Neuraminidase Health Dictionary

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Neuraminidase: From 1 Different Sources

(NA, N) a glycoprotein projecting from the surface layer of the lipid bilayer envelope of *influenza virions. It attacks sialic acid residues on host cells and may be involved in virus release. It is a key target for antibody attack and therefore is important in vaccination.
Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Influenza

n. a highly contagious virus infection that affects the respiratory system. Types A and B are the forms that most commonly cause outbreaks in humans. The viruses are transmitted by coughing and sneezing. Symptoms commence after an incubation period of 1–4 days and include headache, fever, loss of appetite, weakness, and general aches and pains. They may continue for about a week. With bed rest and aspirin most patients recover, but a few may go on to develop pneumonia, either a primary influenzal viral pneumonia or a secondary bacterial pneumonia. Either of these may lead to death from haemorrhage within the lungs. The main bacterial organisms responsible for secondary infection are Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus, against which appropriate antibiotic therapy must be given.

An influenzal infection provides later protection only against the specific strain of virus concerned; the same holds true for immunization. Strains are classified according to the presence of different subtypes of two glycoproteins (antigens) on the viral surface: *haemagglutinin (H) and *neuraminidase (N). Small changes in the structure of these antigens, which occur frequently in influenza A and B viruses, require the continual development of new vaccines to protect against annual outbreaks of the disease. Major changes in antigenic structure occur much more rarely, when there is genetic recombination between strains that can infect more than one species (most strains of the virus are highly species-specific). However, when it does occur, it could result in the development of hybrid strains causing new forms of influenza that are difficult to contain; the pandemic of 1918–19 is thought to have arisen in this way (see also avian influenza; swine influenza).... influenza

Oseltamivir

n. an antiviral drug that acts by inhibiting the action of the enzyme *neuraminidase in viruses, which reduces their replication in host cells. Oseltamivir is administered orally for the prevention and treatment of influenza A and B. To be effective, the drug must be taken within 48 hours of exposure to influenza (for prophylaxis) or onset of symptoms (for treatment).... oseltamivir

Zanamivir

n. an antiviral drug that acts by inhibiting the action of neuraminidase in viruses. This enzyme destroys the receptor sites on the surface of the host cells. Zanamivir is used for the treatment and prevention of influenza A and B. To be effective, the drug must be taken within 48 hours of the onset of symptoms (for treatment) or within 36 hours of exposure (for prevention). It is liable to cause tightening of the bronchial tubes and this may be dangerous in people with asthma.... zanamivir

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