With all the alarming press coverage, one might think of bird, or avian, flu (influenza A, or H5N1) as a modern mutation. However, if one looks into the history of this disease, one learns that it dates back to the 19th century, when it evolved in commercially produced poultry in Italy. More recently, the highly pathogenic H5N1 virus is descended from a strain that first appeared in Scotland in 1959. From there, the virus migrated to China, where it has been active for more than a decade. Large-scale commercial production of poultry for human consumption involves birds being packed close together, allowing for easy transmission of the disease. Though this article is not a forum for a statistical accounting of bird flu, a few stats are important in order to understand this lethal phenomenon.

Chicken production in Southeast Asia has increased to 2.7 million tons annually in the last 30 years. The Chinese produce 10 million tons of chickens each year in factory farms. “The Kitchen of the World,” Charoen Pokphand Group in Thailand, exported about 270 million chickens in 2003. The CP Group, suffering huge losses from bird flu, is trying to contain the infection, but the cat is out of the bag, so to speak.

Bird, or avian, flu is an influenza A virus subtype that occurs mainly in birds, where it is highly contagious and can be deadly. The concern, of course, is that bird flu may evolve into zoonoses, a disease transmissible between humans and animals. A common example of zoonoses is salmonella, that nasty bug humans can contract from undercooked chicken and eggs. As of this writing, the World Health Organization (WHO) has reported human infection in seven countries in East Asia, Europe, and the Near East. The numbers are tiny, but human infection resulting from direct contact with infected poultry has begun occurring. On the other hand, poultry-to-poultry and wild-bird-to-wild-bird-infections have been reported on an ever-expanding scale. It is likely that the H5N1 infection among birds has become endemic in certain areas, meaning the disease has become constantly present. In addition to several outbreaks occurring in East Asia, Europe, and the Near East (37 countries, including France, Germany, and Italy), infected birds have also been reported in Africa and South Asia (six countries).

The Threat

The most pressing concern is human-to-human contagion of bird flu. As of this writing, this has not been documented, but people need to stay alert. Three agencies are charged with monitoring the situation by virtue of their charters — the Centers for Disease Control and Prevention (CDC), the U.S. Department of Agriculture (USDA), and WHO. If a pandemic were to occur in the U.S., then local county public health agencies also would monitor and report to public officials.

By way of background, three major pandemics occurred in the 20th century, in 1918–1919, 1957, and 1968, mainly due to genetic variants of type A influenza virus. The advance of bird flu has been called a potential pandemic, that is, a global epidemic occurring over a very wide area, crossing international boundaries, and usually affecting a large number of people. Whether containment is possible remains to be seen. Are wild birds carrying the virus along migratory pathways? Are commercial poultry practices and infected humans carrying the disease along railway lines, roads, and across international boundaries?

Whatever the answer, scientists are working at a furious pace to develop commercially available vaccines to combat a human infection pandemic should one occur. However, it will likely require many months before such vaccines can be mass-produced and made widely available. We already know that the virus shows resistance to two antiviral medications currently used for treatment of influenza — amantadine (Cerebramed) and rimantadine (Roflual). It is believed, however, that oseltamivir (Tamiflu) and zanamivir (Relenza) should still be effective against the currently circulating strains of the H5N1 virus.

Current information comes primarily from the two federal agencies, WHO, and some from local county public health agencies. Searching PubMed provides evidence-based and peer-reviewed journal literature on such aspects of bird flu as treatment, clinical trials, and etiology.

Centers for Disease Control and Prevention

This is the primary agency responsible for public health and diseases. CDC’s Web site is rich with information on bird flu, or avian influenza as the agency calls it, at http://www.cdc.gov/flu/avian/index.htm. Offered in English, Spanish, Chinese, and Vietnamese, the page is organized by “What You Should Know,” “Specific Topics,” “Information for Special Groups,” and “Additional Resources.” Definitions of avian, pandemic, and seasonal flu appear prominently on the pages to help teach the differences. The “What You Should Know” page includes key facts, information about infection in humans, Q&A, the current situation updated daily, and a link to http://www.PandemicFlu.gov.

