In 1931 Shope worked as researcher and together with
Paul A. Lewis at
Rockefeller University discovered that the cause of
swine flu was virtually identical to
bacillus influenza, a bacterium that had in 1892 been identified as the cause for
human influenza. Shope and Lewis went on to identify a
virus that also had links to influenza, putting into doubt the thesis that flu was caused by a
bacterial infection. Soon after this controversial discovery, Lewis traveled to Brazil to study an outbreak of
yellow fever. The 28 year old Shope had put himself forward for this research trip, but his offer was refused by Lewis. Instead Shope continued to research swine flu. Lewis did not return from the research trip, as he died of a yellow fever infection brought about by a
laboratory accident. Shope continued his work at the Department of Animal Pathology at the Rockefeller Institute for Medical Research in
Princeton, New Jersey. Throughout the
1930s Shope continued to research swine flu. While studying swine flu on farms in
Iowa Shope discovered that
virus infections caused the
mad itch, also known as pseudorabies, in cattle. Shope also discovered that virus infection caused
fibroma in the
cottontail rabbits he had hunted in
New Jersey, and that a virus infection was also responsible for the
papillomatosis in the cottontail rabbits he had observed in Iowa. By the late 1930s Shope had established himself as a well-known expert with a reputation as a
virus hunter. Shope left the Rockefeller Institute to join a research team the
Canadian Department of National Defence and the
US War Department established to investigate
rinderpest. In 1943 Shope presented his team's research on rinderpest at a meeting hosted by
George Merck. ==Family==