Virology in order to immunize others. In 1717 Lady Mary Wortley Montagu observed the practice in Istanbul and attempted to popularize it in Britain, but encountered considerable resistance. In 1796 Edward Jenner developed a much safer method, using cowpox to successfully immunize a young boy against smallpox, and this practice was widely adopted. Vaccinations against other viral diseases followed, including the successful rabies vaccination by Louis Pasteur in 1886. The nature of viruses however was not clear to these researchers. In 1892, the Russian biologist Dmitry Ivanovsky used a Chamberland filter to try to isolate the bacteria that caused tobacco mosaic
1972 Yugoslav smallpox outbreak the disease was considered to be eradicated in Europe. The population of Yugoslavia had been regularly vaccinated against smallpox for 50 years, and the last case was reported in 1930. This was the major cause for the initial slow reaction by doctors, who did not promptly recognize the symptoms of the disease. In October 1970, an Afghan family went on pilgrimage from Afghanistan, where smallpox was endemic, to Mashhad in Iran, triggering a massive epidemic of smallpox in Iran that would last until September 1972. By late 1971, smallpox-infected devotees on pilgrimage had carried the smallpox from Iran into Syria