If someone with HIV is diagnosed with one of these opportunistic infections (even if the CD4 count is above 200), he or she is said to have AIDS. AIDS usually takes time to develop from the time a person acquires HIV--usually between 2 to 10 years or more.
It has been thought that the wheel was invented in 8000 B.C but the oldest discovered wheel dates back to 3500 B.c. It was discovered in Mesopotamia (nowadays in Iraq). Below are the timelines of wheels and its usage in different era.
The Evolution of the Wheel. The true beginnings of the wheel date back possibly as far as the Paleolithic era (15,000 to 750,000 years ago). This wheel was nothing more than a log, laid alongside others, which was placed beneath a load to be moved. Invention of the Wheel at ThinkQuest.