A lot of people been wondering, where does HIV come from? And why did it reach America? In the process of finding when and where the virus took hold in America, a man was exonerated and accused of spreading the disease in North America. According to sociologist William Darrow, a sociologist together with his colleagues in CDC (US Centers for Disease Control and Prevention), went to California to investigate cases of Kaposi's Sarcoma, a type of skin cancer among gay men.

Darrow then knew that the skin cancer was later shown to be a complication of HIV infection, sexually transmitted. Then one day when three men from different countries told Darrow they all have sex with the same person; Gaetan Dugas, a French-Canadian flight attendant.

Gaetan Dugas was later on called "Patient Zero". It seems that the journalists misunderstood and he was since mistakenly knwon as the person who brought the HIV in America. Even in the best-selling book "And the Band Played On", chronicled the early days AIDS in America.

An analysis made using the eight old blood serum samples from gay men that have HIV shows that the virus had been circulating since 1970's in North America, as it arrived in the continent through the Caribbean from Africa.

A historian at the University of Cambridge, Richard McKay questioned the idea of a "Patient Zero" and suggested that the epidemic entered North America. McKay made a team and found a genetic traces of HIV and sequence the three samples came from San Francisco and the other five from New York, Nature reports.

Dugas would have been a teenager at the time and unlikely to be sexually active and much less partnering to a lot of people as to have claimed that he had sex with, NPR reports. Worobey's analysis of Dugas blood showed that the HIV strain that eventually killed him doesn't match the others.

According to Beatrice Hahn, a microbiologist at the University of Pennsylvania,  it's so easy to jump into conclusions about the epidemic that doesn't immediately cause disease. HIV can stay in the body for over 10 years before making a person ill.

Many gay men resisted the idea that unprotected sex spread HIV. A dermatologist says that it was difficult because they fought for sexual freedom, recognition and acceptance so much - to be told that every gay man in a potential carrier of this epidemic.