H7N7

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colspan=2 style="text-align: center; background-color: rgb(250,250,190)" | Influenza A virus subtype H7N3
colspan=2 style="min-width:15em; text-align: center; background-color: rgb(250,250,190)" | Virus classification
Species	Influenza A virus

Influenza A virus subtype H7N3 is a subtype of the species Influenza A virus, which is a member of the Orthomyxoviridae family. This subtype is one of several that can infect birds, and it has occasionally been known to infect humans, leading to concerns about its potential to cause a pandemic.

Virology

Influenza A viruses are characterized by two surface proteins: hemagglutinin (HA) and neuraminidase (NA). The H7N3 subtype is defined by the presence of the seventh type of hemagglutinin and the third type of neuraminidase. These proteins play crucial roles in the virus's ability to infect host cells and in the release of new viral particles.

Hemagglutinin (HA)

The hemagglutinin protein is responsible for binding the virus to the host cell. It recognizes and attaches to sialic acid receptors on the surface of epithelial cells in the respiratory tract. The H7 subtype of hemagglutinin is one of the less common subtypes in humans but is more frequently found in avian species.

Neuraminidase (NA)

Neuraminidase facilitates the release of progeny viruses from infected cells by cleaving sialic acid residues. This action is crucial for the spread of the virus within the host and to new hosts.

Epidemiology

H7N3 has been primarily associated with outbreaks in poultry. It has been detected in various countries, often leading to culling of birds to prevent the spread of the virus. Human infections with H7N3 are rare but have been reported, typically in individuals who have had direct contact with infected birds.

Clinical Features

In humans, H7N3 infections can cause symptoms similar to those of other influenza viruses, including fever, cough, sore throat, and muscle aches. In some cases, conjunctivitis (eye infection) has been reported. Severe cases can lead to pneumonia and other complications, particularly in individuals with underlying health conditions.

Prevention and Control

Preventing the spread of H7N3 involves monitoring and controlling outbreaks in poultry populations. Measures include culling infected birds, vaccination of poultry, and biosecurity practices to prevent the introduction of the virus into flocks. For humans, avoiding contact with infected birds and practicing good hygiene are key preventive strategies.

Research and Development

Research is ongoing to develop vaccines and antiviral drugs that are effective against H7N3. Understanding the genetic makeup of the virus and its ability to reassort with other influenza viruses is crucial for predicting and preventing potential pandemics.

Also see

• Influenza A virus subtype H5N1
• Influenza A virus subtype H7N9
• Avian influenza
• Influenza pandemic