Health- Seasonal Influenza(H7N9), Influenza Type A Viruses and Subtypes and People Should Get or Not Receive The Flu Shot(TIV)

Note: This is an old article which I published on April 29, 2013

Avian Influenza A (H7N9) Virus

Human infections with a new avian influenza A (H7N9) virus continue to be reported in China. The virus has been detected in poultry in China as well. While mild illness in human cases has been seen, most patients have had severe respiratory illness and some people have died. 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.

An investigation by Chinese authorities is ongoing. Many of the people infected with H7N9 are reported to have had contact with poultry. However some cases reportedly have not had such contact. Close contacts of confirmed H7N9 patients are being followed to determine whether any human-to-human spread of H7N9 is occurring. No sustained person-to-person spread of the H7N9 virus has been found at this time.

Human infections with avian influenza (AI, or “bird flu”) are rare but do occur, most commonly after exposure to infected poultry (Bird-to-human spread). Limited person-to-person spread of bird flu is thought to have occurred rarely in the past, most notably with avian influenza A (H5N1). Based on this previous experience, some limited human-to-human spread of this H7N9 virus would not be surprising. Most important, however, is that this transmission not be sustained (ongoing).

Influenza viruses constantly change and it’s possible that this virus could become able to easily and sustainably spread between people, triggering a pandemic. CDC is following this situation closely and coordinating with domestic and international partners. 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. CDC also has issued guidance to clinicians and public health authorities in the United States, as well as provided information for people traveling to China. This is an evolving situation and there is still much to learn. CDC will provide updated information as it becomes available.

 Click Credit/Source: http://www.cdc.gov/flu/avianflu/h7n9-virus.htm

Influenza Type A Viruses and Subtypes

There are three types of influenza viruses: A, B and C. Human influenza A and B viruses cause seasonal epidemics, generally between October and May, of disease in the United States.

Wild aquatic birds are the natural hosts for all known influenza type A viruses - particularly certain wild ducks, geese, swans, gulls, shorebirds and terns. Influenza type A viruses can infect people, birds, pigs, horses, dogs, marine mammals, and other animals. Influenza type A viruses are divided into subtypes on the basis of two proteins on the surface of the virus: hemagglutinin (HA) and neuraminidase (NA). For example, an “H7N2 virus” designates an influenza A virus subtype that has an HA 7 protein and an NA 2 protein. Similarly an “H5N1” virus has an HA 5 protein and an NA 1 protein. There are 17 known HA subtypes and 10 known NA subtypes. Many different combinations of HA and NA proteins are possible. All known subtypes of influenza A viruses can infect birds, except subtype H17N10 which has only been found in bats. Only two influenza A virus subtypes (i.e., H1N1, and H3N2) are currently in general circulation among people. Some subtypes are found in other infected animal species. For example, H7N7 and H3N8 virus infections can cause illness in horses, and H3N8 virus infection can also cause illness in dogs.

Avian influenza A viruses are classified into two categories (low pathogenic and highly pathogenic) that refer to their ability to cause severe disease, based upon molecular characteristics of the virus and mortality in birds under experimental conditions. Infection of poultry with low pathogenic avian influenza A (LPAI) viruses may cause no disease or mild illness (such as ruffled feathers and a drop in egg production) and may not be detected. Infection of poultry with highly pathogenic avian influenza A (HPAI) viruses can cause severe disease with high mortality. Both HPAI and LPAI viruses can spread rapidly through poultry flocks. HPAI virus infection can cause disease that affects multiple internal organs with mortality up to 90-100% in chickens, often within 48 hours. However, ducks can be infected without any signs of illness. There are genetic and antigenic differences between the influenza A virus subtypes that typically infect only birds and those that can infect birds and people.

Three prominent subtypes of avian influenza A viruses that are known to infect both birds and people are:

Influenza A H5

Nine potential subtypes of H5 viruses are known (H5N1, H5N2, H5N3, H5N4, H5N5, H5N6, H5N7, H5N8, and H5N9). Most H5 viruses identified worldwide in wild birds and poultry are LPAI viruses. Sporadic H5 virus infection of humans, such as with highly pathogenic avian influenza A (H5N1) viruses currently circulating among poultry in Asia and the Middle East have been reported in 15 countries, often resulting in severe pneumonia with approximately 60% mortality worldwide.

Influenza A H7

Nine potential subtypes of H7 viruses are known (H7N1, H7N2, H7N3, H7N4, H7N5, H7N6, H7N7, H7N8, and H7N9). Most H7 viruses identified worldwide in wild birds and poultry are LPAI viruses. H7 virus infection in humans is uncommon, but has been documented in persons who have direct contact with infected birds, especially during outbreaks of H7 virus among poultry. Illness in humans may include conjunctivitis and/or upper respiratory tract symptoms.

In humans, LPAI (H7N2, H7N3, H7N7) virus infections have caused mild to moderate illness.

HPAI (H7N3, H7N7) virus infections have caused mild to severe and fatal illness.

On April 1, 2013, the first known human cases of infection with avian influenza H7N9 viruses were reported. These were associated with severe respiratory illness and death.

Influenza A H9

Nine potential subtypes of H9 are known (H9N1, H9N2, H9N3, H9N4, H9N5, H9N6, H9N7, H9N8, and H9N9); all H9 viruses identified worldwide in wild birds and poultry are LPAI viruses. H9N2 virus has been detected in bird populations in Asia, Europe, the Middle East and Africa. Rare, sporadic H9N2 virus infections of humans have been reported to cause generally mild upper respiratory tract illness.

