Good evening,
Thanks for your question; the answer is true for all infections, not just AIDS.
The time between exposure and appearance of clinical manifestations is called the incubation period.
When a bacterium or virus enters the body through the skin or the lining of the airway or digestive system, we don't notice anything for a while. The little beastie starts to multiply and the body's defense mechanisms notice it and gear up to fight it. Depending upon what the beastie is, some time passes before we begin to realize that there's a fight going on.
The body temperature rises, chemicals are produced that aim to destroy the invaders, white blood cells mobilize to swallow them, and many other things happen.
The clinical manifestations of any invasion depend upon which defenses are called into play; these are the immune mechanisms. Not all are harmless; some cause damage to normal tisue while they are fighting the invaders. An example is a boil; the pus is an accumulation of white blood cells that have killed the bacteria and died in the process and tissue cells that have been killed in the processs.
With AIDS, there is no direct, visible tissue damage. The HIV enter cells and multiply, The damage they do is to impair the ability of certain immunosupressive cells to destroy not only the HIV itself but also most other invaders that come along. Therefore, AIDS deaths are the result of other invaderss which the normal body would fight off but which the immunocompromized body can not.
The incubation period for the common cold is 7 to 10 days. For some infections it is shorter; for others, it is far longer, years for some.
Thanks again for asking us; we're here to help you.
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