Poliovirus detected in Brazil
On 18 June 2014, the Brazil International Health Regulations National Focal Point reported the detection of wild poliovirus type 1 (WPV1) in sewage samples collected in March 2014 at the International Airport of Viracopos in Campinas, São Paolo. WPV1 was detected in sewage only during routine environmental surveillance, which Brazil has carried out for 20 years.
Sewage samples collected from the same site subsequent to the detection of WPV1 have been either negative or only positive for Sabin strains or non-polio enteroviruses. To date no cases of paralytic polio have been reported and there is no evidence of transmission of WPV. There has been no indigenous transmission of wild poliovirus reported in Brazil since 1989.
Genetic analysis of the virus detected in Brazil showed a close match with a strain of poliovirus recently isolated from a case of polio in Equatorial Guinea. As of 25 June 2014, five cases of polio have been confirmed in Equatorial Guinea. Prior to 2014, no cases had been reported from Equatorial Guinea since 1999.
The public health authorities in Brazil are strengthening surveillance for acute flaccid paralysis (AFP) and engaging in active case finding. Regular national immunisation campaigns each year from the 1980s until 2011 have achieved over 95 per cent coverage, and the Americas Region has been free of wild poliovirus transmission since 1991 with the last case of polio in Brazil being in 1989.
The Pan American Health Organization and the World Health Organization assess the risk of further international spread of this virus from Brazil as very low due to a the immediate response by Brazilian authorities and high vaccination levels of local population immunity. Based on current evidence, the country is not considered polio-affected.