Change: There were only format changes (bold, italics, etc.) in this version. See this version for details. (Word count: 940)

Change:  Researchers will never know precisely how all the 130 people who have died of H5N1 avian influenza acquired the disease. But the details of their   View changes from previous version. (Word count: 940)

Change: China contracted the virus. All of them recovered.H7N2 –-- a low pathogenic virus.virus, Therethere is only one known case of H7N2 infecting a human. H7N3 –-- this is a highly pathogenic virus, albeit less dangerous than H5N1. In 2004 when2004, it attackedaffected eighteen   View changes from previous version. (Word count: 778)

Change: possibly infected birds have been destroyed. The World Health Organization (WHO) considers the destruction of sick or exposed birds the first line of defense against avian flu.See alsoMutation and antigenic shiftBird flu and SARSInfection in humansDiagnosis and treatment   View changes from previous version. (Word count: 766)

Change: The A strain poses threatHumans can become infected by the three types of influenza viruses (A, B, and C). Influenza B and C viruses are much less dangerous and have never caused pandemics. The A strain, however, poses a problem.Avian influenza is an   View changes from previous version. (Word count: 755)

Change: There were only format changes (bold, italics, etc.) in this version. See this version for details. (Word count: 750)

Change: and H3N2. The Influenza B and C viruses are much less dangerous and they have never caused pandemics.H3N2 SubtypesUnderstanding subtypesInfluenza A viruses are divided into several subtypes, basing on the kinds of hemagglutinin   View changes from previous version. (Word count: 751)

Change: There are two ways of that:Viruses antigenicchange driftin andthe antigenicfollowing shift.two ways:Antigenic driftdrift:This happensis continuouslya andcontinuous isshift caused by the point mutation in the two genes coding   View changes from previous version. (Word count: 754)

Change: Created by mark Feb 15 2006, 12:42 PM EST for: Create