H7N9 Influenza A virus
Expatriates are encouraged to monitor the Centres for Disease Control and Prevention (CDC) website by searching for the keyword "China" on this site and the China page of the World Health Organization (WHO) website regarding communicable diseases in the region.
What are the influenza viruses (flu viruses)?
There are three main types of influenza virus - A, B and C. Influenza B and C viruses normally only infect humans. Influenza A viruses can infect humans, animals and birds.
On the surface of the influenza A virus there are two types of proteins called haemagglutinin (H) and neuraminidase (N). There are sixteen types of haemagglutinin protein and nine types of neuraminidase protein. There are many different sub-types (strains) of influenza A and they are named according to which surface proteins are present - for example, influenza A(H1N1), A(H1N2), A(H2N3), etc.
Influenza A viruses are more able than most viruses to mutate to produce new strains. Slight changes are called 'antigenic drift' of existing virus strains. A more dramatic change, when a completely new strain emerges, is called 'antigenic shift'. It is this ability of the influenza A viruses to mutate that makes them able to cause new types of flu illness as new strains emerge.
What you should know about A(H7N9).
Thus far, most patients with this infection have had severe pneumonia. Symptoms include fever, cough and shortness of breath. However, information is still limited about the full spectrum of disease that infection with influenza A(H7N9) virus might cause.
We do not know why this virus is infecting humans because we do not know the source of exposure for these human infections. However, analysis of the genes of these viruses suggests that although they have evolved from avian (bird) viruses, they show signs of adaptation to growth in mammalian species. These adaptations include an ability to bind to mammalian cells, and to grow at temperatures close to the normal body temperature of mammals (which is lower than that of birds).
The influenza A(H7N9) virus is different from influenza A(H1N1) and A(H5N1). All three viruses are influenza A viruses but they are distinct from each other. H7N9 and H5N1 are considered animal influenza viruses that sometimes infect people. H1N1 viruses can be divided into those that normally infect people and those that normally infect animals.
Although both the source of infection and the mode of transmission are uncertain, it is prudent to follow basic hygienic practices to prevent infection. They include hand and respiratory hygiene and food safety measures.
Hand hygiene
Influenza viruses are not transmitted through consuming well-cooked food. Because influenza viruses are inactivated by normal temperatures used for cooking (so that food reaches 70°C in all parts — "piping" hot — no "pink" parts), it is safe to eat properly prepared and cooked meat, including meat from poultry and game birds.
Diseased animals and animals that have died of diseases should not be eaten.
In areas experiencing outbreaks, meat products can be safely consumed provided that these items are properly cooked and properly handled during food preparation. The consumption of raw meat and uncooked blood-based dishes is a high-risk practice and should be discouraged.
When visiting live markets, avoid direct contact with live animals and surfaces in contact with animals. If you live on a farm and raise animals for food, such as pigs and poultry, be sure to keep children away from sick and dead animals; keep animal species separated as much as possible; and report immediately to local authorities any cases of sick and dead animals. Sick or dead animals should not be butchered and prepared for food.
The Chinese government is actively investigating this event and has heightened disease surveillance. Retrospective testing of recently reported cases with severe respiratory infection may uncover additional cases that were previously unrecognized. An inter-government task force has been formally established, with the National Health and Family Planning Commission leading the coordination along with the Ministry of Agriculture and other key ministries. The animal health sector has intensified investigations into the possible sources and reservoirs of the virus.
Source: www.who.int
Keeping up with developments
This article is just a brief introduction and overview to influenza. To keep as up to date as possible, and for more detailed information visit:
Department of Health - www.dh.gov.uk
Health Protection Agency - www.hpa.org.uk
World Health Organisation - www.who.int
Centre for Disease Control - www.cdc.gov
Clinic telephone +86 (0574) 86000000 (Mon-Fri closed)
Website designed and maintained by Foreigners Medical Clinic, Ningbo Development Zone Central Hospital
All content on this website in its entirety is subject to copyright. No part is to be copied without express written permission of Ningbo Development Zone Central Hospital 宁波开发区中心医院
What are the influenza viruses (flu viruses)?
There are three main types of influenza virus - A, B and C. Influenza B and C viruses normally only infect humans. Influenza A viruses can infect humans, animals and birds.
