Avian Flu: How Threatening Is It?
By Ruth Werner
Avian Flu: How Threatening Is It?
By Ruth Werner
Fall is here, and with it, another flu season. Last year, we were bombarded with information (some of it pretty alarmist) about flu, flu vaccines and the emergence of a dangerous new player on the field of infectious disease: avian flu. Since massage therapists work closely with lots of people, and because we are health care professionals, it behooves us to be up to speed on the latest developments about flu, and I am here to help.
A brief disclaimer: this information changes almost daily, but it's accurate as of mid-September, 2005.
What is It?
Flu (short for influenza) is a viral infection of the respiratory tract. Flu viruses are classified as type A, B or C. Type A flu is by far the most aggressive, with the highest risk of significant complications or even death.
In the United States, often we don't consider flu to be a significant health issue, but for at-risk populations it can be a life threatening infection. Anywhere from 5% to 20% of the population has flu each year. It accounts for 200,000 hospitalizations and 36,000 deaths, mostly from pneumonia. The people most at risk for the serious complications of flu are the very young, the elderly or people with underlying diseases that affect lung or immune system function.
How Does It Work?
Flu viruses work in the usual way of infectious agents: they gain access to the body (often inhaled as airborne particles, although it can be spread by hand from contaminated surfaces) and then they invade their target cells. In this case, mucus-producing cells that line the respiratory tract. Once the infection becomes established, the immune system response causes most of the extreme symptoms, which appear one to three days after exposure. Flu is most communicable for three to seven days from onset of symptoms, depending on the age and health of the infected person.
Signs and Symptoms
In most cases, flu symptoms look like a bad cold: respiratory irritation with runny nose and dry cough; sore throat, headache, chills and a long-lasting high fever. Flu-related fevers often go over 102° in adults, and they might last for three days or more.
Unlike colds, flu infections affect more than the upper respiratory tract. Many patients experience aching muscles and joints, as well as debilitating fatigue. (One area flu viruses generally won't attack, however, is the gastrointestinal tract. What commonly is referred to as "stomach flu" is far more likely to be infection with norovirus or a case of food poisoning).
Flu symptoms usually appear one to three days after exposure to the virus, and they might persist for up to two weeks. If they last longer than that, or if the coughing begins to produce a lot of phlegm, the original viral infection might have opened the door to bacterial pneumonia: a potentially serious or even life threatening complication.
The Flu Vaccine
Every year, a flu vaccine is created from live, weakened viruses, based on predictions about which types of virus will be most active. Because predominant viruses change quickly, the vaccine is only effective for a year. For the 2005/2006 flu season, the vaccine is being distributed only to high-priority populations until late October; then it will become available to the general population. It's available in an injectable form or as a nasal spray (although the spray is recommended only for people between four and 49 years old).
I'm not going to open the floor to a debate about vaccinations here; that is a completely personal decision, and each individual must weigh possible benefits and risks. The Centers for Disease Control and Prevention caution, however, that persons who are allergic to chicken eggs, who have a history of Guillain-Barre syndrome or who have had an extreme reaction to a previous vaccine should not receive the flu vaccine.
Avian Flu: What's the Difference?
The avian flu that made the news last year is an infection with a particular subset of type A virus, called H5N1. (Other subtypes infect birds as well, but they appear to be much less dangerous to humans). The "H" stands for hemagglutinins; the "N" stands for neuraminidase. These are surface proteins on the virus; every flu virus is classified by what type of H or N it is. Water birds (ducks and geese) particularly are vulnerable to H5N1, although they often don't die from it. They shed virus in oral and nasal secretions, and in bird droppings. Wild birds can spread the infection to domestic poultry it's far more likely to kill chickens than ducks and from that point humans might be exposed.
Here's where it gets tricky. Bird-to-bird transmission of H5N1 is easy. Bird-to-human transmission of H5N1 is harder, but not impossible; it has happened a few dozen times in Thailand, China, and Vietnam. Symptoms are similar to human flu, with the added risk of conjunctivitis and viral pneumonia, but the mortality rate among infected humans is very high, close to 50%. So far, human-to-human transmission of H5N1 is very rare indeed, and might have happened only a few times that we know of. That's because H5N1 doesn't have many of the properties that make viruses easily transmissible between humans.
But that could change, and that's what health officials are worried about. At this moment, researchers foresee two possible ways for H5N1 to become easily transmissible between humans:
- A human could be co-infected with human flu and avian flu viruses; the viruses could "reassort" to adopt the qualities that make the human flu virus so communicable.
- A pig could be co-infected with human flu and avian flu viruses, and the viruses could reassort there. Flu passes more easily from pigs to humans than from birds to humans.
How high is this risk? That depends on whom you ask. While some public health officials are talking about "a time bomb waiting to go off," others point out that we are much better prepared to deal with an aggressive infection like H5N1 today than we were the last time a threat with a similar scope (Spanish flu, 1918-1921) hit the scene. Specifically, we are better at diagnosing the problem and aggressively isolating infected people, which, as we saw with SARS (Severe Acute Respiratory Syndrome), can quickly and effectively contain the problem.
On the other hand, no vaccine for avian flu has yet been developed (although this is being worked on), and it turns out H5N1 is resistant to the two most common anti-viral medications we have available: amantadine and rimantadine. So, our ability to shorten the lifespan of the infection is limited.
Massage and Flu
A person with flu who receives a rigorous, circulatory massage might find themselves with a much more serious infection than they would otherwise have. A person who receives massage after the infection has peaked and is on the mend, might find that recovery comes more quickly. However, two cautions must be kept in mind. The first is that squeezing several days of recovery into one or two days might make the client feel sick again. The client should know this is a possibility. The second is that a person recovering from flu still might be shedding virus.
What about our own self care? Like it or not, massage therapists are role models for taking excellent care of our own health. This means eating right, exercising, and getting good quality sleep: we all know these measures are the most important parts of keeping our immune systems strong. I will add one final point: if you're sick, be sick. Stay home. Drink hot fluids, get some rest. Do yourself and your clients a favor by investing your time and energy into conquering your infection, not into hiding your symptoms.
For Next Time
I would like to continue our exploration of emerging and re-emerging infections with a discussion of pertussis: whooping cough. This disease, which can be quite dangerous for young children, is on the upswing for two reasons: incomplete childhood immunizations and the fact that the pertussis vaccine doesn't have the lifespan we once thought it did. So, adults who were assumed to be protected are not. I would be especially interested to hear from people who have had this or seen this infection among their clients or children. Write to me and let me know: what's on your table?
Until then, many thanks and many blessings.
- Ruth Werner. A Massage Therapist's Guide to Pathology, 3rd edition. © Lippincott Williams & Wilkins 2005.
- Marc Siegel. Don't worry, be healthy: Fear is more likely to get you than the avian flu. Slate Magazine 9/13/05. ©2005 Washington Post Newsweek Interactive Co. LLC. URL: slate.msn.com/id/2126233/.
- Key Facts About Influenza and the Influenza Vaccine. September 7, 2005. Centers for Disease Control and Prevention. URL: www.cdc.gov/flu/keyfacts.htm.
- Transmission of Influenza A Viruses Between Animals and People. Centers for Disease Control and Prevention. URL: www.cdc.gov/flu/avian/gen-info/transmission.htm.
- Avian Influenza Infection in Humans. Centers for Disease Control and Prevention. May 24, 2005. URL: www.cdc.gov/flu/avian/gen-info/avian-flu-humans.htm.
Special thanks to David Jackson, Communicable Disease Surveillance Program Manager, Utah Department of Epidemiology.