The latest flu outbreak isn’t likely to make you cough, sneeze and ache all over…not unless you have feathers. The epidemic may make your breakfast omelet more expensive, but eating your usual eggs, turkey or chicken will not make you sick.
Since first discovered in poultry flocks in late 2014, nearly 45 million chickens, turkeys and other poultry have been euthanized in efforts to control the most recent avian influenza outbreak. According to the USDA more than 205 producers have had birds test positive for the virus. When the virus is detected all the birds in affected facilities are killed and composed or rendered. Flocks, including backyard laying hens and small scale free-range operations, within 6 miles of the infected flocks are tested and quarantined for six weeks. No eggs or any other poultry products are allowed to leave the farm until the tests come back clear. So far, the USDA lists only 18 backyard flocks as having tested positive. One of those was a “backyard” operation housing almost 6000 pheasants. It seems that, so far, laying hens and turkeys have been affected at much a higher rate than other kinds of poultry. The disease was initially thought to be spread by migrating waterfowl who can carry the disease, but rarely get sick from it.
While the Center for Disease Control is recommending that anyone working in close contact with infected birds be monitored for flu-like symptoms, as yet, there are no cases of humans contracting this particular strain of virus.
So why do commercial egg laying chickens and turkeys get sick and wild ducks don’t? Why are there only 18 cases of the thousands of backyard flocks testing positive? Even the epidemiologists are scratching their heads. Their usual theories of how the disease is spread are, so far, not holding up.
The US produces 240 million turkeys a year. Most of them are raised in houses holding thousands of birds. Ninety percent of the turkeys raised commercially in the world are bred by two companies. Ninety-nine percent of all turkeys raised in the US are a couple of strains of Broad Breasted Whites, a cross between Broad Breasted Bronze and White Holland turkeys. They were selectively bred to grow quickly, use feed efficiently, have large breasts and white feathers which leave no dark specks in the skin when plucked. The breasts of these birds have gotten so large that the males cannot mount the hens to breed them. The hens must be artificially inseminated. A Broad Breasted White turkey tom can reach 38 pounds in a mere 18 weeks from hatching.
So what does the fact that 240 million turkeys all share the same great grandparents have to do with the bird flu? With genetic diversity comes a diversity of disease resistance and immunity. If Broad Breasted Whites share a genetic characteristic that makes them particularly susceptible to the H5N2 virus, then all the turkeys in all the barns in Minnesota probably share the problem.
Biosecurity systems attempt to keep the viruses out of the barns, but obviously these efforts are either not stringent enough or are not followed 100 percent of the time. Once inside the barn, the lack of genetic diversity in many of our commercially produced poultry seems likely part of the reason this disease has spread so quickly. These birds are also raised in close quarters where diseases can spread quickly from bird to bird in spite of all the best efforts of the producers raising them. Chickens may have as little room as a half a square foot per bird while a 20 pound turkey may have four square feet to spread his wings. They spend their days beak to beak, nose to nose, sneeze to sneeze.
Perhaps the experts should be studying why, in spite of there being thousands of small chicken flocks on farms and suburban backyards, only 18 of them have so far tested positive for the virus. Even though small flocks are often outside and potentially exposed to wild birds, they don’t seem to be getting sick as frequently. Backyard flocks generally are genetically diverse both in species and in breeds. Backyard breeds tend to be older breeds that grow more slowly. Perhaps like children who play in the dirt, backyard chickens have more robust immune systems. Often they have more room and much fresh air and warm sunshine, two of the factors that experts say may slow down the spread of the disease as summer warms up.
The journal “Science,” in a recent article declared the outbreak “enigmatic.” “All the old dogma about high-path influenza transmission has just gone out the window,” Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, told the journal. “We’re in totally uncharted territory.”
For now, however it spreads, if you don’t have feathers or you don’t hang out with friends with feathers, the most recent avian flu epidemic probably isn’t going to make you sneeze.
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