Bird Flu Basics: An EMS Guide for the Avian Flu

A new influenza strain - H5N1 avian flu - has caused increasing concern among healthcare providers and planners over the past seven years. Consequently, dozens, if not hundreds, of experts are stepping forward to offer advice and opinions, not all of which will be accurate. In a bid to sort through this sea of information, here's a primer on what you need to know about "bird flu."

HISTORY OF INFLUENZA

Influenza has been around for thousands of years in multiple strains that are constantly evolving or mutating. Each year, the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) make their most educated guesses at what will be the dominant influenza strain(s) to hit the world during the next flu season and then create a flu vaccine to counter it. They don't always get it right. In 1998, they guessed at a strain of the Hong Kong flu. What actually roared into the U.S. was a different strain dubbed the Australian flu - a highly contagious illness that entered the country via travelers arriving at Los Angeles International Airport (LAX) and swept like wildfire through Southern California. It was weeks before researchers could isolate the flu strain and develop a vaccine to immunize and protect the population. In the meantime, those folks most vulnerable to the influenza virus - the elderly, the young and the immunosuppressed - became very ill, and many hospitals in Southern California were filled to capacity.

Eighty-seven years ago, the Spanish flu killed more than twice as many people as did World War I. Figures from the WHO and CDC estimate between 20 and 50 million people around the world lost their lives to the pandemic. In New York City alone, Spanish flu claimed the lives of more than 850 people in just one day in October 1918. By the time the disease ran its course, 675,000 infected Americans had died. During the one-year pandemic, the Spanish flu proved deadlier than the Black Plague. The death toll in India reached 12 million, and millions more died in Europe and Africa. The pandemic ended not because science and medicine created a vaccine to stop it, but because the virus (now thought to be a strain of bird flu) mutated to a less deadly form, by which time people had developed some immunity to it. Humans are not the only species susceptible to influenza viruses. There are currently 15 different types of avian influenza infecting birds around the world. The current strain, H5N1, which was first noticed in Hong Kong in 1997, is highly contagious and easily transmitted between bird species, with a high mortality rate among birds.¹ It has a six- to eight-day incubation period, which allows an infected fowl to follow a portion of its migratory path before it is incapacitated by the disease. In the meantime, it can infect dozens, if not hundreds of other birds along the way. With the increasing urbanization and growth into former wildlands and wetlands, the avian population is crowded into smaller and smaller habitats, thereby increasing the chances of exposure and spreading these avian flu viruses.

Additionally, this same expansion brings domestic fowl and wild birds in closer proximity and thus facilitates the spread of the H5N1 virus in their respective populations. In the seven years since H5N1 first emerged, it has spread via migratory routes from Southeast Asia across China and Russia and, this year, into Turkey, Romania and Greece. Although no human infections have been reported outside of Asia, it is feared that within a year the disease will spread into Africa and across to North and South America via these migration routes.²

While the current H5N1 avian virus has resulted in the deaths of over 140 million birds, it is actually difficult for humans to catch in its present form. Only 138 human cases have been reported since this strain emerged, and almost all of them have been in people who live and work with birds or ate diseased chickens or ducks.³ There has been only one confirmed case of an infected person passing the flu to another person: An 11-year-old girl in Thailand passed the disease to her mother and both died.⁴

This strain of influenza has a greater than 50% mortality rate among humans. While this alone is reason for concern, what really has world healthcare providers and planners worried is that the H5N1 virus strain already contains five of the 10 mutations that made the Spanish flu so contagious and deadly.⁵ The big concern is that H5N1 virus will either mutate to a more deadly strain or infect a human who already is immunosuppressed with another flu virus, and the two viruses could mix to form a contagious strain. This is a real possibility if the disease spreads to Africa, which is already in the throes of an AIDS epidemic.

Symptoms of the avian flu can include standard influenza symptoms (fever, chills, cough, sore throat, muscle aches, headaches), as well as severe pneumonia, acute respiratory distress, severe diarrhea, bloody nose and gums, encephalitis, seizures, coma and death.⁶ Currently, several human H5N1 vaccines are in development and starting field trials, but they are still years away from final approval and production should they prove effective.

Current prevention and treatment strategies are based on the use of two antiviral drugs. The first is oseltamivir, manufactured by Roche and marketed under the trade name Tamiflu. Tamiflu does not prevent infection from the avian flu virus, but rather prevents the infected cells from replicating and infecting other cells. To be effective, Tamiflu must either be taken in advance of exposure or within the first couple days after exposure. Based on limited patient treatment studies with very small groups of patients, the CDC is "suggesting" that Tamiflu be taken in combination with zanamivir, trade name Relenza, an antiviral medication that is taken via inhalation.

The problem is that there are currently only about 4 1/2 million doses of Tamiflu available in the United States and more than 10 million firefighters and EMS personnel.the front lines of healthcare providers. And this number does not take into account emergency department and health clinic person- For More Information Circle 43 on Reader Service Card nel, who also would be on the medical front lines of an outbreak.

To avoid the flu vaccine hoarding that occurred in the U.S. and Canada in 2004, Roche has temporarily suspended sales of its antiviral drug in the U.S. and Canada while it works out licensing and manufacturing agreements with other pharmaceutical companies worldwide.⁷

ROLE OF EMS

It may also be necessary for EMS personnel to add a travel history to all patient assessments. Finally, get a flu shot. Flu shots add protection against Type-A influenza, and some believe they will help against avian flu.

CONCLUSION

It's essential for the healthcare community to have plans in place to deal with a pandemic. To learn more about the H5N1 avian flu, see the CDC's Avian Flu Fact Sheet online at www. cdc.gov/flu/avian/gen-info/facts.htm. For emergency managers and planners, the U.S. Department of Health and Human Services (HHS) has a free online Pandemic Influenza Tabletop Exercise at www.hhs.gov/nvpo/pandemics/tabletopex.html. This program includes everything from guidelines on how to run or facilitate this tabletop exercise to mock press releases, and even video news clips. At the time this article was written, HHS was in the process of upgrading the Pandemic Influenza Tabletop Exercise to include recent developments and events.

References

1. Barishansky R. O'Connor K. Bugs without borders: what EMS needs to know about emerging infections. Emerg Med Serv 33(10):50-59, 2004.
2. Avian flu will reach us. Live Science, October 21,2005. www.livescience.com/humanbiology/051021_flu_birds.html.
3. Adler J. The fight against the flu. Newsweek, pp. 38-45, October 31, 2005.
4. Siemaszko C. Bird flu menace brewing. New York Daily News, February 27, 2005.
5. H5N1: A science story. Newsweek, October 31, 2005, p. 44.
6. Apisarnthanarak A. Atypical avian influenza. www.cdc.gov/ncidod/EID/vol10no7/04-0415.htm.
7. Reuters. Roche withholds tamiflu in U.S. to stop hoarding. October 27, 2005.