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 wooden wheel. The wooden wheel belonged to a prehistoric two-wheel cart â a pushcart. Similar wheels have been found in the hilly regions of Switzerland and southwest Germany, but the Ljubljana Marshes one is bigger and older. It shows that wooden wheels appeared almost simultaneously in Mesopotamia and Europe.