SUNDAY, SEPTEMBER 25, 2016

WHO reports detection of poliovirus in Brazilian sewage samples

The World Health Organization's National International Health Regulations Focal Point for Brazil reported on June 18 that it discovered wild poliovirus type 1 (WPV1) in sewage samples taken in March at the Viracopos International Airport.

Sewage samples taken from the same site after the discovery of WPV1 were negative or only positive for Sabin strains or non-polio enteroviruses. No cases of paralytic polio have been reported.

Genetic sequencing of the samples found in Brazil match a WPV1 strain recently isolated from a case in Equatorial Guinea. The WHO is conducting additional epidemiological testing.

There have been no indigenous wild poliovirus transmissions in the Americas since 1991, and Brazil has not seen any since 1989. Brazil increased surveillance to detect any transmissions of WPV1 following the positive test results from the sewage samples.

The vaccination rate against polio in the Campinas municipality in São Paulo, where the samples were taken, is higher than 95 percent.

The WHO determined that Brazil has not been re-infected with wild poliovirus, and that the incident stemmed from a WPV1 importation. Travelers to the area where WPV1 was detected are still encouraged to receive a poliovirus vaccination.

The discovery of WPV1 in the Brazilian samples was made during routine testing of the water.