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15. The H5N1 Virus: Avian Flu or Bird Flu

Pandemic Concerns Today

Here are some of the headlines from reputable sources such as the CDC, World Health Organization, HHS, etc. It is no wonder that we are in a potential state of anxiety with pandemic concerns growing almost daily:

Seasonal Flu Versus Pandemic Flu

Seasonal Flu
Pandemic Flu

Do Nurses Need to Worry About the Avian Flu: H5N1 Virus?

“It could be the disaster of our time. Three billion dollars is not enough” North Dakota Sen. Kent Conrad said regarding the emergency funds the Bush administration requested from Congress. Late in 2005, Congress approved more than $3 billion in emergency money.

No government in the world is ready now. Never before has the world been able to see flu pandemic on the horizon or had so many possible tools to minimize its impact once it arrives.

Brief History of H5N1 Virus

Nearly every news station, magazine, radio station, and newspaper has some sort of coverage on the latest casualties on a daily basis. Despite cries to become prepared, it does not appear that has come to fruition as of yet, anywhere.

Spread of avian flu was thought to occur from infected birds only. However, in January 2005, the New England Journal of Medicine reported the first documented probable human-to-human transmission of the new avian flu disease.

“A 48-year-old Thai man who died yesterday had H5N1 avian influenza, marking Thailand’s first human case in more than a year,” according to Thai officials and the World Health Organization (Oct 20, 2005).

On Oct. 19, 2005 outbreaks were reported in European Russia, China, and Vietnam, with similar outbreaks in Turkey and Romania. A cat in Germany died of bird flu in Feb. 2006 and another was infected in Austria (March 2006). In May 2006, H5N1reportedly killed seven members of a family in Indonesia. World Health Organization officials believe the infection was passed through human contact (, May 2006.)

The US bans chickens from the following countries that have to date reported chickens infected with H5N1: (current as of March 20, 2006).

Burma (Myanmar)
France (USDA – defined restricted zone only)
South Korea

Avian Flu Expected Soon in the United States

The bird flu could appear in the United States in the next few months as wild birds from infected nations in Asia migrate via Alaska into the continental US. It is believed that in the fall of 2006, when the birds migrate south for winter, the US could see H5NI on its shores.

“As of mid-February 2006, there have been 169 confirmed cases of humans infected with the H5N1 bird flu strain; 91 people have died, according to the World Health Organization. Almost all human cases have been traced to close contact with infected poultry.” (NPR March 16th, 2006: Questions and Answers: Preparing for a Flu Pandemic, by Robert Siegel and Melissa Block).

Changing Statistics

What is significant with the above statistics is that the lethal percentage is higher than 50%. This is very alarming. The facts are changing daily, as are the numbers. Fear has already set in for a multibillion-dollar French poultry industry, the leader among 25 nations. Japan has suspended imports of French poultry and poultry products as well as poultry from Hong Kong. The current method of trying to abate this virus is through culling (killing) massive amounts of chickens. People are afraid to consume eggs, and other poultry products in Europe, especially Brussels, despite assurances that it is all safe.

The past makes one thing certain: even if the dreaded H5N1 never mutates into a form that can spread easily between people, some other flu virus surely will. The stronger our defenses, the better we will weather the storm when it strikes. “We have only one enemy,” CDC director Gerberding has said repeatedly, “and that is complacency.” According to Frederick G. Hayden, a University of Virginia virologist who is advising WHO on treating avian flu victims. “Unless this virus changes dramatically in pathogenicity,” he asserts, “we will be confronted with a very lethal strain.”

The H5N1 strain of the avian flu virus, originally found in birds throughout Southeast Asia, has infected a number of species, including domestic poultry, pigs, and people. Scientists fear that a genetic exchange between bird and human flu viruses or the accumulation of H5N1 mutations could soon make efficient person-to-person transmission possible.

Most H5N1 casualties have suffered acute pneumonia deep in the lower lungs caused by the virus itself and in some cases blood tests indicated unusual cytokine activity. But the virus is not always consistent. In some patients, it also seems to multiply in the gut, producing severe diarrhea. The version of the strain that has infected most human victims is also resistant to an older class of antivirals (amantadines), possibly as a result of those drugs having been given to poultry in parts of Asia.

In February 2004, the avian influenza virus was detected in pigs in Vietnam. That increased fears of the emergence of new variant strains. In November 2004 the director for the western region of WHO said that a pandemic of influenza was inevitable and called for urgent plans to combat the virus. The director continued to warn that it is feared that if the avian influenza virus undergoes a shift with a human influenza virus, the new subtype created could be both highly contagious and highly lethal to humans.

From January 2004 to early February 2005, the feared H5N1 spread through 8 Asian countries; at least 44 persons were infected, 32 of those individuals died.

