5. Species Infected by Influenza A H and N Subtypes H15,16 H14 H13 H12 H11 H10 H3 H2 H1 H9 H8 H7 H6 H5 H4 N9 N8 N7 N6 N5 N3 N4 N2 N1
6. Influenza Transmission Across Species: Reassortment in Pigs Human-to-Human Transmission Avian Virus Human Virus Swine Virus Swine/Avian/ Human Reassorted Virus
[Presenters: This slide set was developed by the International Team, Centers for Disease Control and Prevention. Content is current as of the dates on individual slides. To update the global numbers of cases, deaths, countries affected and to access the latest maps, consult the following weblinks. Slides : Cases, countries, deaths: http://www.who.int/csr/disease/swineflu/en/index.html Daily situation updates: http://www.who.int/csr/disease/swineflu/updates/en/index.html
Influenza A viruses are further subtyped by two proteins on the viral surface, called hemagglutinin (or HA) and neuraminidase (or NA). Hemagglutinin allows the virus to attach to host cells, while neuraminidase allows the virus to escape infected cells, and then go on to infect more cells. There are 16 known hemagglutinin and 9 known neuraminidase subtypes for Influenza A. Each hemagglutinin subtype is named using an “H” plus a number, such as type H1, H2, and so on. In the same way, each neruaminidase subtype is named with an “N” plus a number, such as type N1, N2, and so on. Many different combinations of HA and NA proteins are possible.
This figure illustrates the range of species that Influenza A sub-types can infect. The species that specific HA subtypes can infect are listed on the left, and the species that specific N1 subtypes can infect are listed on the right. Note that wild migratory waterfowl can be infected with all subtypes. Within the H5 and H7 subtypes, certain strains can be severe.
Add human-human arrow and emphasize humans.
For the most current numbers visit the CDC H1N1flu website. Numbers are updated every at 11:00 AM EDT.
Source: Wools D. Swine flu prompts EU warning on travel to US. Associated Press. April 27, 2009. http://www.google.com/hostednews/ap/article/ALeqM5g-G1kSAM9yaH00eBrXD2S5s-3ZhgD97QSUMO1 . Accessed April 27, 2009. European Centre for Disease Prevention and Control. Swine influenza (H1N1). April 27, 2009. http://ecdc.europa.eu/en/health_content/Articles/article_20090427.aspx . Accessed April 27, 2009. WHO raises pandemic alert level; more swine flu cases feared. CNN. April 27, 2009. http://www.cnn.com/2009/HEALTH/04/27/swine.flu/index.html . Accessed April 27, 2009. Officials unleash drug arsenal as flu toll rises. Agence France Press. April 27, 2009. http://www.google.com/hostednews/afp/article/ALeqM5gGSyeznluvlTTO6A31IITVNX52FA . Accessed April 27, 2009. Italy finds first suspected swine flu case. crienglish.com April 27, 2009. http://english.cri.cn/6966/2009/04/27/168s479315.htm . Accessed April 27, 2009.
Overview of WHO’s Pandemic Alert Levels Phase 3 of the pandemic alert period is when there are human infections with a new sub-type, but there is no human-to-human spread (or at least very rare instances of spread to a close contact). At this point, the new virus subtype must be characterized rapidly to ensure early detection, notification and response of additional cases. Phase 4 may occur when there are small clusters (e.g., <25 human cases lasting <2 weeks) with limited human-to-human transmission, but spread is highly localized (which suggests the virus does not adapt well to humans). During this phase, WHO describes a variety of measures (such as targeted use of antiviral medications) aimed at containing the virus within a limited area or to delay spread to buy time to implement preparedness measures, such as vaccine development. Phase 5 may occur when there are large clusters (e.g., 25-50 cases lasting 2 to 4 weeks), but human-to-human spread is still localized. The virus may not yet be fully transmissible. At this point, it is imperative to continue efforts to contain or delay spread of the virus, to both avert a pandemic and to implement pandemic response measures. Phase 6 is when transmission to the general population has increased and is sustained, meaning there is a pandemic. All efforts to minimize the impacts of the pandemic are necessary at this time.
The World Health Organization has raised the pandemic flu level to 6 on June 11, 2009. The 1918 pandemic flu event was the most severe to date (>50 million deaths worldwide). Milder pandemics occurred in 1957 (about 70,000 deaths in the U.S.) and 1968 (about 34,000 deaths in the U.S.)
In the United States each year, illness from influenza has a major impact on the people’s health and the nation’s economy.
Parents & Caregivers, Child Care Providers, K-12 Schools, Colleges & Universities, Travelers & Travel Industry, Community mitigation guidelines Use of antiviral medications, masks
We do have medical tools in our arsenal to combat flu.
For updates to this guidance, go to: http://www.cdc.gov/h1n1flu/recommendations.htm
Influenza primarily infects the respiratory tract (nose, throat, and lungs). The disease can cause severe illness and lead to life-threatening complications, such as pneumonia, in many people. ***Diarrhea and vomiting not common symptom of seasonal flu*** ---added runny nose since it is in case definition
It is thought that the main way influenza viruses are spread from person to person is through transmission of respiratory droplets during coughing and sneezing. Close contact (about 6 feet or less) usually is necessary for this type of spread. Influenza viruses also can spread by touching respiratory droplets on yourself, others, or an object, then touching mucus membranes, such as the mouth, nose, or eyes, without washing contaminated hands.
It is very important for anyone with symptoms to avoid contact with others, but seek medical care if any of the symptoms listed in this slide are present. Go to this website for updates: http://www.cdc.gov/h1n1flu/guidance_homecare.htm
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