Biosafety Issues

The first report of a laboratory-associated infection was published in 1941 and described a case of poliomyelitis most likely acquired through washing and grinding infected tissues in preparation for inoculation into monkeys. Two years later, two laboratory workers were accidentally infected with the prototype Lansing (Armstrong) strain while attempting to infect mice. Two additional reported cases of poliomyelitis in laboratory workers were fatal: one in the United States and the
second in South Africa.
Despite the advances in biosafety over the past 40 years, recent evidence indicates that the potential nevertheless exists for transmission of poliovirus from the laboratory to the community. In 1992, a wild-type 1 strain used for IPV production was documented as being transmitted from a worker in a vaccine production facility to his 18-month-old son, who had received the full IPV series. The boy had been suffering from gastroenteritis when, by chance, the wild IPV seed virus was isolated from his stool. In another incident, a child was reported to be infected with a prototype strain of type 3 commonly used in laboratories for research or vaccine production. The source of this infection was not determined.
you can read more about this by clicking the link: http://www.cdc.gov/od/ohs/who/www9829.pdf