It depends on the person, but I know that the average cycle is about 28 days long, and it only occurs once a month, in normal situations.
Hope this helps! :)
Stay smart,
~Mistermistyeyed.
Answer:
The change of existing human infections and creature infections. Infections recently restricted to little, secluded populaces that would now be able to spread because of mechanical or social changes, for example, the improvement of moderate worldwide travel.
Is their a multiple choice ?