The case, which marks the second imported case of wild poliovirus in southern Africa this year following an outbreak in Malawi in February, was found in a Mozambique child who began experiencing the onset of paralysis towards the end of March, according to the WHO.
WHO Regional Director for Africa Matshidiso Moeti said "The detection of another case of wild poliovirus in Africa is greatly concerning. It shows how dangerous this virus is and how quickly it can spread."
Polio invades the nervous system and can cause irreversible paralysis within hours. It cannot be cured, but infection can be prevented by vaccination.
The WHO is supporting large-scale vaccinations targeting millions of children across southern Africa to halt the spread of the virus on the continent, which was declared free of indigenous wild polio in 2020 after eliminating all forms of the wild virus in Africa.
In unvaccinated populations, polio viruses can re-emerge and spread swiftly. Cases of vaccine-derived polio can also occur in places where immunity is low and sanitation is poor, as vaccinated people can excrete the virus, putting the unvaccinated at risk.