The Simian Virus, specifically known as Simian Virus 40 (SV40), is a polyomavirus that was first discovered in the early 1960s in monkeys. It is primarily associated with rhesus macaques and was found in the kidneys of these animals. SV40 gained attention because it was inadvertently introduced into humans through contaminated polio vaccines. Research has shown that SV40 can cause tumors in laboratory animals, raising concerns about its potential effects on human health. While some studies have suggested a link between SV40 and certain human cancers, such as mesothelioma, the evidence remains inconclusive. Ongoing research continues to explore the virus's implications in human disease.