- What is avian influenza?
- What are the symptoms of human infection with avian influenza?
- How do people become infected with avian influenza virus?
- How to prevent avian influenza infection?
- Is it safe to eat poultry and pork products?
- Is it safe to visit live poultry markets or farms?
- Is there a vaccine for prevention of human infection with avian influenza virus?
- How to treat human infection with avian influenza virus?
- Are health care workers at risk from getting avian influenza virus?
- Do avian influenza viruses pose a pandemic threat to humans?
1. What is avian influenza?
Avian influenza is caused by those influenza viruses that mainly affect birds and poultry, such as chickens or ducks. Human cases infected with avian influenza A (e.g. H5N1, H5N6, H6N1, H7N4, H7N9, H9N2 and H10N8) viruses have been identified.
2. What are the symptoms of human infection with avian influenza?
Clinical presentation of avian influenza in humans may range from flu-like symptoms (e.g. fever, cough, sore throat, muscle aches) to severe respiratory illness (e.g. chest infection). Eye infection (conjunctivitis) and gastrointestinal symptoms (e.g. nausea, vomiting and diarrhoea) have also been reported.
3. How do people become infected with avian influenza virus?
People mainly become infected with avian influenza virus through contact with infected birds and poultry (live or dead) or their droppings, or contact with contaminated environments (such as wet markets and live poultry markets). Human-to-human transmission is inefficient.
4. How to prevent avian influenza infection?
Members of the public are reminded to take heed of the following preventive advice against avian influenza:
- Avoid contact with birds, poultry or their droppings
- Wash hands thoroughly with liquid soap and water immediately if you have been in contact with birds, poultry or their droppings.
- When buying and handling live chickens, do not blow at their bottoms.
- Maintain good personal hygiene
- Perform hand hygiene frequently, especially before and after touching the mouth, nose or eyes; before eating; after using the toilet; after touching public installations such as handrails or door knobs; or when hands are contaminated by respiratory secretion after coughing or sneezing.
- Wash hands with liquid soap and water, and rub for at least 20 seconds. Then rinse with water and dry with either a clean cotton towel or a paper towel.
- If hand washing facilities are not available, or when hands are not visibly soiled, hand hygiene with 70 to 80% alcohol-based handrub is an effective alternative.
- Cover your mouth and nose with tissue paper when coughing or sneezing. Dispose of soiled tissues into a lidded rubbish bin, then wash hands thoroughly.
- When having respiratory symptoms, wear a surgical mask, refrain from work or attending class at school, avoid going to crowded places and seek medical advice promptly.
- Maintain good environmental hygiene
- Maintain good indoor ventilation. Avoid going to crowded or poorly ventilated public places. High-risk individuals may consider putting on surgical masks while in such places.
- Regularly clean and disinfect frequently touched surfaces with 1 in 99 diluted household bleach (mixing 10 ml of bleach containing 5.25% sodium hypochlorite with 990 ml of water) for non-metallic surfaces. For metallic surfaces, 70% alcohol should be used.
- Maintain drainage pipes properly and regularly (about once a week) pour about half a litre of water into each drain outlet (U-traps). The water seal will prevent foul odour, insects and dirt (including microorganisms) in the soil pipe from entering the premises via drain outlets.
- Arrange immediate inspection and repair by qualified technician if there is defect in the trap or foul odour coming out from drain outlets.
- Observe food hygiene
- Five keys to food safety:
- Choose safe raw materials
- Keep hands and utensils clean
- Separate raw and cooked food
- Cook thoroughly
- Keep food at safe temperature
- Wash eggs with detergent if soiled with faecal matter and cook and consume them immediately. Eggs should be cooked thoroughly until the white and yolk become firm. Do not eat raw eggs or dip cooked food into any sauce containing raw eggs.
- Poultry should be cooked thoroughly. If there is pinkish juice running from the cooked poultry or the middle part of its bone is still red, the poultry should be cooked again until fully cooked.
- Build up good body immunity and have a healthy lifestyle. This can be achieved through balanced diet, regular exercise and adequate rest.
- Do not smoke and avoid alcohol consumption.
5. Is it safe to eat poultry and pork products?
It is safe to eat properly prepared and cooked meat because influenza viruses are inactivated by sufficient heating, normal temperatures used for cooking (such that food reaches 70°C in all parts) will kill the virus. Therefore, poultry should be cooked thoroughly. If there is pinkish juice running from the cooked poultry or the middle part of its bone is still red in colour, the poultry should be cooked again until fully cooked. Eggs should be cooked well until the white and yolk become firm. Do not eat raw eggs or dip cooked food into any sauce containing raw eggs.
Moreover, consumption of raw meat and uncooked blood-based dishes is a high-risk practice and is discouraged. Sick animals should not be eaten.
6. Is it safe to visit live poultry markets or farms?
Members of the public should avoid visiting poultry markets or farms as exposure to infected poultry or its contaminated environment are important risk factors of human infection of avian influenza.
7. Is there a vaccine for prevention of human infection with avian influenza virus?
At present, only vaccine against H5N1 is available on the market and is only recommended for use by specific laboratory workers at higher risk of exposure to avian influenza A (H5N1) virus. There is no vaccine to prevent other avian influenza in humans. Seasonal influenza vaccine cannot prevent avian influenza, however it can help reduce the chance of complications and hospitalisation from seasonal influenza.
8. How to treat human infection with avian influenza virus?
Symptoms are mainly relieved by supportive treatment. Patients should get adequate rest and drink plenty of fluids. People with flu-like symptoms should seek medical advice, especially those with weakened body resistance, or if their condition deteriorates (e.g. developing persistent high fever or shortness of breath). Some anti-viral drugs may be effective in treating the condition. Doctor will prescribe antiviral drugs (e.g. Tamiflu) to a patient depending on the circumstances and health needs of the patient.
9. Are health care workers at risk from getting avian influenza virus?
As health care workers often come into contact with patients with infectious diseases, appropriate infection prevention and control measures should be consistently applied in health care settings, and the health status of health care workers should be closely monitored. Please refer to the relevant guidelines for health professionals at http://www.chp.gov.hk/en/view_content/28620.html
10. Do avian influenza viruses pose a pandemic threat to humans?
Since avian influenza viruses do not commonly infect humans, there is little or no immune protection against them in the human population. If an avian influenza virus acquired the capacity to spread easily from person to person, either through adaptation or acquisition of certain genes from human viruses, an influenza pandemic can occur.