More children are diagnosed with mysterious paralysis of the disease in the past few weeks, and health authorities in the United States are not yet sure of that.
This year's figure could exceed the similar results of the outbreaks recorded in 2014 and 2016, officials said. The disease remains rare: in 27 countries, 90 cases have been reported, according to Centers for Disease Control and Prevention (CDC).
It is still unknown, causing some children to lose the ability to move their face, neck, back, arms or legs. Symptoms usually occur about a week after children have a fever or respiratory illness.
Health authorities refer to the condition as acute flaccid myelitis. No one died of the disease this year, but it's fun to claim that at least half of patients are not recovering from paralysis and severe complications.
Polio and Western Nile viruses have been discarded. Doctors suspect that the cause may be some kind of enterovirus, which in most people causes cold symptoms.
The first wave of mysterious cases in 2014 coincided with the generalized rise in enterovirus-related diseases called EV-D68.