Health Problems of the Elderly

What is the difference between “influenza”, “avian flu” and “pandemic flu”?

”Influenza”: Influenza (flu) is a highly infectious disease of the respiratory tract. It is caused by various types of influenza viral strains. Three types of influenza viruses are recognized: A, B and C. Infection caused by influenza A viruses is more common. Symptoms include fever, headache, muscle ache, runny nose, cough and sore throat. In Hong Kong, the disease is more common in periods from January to March and from July to August. For healthy individuals, influenza is usually self-limiting with recovery in two to seven days.

“Avian flu”: The virus causing avian flu is also a type of influenza A virus. It is known previously to infect birds only. Although transmission of avian flu virus to human has been observed, human to human transmission is inefficient.

“Pandemic flu”: A pandemic spreads around the world affecting a large number of people across many countries. The speed with which the disease spreads around the world can be exceptionally high. Pandemic influenza is due to the emergence of a new flu virus which is markedly different from formerly circulating strains. As the population will have very little or no immunity to the new strain, pandemic influenza is usually associated with a greater number of cases, higher severity of illness and consequently a higher death toll. It is generally believed that the next pandemic flu would be caused by avian flu.

What is the difference between normal flu and avian flu?

Avian flu has similar clinical presentation as normal flu. Normal flu is transmitted from person to person while avian flu arises from contact with live infected birds. However, it is more likely to result in high fever and complications, like chest infection, respiratory failure, multi-organ failure and even death.

Is there a real threat for pandemic flu?

Pandemic flu occurs roughly every 10 to 50 years and there were three flu pandemics during the last century. In view of the recent occurrence of avian influenza outbreaks among birds in Asia and Europe and transmission of avian flu virus to human has been observed, a pandemic flu caused by avian flu is a real threat. Experts predict another pandemic will occur but cannot say exactly when it will happen. Thus it is very important that everyone should be prepared and take preventive measures.

How could we prevent flu?

to prevent normal influenza:

• Adopt a healthy lifestyle with a balanced diet, adequate sleep, regular exercise and
  do not smoke
  
• Wash hands, especially before touching eyes, mouth and nose; after going to toilet; before handling food or eating; when hands are contaminated by respiratory secretion and after touching public installations
  
• Ensure good indoor ventilation
  
• Avoid going to crowded public places during peak seasons of influenza
  
• Influenza vaccination is an effective way of preventing complications of influenza among the high risk groups

to prevent avian influenza:
In addition to the above preventive measures, you should:

• Avoid touching live poultry or their droppings
  
• Wash your hands thoroughly with liquid soap and water immediately after contact with live poultry, birds or their droppings
  
• Cook poultry and eggs thoroughly before eating

When the following happens, what should we do?

If you have flu symptoms such as fever, headache, muscle ache, runny nose, cough and sore throat, you should:

• Consult your doctor promptly, and wear a mask
  
• Tell your doctor your travel history if you have been to places with outbreak of avian influenza reported
  
• Observe good personal hygiene. Keep hands clean and wash hands properly with soap
  
• Maintain good indoor ventilation

When the pandemic comes, you should:

• Step up hygienic practices like washing hands and keeping the environment clean and maintain good ventilation.
  
• Avoid crowded or poorly-ventilated places.
  
• Wear a mask if you develop flu-like symptoms, when caring for the sick, and when visiting hospitals and/or clinics.
  
• Watch out for the latest situation of the influenza pandemic and further announcements from the government.
  
• Pay attention to and comply with guidelines issued by the government with respect to traveling, port health control and suspension of public events as needs arise.

Are the following preventive measures effective?
Can “flu shots” prevent avian flu?
The vaccine can help to reduce the chance of complications and hospitalisation resulting from human influenza. Hence, influenza vaccination is recommended for the elderly. However, up to now, influenza vaccine cannot prevent avian influenza.

Should I self medicate oseltamivir (Tamiflu) to prevent infection?
Oseltamivir can be taken for prevention of flu but it should be prescribed by registered doctors. Self-medication is not advised because of potential side effects and possibility of emergence of antiviral resistance.

For details, please visit the Centre for Health Protection Website www.chp.gov.hk

Elderly Health Services
Department of Health
November 2005

Related topics

Influenza Vaccination