The virus has killed or led to the slaughter of millions of birds, mostly in Asia but in parts of Europe also. Perhaps the number of people who have died as of this writing does not seem like high, but it signifies a high percentage. By Feb. 2006 H5NI had spread to India, Turkey, Africa, and Europe.

Is H5N1 the Same Strain as Was Found in 1918 Spanish Flu?

There is debate about the risks associated with H5N1. Does it come from birds only? Is it like the Spanish flu? There is evidence to show that this strain of influenza has been around for at least 10 years, and more people are infected with it, than those who present with illness. It is thought that a strain of swine flu directly transmissible to humans was responsible for the human Spanish Flu. ‘’The hemagglutinin gene matches closest to swine influenza viruses, showing that this virus came into humans from pigs,’’ said Taubenberger, the molecular pathophysiologist studying types of influenzas. Immediately, Dr. Taubenberger and his colleagues were struck by an oddity: the chain of nucleotides that coded for the amino acids in the protein were arranged differently from those found in any other bird flu. When he compared the 1918 virus with today’s human flu viruses, Dr. Taubenberger noticed that it had alterations in just 25 to 30 of the virus’s 4,400 amino acids.

Influenza isn’t the only viral threat we face. There are other viruses out there, some of which are more lethal. The 1918 virus appears to be a bird flu virus. But if it is from a bird, it is not a bird anyone has studied before. It is not like the A (H5N1) strain of bird flu in Asia. Perhaps this is where the confusion between the swine flu and bird flu comes into play. No one seems to have the answers to date.

Some experts like Dr. Peter Palese of the Mount Sinai School of Medicine in New York say the A (H5N1) flu viruses are a false alarm. He notes that studies of serum collected in 1992 from people in rural China indicated that millions of people there had antibodies to the A (H5N1) strain. That means they had been infected with an H5N1 bird virus and recovered, apparently without incident. Despite that, and the fact that those viruses have been circulating in China more than a dozen years, almost no human-to-human spread has occurred.

Dr. Taubenberger said he could argue it either way. “It’s a nasty virus,” he said. “It is highly virulent in domestic birds and wild birds. The fact that it has killed half the humans it has infected makes it of concern, and the fact that it shares some features with the 1918 virus makes it of concern. But the fact that it has circulated in Asia for years and hasn’t caused a pandemic argues against it. Maybe there are some biological barriers we don’t understand.”

Avian Flu Caused by H5N1

Symptoms of Avian Flu

Initial symptoms are more likely to include diarrhea in avian flu than in ordinary flu. The problem can appear up to a week before any respiratory symptoms. That feature, combined with the detection of viral RNA in stool samples, suggests that the virus grows in the gastrointestinal tract.

Lower respiratory tract symptoms such as shortness of breath appear early in the course of the illness, whereas upper respiratory symptoms such as runny nose are less common. Also, unlike in ordinary flu cases, the virus may be found in larger amounts in the throat than in the nose. Most cases so far have been linked with exposure to poultry. Specific activities that have been implicated include plucking and preparation of diseased birds; handling fighting cocks; playing with poultry, especially asymptomatic infected ducks; and consumption of duck’s blood or possibly undercooked poultry.

As of March 2006, the bird flu was found in Israel, and police had set up roadblocks to chicken farms. Denmark and other European Countries reported cases in the beginning of 2006. In Feb. 2006 2 cats were infected, as well as a dog. There is concern that if the mammals are infected and don’t come down with the illness, that the virus is mutating quickly as it adapts. In March 06, Afghanistan, India, Germany, Camaroon, Nigeria, Ethiopia, Gambia, Egypt, and Israel have reported cases of H5NI. As the flu spreads, countries with HIV/AIDS, Malaria, and food shortages have a huge risk factor for more rapid illness.


Some reports indicate the virus may incubate longer than other human flu viruses before causing symptoms. Incubation periods in ordinary flu range from 1 to 4 days, with an average of 2 days, according to the Centers for Disease Control and Prevention (CDC). In H5N1 cases, the incubation time has mostly been from 2 to 4 days but has stretched to 8 days, the WHO report says. In household clusters of cases, the time between cases has generally ranged from 2 to 5 days but sometimes has been as long as 17 days.

Avian Influenza Transmission

Influenza is highly contagious, with an attack rate of 10% to 20% from the day before symptoms begin through approximately 5 days after onset in adults. It is transmitted through coughing and sneezing by the infected individual. Influenza is airborne in contrast to droplet transmission in which heavier particles are transmitted to those with close contact (less than 3 to 6 feet depending on the organism). Airborne transmission is especially significant in congregate situations like institutions, daycare facilities, airplanes, and cruise ships. Contaminated hands are a frequent source of transmission and infection.

