| H5N1 is a type of avian influenza virus (bird flu | | | | antigenically varying from influenza virus type A |
| virus) that has mutated[1] through antigenic drift | | | | and influenza virus type C, that causes various |
| into dozens of highly pathogenic varieties, but all | | | | respiratory illnesses in humans. |
| currently belonging to genotype Z of avian | | | | A myxovirus of the genus Influenzavirus, |
| influenza virus H5N1. Genotype Z emerged | | | | antigenically varying from influenza virus type B |
| through reassortment in 2002 from earlier highly | | | | and influenza virus type C, that causes acute |
| pathogenic genotypes of H5N1[2] that first | | | | respiratory illness in humans. |
| appeared in China in 1996 in birds and in Hong | | | | Influenza caused by infection with a strain of |
| Kong in 1997 in humans[3]. The "H5N1 viruses | | | | influenza virus type C. |
| from human infections and the closely related | | | | People should get vaccine who are: |
| avian viruses isolated in 2004 and 2005 belong to | | | | People 65 years of age or older. |
| a single genotype, often referred to as genotype | | | | Resident of nursing home and other chronic-care |
| Z." [1] | | | | facilities. |
| The avian influenza subtypes that have been | | | | Adults and adolescents with chronic pulmonary or |
| confirmed in humans, ordered by the number of | | | | cardiovascular disorders, including asthma. |
| known human deaths, are: H1N1 caused Spanish | | | | Health care workers, care givers and others who |
| flu, H2N2 caused Asian Flu, H3N2 caused Hong | | | | might transmit influenza virus to persons at |
| Kong Flu, H5N1, H7N7, H9N2, H7N2, H7N3, H10N7. | | | | high-risk for complications from infection. |
| All avian influenza (AI) viruses are type A | | | | People who are less able to fight infections |
| influenza virus in the virus family of | | | | because of a disease they are born with, infection |
| Orthomyxoviridae and all known strains of | | | | with Human Immunodeficiency Virus (HIV), |
| influenza A virus infect birds. Influenzavirus type A | | | | treatment with medications such as long-term |
| is subdivided into subtypes based on hemagglutinin | | | | steroids, and/or treatment for cancer with X-rays |
| (H) and neuraminidase (N) protein spikes from the | | | | or medications. |
| central virus core. There are 16 H types, each | | | | Adults and adolescents who required regular |
| with up to 9 N subtypes, yielding a potential for | | | | medical follow-up or hospitalization during the |
| 144 different H and N combinations. | | | | preceding year because of chronic illnesses |
| Avian influenza (also known as bird flu, avian flu, | | | | (including diabetes mellitus), kidney diseases, and |
| influenzavirus A flu, type A flu, or genus A flu) is | | | | blood cell diseases such as sickle cell anemia. |
| a flu due to a type of influenza virus that is | | | | Women who will be in the second or third |
| hosted by birds, but may infect several species | | | | trimester of pregnancy during the flu season |
| of mammals. | | | | (December - March). |
| An influenza pandemic is a large scale epidemic of | | | | Persons 6 months to 18 years of age who |
| the influenza virus, such as the 1918 Spanish flu. | | | | receive long-term aspirin therapy and therefore |
| The World Health Organization (WHO) warns that | | | | might be at risk for developing Reye syndrome |
| there is a substantial risk of an influenza pandemic | | | | after influenza. |
| within the next few years. One of the strongest | | | | This article is prepared by the editor of on the |
| candidates is the A(H5N1) subtype of avian | | | | basis of current updates and reviews on avian flu |
| influenza. | | | | pandemic. |
| A myxovirus of the genus Influenzavirus, | | | | |