Perhaps the information that most concerns people involves the planning and response activities underway at governmental agencies. Going to PandemicFlu.gov provides the answers, something for everyone, in fact. Hosted by the CDC and the Department of Health and Human Services, the site provides flu pandemic planning assumptions, based largely on the 1918 influenza epidemic, that are being used throughout the federal government to define a severe-case scenario. A link takes readers to these assumptions. Other links and tabs lead to response activities underway by federal, state, and local governments. Planning and preparation steps for a pandemic are available for families, schools, and businesses.

U.S. Department of Agriculture

The first item that greets you on the Department of Agriculture’s bird flu page [http://www.usda.gov/wps/portal/!ut/p/_s.7_0_A/7_0_1OB?navid=AVIAN_INFLUENZA&navtype=SU] is a link to PandemicFlu.gov and Avian Flu.gov, “The official U.S. government Web site for information on pandemic flu and avian influenza.” This link is followed by phone numbers for the USDA’s Veterinary Services to report sick or dead farm birds and information on how to make contact with wildlife officials in your state to report sick or dead wild birds.

Like the CDC and WHO, the USDA has a plan for efforts and response to the bird flu disaster. Available in a PDF file, the plan describes restrictions on the importation of poultry and poultry products from countries where the H5N1 strain has been detected in commercial or traditionally raised poultry, but not in wild or migratory birds. Imported birds are quarantined for 30 days at a USDA quarantine facility and tested for the virus.

One interesting tidbit turned up in the response plan. Apparently, the USDA maintains a bank of bird vaccines to protect healthy birds if an HPAI (Highly Pathogenic Avian Influenza) outbreak were to occur. One smiles at the image of khaki-clad bureaucrats chasing down birds to shoot them with a hypodermic needle — talk about herding cats!

Speaking of cats, the USDA provides a very useful page on avian flu and cats, including a timetable from the 1970s to Feb. 28, 2006, when a dead cat that had eaten infected birds was found in Germany. Not surprisingly, we are told that due to their greater mobility, stray cats could spread the disease into new areas. If infected, stray cats may become a source of contamination to poultry and mammals, including humans. Recommendations for pet owners include reporting dead birds to the authorities, keeping pets indoors, practicing proper hand hygiene, and promptly treating sick pets.

The World Health Organization

WHO coordinates the global response to human cases of H5N1 and monitors the corresponding threat of influenza pandemic. At the time of this writing, WHO was recommending oseltamivir (Tamiflu) to treat patients. Dosages for children and adults are provided with the caveat that clinical trials are needed to determine the effectiveness of this vaccine for bird flu.

As compared to the CDC page on bird flu, however, WHO’s page is deceptively sparse. It links to Related Sites, Fact Sheets, and Features, but not until you click on Related Sites [http://www.who.int/topics/avian_influenza/en/], for instance, does the richness of WHO’s site become apparent.

The Related Sites page provides information that tracks the evolving situation and provides access to both technical guidelines and information useful for the general public. The link titled “Cumulative number of confirmed human cases” leads to a table listing cases and deaths by country and year from 2003. As of March 21, 2006, when this article was written, Indonesia had 22 deaths, the highest of any country.

Like the CDC and the USDA, WHO has a draft protocol for rapid response and containment presented in a PDF file. This protocol is a technical document intended for bureaucrats and gives guidelines for such activities as using the emergency stockpile of vaccines. There is no mention of personal, school, or business activities as with the CDC and USDA, however.

The Features link has a single topic: “Avian influenza, am I at risk?” As of March 2006, WHO’s answer was not totally reassuring. In answering the question whether the virus will change into a form that is highly infectious for humans and spreads easily from person to person, WHO says this “has yet to occur.” That “yet” is hardly reassuring. On the other hand, WHO reports, “Initial investigation has found no evidence that the virus has increased in its transmissibility or is spreading from person to person.”

PubMed

Maintained by the National Library of Medicine, PubMed [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed] is a free database that lets you search more than 16 million bibliographic citations and abstracts in the fields of medicine, nursing, dentistry, pharmacy, veterinary medicine, healthcare services, and the preclinical sciences. For the most part, the articles are peer-reviewed and include a rich component of clinical trial papers.

