Novel Influenza A Virus Infections

Novel Influenza A Virus Infections


  1. Novel influenza A viruses include any emerging subtype belonging to the genus of influenza A virus except several seasonal influenza strains such as H1N1 and H3N2, etc., which are currently circulating in the human population. Of all novel influenza A viruses, H5N1, H5N6 and H7N9, respectively have a high case fatality rate of up to 55%, 65% and 40% and pose a considerable threat to humans.
  2. People contract novel influenza A virus infections mainly through exposure to infected animals (e.g., poultry or swine) or potentially contaminated environments. Information to date suggests that these viruses do not transmit easily from human to human, and do not support sustained human-to-human transmission. Novel influenza A virus’s incubation period is estimated to be 10 days after exposure, and its period of communicability is from 1 day before the onset of symptoms to the day when the patient’s specimen is tested negative.
  3. Different subtypes of novel influenza A viruses may lead to diseases ranging from mild conjunctivitis, influenza-like illness such as high fever and cough, to very serious illness, including severe pneumonia, acute respiratory distress syndrome (ARDS), septic shock and multi-organ failure that could lead to death.


  1.  Influenza A(H5) subtype viruses have the potential to cause disease in humans and thus far, no human cases, other  than those with influenza A(H5N1) and A(H5N6) viruses, have been   reported to WHO.
  2. Human infections with A (H7N9) virus were first reported in China since March 2013. As of June 5, 2018, 1,568  confirmed cases were reported to the World Health Organization (WHO).
  3. The confirmed cases of novel influenza A virus infection in Taiwan:
    • H6N1: To date, one domestic case with H6N1 avian influenza was confirmed in 2013.
    • H7N9: Five imported cases were confirmed between 2013 and January 2018, and two of them died. 

Novel Influenza A Virus Infections Surveillance in Taiwan

  1. Taiwan National Infectious Diseases Statistics System (NIDSS)
  2. Fever screening at international airports and seaports.
  3. Self–reporting through the toll–free 1922 hotline or local public health authority.

Risk Assessment

The overall public health risk from currently known influenza viruses at the human-animal interface (e.g. H5N6, H7N9 etc.) has not changed, and the likelihood of sustained human-to-human transmission of these viruses remains low. Further human infections with viruses of animal origin are expected. The risk of these viruses to circulate in the community remain low in Taiwan. 

Prevention and Control

1. Taiwan CDC urges the public to adhere to the “5 Do’s and 6 Don’ts” guidelines to prevent the
   occurrence of novel influenza infection.
   (1) The “5 Do’s” include:

        a. Consume only thoroughly cooked meat/animal products (e.g. poultry, eggs and pork);

        b. Wash hands thoroughly with soap and water;

        c. Wear a mask and seek immediate medical attention when symptoms develop, and inform the

           doctor of your job and exposure history;

        d. People who have long-term or repeated exposure to animals (e.g. poultry and pigs), including
            animal growers and workers, should receive influenza vaccine;

        e. Take appropriate protective measures when working in animal farm or slaughterhouse.

   (2) The “6 Don’ts” include:

        a. Don’t consume raw or undercooked meat/animal products (e.g. poultry, eggs and pork);

        b. Don’t smuggle or purchase animals from unknown sources;

        c. Don’t touch or feed animals especially migratory birds or poultry;

        d. Don’t release animals into the wild or randomly abandon animals;

        e. Don’t keep domesticated and wild animals together;

        f.  Don’t visit animal farm.
2. When traveling to the novel influenza affected areas

   (1) Look up any outbreak informationat your travel destinations.

   (2) Avoid visiting slaughterhouses, animal farms, and wet markets. Also, avoid feeding or touching

   (3) Be aware of personal hygiene. Keepthe habits of frequent hand washing. Using handsanitizer with
       70% alcohol can be an alternative option.

   (4) Do not touch animals and their excrement. In case of accidental contact, immediately wash hands
        with soap and water.

   (5) Should one develop symptoms suchas fever, cough, sore throat, and conjunctivitis during the trip,
        report to thetour leader and wear a mask to seek medical attention as soon as possible.

   (3) Never bring animals back to Taiwan.

3. When returning from novel influenza affected areas 

   (1) Should one have had physical discomfort during the trip, fill out and submit a “Communicable
       Disease Survey Form” when arriving in Taiwan.

   (2) After returning from novel influenza-affected areas, measure body temperature twice everyday
       (once in the morning and once in the evening) and self-monitor health status for the following ten

   (3) If influenza-like symptoms such as fever (38℃ and above), cough,and sore throat develop, put on
        a mask , go to seek medical care andvoluntarily inform the physician of the followings:
        1. symptoms, 2. recent travel history, and 3. animals exposure history.

   (4) For more information, please visit the Taiwan CDC’s website  or call the toll-free hotline 1922
        (or 0800-001922) for assistance in seeking medical attention in order to ensure the health and
        well-being of all.


1. Why do novel influenza A viruses warrant extra concern?

  Novel influenza A virus infection in humans may cause serious illness and has a high mortality
  rate. If an animal influenza virus that develops the ability to transmit easily from person to
  person could theoretically carry a risk of causing a pandemic while retaining its capacity to cause
  severe disease, the consequences for public health could be very serious.

2. What subtypes of novel influenza A virus have caused human cases?

   Novel influenza A virus subtypes having been recognized to be transmitted to humans and cause
   diseases include H1N1v, H1N2v, H3N2v, H5N1, H5N6, H6N1, H7N2, H7N3, H7N4, H7N7, H7N9, H9N2,
   H10N7, and H10N8. Besides H1N1v, H1N2v, H3N2v that originate from infected swines, the rest of the
   subtypes are from infected birds. The symptoms of humans infected withnovel influenza A viruses are
   similar to those of seasonal influenza infection (ex. H6N1, H9N2, etc.), but some involves complicated
   pneumonia and even death (e.g., H5N1, H7N9, etc.). 

3. What is the recent epidemic of human H5N1 or H7N9 influenza virus infection?

    Cumulative number of confirmed human H5N1 influenza casesreported to WHO,
    please visit WHO's website at: Latest table.

    Cumulative number of confirmed human H7N9 influenza cases reported to WHO,
    please visit WHO's website at: Current risk assessments.

4. Are there vaccines effective against novel influenza A viruses in humans?

    Besides vaccines against H5N1 influenza viruses, there are currently no available vaccines effective
    against other novel influenza A subtypes yet. Vaccines against H7N9 influenza viruses are now under

5. Are there antivirals effective against novel influenza A viruses in humans?

   In most cases, novel influenza in humans develops into a serious disease that should be treated
   promptly in the hospital and may require intensive care, where available. The antivirals such as
   oseltamivir, zanamivir or peramivir can reduce the severity of illness and prevent death, and should
   be used as soon as possible.

6. Is it safe to eat meat/animal products, for example, poultry, eggs, and pork?  

   Because influenza viruses are inactivated by normal temperatures used for cooking, meat products
   and eggs can be safely consumed provided they are properly handled during food preparation and
   thoroughly cooked (so that food reaches 70°C in all parts, e.g., poultry meat is not pink). In areas
   experiencing outbreaks, the consumption of raw or incompletely cooked meat products and eggs is a
  high-risk practice and should be discouraged. Animals that are clearly sick or that have died of
  diseases or died unexpectedly should not be eaten.

More information

  1. Taiwan National Infectious Diseases Statistics System (NIDSS)
  2. WHO
  3. OIE
  4. USCDC



Cultivate Good Habits to Prevent Influenza and Novel Influenza A.jpg
發佈日期 2014/11/25