禽流感英文介绍课件.ppt

Avian influenza?— known informally as?avian flu?or?bird flu?— refers to “influenza?caused by?viruses adapted to birds.The version with the greatest concern is?highly pathogenic avian influenza?(HPAI). “Bird flu” is a phrase similar to “swine flu,” “dog flu,” “horse flu,” or “human flu” in that it refers to an illness caused by any of many different strains of influenza viruses that have adapted to a specific host. All known viruses that cause influenza in birds belong to the species?influenza A virus. All subtypes (but not all strains of all subtypes) of influenza A virus are adapted to birds, which is why for many purposes avian flu virus?is?the influenza A virus. (Note, however, that the A does?not?stand for avian). HA：Hemagglutinin 红细胞凝集素 NA：Neuraminidase 神经氨酸酶 M2：离子通道蛋白 NP：核蛋白 HA refers to a substance that causes red?blood cells to?agglutinate（凝集）. NA catalyze the hydrolysis（水解） of terminal?sialic acid（唾液酸） residues from the newly formed?virions?and from the host cell receptors. * At present 16 HA subtypes have been recognised（H1-H16）and nine NA subtypes（N1-N9）。Each virus has one HA and one NA antigen，apparently in any combination。all influenza A subtypes in the majority of possible combinations have been isolated from avian species。to date only viruses of H5 and H7 subtype have been shown to cause HPAI in susceptible，but not all H5 and H7 viruses are virulent。 * If you suspect you may have come into contact with the influenza A virus, look for the following: Fever cough Muscle aches Sore Throat（咽喉痛） Eye infections Pneumonia（肺炎） Severe respiratory diseases （严重的呼吸道疾病） How to Prevent Getting the Avian Flu 1。 Avoid places that birds frequent. Bird baths,bird feeders, roofs and trees are common places where birds leave droppings or saliva. You may inadvertently infect yourself with avian flu by touching these objects and then touching your mouth. Avoid direct contact with wild birds, as there is no way to tell if these birds are in