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Biosecurity Best Defense Against Avian Flu

posted on July 28, 2006

A bird flu outbreak was confirmed in Laos this week where more than 25-hundred chickens were found dead of the H-5-N-1 strain of the virus.

It is the same strain of virus that a pharmaceutical company this week said can mass produce a vaccine to immunize people.

GlaxoSmithKline said it can produce large quantities of the vaccine because it uses lower doses than other vaccines, of an inactivated strain of H-5-N-1.

The announcement follows what the company called encouraging results from a clinical trial conducted on 400 adults in Belgium.

Worldwide, bird flu has become a preoccupation for health workers stockpiling vaccine, and the government stepping up testing of migratory fowl. In farm country, the focus is on bio-security. Laurel Bower Burgmaier explains.


Biosecurity Best Defense Against Avian Flu

Dr. Darrel Trampell, Iowa State University: "I think we should be concerned about the potential. But, it's very important to realize that the virus present in Asia and Europe is not in this country and it's not on the North American continent."

Dr. Darrell Trampel is the Extension Poultry Veterinarian and Veterinary Diagnostician at Iowa State University. He says low pathogenic strains of avian influenza have shown up from time to time in U.S. poultry flocks, and, although rare, other high pathogenic strains have occurred in this country as well.

Dr. Darrell Trampel, Iowa State University: "Avian influenza in poultry occurs sporadically and almost always is low pathogenic. In most cases, farmers don't even know the virus is in the flock. The strains are unique in how severe they are killing birds and they are also unique in that people when exposed to the sick birds develop the disease."

While the idea of a worldwide avian flu pandemic is scary for anyone, it's especially worrisome for people who make a living in egg and poultry production. The appearance of a highly pathogenic H5N1 influenza could be economically disastrous for the U.S. poultry industries. Financial losses accrue from the depopulation of affected and exposed flocks, loss of markets, and costs of clean-up and disinfection. One example is the 1983-84 outbreak of a highly pathogenic strain in the Northeast, which cost the U.S. government $65 million. Some 17 million birds had to be killed, resulting in a 30 percent increase in retail egg prices.

Dr. David Halvorson is a renowned researcher, veterinarian and professor at the University of Minnesota, specializing in avian respiratory diseases and virus security issues.

Dave Halvorson, University of Minnesota: "The most important thing to do here in animal agriculture is to prevent the introduction of any kind of influenza. And we call this biosecurity, which is a four-dollar word for isolation, sanitation, and traffic control."

Avian flu may have less opportunity for widespread infection in U.S. commercial flocks because of the poultry confinement facilities used here. In many developing countries, people, poultry and pigs all live in the same building, making it very easy for a virus to go from one to another. According to United Nations officials, farmers in these parts of the world are completely unprepared, lacking the money and the scientific infrastructure to control outbreaks of the virus.

The U.S. commercial poultry industry long has taken action against bird diseases. Mark Friedow works for Sparboe Companies, the nation's fifth largest egg producer. Employees in Sparboe facilities follow strict biosecurity guidelines.

Mark Friedow, Sparboe Companies: "What we've done is taken the approach of making sure that the facilities are constructed so that we can eliminate access by other rodents and animals. Then, we've made sure that our people go through a biosecure program and that everything coming into the farm really needs to be there."

In general biosecurity standards, large commercial poultry operations are much more stringent than those associated with small farm flocks. The commercial industry believes confining poultry and laying hens is the best way to keep the birds safe and to keep diseases out.

Dr. Darrell Trampel, Iowa State University: "Poultry that are outside are at a much greater risk than commercial poultry that are housed indoors. Because of this, many of the countries in Europe have mandated that the poultry outdoors be taken and placed in confinement to reduce the risk of exposure. And, we know from experience in the Midwest that when turkeys were moved from out on the range or living outdoors and put into confinement houses, the incidents of influenza in these birds plummeted by 95 percent or more."

Researchers say wild and domestic waterfowl can carry avian influenza in their intestinal tracts and not get sick with it. They add because of this, the idea that migratory birds can infect unhoused birds with bird flu is not such a big leap.

Dr. David Halvorson, University of Minnesota: "It is kind of a conflict, that on the one hand we have people wanting poultry to be raised in a more natural environment. And on the other hand, we have this need to protect ourselves from these infections. A lot of issues get raised and I don't know how it's going to settle out."

At the University of Minnesota, Halvorson and his students research avian respiratory diseases, studying wild water fowl, live poultry markets and domestic flocks. Their work helps pinpoint what kinds of viruses are circulating in all types of birds. Halvorson knows firsthand how farmers are affected by avian flu.

Dr. David Halvorson, University of Minnesota: "About two weeks after I got here, the turkey industry suffered the largest influenza outbreak they had ever had. It involved over 150 flocks and economic losses to the growers of over 10 million dollars. So, that was my introduction to avian influenza and what a severe disease it was."

Halvorson explains until the range production stopped, Minnesota had a lot of low pathogenic influenza –not the high pathogenic strain currently in Asia. In response to the Hong Kong outbreak of highly pathogenic influenza in 1997, Minnesota and the rest of the U.S. decided that a significant change had to occur. So, starting in 1998, less than one percent of Minnesota's turkeys were being ranged.

Dr. David Halvorson, University of Minnesota: "Prior to 1998, we averaged approximately 50 flocks a year where we would detect avian influenza in turkey flocks. After 1998, let's say for the next seven years, I think we saw a total of either three or four flocks of turkeys in that period. So, that was a dramatic change in avian influenza infection in turkeys."

While the H5N1 strain currently killing poultry and humans in other parts of the world hasn't been detected in the U.S. yet, state and federal officials aren't taking any chances. Many states have a surveillance program to detect avian influenza. The Department of Agriculture, along with the Departments of the Interior and Health and Human Services, are expanding screening for H5N1 in migratory birds. The wild bird monitoring plan is part of the President's National Strategy for Pandemic Influenza Preparedness. Last December, Congress appropriated $3.8 billion to help the nation prepare.

Dr. Darrell Trampell, Iowa State University: "It is important to realize that even if the virus did get into this country and into our poultry in this country, we have a wonderful system to find the virus and to stamp out and eradicate the virus. Our abilities in this country and the resources we have are entirely different than those in Southeast Asia. And, the resources will allow us to quarantine affected areas and totally eradicate the virus in a much more efficient fashion than they are able to do to date over in Asia."

For Market to Market, I'm Laurel Bower Burgmaier.


Tags: agriculture animals birds chickens diseases farmers food safety health influenza news poultry security