Although avian influenza (commonly referred to as bird flu) poses little threat to the public, health officials are keeping a wary eye on reported cases as highly infectious strains of this flu continue to spread in commercial poultry (such as chicken and turkey), backyard flocks, and wild birds.
The United States Geological Survey on Tuesday confirmed detection of H5 and H5N1 avian viruses in 34 states. The Texas Animal Health Commission recently recorded the state’s first incidents of highly pathogenic avian influenza (HPAI) when the virus was discovered in a commercial pheasant flock in Erath County. In North Carolina, the department of agriculture this week suspended all poultry shows and public sales until further notice as infections broadened there.
An estimated 22.8 million birds have been lost so far this year because of the virus, reported the Center for Infectious Disease Research and Policy. Iowa — which is the nation’s largest egg producer — has been particularly hard hit, losing at least 13.2 million poultry. The situation there has become so dire that Governor Kim Reynolds issued a disaster proclamation.
“The way to contain this flu is unfortunate,” says William Schaffner, MD, an infectious-disease specialist and a professor of preventive medicine and health policy at the Vanderbilt University School of Medicine in Nashville, Tennessee. “What you do is actually kill a lot of poultry in order to prevent areas from becoming hot spots for bird flu.”
Outbreak Driving Up Egg Prices
The ripple effect of this huge loss can be seen on supermarket shelves: Egg prices have shot up by about 52 percent since February 8, when the first confirmed case of HPAI was found on a turkey farm in Indiana, according to The Wall Street Journal.
Risk to Humans Is Real, but Low
Should the average American be worried about this major outbreak among birds? The Centers for Disease Control and Prevention (CDC) says no. Human infections with avian viruses are uncommon.
Dr. Schaffner notes that these bird viruses, fortunately, do not seem to attach efficiently to the cells we have in our upper airways, noses, and throats. And since they do not spread readily from bird to human, the viruses do not easily transmit from person to person either. He added that consumers also need not worry about getting the illness from consuming or touching store-bought eggs and chicken.
Still, transmission is possible. CDC figures show that since 1997 more than 880 people worldwide have contracted HPAI and about half died of the disease. Symptoms can range from mild upper-respiratory tract symptoms and lower-respiratory tract disease to severe pneumonia with respiratory failure, encephalitis (inflammation of the brain), and multi-organ failure.
Most people who have gotten avian flu live with or work among poultry. “Some people may have job-related or recreational exposures to birds that put them at higher risk of infection,” writes the CDC.
On the Alert for Mutations of the Virus
While not overly concerned about the human impact of this latest avian flu outbreak, public health officials are on the alert for mutations that could be more harmful to people. The 2009 H1N1 pandemic or swine flu outbreak originated in pigs, but scientists later found that the flu was a recombinant form of flu strains from birds and humans.
The different types of flu viruses mixed within pigs, swapping genes and giving rise to a variant that could infect human cells and reproduce.
“In this case, bird flu and human flu strains got together and exchanged genetic elements,” says Schaffner. “The pig acted as a kind of test tube and produced a new flu that could spread to humans. This happens rarely, but the world's influenza laboratory communities are constantly on the alert for that possibility.”
How to Protect Yourself
As a general precaution, people are advised to avoid direct contact with wild birds and observe them only from a distance. Wild birds can be infected with bird flu viruses without appearing to be sick.
Individuals should avoid chickens and other poultry that appear ill or have died and avoid contact with surfaces that appear to be contaminated with feces from wild or domestic birds.
Because flu viruses are constantly changing, the CDC says it will continue to monitor these viruses to look for genetic or epidemiological changes suggesting that they might spread more easily to and between people.