Two other polio cases were reported in August. Nigeria was on track to be certified free of the virus next year.
“A third child has been paralyzed by wild polio virus type one (WPV1) in Borno state,” WHO said in a statement.
“It’s all linked to the same outbreak,” WHO said, adding: “detection of new cases is not unexpected and can be anticipated, particularly as disease surveillance is being strengthened including by conducting retrospective case searches.”
The three cases appear to come from the same strain of the disease circulating in the northeast for years, said Stephanie Mucznik, spokesperson for Rotary International, which is working with the Nigerian government to eradicate polio.
Mucznik said the latest case concerned a two-year-old boy suffering from the onset of paralysis on August 6 in the Monguno area.
“Genetic sequencing of the isolated viruses suggests they are most closely linked to WPV1 last detected in Borno in 2011, indicating the strain has been circulating without detection since that time,” Mucznik said.