The Gambia declared this Wednesday a “public health emergency” after detecting poliovirus cases in samples collected from environmental sewers.
“Two samples of sewage from Banjul and Kotu [a tourist town near Banjul] were positive for the poliovirus,” said Gambian Health Minister Ahmadou Lamin Samateh. “It is important to note that this finding indicates that poliovirus is circulating, but it does not mean that cases of paralysis have been detected among the population,” he added.
The detection of these cases comes after introducing a new sampling policy in the country in May, which supports the World Health Organization (WHO).
By declaring this public health emergency, authorities will launch an awareness campaign and increase epidemiological surveillance. The Government is also planning “at least two mass vaccination campaigns” targeting children under 5 years of age.
Wild poliovirus was endemic around the world until a vaccine was discovered during the 1950s. The Gambia was declared polio-free in 2004, according to the Ministry.
In August of last year, W.H.O announced that wild poliovirus had been “eradicated” from Africa after four consecutive years of no reported cases and massive efforts to immunize children, calling the occasion a “historic moment.” Wild poliovirus is now only found in Pakistan and Afghanistan.
However, another form of poliovirus, derived from a vaccine strain, can be spread through faeces in areas with poor sanitation. According to the WHO, this attenuated form has become more dangerous after a mutation that occurs when vaccine coverage is low, allowing the virus to multiply.
On Tuesday, Uganda confirmed detection of circulating type 2 poliovirus of vaccine origin (cVDPV2) in plant samples in Kampala waters, which authorities link to decreased immunization due to the covid-19 pandemic.
Around two dozen countries have detected cVDPV strains in recent months, such as Kenya, South Sudan, or the Democratic Republic of Congo (DRCongo).
Polio is an infectious disease that mainly affects children under five years of age and has no cure, presenting symptoms such as fever, fatigue, vomiting, and headaches, which can cause, in some cases, paralysis of the extremities of the body.