Diseases, Conditions, Syndromes

Flu shot much more effective this year, CDC says

This year's flu shot is already outperforming the vaccine issued during the tough 2017-2018 influenza season, federal health officials reported Thursday.

Diseases, Conditions, Syndromes

Bird flu shuffle probes viral compatibility

When influenza viruses that infect birds and humans meet in the same cell, they can shuffle their genomes and produce new strains that might have pandemic potential. Think of this process, called reassortment, as viruses ...

Genetics

Decoding the human immune system

For the first time ever, researchers are comprehensively sequencing the human immune system, which is billions of times larger than the human genome. In a new study published in Nature from the Human Vaccines Project, scientists ...

Immunology

Researchers design new anti-influenza drugs

Researchers at LSTM and Imperial College London have designed drugs which could help combat any potential new flu pandemic, by targeting the receptors of the cells by which the virus gains entry to the human body.

Diseases, Conditions, Syndromes

Flu vaccination keeps COPD patients out of the hospital

A new study published in the January issue of Chest establishes that patients with chronic obstructive pulmonary disease (COPD) face heightened risks of death, critical illness, and hospitalization if they develop the flu ...

Diseases, Conditions, Syndromes

Designing antibodies to fight the flu

The influenza virus is an annual threat to public health around the world. Rapid changes in viral surface proteins (antigens), however, make it difficult to identify antibodies with broadly neutralizing activity against different ...

Diseases, Conditions, Syndromes

Why Asian horses don't get sick with the flu

Avian influenza viruses infect horses in Mongolia but do not cause large outbreaks of disease because they failed to acquire key genetic changes to enable greater cross-species transmissibility, according to a study published ...

Medical research

How lung tissue forms immune cell hubs in times of need

Immunology researchers at the Babraham Institute have discovered how lung tissue in mice is remodelled in response to infection with influenza in order to support an immune system response. A key result of this tissue remodelling ...

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Influenza, commonly referred to as the flu, is an infectious disease caused by RNA viruses of the family Orthomyxoviridae (the influenza viruses), that affects birds and mammals. The most common symptoms of the disease are chills, fever, sore throat, muscle pains, severe headache, coughing, weakness/fatigue and general discomfort. Although it is often confused with other influenza-like illnesses, especially the common cold, influenza is a more severe disease than the common cold and is caused by a different type of virus. Influenza may produce nausea and vomiting, particularly in children, but these symptoms are more common in the unrelated gastroenteritis, which is sometimes, inaccurately, referred to as "stomach flu." Flu can occasionally cause either direct viral pneumonia or secondary bacterial pneumonia.

Typically, influenza is transmitted through the air by coughs or sneezes, creating aerosols containing the virus. Influenza can also be transmitted by direct contact with bird droppings or nasal secretions, or through contact with contaminated surfaces. Airborne aerosols have been thought to cause most infections, although which means of transmission is most important is not absolutely clear. Influenza viruses can be inactivated by sunlight, disinfectants and detergents. As the virus can be inactivated by soap, frequent hand washing reduces the risk of infection.

Influenza spreads around the world in seasonal epidemics, resulting in the deaths of between &10000000000250000000000250,000 and &10000000000500000000000500,000 people every year, up to millions in some pandemic years. On average 41,400 people died each year in the United States between 1979 and 2001 from influenza. In 2010 the Centers for Disease Control and Prevention (CDC) in the United States changed the way it reports the 30 year estimates for deaths. Now they are reported as a range from a low of about 3,300 deaths to a high of 49,000 per year.

Three influenza pandemics occurred in the 20th century and killed tens of millions of people, with each of these pandemics being caused by the appearance of a new strain of the virus in humans. Often, these new strains appear when an existing flu virus spreads to humans from other animal species, or when an existing human strain picks up new genes from a virus that usually infects birds or pigs. An avian strain named H5N1 raised the concern of a new influenza pandemic, after it emerged in Asia in the 1990s, but it has not evolved to a form that spreads easily between people. In April 2009 a novel flu strain evolved that combined genes from human, pig, and bird flu, initially dubbed "swine flu" and also known as influenza A/H1N1, emerged in Mexico, the United States, and several other nations. The World Health Organization officially declared the outbreak to be a pandemic on June 11, 2009 (see 2009 flu pandemic). The WHO's declaration of a pandemic level 6 was an indication of spread, not severity, the strain actually having a lower mortality rate than common flu outbreaks.

Vaccinations against influenza are usually made available to people in developed countries. Farmed poultry is often vaccinated to avoid decimation of the flocks. The most common human vaccine is the trivalent influenza vaccine (TIV) that contains purified and inactivated antigens against three viral strains. Typically, this vaccine includes material from two influenza A virus subtypes and one influenza B virus strain. The TIV carries no risk of transmitting the disease, and it has very low reactivity. A vaccine formulated for one year may be ineffective in the following year, since the influenza virus evolves rapidly, and new strains quickly replace the older ones. Antiviral drugs such as the neuraminidase inhibitor oseltamivir can be used to treat influenza, however the effectiveness is difficult to determine due to much of the data remaining unpublished.

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