A virus eradicated from Brazil in 1989 was detected in sewage samples taken near Sao Paulo, the largest city in the country hosting a venue for the World Cup. The World Health Organization said no human cases have been reported thus far.

Taxi drivers watch a telecast at a taxi station in Sao Paulo on June 23, 2014, as Brazil face Cameroon in their Group A match of the FIFA World Cup 2014. (AFP/Eitan ABRAMOVICH/Getty Images)

Taxi drivers watched a telecast at a taxi station in Sao Paulo as Brazil faced Cameroon in their Group A match of the FIFA World Cup 2014. Sewage samples taken a few months before the games turned up a polio virus, but no human cases have been reported. (AFP/Eitan ABRAMOVICH/Getty Images)

“[The] virus has been detected in the sewage only … To date no case of paralytic polio has been reported,” WHO said in a statement, according to Reuters, noting that the sewage samples were collected in March.

WHO doesn’t consider the presence of the virus too risky at this point given that Brazil’s last immunization for the crippling disease was last year with an estimated 95 percent in Sao Paulo being vaccinated.

“It is important to clarify that this detection does not mean any change in the epidemiological situation of Brazil or a threat to the elimination of the disease,” WHO said in its statement. ”The high immunity appears to have prevented transmission.”

The risk of international spread from a country like Brazil is considered “very low,” according to Reuters.

Still, a couple of months ago WHO overall said the current spread of polio from other countries was an international public health emergency that could grow and ultimately unravel the nearly three-decade effort to eradicate the disease.

It called the ongoing polio outbreaks taking place in Asia, Africa and the Middle East an “extraordinary event” requiring a coordinated international response.

“Until it is eradicated, polio will continue to spread internationally, find and paralyze susceptible kids,” Dr. Bruce Aylward, who leads WHO’s polio efforts, said.

An Iraqi doctor gives a polio vaccine to a child in Baghdad, Iraq, Wednesday, May 14, 2014. With the assistance of international health organizations, Iraqi health officials are scrambling to vaccinate millions of children across Iraq against the highly contagious polio virus in response to the outbreak of the disease in the country as well as the region, a spillover from the three-year-old war in neighboring Syria where a handful of children have been affected. (AP/ Khalid Mohammed)

An Iraqi doctor gives a polio vaccine to a child in Baghdad in May. With the assistance of international health organizations, Iraqi health officials are scrambling to vaccinate millions of children across Iraq against the highly contagious polio virus in response to the outbreak of the disease in the country as well as the region, a spillover from the three-year-old war in neighboring Syria where a handful of children have been affected. (AP/ Khalid Mohammed)

Polio usually strikes children under five and is most often spread via infected water. There is no specific treatment or cure, but several vaccines exist.

The Centers for Disease Control and Prevention recommends those traveling to countries with polio outbreaks become vaccinated if they haven’t already or receive a one-time booster shot.

The issue regarding disease vaccination as a whole has been a popular discussion point in the United States as the largest measles outbreak to hit the country in decades is in full swing. A large outbreak in an Ohio Amish community, which included many unvaccinated individuals, has them reconsidering their stance on vaccination.

The Associated Press contributed to this report.