Avian Influenza Can Be Spread from Farm to Farm by:
Diagnostic Problems

Accurate diagnosis of influenza on the basis of symptoms alone is difficult. The quickest way to decide if the patient has influenza, or some other disease, is to use a rapid diagnostic test for influenza. However, false negative and false positive results do occur. Within 3 to 4 days after onset of influenza, the virus can be found from throat and/or nasopharyngeal swabs. Highest viral shedding occurs during the first 4 days of illness. Nasopharyngeal specimens generally are more accurate. There are several rapid diagnostic tests available, and these tests can usually detect the influenza virus within 30 minutes. (CDC. Prevention and Control of Influenza Recommendations of the Advisory Committee on Immunization Practices. MMWR July 29, 2005. 55 (RR08); 1-40.)

Influenza Diagnosis Confirmation
New Testing For Influenza Strains

A new computer “chip” can test for 11 different influenza strains, including avian flu, in less than a quarter of the time it now takes to diagnose flu in patients, according to a Reuters report. The test devised at the University of Colorado is still being validated, but the researchers hope to develop it into an on-the-spot test for influenza. “If we could put this technology in every doctor’s office that would be fantastic,” said Kathy Rowlen, a chemistry and biochemistry professor at the university who helped direct the research.

“The current gold standard for doing strain analysis takes about three to four days. That is going to be way too long if we get a highly virulent form of avian influenza that becomes human-adapted.” There are quick tests for influenza, but they only tell if a patient has it or not and do not differentiate among strains.

Gold Standard Testing

Testing for influenza A (H5N1) should be considered on a case-by-case basis in

consultation with state and local health departments for hospitalized or ambulatory patients with:

Prevention of Pandemic Influenza

According to Gregory Poland, M.D. of the Mayo Clinic: “ First, if everyone gets a seasonal flu vaccine, it will theoretically decrease the chance of a pandemic strain developing. This is because some pandemic strains can occur when a person is infected with two or more viruses that exchange viral genetic material. Getting a seasonal flu vaccine potentially reduces the opportunity for that to happen.” (Infectious Disease Feb. 20, 2006, Bird flu vaccines: Challenges of preventing a pandemic).

If a patient is known to have, or suspected of having, respiratory avian influenza, they should be segregated in the waiting room, be provided with a surgical or procedural mask, be given tissues and a way to dispose them, and not be kept in the waiting room for an extended period. A nasopharyngeal swab or aspirate should be collected and sent to the local public health laboratory. It is important to keep the local health agencies aware of any such suspected illness so that the full use of available resources can be made.

The specimen should then be forwarded to the state laboratory for reverse transcription - polymerase chain reaction (RT-PCR) for influenza A analysis and, if possible, for H1 and H3 analysis. Should the state not have the capacity to perform these tests, or if the tests are positive, the specimen could be sent to the CDC. As mentioned earlier, only a level 3+ laboratory.

Ban Importation of Chicken

It is also important to note that the United States has annually imported an estimated 20,000 birds from countries with current avian influenza outbreaks, according to the U.S. Fish and Wildlife Service. Today there is a ban on some of these countries from exporting to the USA.


The current outbreak of avian influenza has prompted the killing (culling) of more than 200 million birds. In February 2004, different strains of avian flu were detected among several flocks of birds in the U.S. and state officials ordered the destruction of hundreds of thousands of birds.

The avian influenza strain found in Delaware was (H7N2), in Pennsylvania the strain was (H2N2), and the (H5N2) strain was found in Texas. The strain found in Texas has been determined to be ‘highly pathogenic’ to birds. The strain of avian influenza in Texas is not the same as the strain that is affecting Asia. There does not appear to be any connection between the illness in the flocks on the East Coast and the flock in Texas.


Sometimes influenza strains can become resistant to antiviral drugs, and therefore the drugs may not always be effective. For example, analyses of some of the 2004 H5N1 viruses isolated from poultry and humans in Asia have shown that the viruses are resistant to two of the medications (amantadine and rimantadine), which is why oseltamivir (Tamiflu) appears to be the choice medication to date. Although Tamiflu is designed to inhibit the protein neuraminidase, it recently was shown to be less effective than first thought.

The prescribed treatment for Spanish Flu in 1918 was Epsom salts, quinine tablets, bleeding, castor oil, digitalis, morphine, enemas, aspirin, tobacco, hot baths, cold baths, iron tonics, and expectorants of pine tar. Today we may add antibiotics to the mix and perhaps some antivirals but other than despite technological advancements, our arsenal to fight the unknowns are not much better than in 1918.

Vaccine Development

Several companies have initiatives, many supported by government contracts, to develop a bird flu vaccine. These are all in development and testing, however, and not likely to be available for at least another one to two years. Three development approaches exist and are being tested.

One bird flu vaccine, which works similarly to the seasonal flu vaccine, is in clinical trials. However, this vaccine requires two doses of 90 micrograms (mcg) one month apart and won’t be sufficient should a pandemic occur.

