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or bacterial lifeforms with shorter reproductive cycle times?

I'm looking for actual time frames.

2006-07-31 17:28:55 · 3 answers · asked by claypigeon 4 in Science & Mathematics Biology

3 answers

There are three types of influenza viruses, known as A, B, and C. Type A, the most dangerous, infects a wide variety of mammals and birds. It causes the most cases of the disease in humans and is the type most likely to become epidemic. Type B infects humans and birds, producing a milder disease that can also cause epidemics. Type C apparently infects only humans. It typically produces either a very mild illness indistinguishable from a common cold or no symptoms at all. Type C does not cause epidemics.
Influenza type A and B viruses continually change. Some changes involve a series of genetic mutations that, over a period of time, cause a gradual evolution of the virus. Called antigenic drift, this process accounts for most of the changes in influenza viruses that occur from one year to the next. Other changes, less common but more injurious, involve abrupt changes in the hemagglutinin or neuraminidase. This type of change is called antigenic shift and results in a new subtype of the virus. Type A viruses undergo both kinds of transformations; influenza type B viruses apparently change only by the process of antigenic drift.

2006-07-31 20:18:43 · answer #1 · answered by ? 3 · 0 1

Wikipedia

2006-08-06 19:21:18 · answer #2 · answered by rod 5 · 0 0

Spread is rapid via aerial droplets and fomites with inhalation into the pharynx or lower respiratory tract.
Incubation is short: 1-3 days. Rapid spread leads to epidemics

2006-08-02 08:27:45 · answer #3 · answered by ATP-Man 7 · 0 0

fedest.com, questions and answers