Updated on 3 March 2014
Both Dr Waubant and Dr Haren however told the media that although they have found five cases, there are preliminary reports of several more.
Dr Carol Glaser, chief of the Encephalitis and Special Investigation Section at the California Department of Public Health, said the state is aware of the paralysis cases but believes the risk to families is low.
Media reports added that the poliovirus has been eradicated in the United States for more than 30 years. As per the World Health Organization, only three countries in the world are not yet free of the disease yet - Afghanistan, Pakistan and Nigeria.