News about a poliolike illness detected in California has created quite a stir in the news media, but there is some disagreement about how concerning these rare cases are.
In the autumn of 2012, Keith Van Haren, MD, a pediatric neurologist at the Lucile Packard Children’s Hospital at Stanford University in California, and other neurologists across the state noticed an unusual trend: the emergence of several cases of sudden-onset paralysis in children who also had motor neuron injury. He and his colleagues normally can expect to see 1 such case a year, he said. But as he and his colleagues describe in an abstract released in February that will be presented at the American Academy of Neurology’s annual meeting in late April, 5 such cases were reported within a period of 18 months, including 2 that tested positive for human enterovirus 68. This virus has been linked to clusters of respiratory illness, and at least 1 case involving neurological symptoms had previously been reported. According to Van Haren, a total of 20 such cases have been detected in California in the past 18 months.
“The physician community is taking this very seriously, and is invested in figuring out the cause,” Van Haren cautioned. “But it remains rare.”
Benjamin Haynes, a Centers for Disease Control and Prevention (CDC) spokesperson, said the agency is closely monitoring the situation and has consulted with officials from the California Department of Public Health. But so far, it does not appear that the number of cases rise above the background rates of sudden-onset paralysis that would be expected in California in a given year, Haynes said. Acute flaccid paralysis can have a number of causes, including tick paralysis, Guillain-Barré syndrome, and botulism. However, it is not a condition physicians are required to report to the CDC, so the data are limited.
“At this time, CDC does not think the situation in California poses a public health threat, but we encourage parents to speak with their doctors or pediatricians if they have concerns,” Haynes said.
But Van Haren, who is accustomed to seeing patients with more typical presentations of acute paralysis, said he and his colleagues believe these cases are occuring more frequently than the baseline rate, and noted that there are no data on this particular subset of patients. Additionally, he said these patients are presenting with more severe disability and experiencing less recovery than would be expected with most cases of acute flaccid paralysis.
The California Department of Health has not found any common cause among the cases, but will continue to investigate, according to a statement from Gil Chavez, MD, MPH, Deputy Director of the Center for Infectious Disease and State Epidemiologist.