Another company is using a technique called reverse genetics to make a platform or backbone vaccine against the 15 variations of the flu (H1 through H15). We don’t know which of these subtypes could become pandemic. So, what they’re doing is building a generic vaccine against all of the subtypes with the idea that once a stockpile is created for each, it could be quickly distributed in the case of an epidemic of that subtype.

The virus has mutated and is now found in two distinct forms — raising concerns about human infection and complicating the search for an effective vaccine, according to Rebecca Garten of the U.S. Centers for Disease Control and Prevention (CDC). The research team at CDC found that one of the strains caused the disease in people in Vietnam, Cambodia and Thailand in 2003 and 2004. The second strain infected people in Indonesia in 2005. Dr. Nancy Cox, chief of the CDC’s influenza branch, stressed that neither of the strains can pass easily from human to human, yet.

The Avian Flu Pandemic Influenza is Different from Avian Influenza

As we’ve seen, avian influenza refers to a large group of different influenza viruses that primarily affect birds. On rare occasions, these bird viruses can infect other species, including pigs and humans. The vast majority of avian influenza viruses do not infect humans. Once the antigenic drift and shift happen, it will no longer be a bird virus. It will be a human influenza virus. Influenza pandemics are caused by new influenza viruses that have shifted (see antigenic shift and drift) to humans.

Influenza Compared to SARS

Sudden Acute Respiratory Syndrome (SARS) was first reported in Mainland China in February 2003. The incubation period is commonly 2 to 7 days, but can be as long as 10 days. It almost always begins with a fever greater that 100.4 degrees F (38 degrees C). Chills and rigor and sometimes headache, malaise, and myalgias usually accompany the fever. Initially, there may be only mild respiratory symptoms. After 3 to 7 days, the lower respiratory phase begins with a dry cough and dyspnea.

The illness becomes more severe in the second week at which time a chest x-ray often reveals bilateral disease. Many patients progress to ventilator failure. The estimated overall case fatality rate is 9.6%. It is greater than 50% in those older than 65 years of age although this high fatality rate is probably influenced by the presence of other chronic complicating conditions.

In comparing influenza and SARS, the degree of fever is too similar to be distinguishing and both exhibit chills. Respiratory symptoms accompany the onset of influenza. In SARS, the chills may be more severe with rigor. The incubation period is much longer for SARS than influenza but that factor is rarely helpful because it is difficult to determine the incubation start date.

However, in SARS, respiratory symptoms initially are mild and develop 3 to 7 days after onset. A cough develops sooner than in influenza and usually there is no dyspnea. The chest x-ray of a patient with influenza, or early in SARS, is usually normal. SARS progresses rapidly, so there are usually generalized, patchy, interstitial infiltrates on a chest x-ray. The patient with influenza generally starts to improve after 5-to-7 days, but with SARS continues to deteriorate slowly until the patient becomes severely ill in the second week.

Severe Acute Respiratory Syndrome (SARS)

The CDC continues to recommend consideration of testing for SARS in patients who require hospitalization for radiographically confirmed pneumonia or ARDS without identifiable etiology AND who have one of the following risk factors in the 10 days before the onset of illness:

Ways to Prevent Spread of SARS or Infectious Influenza

All healthcare workers face a wide range of hazards on the job, including blood and body fluid exposure as well as musculoskeletal injuries related to ergonomic hazards from lifting and repetitive tasks; nursing personnel experience these hazards most frequently. (Centers for Disease Control and Prevention.Worker health chart book, 2000. Cincinnati OH).

Every year, approximately 600,000–800,000 occupational needlestick injuries occur in the United States (Occupational outlook handbook, 2002–2003 edition. Washington: U.S. Department of Labor, Bureau of Labor Statistics; 1999.) In many countries, nurses were the largest single group affected by SARS (Booth CM, Boone RH, Tomlison G, Detsky AS. Clinical features and short-term outcomes of 144 patients with SARS in the greater Toronto area. JAMA 2003, 280-9).

Infection prevention largely depends on placing barriers between a susceptible host (person lacking effective natural or acquired protection) and the microorganisms. Colonization means that pathogenic organisms are present in a person but are not causing symptoms or clinical findings (i.e., cellular changes or damage). Colonized persons, however, can be a major source of transfer of pathogens to other persons (cross- contamination), especially if the organisms persist in the person (chronic carrier), such as with HBV, HCV and HIV.

Infection means that the colonizing organisms now are causing an illness or disease (cellular response) in the person. Coming in contact with and acquiring new organisms, while increasing the risk of infection, usually does not lead to infection because the body’s natural defense mechanisms, including the immune system, are able to tolerate and/or destroy them.

Key Updates for Preventing Spread