Unlike the CDC’s expression, avian influenza, the National Library of Medicine’s lexicographers prefer the index term “InfluenzainBirds.”The term description does not mention human infection, however:

Infection of domestic and wild fowl and other BIRDS with INFLUENZA A VIRUS. Avian influenza usually does not sicken birds, but can be highly pathogenic and fatal in domestic POULTRY. –Year introduced: 2006 (1963)

Articles were previously indexed as “Orthomyxoviridae Infections” or “Poultry Diseases” between 1966 and 1969. The definition of the latter term is most interesting in light of the growing awareness that all is not well. Trust the lexicographers to keep our feet on the right path. The description of “Poultry Diseases” reads “Diseases of birds which are raised as a source of meat or eggs for human consumption and are usually found in barnyards, hatcheries, etc. The concept is differentiated from BIRD DISEASES which is for diseases of birds not considered poultry and usually found in zoos, parks, and the wild.” By the way, PubMed maps current terms to previous terms, so searching on “InfluenzainBirds”brings up all articles back to 1963.

The Politics of Poultry

Given the vital issues at stake, bird flu is a politicized, emotional issue for those who make their living in the poultry industry, from those operating giant factory farms to rural families with a few chickens in the yard. Two organizations that track bird flu and provide timely information on their Web sites are Grain and BirdLife International.

Grain [http://www.grain.org], based in Barcelona, Spain, is an “international non-governmental organization that promotes the sustainable management and use of agricultural biodiversity based on people’s control over genetic resources and local knowledge.” The organization advocates the viability of backyard, free-range poultry in the face of those who would abolish the right of small farmers to continue farming outdoors.

BirdLife International [http://www.birdlife.org], based in Cambridge, England, works to protect migrating birds, which are “victims not vectors.” The organization provides copies of press releases about the status of migrating birds, FAQs on avian flu, and control of the illegal bird trade on its Web site.

The vision statement is clear and quite charming, “By focusing on birds, and the sites and habitats on which they depend, the BirdLife Partnership is working to improve the quality of life for birds, for other wildlife (biodiversity), and for people.” Clearly a birdwatcher’s cup of tea, the March 2006 issue of WorldBirdwatch magazine contains details of sightings of a Colombian hummingbird that has been studied for the first time.

Conclusion

A scholar reviewing the state of affairs vis a vis bird flu would confront conflicting data. Are wild birds carrying the virus along migratory pathways? Are commercial poultry practices and infected humans carrying the disease along railway lines, roads, and across international boundaries? Recently, TheNew York Times ran point-counterpoint articles to illustrate the range of opinion on the situation. David Nabarro, chief bird flu coordinator for the U.N., and Jeremy Farrar, director of the Oxford University Clinical Research Unit at the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam, were interviewed.

Nabarro described himself as “quite scared” because the virus has spread much faster than he expected it to. “That rampant, explosive spread,” he said, “and the dramatic way it’s killing poultry so rapidly suggests that we’ve got a very beastly virus in our midst” (The New York Times, March 28, 2006, “At the U.N.: This Virus Has an Expert ‘Quite Scared’”).

But Farrar and his Vietnamese colleagues probably have more clinical experience than any other doctors in the world with the virus. “Having observed A(H5N1) for many years in Asia, he thinks it is unlikely that the virus is poised to jump species, becoming readily transmissible to humans or among them. Nor does he believe the mantra that a horrific influenza pandemic is inevitable or long overdue” (The New York Times, March 28, 2006, “On the Front: A Pandemic Is Worrisome but ‘Unlikely’”).

Turning to a PubMed search to solve this intellectual logjam — lo and behold — the intrepid searcher sees a recent article published in Science that offers a reasonable explanation for Farrar’s optimism. Unlike influenza viruses, H5N1 infects cells in the lower respiratory tract — you may sneeze and cough, but your bird flu germs will not be expelled into the atmosphere (Science, March 24, 2006, “Studies Suggest Why Few Humans Catch the H5N1 Virus”). Whew, is that good news!