A mysterious polio like illness that has left children in US, Canada and Europe paralysed, is caused by a virus called Enterovirus D68 reveal researchers at University of New South Wales (UNSW) in Australia after analysing scientific literature on acute flaccid myelitis.
The Centres for Disease Control and Prevention define AFM as a condition that affects the nervous system, specifically the spinal cord and is characterised by a sudden weakness in one or more arms or legs along with loss of muscle tone and reflexes. “In 2014, children in the US began to be diagnosed with a mystery illness that caused a polio-like paralysisMore than 120 children developed the condition, known as acute flaccid myelitis, in the US alone but experts were baffled as to the cause,” said Professor Raina MacIntyre of UNSW. The study was published in the journal Eurosurveillance.
That same year there were also unusually large outbreaks of infection with Enterovirus D68, or EV-D68 – a virus known since the early 1960s to cause runny noses, coughs, muscle aches, fever and difficulty breathing. About 2,280 people in the US, Canada and Europe were infected with the virus, many of them children, and their respiratory symptoms were more severe than usual, researchers said. Clusters of the paralysing illness, also mostly in children, were reported in the same regions, they said.
“This raised the possibility of a link between EV-D68 and acute flaccid myelitis. However, the virus had never been known to cause paralysis before,” said MacIntyre. The team applied the Bradfield Hill criteria – a set of nine principles developed to determine causality. The method used to prove that smoking caused cancer is now an accepted tool to determine causality. “We are first to use his approach to analyse the relationship between EV-D68 and acute flaccid myelitis. Our results show that it is very likely that EV-D68 is the cause of the mystery illness and the paralysis of children,” said MacIntyre.
The best known cause of AFM is polio. In India ever since it was certified to be polio free cases of acute flaccid paralysis have been routinely investigated to look for the dreaded virus. A total of 59,436 AFP cases were investigated in India in 2012, another 53,421 in 2013 and 53,383 in 2014. Not a single AFP case has tested positive for polio in 2012, 2013 and 2014.
