Following the confirmation of eight cases on Friday, Burundian health officials declared an epidemic of the poliovirus in circulation, the first such finding in more than three decades, according to a statement from the World Health Organization.
An unvaccinated 4-year-old boy in the western Burundian district of Isale and two other kids who were his contacts were verified to have the infections, according to the WHO.
Five wastewater samples from environmental surveillance programs further supported the discovery of the poliovirus type 2 in circulation.
When the weaker strain of the virus present in the oral polio vaccination is persistently spread among under-immunized people, circulating poliovirus type 2 infections may develop.