Purdue News Service

Symptoms of bird flu

The characteristics of the avian flu caused by the H5N1 virus differ from those associated with a typical seasonal flu in a variety of ways:

Typical seasonal influenza is a largely respiratory infection and is less likely to cause severe illness because many will have partial immunity. Illness normally lasts one to two weeks and is:

• Usually less virulent — meaning it will make fewer people ill.

• In the United States alone, seasonal flu kills about 36,000 people annually.

• Less likely to cause pneumonia early in the illness, if at all.

• Most severe for the youngest and oldest of the population.

• Most likely to strike in winter and includes just one wave.

H5N1 Type A influenza virus, on the other hand, is expected to be more severe because humans have little or no immunity. Illness is expected to last for several weeks, and it is expected to:

• Strike 15 percent to 30 percent of the population.

• Cause three to seven times more deaths than seasonal influenza.

• Lead to viral pneumonia in the first two days of the illness.

• Be severe for all ages.

• Strike at any time during the year and come in multiple waves.

The H5N1 virus is expected to be more resistant to antiviral medicine, such as Tamiflu, which currently is in limited supply. There currently is no vaccine to protect against this new virus.

If you suspect you may have symptoms of H5N1 flu, commonly called bird flu, isolate yourself from others and contact a health-care provider. Have those you have been near in the previous 24 to 48 hours contacted and ask that they quarantine themselves for at least a day and monitor for symptoms.

Unless you are experiencing life-threatening symptoms, do not go directly to the hospital or doctor's office until you have talked to your physician.

Detection in humans

The test provides preliminary results on suspected H5 influenza samples within four hours once a sample arrives at the lab and testing begins. Previous testing technology would have required at least two to three days to render results. If the presence of the H5 strain is identified, then further testing is conducted to identify if the H5N1 subtype — commonly known as avian flu or bird flu — is present.

Treatments

Most of the viruses that have caused human illness and death from avian flu appear to be resistant to two older antivirals — amantadine (commonly known as Symadine or Symmetrel) and rimantadine (commonly known as Flumadine).

However, two newer antiviral medications, oseltamivir (Tamiflu) and zanamavir (Relenza), show more promise in treating avian flu. These newer antivirals might be able to lessen the effects of a new H5N1 avian flu, improve the chances an infected person to survive the virus and speed up recovery.

Patients must receive medication within 48 hours of symptom appearance to reduce to the impact of the disease. But experts say long-term treatment with such medications is not recommended due to the high cost involved. Treatment most likely would be limited to two to four weeks.

The Centers for Disease Control and Prevention will provide guidance as to which groups would have priority in receiving these drugs. Most likely, persons 65 years and older with serious chronic conditions would receive priority.

Currently, Tamiflu is licensed for the treatment of influenza A, the virus group that causes avian flu, but there is only one manufacturer of this drug, which could limit its availability.

In addition to taking antivirals, if available, experts say those infected should get plenty of sleep, drink plenty of fluids and take over-the-counter medicine such as aspirin or acetaminophen (Tylenol).

Caretakers should use a fit-tested respirator, at least as protective as a National Institute of Occupational Safety and Health-approved N95 filtering face piece (disposable respirator) when entering the room.

Caretakers should also pay careful attention to hand hygiene before and after all patient contact or contact with items potentially contaminated with respiratory secretions. Gloves and a gown should be used for all patient contact. Goggles or face shields are recommended when within three feet of the patient.

When possible, patients should also be placed in an airborne isolation room. Such rooms should have monitored negative air pressure in relation to corridor, with six to 12 air changes per hour (ACH), and exhaust air directly outside or have recirculated air filtered by a high-efficiency particulate air filter, known as a HEPA filter.