Yvette J. Johnson is a professor of veterinary clinical medicine. She studies clinical epidemiology and infectious diseases. She’s been keeping her eyes on the avian influenza that has spread to Russia, the Middle East and parts of Africa. While there are many strains of bird flu, the worrisome one is the highly infectious strain H5N1. Through April, 113 people had died. Experts predict that migrating birds may carry the flu to the U.S. Northwest this year. Johnson was interviewed by News Bureau life sciences editor Jim Barlow.
Avian flu is in the news with increasing alarm. Is the risk rising?
The situation has changed quite a bit since last fall. First, the pace at which the disease in birds has spread westward has increased. The virus appeared to remain in birds in Southeast Asia from 1997, when it was first reported in Hong Kong, to 2004 when it moved into Eurasia and the Middle East. Since last year it has been reported in birds across Eastern and Western Europe.
Secondly, migratory waterfowl were thought to only spread low pathogenic strains that didn’t mutate into a highly pathogenic strain until introduced into domestic poultry populations. Waterfowl usually shed the low-path virus but didn’t get sick or die. Now we are experiencing reports of illness and die-offs in migratory waterfowl infected with the highly pathogenic strain, and more mammalian species may be susceptible.
Last fall you had said that the risk to U.S. commercial flocks is low and that consumers were unlikely to be exposed to the virus by handling poultry meat or eggs. Has that thinking changed?
U.S. consumers still are not likely to be exposed to the virus from handling or consuming poultry meat or eggs. Even if there is an outbreak among commercial poultry in the U.S., sick birds won’t enter the food chain. As the disease moves further westward, there are, however, two concerns.
One, the virus may remain unchanged and enter the U.S. as primarily a bird disease and pose relatively little threat to human health. However, the threat to the $23 billion commercial poultry industry is huge. The last outbreak of high-path avian flu was in 1983 in Pennsylvania. It cost the U.S. $62 million for eradication, and it cost producers an estimated $200 million in morbidity and mortality among chickens and turkeys.
Secondly is the fear that this strain can cause human disease. The virus may mutate to one that is easily transmitted from person to person – thus the potential for the pandemic that everyone is worried about. So far though, it really seems to be hard for humans to get it. The cases have been in people having very close contact with sick birds.
Are we safer in the U.S. because we raise our poultry differently?
In developing countries many people raise chickens in a semi-scavenging scheme where they are outside mingling with wildlife, (whereas) in the United States, most commercial poultry are raised in total confinement. Still, people who have backyard flocks or rear free-range poultry have production systems where the birds may indeed contact wildlife and are often also in the proximity of commercial operations, so they are at greater risk of having a bird flu outbreak. Live bird markets always have been a source of avian influenza, so people who rear poultry at home should avoid these markets to avoid transporting the virus home.
So are there safeguards we should be thinking about?
While there’s no need to panic, we should definitely be concerned. There are lots of things the average person can do to reduce their risk of illness. To prevent exposure to this and many other potential health hazards people should use good hygiene especially when handling and preparing meat. Poultry and eggs should be cooked thoroughly. Cover your cough, wash your hands, and stay home from work or school when you are sick. And lastly, get your annual flu shot; it won’t protect you from avian flu but it will help to prevent the virus from changing into a pandemic strain.
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