1 in Asia, the Pacific region, and East Africa; strain 2 in Ethiopia, Malawi, Nepal, north India, and New Caledonia; strain 3 in Europe, North Africa, and the Americas; strain 4 in West Africa and the Caribbean. This confirms the spread of the disease along the migration, colonisation, and slave trade routes taken from East Africa to India, West Africa to the New World, and from Africa into Europe and vice versa. Skeletal remains discovered in 2009 represent the oldest documented evidence for leprosy, dating to the 2nd millennium BC. Located at Balathal, Rajasthan, in northwest India, the discoverers suggest that, if the disease did migrate from Africa to India during the 3rd millennium BC "at a time when there was substantial interaction among the Indus Civilization, Mesopotamia, and Egypt, there needs to be additional skeletal and molecular evidence of leprosy in India and Africa to confirm the African origin of the disease." A proven human case was verified by DNA taken from the shrouded remains of a man discovered by researchers from the Hebrew University of Jerusalem in a tomb next to the Old City of Jerusalem, Israel, dated by radiocarbon methods to the first half of the 1st century. The oldest strains of leprosy known from Europe are from Great Chesterford in southeast England and dating back to AD 415–545. These findings suggest a different path for the spread of leprosy, meaning it may have originated in Western Eurasia. This study also indicates that there were more strains in Europe at the time than previously determined. Discovery and scientific progress Literary attestation of leprosy is unclear because of the ambiguity of many early sources, including the Indian Atharvaveda and Kausika Sutra, the Egyptian Ebers papyrus, and the Hebrew Bible's various sections regarding signs of impurity (tzaraath). Clearly leprotic symptoms are attested in the Indian doctor Sushruta's Compendium, originally dating to c. 600 BC but only surviving in emended texts no earlier than the 5th century. They were separately described by Hippocrates in 460 BC. However, Hansen's disease probably did not exist in Greece or the Middle East before the Common Era. In 1846, Francis Adams produced The Seven Books of Paulus Aegineta which included a commentary on all medical and surgical knowledge and descriptions and remedies to do with leprosy from the Romans, Greeks, and Arabs.Roman: Celsus, Pliny, Serenus Samonicus, Scribonius Largus, Caelius Aurelianus, Themison, Octavius Horatianus, Marcellus