Researchers indicate that there is mounting evidence that the virus Enterovirus-D68 appears to be behind a growing number of reports involving mysterious, polio-like illnesses that have paralyzed children nationwide over the past several years.
In a study published this week by the U.S. Centers for Disease Control and Prevention (CDC), researchers indicate that there has been a concurrent spike in enterovirus-D68 (EV-D68) infections and cases of acute flaccid myelitis (AFM), which has paralyzed hundreds of people nationwide, mostly young children.
The findings were published in the CDC’s Morbidity and Mortality Weekly Report on March 29, outlining preliminary details from a new surveillance conducted to better understand the emerging health problem.
After cases of acute flaccid myelitis spiked in 2018, impacting more than 300 individual, the CDC established an active prospective D68 surveillance program among pediatric patients at seven U.S. hospitals using the New Vaccine Surveillance Network.
Doctors and health officials have struggled since the first outbreak of the illness in 2014 to determine the exact cause of the infection, which leads to paralysis and weakened limbs in many patients. In October 2018, some experts indicated EV-D68 was the most likely cause of AFM cases, but federal health officials were not convinced.
In 2018, 358 of 2,500 patients tested were positive for EV-D68, roughly 14% of patients. During that same year, the CDC reported 223 confirmed cases of AFM.
In 2017, only two out of 2,400 patients tested positive for EV-D68, less than one percent of patients. Similarly, there were only 35 confirmed cases of AFM in 2017.
The findings add another link between AFM cases and EV-D68, researchers say.
Many researchers indicated EV-D68 was the cause after experiments showed the virus can invade nerve tissue and affect motor function. After the research was released, the CDC established the surveillance network to spur rapid virus testing to help pinpoint a cause. During prior outbreaks, testing wasn’t done quickly enough to conclusively indicate a specific cause.
However, other viruses have also been detected in children affected by AFM. Patients experiencing AFM also tested positive for coxsackievirus A16 and enterovirus A71. The link to EV-D68 is especially hard to prove since symptoms occur after the virus has cleared the respiratory track, making it too late to test for it.
Nevertheless, D68 shows up in respiratory tests for roughly half of AFM patients. This points to EV-D68 as the leading cause of AFM, federal researchers conclude.
AFM is a rare condition that effects the nervous system, especially the spinal cord. It causes sudden paralysis and weakened limbs, which is why many called it “polio-like.”
Most children who are infected with EV-D68 will experience mild cold symptoms, but a small group will get AFM and experience paralysis.
Most patients who have AFM experience a mild respiratory cold about 10 days before developing paralysis. The virus follows an every other year pattern, which suggest there may be fewer cases in 2019. Most infections occur in late summer and early fall.