 Click  Credit/Source: http://www.cdc.gov/flu/avianflu/influenza-a-virus-subtypes.htm

Who Should Get Vaccinated Against Influenza

The following lists include all groups recommended to get the flu vaccine, as well as those who are not recommended to receive either the flu shot or the nasal spray vaccine. Talk to your doctor or nurse if you have any questions regarding what flu vaccine options are best for you and your family.

The following groups are recommended to get a yearly flu vaccine:

• All persons aged 6 months and older should be vaccinated annually.
• Protection of persons at higher risk for influenza-related complications should continue to be a focus of vaccination efforts as providers and programs transition to routine vaccination of all persons aged 6 months and older.
• When vaccine supply is limited, vaccination efforts should focus on delivering vaccination to persons who:
  • are aged 6 months through 4 years (59 months);
  • are aged 50 years and older;
  • have chronic pulmonary (including asthma), cardiovascular (except hypertension), renal, hepatic, neurologic, hematologic, or metabolic disorders (including diabetes mellitus);
  • are immunosuppressed (including immunosuppression caused by medications or by human immunodeficiency virus);
  • are or will be pregnant during the influenza season;
  • are aged 6 months through 18 years and receiving long-term aspirin therapy and who therefore might be at risk for experiencing Reye syndrome after influenza virus infection;
  • are residents of nursing homes and other chronic-care facilities;
  • are American Indians/Alaska Natives;
  • are morbidly obese (body-mass index is 40 or greater);
  • are health-care personnel;
  • are household contacts and caregivers of children aged younger than 5 years and adults aged 50 years and older, with particular emphasis on vaccinating contacts of children aged younger than 6 months; and
  • are household contacts and caregivers of persons with medical conditions that put them at higher risk for severe complications from influenza.

Top

The following groups should not receive the flu shot (TIV):

• People who have ever had a severe allergic reaction to eggs. People who have had a mild reaction to egg—that is, one which only involved hives—may receive TIV with additional precautions. Make sure your healthcare provider knows about any allergic reactions.
• People who have ever had a severe allergic reaction to influenza vaccine.
• People with a history of Guillain–Barré Syndrome (a severe paralytic illness, also called GBS) that occurred after receiving influenza vaccine and who are not at risk for severe illness from influenza should generally not receive vaccine. Tell your doctor if you ever had Guillain-Barré Syndrome. Your doctor will help you decide whether the vaccine is recommended for you.
• People under 65 years of age should not receive the high-dose flu shot.
• People who are under 18 years old or over 64 years old should not receive the intradermal flu shot.
• People who are moderately or severely ill with or without fever should usually wait until they recover before getting flu vaccine. If you are ill, talk to your doctor about whether to reschedule the vaccination. People with a mild illness can usually get the vaccine.

Top

The following groups should not receive the nasal spray vaccine (LAIV):

• Adults 50 years of age and older or children from 6 through 23 months of age. (Children younger than 6 months should not get either influenza vaccine.)
• People who have ever had a severe allergic reaction to eggs. People who have had a mild reaction to egg—that is, one which only involved hives—may receive TIV (not LAIV) with additional precautions. Make sure your healthcare provider knows about any allergic reactions.
• People who have had a severe reaction to the vaccine in the past.
• People with asthma and children younger than 5 years with one or more episodes of wheezing within the past year.
• Pregnant women.
• Anyone with certain muscle or nerve disorders (such as seizure disorders or cerebral palsy) that can lead to breathing or swallowing problems.
• Anyone with a weakened immune system.
• Anyone in close contact with someone whose immune system is so weak they require care in a protected environment (such as a bone marrow transplant unit). Close contacts of other people with a weakened immune system (such as those with HIV) may receive LAIV. Healthcare personnel in neonatal intensive care units or oncology clinics may receive LAIV.
• Children or adolescents on long-term aspirin treatment.
• People with a history of Guillain–Barré Syndrome (a severe paralytic illness, also called GBS) that occurred after receiving influenza vaccine and who are not at risk for severe illness from influenza should generally not receive vaccine. Tell your doctor if you ever had Guillain-Barré Syndrome. Your doctor will help you decide whether the vaccine is recommended for you.

• Your doctor will help you decide whether the vaccine is recommended for you.
• Tell your doctor if you have gotten any other vaccines in the past 4 weeks.
• Anyone with a nasal condition serious enough to make breathing difficult, such as a very stuffy nose, should get the flu shot instead.
• People who are moderately or severely ill with or without fever should usually wait until they recover before getting flu vaccine. If you are ill, talk to your doctor about whether to reschedule the vaccination. People with a mild illness can usually get the vaccine.
• Source:http://www.cdc.gov/flu/protect/whoshouldvax.htm

• CDC Says “Take 3” Actions To Fight The Flu

   My Note, Please click link source in all the articles for complte information and further explanation http://www.cdc.gov/flu/protect/preventing.htm

• H7N9 Outbreak Characterization

• H7N9 infections in people and poultry in a certain country                                              My Note: I did not mention the name of the country mentioned in the article since nobody wants to have any form or kind of virus outbreak. I just want to make public awareness without misconceptions only facts by the researcher in the this source.
• Sporadic infections in humans; many with poultry exposure
• No sustained or community transmission
• Investigation ongoing
• Click Credit/ Source: http://www.cdc.gov/flu/avianflu/h7n9-virus.htm