Subtypes Of The Influenza A Virus
Influenza A is further divided into different subtypes. These subtypes are based off of the combination of two proteins on the viral surface: hemagglutinin and neuraminidase . There are 18 different H subtypes and 11 different N subtypes.
For example, the most common influenza A subtypes that go around seasonally in humans are H1N1 and H3N2. In 2017, H3N2 spread to dogs in Florida. In 2015, this same strain also infected dogs in an earlier outbreak in Chicago.
Influenza A viruses can be further broken down into strains.
Unlike influenza A, influenza B isnt further divided into subtypes. But it can be broken down further into specific viral lineages and strains.
The naming of influenza virus strains is complex. It includes information such as:
- influenza type
- species of origin
- geographical origin
approved by the U.S. Food and Drug Administration in late 2018.
The zanamivir, oseltamivir, and peramivir medications noted above work by reducing the ability of the virus to release itself from infected cells. The newer drug, baloxavir marboxil works by reducing the ability of the virus to replicate.
These antiviral medications are most effective when started within the first 48 hours of your illness. Theyre ineffective in treating illness caused by influenza C.
Over-the-counter medications can be taken to relieve nasal congestion, fever, and aches and pains.
Getting lots of rest, eating a healthy diet, and drinking plenty of fluids helps your body fight the virus as well.
Key Points About The Flu In Children
Influenza is a very contagious viral infection of the respiratory system.
It causes a high fever, body aches, a cough, and other symptoms.
Most children are ill with the flu for less than a week. But some children have a more serious illness and may need to be treated in the hospital. The flu may also lead to lung infection or death.
The flu may be treated with acetaminophen, cough medicine, and antiviral medicine. Your child will also need lots of rest and drinking plenty of fluids.
The best way to prevent flu is to have the yearly flu vaccine. Because the viruses change, researchers create a new flu vaccine each year to help protect against strains of the virus that are currently active. The vaccine is advised for all children 6 months and older.
What Is Influenza A
Influenza A is a type of virus that causes influenza , a highly contagious respiratory illness. If you get it, you will need to rest at home and avoid infecting others. Vaccination can protect you against influenza A.
Both the influenza A and influenza B viruses circulate in the community and change continually, with new strains coming out each winter. This is why yearly vaccination is recommended.
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How Is Flu B Treated
In most cases, treatment for the flu involves home remedies and letting the virus take its course.
However, prescription antiviral medications can be used to treat the flu if it is diagnosed within the first 48 hours of symptoms. This is especially important for high-risk individuals, including people over 65, those who are pregnant, or people with other health conditions.
Since flu B symptoms can be as severe as those caused by flu A, the Centers for Disease Control and Prevention recommends that people over the age of 65 and other high-risk individuals use antiviral medications for flu A and flu B infections. If you feel flu symptoms coming on, call your healthcare provider as soon as possible to start treatment.
Influenza Treatment And Prophylaxis
Summary Of Seasonal Influenza Vaccination Recommendations
TABLE 31. Live, Attenuated Influenza Vaccine Compared with Inactivated Influenza Vaccine for Seasonal Influenza, U.S. Formulations
|Number of included virus strains||3||3|
|Vaccine virus strains updated|
|Persons aged 2-49 yr||Persons aged 6 mo|
|Interval between 2 doses recommended for children aged 6 mo to 8 yr who are receiving influenza vaccine for the first time||4 wk|
|Can be administered to persons with medical risk factors for influenza-related complications||No||Yes|
|Can be administered to children with asthma or children aged 2-4 yr with wheezing during the preceding year§||No||Yes|
|Can be administered to family members or close contacts of immunosuppressed persons not requiring a protected environment||Yes||Yes|
|Can be administered to family members or close contacts of immunosuppressed persons requiring a protected environment||No||Yes|
|Can be administered to family members or close contacts of persons at high risk but not severely immunosuppressed||Yes|
|Can be simultaneously administered with other vaccines||Yes¶|
|If not simultaneously administered, can be administered within 4 wk of another live vaccine||Prudent to space 4 wk apart||Yes|
|If not simultaneously administered, can be administered within 4 wk of an inactivated vaccine||Yes||Yes|
Modified fromMMWR 56, 2007.
Aristea Grammoustianou, Electra Gizeli, in, 2018
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What Are The Different Types Of Flu
There are three types of flu viruses: A, B, and C. Type A and B cause the annual influenza epidemics that have up to 20% of the population sniffling, aching, coughing, and running high fevers. Type C also causes flu however, type C flu symptoms are much less severe.
The flu is linked to between 3,000 and 49,000 deaths and 200,000 hospitalizations each year in the United States. The seasonal flu vaccine was created to try to avert these epidemics.
