Scientific American: A poliolike condition that left more than 100 children in the U.S. at least partially paralyzed in 2014 is back, and not much more is known this time around, officials with the U.S. Centers for Disease Control and Prevention say. The CDC is not ruling out any possible triggers—from infections to toxins, autoimmune reactions to bug bites.
“We have not been able to find a cause for the majority of these” cases, Nancy Messonnier, director of the CDC’s National Center for Immunization and Respiratory Diseases, said Wednesday at a news conference. “And I’m frustrated that despite all of our efforts, we have not been able to identify the cause of this mystery illness.”
But researchers who have studied the muscle-weakening disease—called acute flaccid myelitis (AFM)—most closely say they now have a good understanding of its primary cause, although they still do not know how to treat the condition or halt its progression.
Scientists at the University of Colorado School of Medicine infected mice with a virus that was circulating during the 2014 AFM outbreak as well as during similar spikes of the disease in 2016 and this year. The virus triggered a paralyzing illness in the mice that “looked an awful lot like what we saw in children,” says Kenneth Tyler, chairman of the school’s Department of Neurology. Tyler thinks the virus, called enterovirus D68, has changed since it was first identified in 1962, becoming more dangerous. He has bred mice that develop paralysis after an infection with the current version of enterovirus D68 but not from earlier strains. He has tested a number of possible treatments on his mice but has not yet found any that make a significant difference in the course of their AFM-like illness.
Enterovirus D68 has been linked to some of the human cases of the disease, and although it is not the only cause, it has likely been a driving force behind the three recent outbreaks, says Kevin Messacar, an infectious disease physician and researcher at Children’s Hospital Colorado. He and Tyler say the CDC has been cautious about acknowledging enterovirus D68’s role in the outbreaks.
The virus’s symptoms are similar to those of the common cold and can include coughing, shortness of breath and other asthma-like breathing problems. “Many people will get the infection and very few will get the neurologic disease” that leads to paralysis, Messacar says. In rare cases, about a week after the infection, the child will develop weakness in his or her arms, legs or muscles of the face or throat, he says. Although there is no definitive diagnosis, doctors can identify AFM from a combination of symptoms and an MRI scan, which can reveal spine inflammation.
The CDC’s Messonnier describes AFM as “pretty dramatic” and says the federal agency is escalating its response compared with that in previous years. She also emphasizes it is extremely rare, striking about one in a million children, so parents should not panic—but they should seek medical attention if their child shows signs of sudden weakness or loss of muscle tone in their arms or legs. Since July, the CDC has confirmed 62 cases of AFM in 22 states, and is investigating 65 more possible cases. One child with AFM died last year. Ninety percent of the cases have been in children, she says.
Messonnier… said the cases were definitely not caused by the polio virus, which has not been found in any of the stool samples from affected children. There is no evidence of infection with the mosquito-borne West Nile virus either, she says…
The illness pattern is very similar to the polio outbreak of the 1940s and 1950s, says Andrew Pavia, chief of the Division of Pediatric Infectious Diseases at The University of Utah, except for its scale….
According to the CDC, there were 120 confirmed cases of AFM in the second half of 2014, 22 in 2015, 149 in 2016 and 33 in 2017. “There’s been an increase in AFM in even-numbered years since 2014 that doesn’t appear to be random,” Messacar says, noting that enterovirus infections are most common from July through October in northern states, although they are less seasonal in the South. Research suggests dew point temperature—a combination of humidity and temperature—seem to affect the seasonality and geographic distribution of enteroviruses, he says.
Enterovirus D68 is probably contagious for about as long as the common cold, Messacar says. Whereas the viruses associated with AFM are contagious, AFM does not spread from person to person because it is a rare neurologic complication…
“Satan works through the elements also to garner his harvest of unprepared souls. He has studied the secrets of the laboratories of nature, and he uses all his power to control the elements as far as God allows… It is God that shields His creatures and hedges them in from the power of the destroyer. But the Christian world have shown contempt for the law of Jehovah; and the Lord will do just what He has declared that He would—He will withdraw His blessings from the earth and remove His protecting care from those who are rebelling against His law and teaching and forcing others to do the same. The Great Controversy, page 589.