[4] Hahn and her research group established that wild-living chimpanzees in southern Cameroon were a natural reservoir of the closely related simian immunodeficiency viruses (SIVs).
[3][1] The simian versions of the virus (known as SIVcpz in chimpanzees, and SIVgor in gorillas) became the infection named HIV in humans.
[2] Hahn had herded and milked cows as a child in her native Bavaria, where cattle were important to the rural economy.
[2] After graduating, Hahn began her career with a fellowship from the German Science Foundation in Robert Gallo's National Cancer Institute in Bethesda, Maryland.
In 2011, Hahn joined the faculty of the Perelman School of Medicine at the University of Pennsylvania along with her husband and research partner George Shaw.
She is also a member of the advisory board of the Bill and Melinda Gates Foundation's HIV/AIDS Program and has served on numerous NIH Counsel groups.
All of the patients with the reported disease were gay males and displayed symptoms of a skin cancer and unique form of pneumonia.
They went on to discover that HIV originated from chimpanzees, gorillas, and sooty mangabey strains of simian immunodeficiency virus (SIV).
Contrary to the prevailing scientific opinion, Hahn found that SIV does cause disease in its hosts and that chimpanzees represent a reservoir of HIV.
[1][2][11] Hahn and Shaw had many papers published (including a cover article for Nature) and in 1985 they were both recruited by the University of Alabama at Birmingham's Comprehensive Cancer Center to lead and conduct human retrovirus research.
Simian immunodeficiency viruses (SIVs) are a type of retroviruses that are capable of infecting a myriad of non-human primate species located in Africa.
The two viruses she identified were SIVcpz from chimpanzees (Pan troglodytes) and SIVsmm from sooty mangabeys (Cercocebus atys).
[12] The realization that the transfer of SIVs had generated HIV led Hahn to conclude that presence of Acquired Immunodeficiency Syndrome (AIDS) was due to the cross-species infections of humans by lentiviruses of primate origin.
[12] A careful analysis of the high degree of relatedness between chimpanzees and humans was a major focus in Hanh’s laboratory.
Knowing that chimpanzees and humans share more than 98% sequence identity across their genomes, Hanh sought to uncover what exactly varies in the interactions between virus and host that cause differences in viral pathogenicity.
[13] This proved that the origin of a subspecies' chimpanzee host was what was responsible for two different phylogenetic lineages of SIVcpz strains.