Feasibility And Validation Of Procedures For Removal
In principle, human influenza isolates can be used for the validation of the manufacturing procedures for plasma components. Since different levels of antibody prevalence against influenza A/H1N1, A/H2N2, and A/H3N2 as well as influenza B viruses are present in the population, this should be taken into account in validating the different methods.
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Outpatient Respiratory Illness Surveillance
The U.S. Outpatient Influenza-like Illness Surveillance Network monitors outpatient visits for influenza-like illness , not laboratory-confirmed influenza, and will therefore capture respiratory illness visits due to infection with any pathogen that can present with similar symptoms, including influenza, SARS-CoV-2, and RSV. Due to the COVID-19 pandemic, health care-seeking behaviors have changed, and people may be accessing the health care system in alternative settings not captured as a part of ILINet or at a different point in their illness than they might have before the pandemic. Therefore, it is important to evaluate syndromic surveillance data, including that from ILINet, in the context of other sources of surveillance data to obtain a complete and accurate picture of influenza, SARS-CoV-2, and other respiratory virus activity. CDC is tracking the COVID-19 pandemic in a weekly publication called COVID Data Tracker Weekly Review. Information about other respiratory virus activity can be found on CDCs National Respiratory and Enteric Virus Surveillance System website.
Influenza A Vs Influenza B
Types A and B influenza are the more common forms of this infection, routinely causing seasonal outbreaks. Type C influenza usually only causes mild respiratory infections.
Type B influenza can be just as severe as type A influenza but is less common throughout the flu season compared to type A.
Humans are the natural host for type B infection. Type B viruses mutate much slower than type A infections and are categorized by strains, but not subtypes. The B virus strains take longer for their genetic makeup to change than influenza A. This drastically reduces the risk of a widespread pandemic due to type B influenza.
Type A influenza can be dangerous and is known to cause outbreaks and increase your risk of disease. Unlike a type B infection, type A viruses are categorized by subtypes and strains. Influenza A mutates faster than influenza B, but both viruses are always changing, creating new strains from one flu season to the next. Past flu vaccinations will not prevent infection from a new strain.
Wild birds are the natural hosts for a type A virus, also called avian flu and bird flu. This infection can also spread to other animals and humans. This, combined with the ability of type A influenza to mutate faster than type B, can cause pandemics.
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Can Flu B Be Prevented
The best way to prevent the flu is by getting your annual flu vaccine. The flu vaccine protects against the most common flu strains. For the 2021-2022 flu season, the vaccine protects against two flu A, and two flu B strains.
In addition to getting vaccinated, you can protect yourself from the flu by practicing good hygiene, including frequent hand washing. Since the pandemic started, flu cases have been lower, suggesting that COVID precautions such as social distancing and wearing masks might also help prevent flu.
Blood And Plasma Donors
The peculiarities listed for the pandemic case refer to Step 6 of the definition of a pandemic according to the WHO ,1), to the extent that blood donor services are affected. It is therefore necessary for blood donor services to receive the current epidemiological ratings. In the case of a pandemic, an appropriate and coordinated reaction of the blood donor services to the current epidemic situation must be made possible by integrating all blood donor services into the pandemic plans of the Länder and laying down the flow of information.
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A Vs B: Severity And Recovery
An uncomplicated infection with either influenza A or influenza B can cause symptoms that last around one week. Some people may still have a cough or feel fatigued after two weeks.
Some influenza A subtypes can cause more severe disease than others. For example, in the recent past influenza A viruses have been associated with more hospitalizations and deaths in children and the elderly than in other age groups, according to the CDC.
In the past, it was thought that infection with influenza A was more severe than infection with influenza B. However, a 2015 study in adults with influenza A and influenza B found they both resulted in similar rates of illness and death.
Additionally, in a Canadian study looking at children 16 years old and younger, influenza B infection was associated with a higher risk for mortality than influenza A.
Influenza C is regarded as the least serious of the three types that humans can get. It typically produces a mild respiratory illness in adults. But theres some evidence that it can cause serious respiratory illness in children under age 2.
The CDC estimates that each year, from 2010 to 2018, influenza infection resulted in between 9.3 and 49 million illnesses, 140,000 to 960,000 hospitalizations, and 12,000 to 79,000 deaths.
The Best Time To Get Your 2022 Flu Shot According To A Vaccine Expert
According to the Centers for Disease Control and Prevention, everyone 6 months and older should get their flu shot every season, with a few rare exceptions.
While the flu has a reputation of being mild, that is not the case for many people. The flu kills tens of thousands of people every year the CDC noted that it has caused 52,000 deaths annually between 2010 and 2020.
