Human Swine Influenza

Background
A number of confirmed human cases of swine influenza A/H1N1 (swine flu) infection have been reported in Mexico and several other countries.

Originally known to circulate among pig populations, the swine flu viruses do occasionally infect human beings. In this present international swine flu outbreak, human-to-human transmission has occurred.

Symptoms
The symptoms of human swine influenza are usually similar to those of human seasonal influenza and include fever, lethargy, loss of appetite and coughing. Some people infected with swine flu may also have a runny nose, sore throat, nausea, vomiting and diarrhoea.

Mode of transmission
Human-to-human transmission of swine flu is thought to occur in the same way as seasonal flu is spread among people, mainly through coughing or sneezing. People may also become infected by touching objects soiled with flu viruses and then touching their nose or mouth.

Swine flu has not been shown to be transmissible to people through eating properly handled and cooked pork or pork products. Cooking pork to an internal temperature of 70ΆXC (160ΆXF ) kills the swine flu virus.

Management
People who develop flu symptoms should put on a mask and consult a doctor as soon as possible. Those who have been to affected places or been exposed to sick persons should tell the doctor the travel and contact history. Antiviral agents can reduce the severity and duration of illness but must be used under doctor's prescription. It is important for people not to self-medicate.

Prevention
Since H1N1 swine flu viruses are very different from human H1N1 viruses, vaccines for human seasonal flu will not provide protection against H1N1 swine flu viruses.

Members of the public should observe the following precautionary measures:

• Keep hands clean and wash hands properly. Alcohol-based handrub is also effective when hands are not visibly soiled.
• Avoid touching mouth, nose or eyes.
• Wash hands with liquid soap promptly if they are dirtied by respiratory secretions, e.g. after sneezing or coughing.
• Cover nose and mouth when sneezing or coughing.
• Do not spit. Always wrap nasal and mouth discharges with tissue paper, and dispose of the tissue paper properly in a rubbish bin with a lid.
• Wear a mask when respiratory symptoms or fever develop. See a doctor right away.
• Do not go to work or school if you develop influenza-like symptoms.

Avoid travelling to affected places unless it is absolutely necessary. If such a visit is unavoidable:

• During the trip: put on a mask and do not have contact with sick people.
• After returning: pay close attention to your health and wear masks for 7 days. Seek medical consultation from public clinics or hospitals right away if fever or influenza-like symptoms appear.

Centre for Health Protection of the Department of Health Website www.chp.gov.hk
24-Hour Health Education Hotline of the Department of Health 2833 0111
Source: Department of Health

VI/vn/No. 58 (May-2009)