 birds were sampled in Delaware.
Birds make a complicated subject of study because there are thousands of species, said Richard Slemons, a veterinary professor at Ohio State University and one of the country?s leading experts on avian influenza surveillance.
With humans, for instance, there is just one species to look at, he said. The same is true with swine. But with birds, there are some 9,500 species, he said.
?We?re trying to see what happens? within flyways, he said.
So when state wildlife officials were collecting their samples, former state wildlife administrator H. Lloyd Alexander came along to collect samples for Slemons? flyway research project.
Early Wednesday morning, Rob Hossler, a state wildlife biologist, and a team of scientists headed to Rehoboth Beach.
They set up two metal cages just off the shoreline of Silver Lake, baited the bottom with corn and waited.
The birds are already here ? back from feeding in a field and Hossler expected them to spend most of the day oafing on the lake.
The cages, about the size of a portable kennel for a St. Bernard-size dog, allow the birds to come in to feed. But once inside, these ducks that dive to retrieve kernels of corn, can?t figure out how to get back out.
The researchers load poultry crates on a canoe, wade it out into the lake and use big flounder nets to scoop the ducks out of the cage.
The ducks flap and splash but Hossler said they are among the easiest birds to work with because they are so calm.
Canvasbacks, which take their Latin name from the wild celery they like to eat, are stunning birds with a gray-white body that looks like an artist?s canvas. The males have a rusty red head and red eyes. Females have a more muted, reddish-brown head and darker body.
The scientists set up shop in a portable trailer, working quickly to process the birds. One team takes a swab from each duck?s throat. Another researcher takes a fecal sample from the butt and a third scientist attaches a metal tracking band to each duck?s leg. The duck is then passed to Alexander who takes a second fecal sample, which will be shipped to Slemons? lab for study.
The state samples go to the University of Delaware for an initial screening and any that are positive for bird influenza are sent to a federal laboratory in Ames, Iowa for genetic screening to further identify the viral strain, Gelb said.
Bird viruses take many forms and most are harmless, he said.
The numbering system is based on two proteins in the virus. If you think of the virus looking like a tire on a wheel, both proteins are on the outer edge of the tire. The H part is a surface protein called Haemagglutinin. That refers to the ability of the protein to make red blood cells clump together, Gelb said.
The N part is for a second surface protein that is more like an enzyme, called Neuraminidase, he said.
Within the influenza world, there are 16 different H types and 9 different N types, which can join to form many distinct combinations, Gelb said.
For instance, the Avian Influenza that is of most concern for humans is the highly pathogenic H5N1 strain.
In Delaware, there have been birds with an H5N1 strain but none has been the highly pathogenic form that has been seen in Asia, he said.
Besides interest in the virus, state officials would also like to find out more about the state?s small canvasback population.
The birds were once among the most important market ducks in the Atlantic Flyway, Hossler said.
Canvasbacks were heavily hunted in a time when mallards weren?t found in our area, he said.
?This was the duck that created market hunting,? Hossler said.
This is the second year state officials have banded and tested canvasbacks and they suspect the birds may fly to Lake Erie and then west to the Dakotas for breeding. But with more band returns, they should be able to piece together where the Delaware birds go, Hossler said.
The last comprehensive work on canvasbacks in Delaware was in the 1960s, he said.
SUSSEX: Del. officials monitor ducks for avian flu
By Molly Murray
The News Journal
REHOBOTH BEACH ? Delaware?s largest population of canvasback ducks spends the winter in an unlikely place ? Silver Lake in Rehoboth Beach.
There isn?t a marsh here but the birds, a flock of about 300, keep returning year after year to this safe haven amid the swank oceanfront homes and private gazebos that line the lake.
For state wildlife officials, the resting area has become a perfect laboratory ? to band and track the movements of these ducks and to study the population for Avian Influenza.
The canvasbacks are one of seven species of migratory birds that will be tested for the virus in Delaware this year.
?We have bird flu all the time,? said Jack Gelb Jr., chairman of the University of Delaware?s Animal and Food Science Department and Director of the Avian Biosciences Center. But what scientists and researchers have seen in the wild bird population hasn?t caused concern.
