miércoles, 10 de abril de 2013

CDC - Seasonal Influenza (Flu) - Avian Influenza A (H7N9)

CDC - Seasonal Influenza (Flu) - Avian Influenza A (H7N9)

Avian Influenza A (H7N9) Virus

On April 1, 2013, the World Health Organization (WHO) first reported 3 human infections with a new influenza A (H7N9) virus in China. Additional cases have been reported sinceExternal Web Site Icon. At this time, no cases of H7N9 outside of China have been reported. The new H7N9 virus has not been detected in people or birds in the United States.
Most reported cases have severe respiratory illness and, in some cases, have died. According to WHO, no person-to-person spread of the H7N9 virus has been found at this time, and the reported cases are not linked to each other. An investigation by Chinese health authorities is ongoing to find out the source of these infections and detect any more cases.
This new H7N9 virus is an avian (bird) influenza (flu) virus. Human infections with avian influenza (AI, or “bird flu”) are rare but have occurred in the past, most commonly after exposure to infected poultry. However, this is the first time that this bird flu subtype (H7N9) has been found in people. This virus is very different from other H7N9 viruses previously found in birds.
This is a “novel” (non-human) virus and therefore has the potential to cause a pandemic if it were to change to become easily and sustainably spread from person-to-person. So far, this virus has not been determined to have that capability. However, influenza viruses constantly change and it’s possible this virus could gain that ability. CDC takes routine preparedness actions whenever a new virus with pandemic potential is identified, including developing a candidate vaccine virus to make a vaccine if it were to be needed. There is no licensed H7 vaccine available at this time.
CDC is following this situation closely and coordinating with domestic and international partners.
In addition, CDC is:
  • Issuing guidance to U.S. clinicians and public health departments on how to test for this virus
  • Modifying test kits so that this specific virus can be easily and accurately identified
  • Reviewing genetic sequences of the virus to learn more about it
  • Gathering more information to make a more extensive assessment of the public health risk posed by this virus
The sequences of the first three viruses were posted to GISAIDExternal Web Site Icon by China and are publicly available. Some of the genetic changes have been associated with increased transmissibility of other AI viruses to mammals based on animal studies involving ferrets in the past. So far, all three viruses seem to be susceptible to the influenza antiviral drugs oseltamivir and zanamivir, but they are resistant to the adamantanes.
This is an evolving situation and there is still much to learn. CDC will provide updated information as it becomes available.
General information about avian influenza viruses and how they spread is available at Avian Influenza A Virus Infections in Humans.

Additional Information

CDC has issued a Health Alert Network (HAN) to notify clinicians of the current H7N9 situation in China.
WHO has posted Frequently Asked QuestionsExternal Web Site Icon on human infection with A(H7N9) avian influenza virus, China.
The Chinese Center for Disease Control and Prevention has posted a Question & Answer document related to this situation available at "Questions and Answers about human infection withA(H7N9) avian influenza virusExternal Web Site Icon."
The European Centre for Disease Prevention and Control has published a rapid assessment on the emergence of the H7N9 virus in China available at "Rapid risk assessment: Severe respiratory disease associated with a novel influenza A virus, A(H7N9) ChinaExternal Web Site Icon."

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