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Influenza Virus Description

Influenza is the virus responsible for a disease commonly called "the flu." Influenza has several strains, and the virus brings a wide degree of severity in symptoms. Some people only suffer from a mild cough and the sniffles, but others experience aches, pains and high fever, and even death can occur with the infection. Scientists attempt to keep the public safe by providing a flu vaccine every season.

  1. Types

    • Influenza has three types of strains. Influenza A is the common strain associated with mild to severe respiratory illnesses. Influenza B is also associated with respiratory illnesses, except this type is far less common. There is also the influenza C virus, but this is even less common and does not cause disease. Influenza C causes only mild respiratory symptoms and is not included in vaccinations.

    Antigenic Drift

    • Antigenic drift is a common, evolutionary change that happens over long periods of time. Antigenic drift occurs as the virus mutates to adapt to its environment. The environment may be natural, or it can be a mutation that defends the virus against antiviral medication. As the virus adapts, it can become more virulent and dangerous to humans.

    How Antigenic Shift Works

    • Antigenic shift is an abrupt change in the viral proteins. Antigenic shift protects the virus from detection from the body's immune system. This is more dangerous to humans, especially those who are immunocompromised. Influenza mutates often, which is why a new flu vaccine is distributed every flu season.

    Reservoirs

    • Reservoirs of the flu are animals like pigs and birds. The virus lays dormant in farm animals until sudden antigenic shift occurs. Humans who come into contact with these animals are infected with new strains. This is the basis of the avian and swine flu strains that made headlines in the news.

    Pets

    • The flu is able to infect dogs, but some canine flu strains are asymptomatic. These strains can be passed to humans. The death rate of canine infections is low. Symptoms of the canine flu are running nose, cough and fever. Dogs are also able to pass the virus to other dogs.

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