Bird Flu in the news…Again? Still?

An old player in a new game

The first highly pathogenic avian influenza (HPAI) virus was isolated on the Italian peninsula in 1878. Like many immigrants of the Ellis Island era, the ‘Fowl Plague,’ as it became known, reached the shores of the U.S. via New York City sometime in 1924. The initial outbreak and another outbreak that occurred five years later were contained by destroying the poultry stock in the entire area.

When a highly pathogenic influenza virus is found in a flock, it is presumed that the virus will be transmitted indefinitely through the birds’ stool. Complete destruction of all the birds is considered to be the only option for eradicating the outbreak, even if the birds show no sign of infection. That practice continues today, with the large-scale culling of flocks used to eliminate the presence of the virus.

Culling is accepted internationally as a legitimate public health measure since the 1700s when it was first implemented to contain an outbreak of rinderpest, a diarrheal disease in cattle. However, the fact that culling is such a common intervention does not mean it is necessarily supported by scientific evidence. Being resource (manpower, time, monetary costs) intensive, from a public health perspective, a careful analysis of the available evidence is needed. An immediate argument against culling is that animals suffer both emotional and physical pain (McMillan, 2003) between the moment they are hurt (shot, poisoned, etc.) and their death. Researchers from the Centre for Biomedical Ethics, National University of Singapore, and Sourasky Medical Center in Tel Aviv, Israel have concluded that culling has not been proven effective or cost-effective from a scientific perspective and should be highly contested from a societal perspective.

Records show that since 1959, there have been 21 reported outbreaks of HPAI worldwide. The majority have occurred in Europe, with a few emerging in Mexico and Canada. Of the 21 incidents, five resulted in significant losses to regional economies. Minor outbreaks occurred sporadically throughout the U.S. and abroad until 1983, when a major epidemic of highly pathogenic H5N2 appeared on farms in rural Pennsylvania. Two years and $60 million later, the outbreak had been controlled. However, nearly 17 million birds—mostly chickens and domestic ducks—had been destroyed, leading to escalated consumer costs of approximately $349 million, mostly due to a 30 percent jump in retail egg prices.

In another part of the world and almost twenty years later (2001), H5N1 viruses were isolated at the Western Wholesale Food Market in Hong Kong from geese imported into the central slaughterhouse. Widespread testing was undertaken and many birds throughout the province were found to be positive, prompting authorities to order the slaughter of virtually all poultry—chickens, ducks, geese, and quail—in the territory. The slaughter of 1.2 million birds cost the farms and markets across the region more than $10 million.

The preceding chronology illustrates that avian influenza outbreaks have occurred in the U.S. and around the world with varying degrees of severity for decades. Taken in context, the real concern is about the economic losses to local farmers and the poultry industry. However, the nation and the economy have weathered HPAI outbreaks in the past; this is nothing new. Keep that in mind—and don’t panic—if and when the media starts hawking the “arrival of H5N1” in this country.

Bird flu, Round 1

The bird flu hype first appeared on the world stage in May 1997 through an ironically innocent setting. A Hong Kong preschool had set up a small petting zoo on its grounds, making a home for five chickens and eight ducks. The children were delighted to spend time with their new-feathered friends. Several days later, a three-year-old boy in the class began to cough. The illness and fever progressed rapidly. The boy’s parents rushed him to the hospital where he was admitted with pneumonia and respiratory distress. Six days later, the child died suddenly from complications of multiple organ system failure. The doctors requested an autopsy but no underlying immunodeficiency or cardiopulmonary disease was identified. Three months later, tracheal washings that had been sent to a reference laboratory in the Netherlands and the U.S. CDC identified viruses to be viruses avian influenza A virus, H5N1. In a report published later, researchers held that this particular bird flu virus had not previously caused infection in humans. The news of the direct bird-to-human transmission sent a chill throughout the medical and scientific community: This was reported to be the first documented isolation of H5N1 in humans and was all public health officials around the globe needed to hear. They believed the next pandemic had arrived.