Strains of flu how many

This convention was accepted by WHO in and published in February in the Bulletin of the World Health Organization, 58 4 see A revision of the system of nomenclature for influenza viruses: a WHO Memorandum pdf icon[ KB, 7 pages]external icon pdf icon external icon.

The approach uses the following components:. Getting a flu vaccine can protect against these viruses as well as additional flu viruses that are antigenically similar to the viruses used to make the vaccine. Seasonal flu vaccines do not protect against influenza C or D viruses or against zoonotic animal-origin flu viruses that can cause human infections, such as variant or avian flu viruses.

In addition, flu vaccines will NOT protect against infection and illness caused by other viruses that also can cause influenza-like symptoms. There are many other viruses besides influenza that can result in influenza-like illness ILI that spread during flu season. To receive weekly email updates about Seasonal Flu, enter your email address:. Skip directly to site content Skip directly to page options Skip directly to A-Z link.

Influenza Flu. Section Navigation. Facebook Twitter LinkedIn Syndicate. Types of Influenza Viruses. Minus Related Pages. Close This is a picture of an influenza flu A virus. What CDC Does. Finally, influenza D viruses primarily affect cattle and are not a problem for humans. The strains recommended for vaccination for the flu season in the northern hemisphere are:. However, flu viruses tend to mutate during flu season, which may alter the effectiveness of the current flu vaccine.

Unfortunately, manufacturers are not able to reissue flu vaccines when this happens because of the way flu vaccines are created and produced for human use. What many call the stomach flu is actually not flu at all. Rather, it is gastroenteritis , which is in no way related to the influenza virus. Influenza is a respiratory illness. While it can cause vomiting and diarrhea, especially in children, it is always accompanied by respiratory symptoms.

Flu vaccines are customized each year to protect against the strains researchers believe are most likely to circulate among humans that season. The vaccine only protects you from the specific strains it contains. It doesn't contain C or D viruses, and it doesn't protect against other viral illnesses with similar symptoms, which often spread during flu season. The Centers for Disease Control and Prevention CDC recommends that everyone over six months old be vaccinated against the flu unless certain health problems prevent it.

Looking to avoid getting the flu? Our free guide has everything you need to stay healthy this season. Sign up and get yours today. Centers for Disease Control and Prevention.

Influenza flu : Types of influenza viruses. Updated November 18, Influenza C and D viruses package eight organized ribonucleoprotein complexes. J Virol. Adaptation of avian influenza virus to a swine host.

Virus Evol. Origin of the pandemic H1N1 influenza A virus as studied by codon usage patterns and phylogenetic analysis.

World Health Organization. Updated April Global epidemiology of avian influenza A H5N1 virus infection in humans, a systematic review of individual case data. Lancet Infect Dis. Centers for Disease Control and Preventions. Influenza flu : Key facts about flu vaccines. Updated April 28, Updated October 11, Asha K, Kumar B.

Emerging influenza D virus threat: What we know so far! J Clin Med. Published Feb 5. Your Privacy Rights. These subtypes are based off of the combination of two proteins on the viral surface: hemagglutinin H and neuraminidase N. 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 , H3N2 spread to dogs in Florida. In , this same strain also infected dogs in an earlier outbreak in Chicago. But it can be broken down further into specific viral lineages and strains. Influenza B infections account for the remaining 25 percent. While most confirmed infections during flu season will be influenza A, the occurrence of influenza B infections can increase late in the flu season. This happened in the to flu season. Both influenza A and influenza B are extremely contagious. People who get either type can spread the virus to others from up to six feet away when they cough or sneeze.

You can also contract the virus by touching a surface that has the virus on it and then touching your nose or mouth. Treatment is focused around relieving symptoms until your body clears the virus naturally. Common antiviral prescriptions include:.

There is also an antiviral drug called baloxavir marboxil Xofluza that was approved by the U. 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.

Over-the-counter medications can be taken to relieve nasal congestion, fever, and aches and pains.