The World Health Organization reported Brazilian health officials discovered strains of the polio virus in sewage routinely tested on June 18 at Viracopos International Airport, in Campinas municipality in the State of São Paulo. Genetic sequencing indicated a close match with a strain of wild polio virus isolated in Equatorial Guinea. Health officials say the virus was detected only in sewage, with no reports of paralytic polio detected, though their investigation is ongoing.
“Based on current evidence, the country is not considered polio-affected,” WHO stated, referring to this exposure as “a poliovirus importation.” Brazil has been free of indigenous WPV transmission since 1989, and the Americas Region since 1991. Vaccination coverage against polio in São Paulo State and Campinas municipality is higher than 95 percent. Given this high level of population immunity and no evidence of transmission, WHO “assesses the risk of further international spread of this virus from Brazil as very low.”
Currently, Campinas is the location of the base camp for the Portuguese and Nigerian World Cup soccer teams. May/June is considered high transmission season for wildpolio virus.
Analyzing the statistics for 2013, WHO estimated 60 percent of polio cases were the result of international spread of wild poliovirus and during the 2014 low transmission season international spread of wild poliovirus had occurred involving three of the currently infected nations. WHO suggested adult travelers contributed to infections transmitted from Pakistan to Afghanistan, from Syrian Arab Republic to Iraq, and from Cameroon to Equatorial Guinea.
In particular, Pakistan, Cameroon, and Syria pose the greatest risk of further exportations in 2014, while Afghanistan, Equatorial Guinea, Ethiopia, Iraq, Israel, Somalia and Nigeria pose an ongoing risk for new exportations, according to WHO. Calling for a “coordinated international response,” WHO recommended affected countries undertake “supplementary immunization campaigns with the oral vaccine, surveillance, and routine immunization.”
Polio primarily affects children under 5 and survives only among the world's poorest and most marginalized communities. One in every 200 infections leads to irreversible paralysis; five to 10 percent of those paralyzed die. WHO has acted as a partner in the Global Polio Eradication Initiative, a private-public partnership formed in 1988 when polio paralyzed more than 350,000 people a year. That initiative has successfully reduced polio by 99 percent, with international health authorities reporting only 406 polio cases in 2013. Three strains of wild poliovirus exist and none of these can survive for long periods outside the body, which is what gives health officials hope that, once enough children are vaccinated, polio will soon die out globally. Type 2 wild poliovirus was eradicated in 1999.