Below, a vaccine expert shares when to get your flu shot this year and why its important to get the jab.
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What Is The Bird Flu
The avian influenza virus causes bird flu. Birds can be infected by influenza A viruses and all of its subtypes. Birds are not capable of carrying either type B or C influenza viruses.
There are three main subtypes of avian flu, including H5, H7, and H9. The subtypes H5 and H7 are the most deadly, while the H9 subtype is less dangerous.
Your Flu Shot Protects More People Than You Think
Not only does your flu shot protect you, but it shields those around you. While you may experience a mild case of the flu, that doesnt mean those around you will have the same luck.
People, unfortunately, gotten used to saying its just the flu, Johansson said, but influenza is a killer and tends to kill the young and the elderly, along with people with diseases like asthma and COPD.
So, while its easy to say, oh, Ive never gotten the flu vaccine and Im fine, its crucial to remember that by vaccinating yourself, youre reducing the risk that the flu will infect someone who may not be fine.
There were some really great studies show when you vaccinate children, you decrease the likelihood of influenza in the elderly, he said. I tell people, dont necessarily get it for yourself, get it for your grandmother or your grandfather.
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What Is The Flu In Children
Influenza is a very contagious viral infection that affects the air passages of the lungs. It causes a high fever, body aches, a cough, and other symptoms. It is one of the most severe and common viral illnesses of the winter season. Most children are ill with the flu for less than a week. But some children have a more serious illness and may need to be treated in the hospital. The flu may also lead to lung infection or death.
Type A Influenza And Its Subtypes
Type A influenza viruses are divided into subtypes, based on the presence of two glycoproteins on the surface of the virus. These glycoproteins are called hemagglutinin and neuraminidase . About 18 hemagglutinins have been identified, although generally, only H1, H2, and H3 are found in human influenza viruses. There are more than 100 types of neuraminidase, but only N1 and N2 have been positively linked to influenza epidemics in humans.
The above image shows the features of an influenza virus, including the surface proteins hemagglutinin and neuraminidase . Following influenza infection or receipt of the influenza vaccine, the bodys immune system develops antibodies that recognize and bind to antigenic sites, which are regions found on an influenza viruss surface proteins. By binding to these antigenic sites, antibodies neutralize flu viruses and prevent them from causing further infection. Source: CDC.
Hemagglutinin and neuraminidase are also called antigens, substances that, when introduced into the body, stimulate the production of an antibody. Currently, there are two subtypes of influenza A viruses found circulating among human populations: influenza A and influenza A .
Wild Birds Provide the Usual Reservoirs
Zhejiang province, China . Shanghai, a city with a population of 24 million, is located on the northern tip of Zhejiang province. Source: Uwe Dedering, Wikipedia Commons.
Genetic Evolution of H7N9 Virus in China, 2013
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Do Different Types Of Flu Viruses Hit The Population Each Year
Different strains of the flu virus mutate over time and replace the older strains of the virus. This is why it’s important to get a flu shot each year to ensure that your body develops immunity to the most recent strains of the virus.
As determined by the CDC, the viruses in a flu shot and FluMist vaccine can change each year based on international surveillance and scientists’ estimations about which types and strains of the flu will be most potent that year. Previously, all flu vaccines protected against three influenza viruses: one Influenza A virus, one Influenza A virus, and one Influenza B virus. Today, FluMist and some traditional flu shots generally cover up to four strains: two Influenza A viruses and two Influenza B viruses.
About two weeks after getting a flu shot or FluMist, antibodies that provide protection against the flu viruses develop in your body. That said, FluMist is also not recommended for use during the 2017-2018 season because it might not be effective.
Lineages Of Influenza A Viruses
Avian influenza A viruses that infect birds have evolved into distinct genetic lineages based on the geographic locations where they were first detected. These different lineages can be distinguished by studying the genetic make-up of these viruses. For example, avian influenza A viruses that were first detected in birds in Asia can be recognized as genetically different from avian influenza A viruses that were first detected among birds in North America. These broad lineage classifications can be further narrowed by genetic comparisons that allow researchers to group the most closely related viruses together. The host, time period and geographical location are often used in the lineage name to help further delineate one lineage from another.
Avian influenza A viruses are classified into the following two categories: low pathogenicity avian influenza A viruses, and highly pathogenic avian influenza A viruses. The categories refer to molecular characteristics of a virus and the virus ability to cause disease and mortality in chickens in a laboratory setting pdf iconexternal icon. HPAI and LPAI are defined and explained below:
Avian Influenza A Viruses
Avian Influenza A Viruses
Avian Influenza A Viruses
Avian Influenza A Viruses
Avian Influenza A Viruses
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