 In the United States on 29 September 2005, the Minnesota Department of Health identified the first occurrence of vaccine derived polio virus (VDPV) transmission in the United States since OPV was discontinued in 2000.The poliovirus type1 infection occurred in an unvaccinated, immunocompromised infant girl aged seven months (the index patient) in an Amish community whose members predominantly were not vaccinated for polio.In 2006, only four countries in the world (Nigeria, India, Pakistan and Afghanistan) were reported to have endemic polio.