Still, scientists and government officials worry that some strains from the wild could infect Delaware?s economically vital poultry industry. They also say a more potent strain of a specific bird flu could come to North America and make people seriously ill.
After years of monitoring, researchers throughout the county have found lots of bird influenza strains in the wild population but none is the potentially lethal, highly pathogenic variety that has been blamed for more than 100 human deaths in Asia.
In 2004, two poultry flocks in Delaware were destroyed after birds became infected with an H7N2 version of bird flu. That virus was tracked back to live bird markets and not to the wild bird population.
As part of an early warning system, scientists throughout the country have sampled thousands of birds in key migratory flyways looking for signs of the disease.
Last year alone, more than 2,000 birds were sampled in Delaware.
Birds make a complicated subject of study because there are thousands of species, said Richard Slemons, a veterinary professor at Ohio State University and one of the country?s leading experts on avian influenza surveillance.
With humans, for instance, there is just one species to look at, he said. The same is true with swine. But with birds, there are some 9,500 species, he said.
?We?re trying to see what happens? within flyways, he said.
So when state wildlife officials were collecting their samples, former state wildlife administrator H. Lloyd Alexander came along to collect samples for Slemons? flyway research project.
Early Wednesday morning, Rob Hossler, a state wildlife biologist, and a team of scientists headed to Rehoboth Beach.
They set up two metal cages just off the shoreline of Silver Lake, baited the bottom with corn and waited.
The birds are already here ? back from feeding in a field and Hossler expected them to spend most of the day oafing on the lake.
The cages, about the size of a portable kennel for a St. Bernard-size dog, allow the birds to come in to feed. But once inside, these ducks that dive to retrieve kernels of corn, can?t figure out how to get back out.
The researchers load poultry crates on a canoe, wade it out into the lake and use big flounder nets to scoop the ducks out of the cage.
The ducks flap and splash but Hossler said they are among the easiest birds to work with because they are so calm.
Canvasbacks, which take their Latin name from the wild celery they like to eat, are stunning birds with a gray-white body that looks like an artist?s canvas. The males have a rusty red head and red eyes. Females have a more muted, reddish-brown head and darker body.
The scientists set up shop in a portable trailer, working quickly to process the birds. One team takes a swab from each duck?s throat. Another researcher takes a fecal sample from the butt and a third scientist attaches a metal tracking band to each duck?s leg. The duck is then passed to Alexander who takes a second fecal sample, which will be shipped to Slemons? lab for study.
The state samples go to the University of Delaware for an initial screening and any that are positive for bird influenza are sent to a federal laboratory in Ames, Iowa for genetic screening to further identify the viral strain, Gelb said.
Bird viruses take many forms and most are harmless, he said.
The numbering system is based on two proteins in the virus. If you think of the virus looking like a tire on a wheel, both proteins are on the outer edge of the tire. The H part is a surface protein called Haemagglutinin. That refers to the ability of the protein to make red blood cells clump together, Gelb said.
The N part is for a second surface protein that is more like an enzyme, called Neuraminidase, he said.
Within the influenza world, there are 16 different H types and 9 different N types, which can join to form many distinct combinations, Gelb said.
For instance, the Avian Influenza that is of most concern for humans is the highly pathogenic H5N1 strain.
In Delaware, there have been birds with an H5N1 strain but none has been the highly pathogenic form that has been seen in Asia, he said.
Besides interest in the virus, state officials would also like to find out more about the state?s small canvasback population.
The birds were once among the most important market ducks in the Atlantic Flyway, Hossler said.
Canvasbacks were heavily hunted in a time when mallards weren?t found in our area, he said.
?This was the duck that created market hunting,? Hossler said.
This is the second year state officials have banded and tested canvasbacks and they suspect the birds may fly to Lake Erie and then west to the Dakotas for breeding. But with more band returns, they should be able to piece together where the Delaware birds go, Hossler said.
The last comprehensive work on canvasbacks in Delaware was in the 1960s, he said.
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