Scientists believe a new polio-like virus is responsible for dozens of unexplained cases of paralysis in children over the last year. The disease, called enterovirus C105, is part of the polio family of viruses and has only recently been discovered, they said.
So far, more than 100 children across 34 US states have suddenly developed acute flaccid myelitis, a condition characterised by muscle weakness or paralysis in the limbs. Previously, researchers believed the cause could be a virus called enterovirus D68 (EV-D68), LiveScience reports.
But only around a fifth of children with paralysis were found to have tested positive for this particular strain, leading them to question whether it was the only cause. As part of a new study, researchers linked one case of paralysis in a six-year-old girl with the novel enterovirus C105. Although it doesn’t conclusively prove that this polio-like virus is the cause, it suggests that viruses other than EV-D68 may be contributing to the outbreak, they said.
The study’s co-author Professor Ronald Turner, of the University of Virginia School of Medicine, said the findings mean people should be aware that “there’s another virus out there that has this association” with paralysis. He told LiveScience journalists, “We probably shouldn’t be quite so fast to jump to enterovirus D68 as the [only] cause of these cases.”
The six-year-old girl developed paralysis after suffering a cold passed on by her family members, as well as a mild fever. When the symptoms of the cold disappeared, she was left with pain in her arms. Then her shoulders began to droop and she started having trouble using her right hand. She was diagnosed with acute flaccid myelitis in the hospital, but tested negative for EV-D68. However, a sample from her respiratory tract tested positive for the newly-discovered polio-like virus enterovirus C105.
This is the first report of the virus in the US, researchers said.
She stayed in the hospital for 5 days and did not respond to treatment with intravenous immunoglobulin, but 8 months after the onset of her illness, her arm weakness had improved.
Dr. Turner said that some tests can miss enterovirus C105, due to variation in its genetic makeup. And it may have gone unnoticed until now as it is new and hard to detect, he added. However, he noted that the viruses have been found in the respiratory tracts of paralysed children, but in tests they have not been found in their spinal fluid. People can have viruses in their respiratory tract that does not affect their nervous system, he explained. In order to more definitively link these cases of paralysis with enterovirus, researchers would need to find the virus in the spinal fluid, he concluded.
Enterovirus C105 was first identified in the Democratic Republic of Congo in late 2010. Since then, Enterovirus C105 has also been identified in a patient in Peru, in a patient in Cyprus, and in another patient in New Zealand. It is an extremely rare virus.
The study will be published in the October issue of the journal Emerging Infectious Diseases.