Researchers have identified a polio-like disease that has caused severe weakness or rapid paralysis in one or more arms and legs in five children from California since 2012. They are presenting their findings at the 66th Annual Meeting of the American Academy of Neurology in Philadelphia, PA, at the end of April.
One of the researchers, Dr. Keith Van Haren, of Stanford University, says:
"Although poliovirus has been eradicated from most of the globe, other viruses can also injure the spine, leading to a polio-like syndrome."
He explains that in the last 10 years, researchers have identified strains of enterovirus linked to polio-like outbreaks among children in Asia and Australia, and adds:
"These five new cases highlight the possibility of an emerging infectious polio-like syndrome in California."
Polio, or poliomyelitis, is an infectious viral disease that can strike at any age and cause paralysis. From the late 1940s to the early 1950s, polio crippled more than 35,000 Americans a year, but thanks to an effective vaccine, the US has been polio-free since 1979, say the US Centers for Disease Control and Prevention (CDC).
In 1988, polio was endemic in more than 125 countries, but through a series of immunization efforts, the incidence has fallen by more than 99% since then. In April 2013, the World Health Organization (WHO) announced they aim to eradicate polio by 2018.
Dr. Van Haren and his colleagues had noticed cases of this new polio-like disease at their medical centers and decided to find out how many there might be altogether in California.
Researchers counted cases over 12 months, excluding illnesses with similar symptoms
The team looked for all polio-like cases among children whose samples were sent to the Neurologic and Surveillance Testing program in California between August 2012 and July 2013.
They counted only cases where the illness caused paralysis in one or more limbs, accompanied by spinal cord MRI scans that explained the paralysis.
Additionally, they excluded cases due to illnesses that can cause similar symptoms, such as Guillain-Barré syndrome and botulism.
The cases involve five children whose illness had left them paralyzed in one or more limbs, and had come on suddenly, reaching peak severity within 2 days of onset. All of the children had received polio vaccinations beforehand, and three of them had a respiratory illness before their symptoms started.
The children's symptoms did not improve with treatment, and their limb function was still poor 6 months later.
While no cause was identified in three of the children, the other two tested positive for a rare virus - enterovirus-68 - that has previously been associated with polio-like symptoms.
Dr. Van Haren says their findings will help efforts to monitor, test and treat the mysterious disease. Although he says the syndrome appears to be very rare, he also urges:
"Any time a parent sees symptoms of paralysis in a child, the child should be seen by a doctor right away."
The McHugh/Sprague Award from the Lucile Packard Foundation funded the case investigation.