Explained: Mozambique confirms wild poliovirus case, first since 1992: What is it? Symptoms, Transmission

Brazzaville/Lilongwe, My 21: Health authorities in Mozambique declared an outbreak of wild poliovirus type 1 after confirming that a child in the country's north-eastern Tete province had contracted the disease.

This marks the second imported case of wild poliovirus in southern Africa this year, following an outbreak in Malawi in mid-February.

So far, one case in Mozambique - the country's first since 1992 - has been detected. The virus was found in a child who began experiencing onset of paralysis in late March.

Genomic sequencing analysis indicates that the newly confirmed case is linked to a strain that had been circulating in Pakistan in 2019, similar to the case reported in Malawi earlier this year.

The case in Mozambique and the earlier one in Malawi do not affect Africa's wild poliovirus-free certification because the virus strain is not indigenous.

Africa was declared free of indigenous wild polio in August 2020 after eliminating all forms of wild polio from the region.

"The detection of another case of wild polio virus in Africa is greatly concerning, even if it's unsurprising given the recent outbreak in Malawi. However, it shows how dangerous this virus is and how quickly it can spread," said Dr Matshidiso Moeti, World Health Organization Regional Director for Africa.

"We are supporting southern African governments to step up the polio fight including carrying out large-scale, effective vaccination campaigns to halt the virus and protect children from its damaging impact."

Further investigations are underway in Mozambique to determine the extent of the risk posed by the new wild poliovirus case and the targeted responses needed. Preliminary analysis of samples collected from three contacts of the newly-detected case were all negative for wild poliovirus type 1.

What everyone should know about

How does polio spread?

Polio is usually spread via the fecal-oral route (i.e., the virus is transmitted from the stool of an infected person to the mouth of another person from contaminated hands or such objects as eating utensils). Some cases may be spread directly via an oral to oral route.

What are the 3 different types of polio?

There are three wild types of poliovirus (WPV) - type 1, type 2, and type 3. People need to be protected against all three types of the virus in order to prevent polio disease and the polio vaccination is the best protection.

Symptoms

Most people who get infected with poliovirus (about 72 out of 100) will not have any visible symptoms.
About 1 out of 4 people (or 25 out of 100) with poliovirus infection will have flu-like symptoms that may include:

• Sore throat
• Fever
• Tiredness
• Nausea
• Headache
• Stomach pain

Transmission

Poliovirus is very contagious and spreads through person-to-person contact. It lives in an infected person's throat and intestines. An infected person may spread the virus to others immediately before and up to 2 weeks after symptoms appear.

Is there a difference between polio and wild polio?

No, there is no clinical difference between the paralysis caused by wild poliovirus, OPV, or VDPV.

Globally, wild poliovirus is endemic only in Afghanistan and Pakistan.

Polio is highly infectious and largely affects children younger than five years. There is no cure for polio, and it can only be prevented by immunization. Children across the world remain at risk of wild polio type 1 as long as the virus is not eradicated in the last remaining areas in which it is still circulating.