A new study suggests that the smallpox vaccine might actually have come from horses, not cows.

Smallpox is an infectious disease caused by variola virus that has killed millions of people over the centuries. The disease is characterized by the growth of innumerable bumps that cover the entire body of the patient.the research suggested that the smallpox vaccine might actually have come from horses, not cows, which would mean we should perhaps be talking about ‘equination’ and ‘equines’.A researcher Clarissa Damaso from Federal University of Rio de Janeiro in Brazil conducted the research.According to Damaso, "The intense mixing and exchange of several smallpox vaccine samples that occurred during the 19th century has resulted in an intricate and complex evolutionary relationship involving different types of viruses and lymphs that we are still trying to understand."

Combining the use of modern technology and access to historical records may eventually shed light on all the ingredients added to this mysterious recipe that has no doubt saved millions of people worldwide over the past 200 years.A British physician Edward Jenner developed a vaccine against smallpox in 1796 and the virus circulating in the vaccine was named as vaccinia virus.​​​​​​​Vaccine comes from the Latin for cow, vacca, as Dr Edward Jenner is famously said to have used the cowpox virus to inoculate an eight-year-old boy, his gardener's son, against deadly smallpox in one of the most ethically dubious, but successful, experiments in history.Cowpox virus, a cousin of variola virus, causes a mild smallpox-like disease in cows.

The story goes that Jenner was told that milkers who acquired the "cow-version" of smallpox were immune to the human version of the disease.They took pustular material from the lesion of a milker and used it to inoculate a young boy.They found that the young boy remained immune to smallpox and the experiment was a milestone in the history of the smallpox vaccine.Following this success, vaccination (from the Latin vacca meaning cow) was adopted worldwide as the main strategy to prevent smallpox.But this is not the case. Virtually all batches of modern smallpox vaccine contain no cowpox virus, but instead what is called vaccinia virus.Full-genome sequencing has revealed that the two viruses are quite different and that one could have not mutated into the other.The research appears in journal of The Lancet Infectious Diseases