Relapsing fever, as its name implies, is an illness characterized primarily by recurrent episodes of fever, often accompanied by fatigue, malaise and other constitutional symptoms. It is caused by at least 15 spirochete species belonging to the genus Borrelia, and can be vectored to humans by either lice or ticks. Louse-borne relapsing fever (LBRF) is caused by Borrelia recurrentis and is transmitted from human to human by the body louse, Pediculus humanus humanus.
This means that the calendar has a cycle of 400 years as far as leap years are concerned. Every 400 years the same leap year schedule appears. During that cycle, 97 leap years occur (once every 4 years except 3 century changes, so 400 / 4 - 3 = 97). By pure coincidence, this happens to be just an integral number of weeks as well This means that every 400 years the Gregorian calendar repeats itself exactly on the same days of the week!
How often will I get my period? A menstrual cycle is counted from the first day of bleeding in one month to the first day of bleeding in the next month. The average menstrual cycle is about 28 days, but cycles that are 21â45 days also are normal. It may take 6 years or more after your period starts for your cycle to get regular. If you do this every month, you may notice a pattern. It may become easier to tell when you will get your next period.