Malawi has declared a polio outbreak after a case was detected in a young child in the capital Lilongwe, the first case of wild poliovirus in Africa in more than five years, the World Health Organization (WHO) said.
Laboratory analysis showed the strain detected in Malawi was linked to one that has been circulating in Pakistan, where it is still endemic, the WHO said in a statement.
“As an imported case from Pakistan, this detection does not affect the African region’s wild poliovirus-free certification status,” the WHO said.
The Global Polio Eradication Initiative said the case in Malawi was in a three-year-old girl who experienced the onset of paralysis in November last year.
Sequencing of the virus conducted in February by South Africa’s National Institute for Communicable Diseases and the U.S. Centers for Disease Control and Prevention confirmed it as type 1 wild poliovirus (WPV1).
“Detection of WPV1 outside the world’s two remaining endemic countries, Pakistan and Afghanistan, is a serious concern and underscores the importance of prioritising polio immunisation activities,” the Global Polio Eradication Initiative said.
The WHO said the African continent was able to respond rapidly response because of a high level of surveillance.
“The last case of wild poliovirus in Africa was identified in northern Nigeria in 2016 and globally there were only five cases in 2021. Any case of wild poliovirus is a significant event and we will mobilize all resources to support the country’s response,” said Modjirom Ndoutabe, polio coordinator in the WHO’s regional office for Africa.
Polio is a highly infectious disease that invades the nervous system and can cause total paralysis within hours. While there is no cure, it can be prevented by vaccine, the WHO said.
“The strain of poliovirus detected (in Malawi) is a close match to a strain last detected in a child with paralysis in the (Pakistani) province of Sindh in October 2019,” said Hamid Jaffery, Director, Polio Eradication, WHO Eastern Mediterranean Region.
“Until we stop transmission of polio in Afghanistan and Pakistan, the world remains at risk,” he told Reuters.
Pakistan is among countries where it is recommended international travellers have polio vaccination certificates.
Pakistan’s health minister Faisal Sultan told Reuters the genetic cluster had disappeared from the country since around 2019.
“Further analysis may reveal its hiding place since then – perhaps somewhere in the world where there are pockets of ‘immunity gap’ and non-existent environmental surveillance,” he said.