There is a high risk of polio spreading in Ebola-ravaged Guinea and Mali, the World Health Organization (WHO) said on Monday, after a Guinean toddler travelled to Mali and became that country's first case of the crippling disease in more than four years.
Preliminary tests by authorities in Mali's capital showed the 19-month-old was paralysed on July 20, seven days before being brought to Bamako for treatment. The strain of the virus is the same as one detected in Siguiri in Guinea's Kankan region, in August 2014.
"The risk of spread is considered to be high in both countries due to low rates of vaccination coverage in both Mali and Guinea," WHO spokesman Cory Couillard said in an emailed comment to Reuters.
"Both countries are taking coordinated emergency response measures to bring the outbreak to an end quickly."
The Mali and Ukraine cases are both vaccine-derived polio, meaning the virus spread after being excreted by people who have been immunised with live oral polio vaccine.
Vaccine-derived polio outbreaks are rare, but pose more of a risk in populations where health systems are fragile and people immunisation coverage is low.
WHO figures show Guinea's polio vaccination coverage fell from 63 percent to 42 percent in 2014, as the Ebola outbreak caused chaos and overwhelmed an already weak national health system. In Mali, by contrast, polio vaccination coverage rose to 84 percent in 2014, from 72-77 percent in preceding years.
There is no cure for polio, which attacks the nervous system and can cause irreversible paralysis within hours of infection. It mainly affects young children in areas with poor sanitation.
A global vaccination campaign has largely stamped out the virus, and only Pakistan and Afghanistan have reported cases of wild polio virus this year. Like Ukraine, Madagascar and Nigeria have suffered vaccine-derived cases.