A bizarre polio-like virus has afflicted a number of California children near the Bay Area over the past several months. Polio is a highly contagious viral infection that usually affects children or those with weak immune systems. The most notable symptom associated with it is paralysis, usually of the spine, which can effectively freeze the limbs of victims, according to Medical News Today. However, vigorous vaccinations campaigns have essentially eliminated polio from the western world altogether for decades now. So what is the illness that is affecting these children?
Keith Van Haren, a pediatric neurologist at Stanford University, explained in a report that between August 2012 and July 2013, five children have developed paralysis in one or more of their limbs over the period of just a few days, according Scientific American. However, all of these children had been previously vaccinated against the polio virus, and even after six months of treatment, none of the children fully recovered function in the most severely affected limb. So what is to blame here?
Tests conducted on the five children concluded that two of them tested positive for a rare virus called enterovirus 68. Part of the same family of viruses as polio, it can cause similar symptoms, and has been linked to polio-like outbreaks among Asian and Australian children over the last decade, according to Reuters. However, the other three children tested negative for the enterovirus. Emmanuelle Waubant, a neurologist at University of California, San Francisco explained that those children who tested negative could have the virus at some point, but were not tested soon enough for the virus to show up in their blood. As a result, the exact cause of their symptoms remains up in the air.
In addition to the initial five children, Van Haren notes, “About 20 cases have been identified in the U.S. so far, all in California, and all occurring in the past 18 months.” The California Department of Public Health has received reports from these 20 cases, but they have yet to find any common link among these instances, according to CTV News.
With 20 cases already reported, the most pressing question would be whether or not this virus will spread. Jane Seward, the Center for Disease Control and Prevention’s Deputy Director of the Division of Viral Diseases, explained that the enterovirus is a “rare outcome” in the children, according to Scientific American. Given that polio has essentially been eliminated in the U.S., Seward continues that diseases with polio-like symptoms are not “nationally notifiable disease[s]” in the U.S., so there is no way “to assess the significance of this number of cases.”
However, based on the data from countries that do track “acute flaccid paralysis,” or polio-like illnesses, the prevalence of these illnesses is about 1 in every 100,000 children under 15 years old. Seward explains that because California has a population of eight million children under 15 years old, “we would expect at least 80 cases of acute flaccid paralysis” in California alone, according to Scientific American. In other words, Seward states that while this outbreak is bizarre, the 20 cases that have been reported are far from an epidemic, and for the most part there is no reason to worry.
Despite this, enteroviruses such as this polio-like illness are not to be taken lightly. Seward notes that, like with any virus, practicing good hygiene is the best way to prevent spreading. In the meantime, though, the exact cause of the outbreak continues to be a source of both intrigue and confusion for doctors.