Have you ever had a patient ask you about their risk for catching the bird flu?  It is currently one of the most talked about viral infections in the media.  Just exactly what is the bird flu and what kind of risk does it hold for mankind?

References to the bird flu are identifying the avian influenza virus, or the family of influenza A viruses normally found in birds.  Although the risk is relatively low, infection with these viruses can occur in humans as well.  The most frequently identified subtype transferred from infected birds to humans is H5N1.  Most of these cases have resulted from contact with infected poultry or areas contaminated by the excretions of infected birds.  The H5N1 bird flu virus may also stick to surfaces or get kicked up in fertilizer dust spreading the contamination to those who do not realize that they have been exposed to the threat.  Very rarely, the avian influenza virus may be spread from one infected person to another but its effect on the newly exposed person is currently limited and weak.

“Human influenza virus” is often used to distinguish those subtypes of the influenza virus that are common among people.  Because of the constantly changing nature of the virus it has been theorized that the current human influenza A viruses originally came from birds and adapted over time to spread among people. While it is true that current infection rates are minimal, it must be taken into consideration that these viruses have a significant capacity for mutation.  Because these viruses do not commonly infect humans, people have little or no immune protection against them. If H5N1 virus were to gain the ability to spread easily from person to person, an influenza pandemic could begin.

After exposure to the virus the incubation period is generally five to seven days, but it can be as short as two days.  Bird flu symptoms may vary according the infecting strain of the virus but they are generally very similar to symptoms of the normal human flu.  Symptoms and complications can include: fever, cough, sore throat, muscle aches, eye infections, severe pneumonia and acute respiratory distress.

Outbreaks of H5N1 in Asia, parts of Europe, the Near East and Africa have resulted in the deaths of 61% of all reported cases of human infection.  These deaths most commonly occur within 10 or 11 days of infection.  Sadly, many that have died are children and young people who have had direct contact with the infected birds.

Respiratory failure is the most life threatening outcome for those infected.  It can rapidly progress to acute respiratory distress syndrome (ARDS) and multi-organ failure.  This is further complicated because there is currently no standard of care for treating these cases.  In an attempt to unify efforts, the World Health Organization (WHO) is requiring any health care provider treating a case of avian flu to report their clinical findings and treatment outcomes.  The nurse can assist with this effort by downloading the information forms located on the WHO web site and keeping accurate nurses notes.

Current studies indicate that some antiviral agents used to treat human influenza are also effective against avian influenza.  However, because of its dynamic nature medication resistance can occur.  It has already been reported that the H5N1 virus that recently caused human illness and death in Asia was resistant to amantadine and rimantadine, two antiviral medications commonly used for influenza.

Another positive study has noted that receiving the current flu vaccination appears to offer a small amount of protection against H5N1 as well.

Current information that has been gathered includes the following care recommendations:

• Oseltamiver antiviral treatment for both the early and late stages of avian influenza.  In some cases it may even be appropriate to double the dosage and add amatadine or rimantadine to the therapy course.
• Corticosteriods are not routinely used, but may be considered for septic shock with suspected adrenal insufficiency.  Prolonged use of steroids in virus-infected patients increases the risk of serious adverse side effects.
• Prophylactic antibiotic treatment is not recommended.
• Oxygen saturation levels should be monitored closely and therapy provided as needed.
• Early respiratory support with invasive positive pressure ventilation (IPPV) can improve patient outcomes.

Nurses should assure their patients that drinking potable water and eating properly cooked foods are not considered to be risk factors for avian influenza.  However, ingesting virus-contaminated products or exposing yourself to virus-contaminated water or soil poses a greater risk. In addition, all patients should be encouraged to obtain an annual flu shot and practice good hand washing techniques. 

 

 

References:

Beigel, J. et. al.  Clinical Management of Human Infection with Avian Influenza A (H5N1) Virus. World Health Organization. August 15, 2007.

Fox, M. Bird Flu May be Spread Indirectly, WHO says.  Reuters Health.  Medline Plus.  January 17, 2008.

Key Facts About Avian Influenza (Bird Flu) and Avian Influenza A (H5N1) Virus. Centers for Disease Control and Prevention.  May 7, 2007.

Medline Plus. Bird Flu. US National Library of Medicine and the National Institutes of Health.  January 23, 2008.

Reuters. Regular Flu Vaccine May Help Against Bird Flu.  MSN Health. December 26, 2007.

 

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