On the surface of the influenza A virus there are two types of proteins called haemagglutinin (H) and neuraminidase (N). There are sixteen types of haemagglutinin protein and nine types of neuraminidase protein. There are many different sub-types (strains) of influenza A and they are named according to which surface proteins are present - for example, influenza A(H1N1), A(H1N2), A(H2N3), etc.
Influenza A viruses are more able than most viruses to mutate to produce new strains. Slight changes are called 'antigenic drift' of existing virus strains. A more dramatic change, when a completely new strain emerges, is called 'antigenic shift'. It is this ability of the influenza A viruses to mutate that makes them able to cause new types of flu illness as new strains emerge.
What you should know about A(H7N9).
Thus far, most patients with this infection have had severe pneumonia. Symptoms include fever, cough and shortness of breath. However, information is still limited about the full spectrum of disease that infection with influenza A(H7N9) virus might cause.
We do not know why this virus is infecting humans because we do not know the source of exposure for these human infections. However, analysis of the genes of these viruses suggests that although they have evolved from avian (bird) viruses, they show signs of adaptation to growth in mammalian species. These adaptations include an ability to bind to mammalian cells, and to grow at temperatures close to the normal body temperature of mammals (which is lower than that of birds).
The influenza A(H7N9) virus is different from influenza A(H1N1) and A(H5N1). All three viruses are influenza A viruses but they are distinct from each other. H7N9 and H5N1 are considered animal influenza viruses that sometimes infect people. H1N1 viruses can be divided into those that normally infect people and those that normally infect animals.
Although both the source of infection and the mode of transmission are uncertain, it is prudent to follow basic hygienic practices to prevent infection. They include hand and respiratory hygiene and food safety measures.
Hand hygiene
- Wash your hands before, during, and after you prepare food; before you eat; after you use the toilet; after handling animals or animal waste; when your hands are dirty; and when providing care when someone in your home is sick. Hand hygiene will also prevent the transmission of infections to yourself (from touching contaminated surfaces) and in hospitals to patients, health care workers and others.
- Wash your hands with soap and running water when visibly dirty; if not visibly dirty, wash your hands with soap and water or use an alcohol-based hand cleanser.
- Cover your mouth and nose with a medical mask, tissue, or a sleeve or flexed elbow when coughing or sneezing; throw the used tissue into a closed bin immediately after use; perform hand hygiene after contact with respiratory secretions.
Influenza viruses are not transmitted through consuming well-cooked food. Because influenza viruses are inactivated by normal temperatures used for cooking (so that food reaches 70°C in all parts — "piping" hot — no "pink" parts), it is safe to eat properly prepared and cooked meat, including meat from poultry and game birds.
Diseased animals and animals that have died of diseases should not be eaten.
In areas experiencing outbreaks, meat products can be safely consumed provided that these items are properly cooked and properly handled during food preparation. The consumption of raw meat and uncooked blood-based dishes is a high-risk practice and should be discouraged.
When visiting live markets, avoid direct contact with live animals and surfaces in contact with animals. If you live on a farm and raise animals for food, such as pigs and poultry, be sure to keep children away from sick and dead animals; keep animal species separated as much as possible; and report immediately to local authorities any cases of sick and dead animals. Sick or dead animals should not be butchered and prepared for food.
The Chinese government is actively investigating this event and has heightened disease surveillance. Retrospective testing of recently reported cases with severe respiratory infection may uncover additional cases that were previously unrecognized. An inter-government task force has been formally established, with the National Health and Family Planning Commission leading the coordination along with the Ministry of Agriculture and other key ministries. The animal health sector has intensified investigations into the possible sources and reservoirs of the virus.
Source: www.who.int
Keeping up with developments
This article is just a brief introduction and overview to influenza. To keep as up to date as possible, and for more detailed information visit:
Department of Health - www.dh.gov.uk
Health Protection Agency - www.hpa.org.uk
World Health Organisation - www.who.int
Centre for Disease Control - www.cdc.gov
Clinic telephone +86 (0574) 86000000 (Mon-Fri closed)
Website designed and maintained by Foreigners Medical Clinic, Ningbo Development Zone Central Hospital
All content on this website in its entirety is subject to copyright. No part is to be copied without express written permission of Ningbo Development Zone Central Hospital 宁波开发区中心医院