CDC warns of virus that can cause polio-like muscle weakness among children

The Centers for Disease Control and Prevention is warning of the spread of a common childhood virus that can cause muscle weakness or paralysis in rare cases.

the CDC issued an alert Friday about enterovirus D68, which most commonly causes respiratory illness in children, with symptoms that are often mild but can become severe. The enterovirus family is large and polio falls within it; Both EV-D68 and poliovirus can invade the nervous system and cause muscle weakness.

Occasionally, EV-D68 can result in a condition called acute flaccid myelitis, or AFM, which is characterized by inflammation in the neck region of the spinal cord. Some people who experience AFM have difficulty moving their arms, while others experience weakness in all four limbs. During a large outbreak in the US in 2014, around 10% of people with EV-D68 he went on to develop AFM.

Full recovery from AFM is rare, and although most patients improve to some degree, the process is often difficult and requires rehabilitation.

This year, the CDC identified more cases of EV-D68 among children with severe respiratory illness than in the past three years combined. There were 84 such cases from March to August 4. By comparison, the CDC identified six such cases in 2019, 30 in 2020, and 16 in 2021.

However, those numbers are likely underestimates because not everyone with respiratory symptoms gets tested for EV-D68.

As of September 2, there have been 13 confirmed cases of AFM this year in the US The CDC said it is investigating an additional 20 cases.

In the past, the CDC recorded spikes in EV-D68 cases every two years. Before the coronavirus pandemic, that was 2014, 2016 and 2018. Dr. Benjamin Greenberg, a neurologist at UT Southwestern’s O’Donnell Brain Institute who treats patients at Children’s Health in Dallas, said the chances are the This pattern appears because children develop immunity to the enterovirus when it spreads, leading to “off” years with increased population immunity. Once immunity declines, case numbers rise again.

Dr. Sarah Hopkins, a pediatric neurologist at Children’s Hospital of Philadelphia, said: “We really thought this would happen in 2020, because we had the last spike in 2018. But then with mask wearing and social distancing and all those things that they limit the spread of a respiratory virus, we did not have that expected peak.”

Greenberg said cases are likely to rise again this year because children have returned to school and other public spaces.

“Now we have a group of children who have never seen the virus, because they were not exposed at school. So we think the population at risk is higher than it was in 2020,” he said.

The seven pediatric medical centers affiliated with the CDC’s New Vaccines Surveillance Network, in Nashville, Tennessee; Houston; Kansas City, Missouri; Cincinnati; Seattle; Pittsburgh; and Rochester, New York, have detected cases of EV-D68 this year. The CDC said they had also received reports of increases in serious respiratory illness among children in Minnesota, Arizona and Utah, raising concerns that some of those infections could also be EV-D68.

The agency tells health care providers to be vigilant for cases of EV-D68 among children and to seriously consider AFM as a possible diagnosis for patients with limb weakness.

But it can be difficult to distinguish the symptoms of EV-D68 from those of respiratory viruses, Greenberg said. Like the common cold, EV-D68 can cause a runny nose, sneezing, and body or muscle aches. Children who require hospitalization tend to have a cough, shortness of breath, wheezing, and, in about half of cases, a fever.

AFM could also be mistaken for a severe case of polio, resulting in a similar condition called acute flaccid paralysis. The United States recorded a case of polio in July and has virus detected in sewage in multiple New York counties.

Greenberg said screening for polio requires “increased awareness among health care providers so they can send out the right tests.”

“It’s really important to know what virus is causing paralysis in patients,” he added.

What is enterovirus D68?

Scientists first identified enterovirus D68 in 1962. At the time, the virus did not circulate widely and resulted in milder illness than it does today, Greenberg said.

The CDC began doing more tests for EV-D68 in 2014, when scientists noticed a change in the behavior of the virus.

“The virus changed over time to acquire the ability to kill neurons to damage the spinal cord,” Greenberg said.

This year’s total cases are lower than 2018. From July to November of that year, the US had 382 cases of EV-D68 among children with acute respiratory illness.

“It doesn’t seem like things have suddenly gotten worse,” said Dr. Keith Van Haren, an assistant professor of neurology at Stanford University, adding, “I’m hopeful that at least there isn’t a tidal wave of new neurological cases until now.” moment”.

Most EV-D68 cases occur at this time of year, from August to November, he said.

If the last few years are any indication, Greenberg said, “in the coming weeks we will see a clear increase in the number of AFM cases, unless the virus has improved.”

Van Haren said it takes one to four weeks for an EV-D68 case to progress to AFM, although the condition can take several forms.

“The results are everything from some mild shoulder weakness to difficulty moving all limbs and sometimes even the need for prolonged respiratory support,” Hopkins said.

Van Haren said that patients typically begin to recover from their respiratory symptoms before neurological symptoms appear.

“When neurological symptoms start, they can start quite suddenly. They can peak over the course of hours in a way that can be a bit surprising,” he said.

Children who develop AFM generally require hospitalization. For reasons that scientists have not yet discovered, children most at risk include those with a history of asthma.

There are no specific treatments for AFM. Doctors may provide antibody therapy to enhance a patient’s immune response or administer supportive care, such as ventilators or fluids.

The best way to protect yourself or your children from EV-D68, experts said, is to be diligent about washing your hands and wearing a mask in public.

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