New Virus, Not EV-D68, Now Suspected in Childhood Paralysis

A novel virus from Peru and the Republic of Congo called enterovirus C105 is now suspected in last year's wave of mysterious cases of sudden childhood paralysis.

Initially, enterovirus D68, the respiratory virus that took the lives of 12 children in the US last year, was the main suspect in these polio-like illnesses, involving at least 118 children, including a cluster of cases in Denver, CO and another in Syracuse, NY.

But soon researchers admitted they were stumped. In the fall of 2014, the CDC asked clinicians to report all such pediatric paralysis cases.

Today, disease detectives at the University of Virginia School of Medicine, Charlotttesville, VA, said they may have broken the case.

In a report to the US Centers for Disease Control and Prevention published today, Liana Horner, MD, and colleagues implicate this new virus—enterovirus C105, in a childhood flaccid paralysis case that was originally suspected as due to infection with EV D68.

It is a single case, so EV-D68 is not completely exonerated, according to the study in the current issue of the CDC’s Emerging Infectious Diseases.

But the facts that EV-D68 behaves more like a rhinovirus than one that causes systemic disease or nerve damage and that it was not found in cerebrospinal fluid of 33 of 41 childhood paralysis cases the CDC investigated led researchers to look for other culprits.

The University of Virginia researchers were able to isolate EV-C105 from one child with acute onset of progressive right upper extremity weakness.

Her parents had become concerned when, after recovering from what seemed to be a routine respiratory infection that lasted 2 days, the 6-year-old had a right shoulder droop. Physicians who examined her noted she had difficulty using her right hand and diminished right patellar reflex.

Nasopharangeal swab testing showed she had EV-C105.

The novel virus was first detected in 2010 inpatients from Peru and the Republic of Congo, and the CDC report said EV-C105 has since spread globally.

It is known to have caused a case of paralysis in the Republic of Congo.

One problem for clinicians is that testing for the virus is challenging, the CDC report said.

There is a “divergence of the 5’-untranslated region in members of this newly emerging subspecies of enterovirus C,” Horner wrote, noting that “many broad-specificity enterovirus real-time reverse transcriptions PCRs target conserved regions of the 5-UTR.”

“For the patient we report, virus in the nasopharyngeal swab sample was identified as a picornavirus by the xTAG Respiratory Virus Panel and by sequence analysis of the viral protein 1 capsid gene,” she said.

Other similar paralysis cases could well be attributed to EV C105, possibly as a co-infection with EV-D68.

But “the presence of this virus strain [EV-C105] in North American may pose a diagnostic challenge,” she and colleagues concluded.

The girl in the reported case stayed in the hospital for 5 days and did not respond to treatment with intravenous immunoglobulin, but 8 months after her the onset of her illness, her arm weakness had improved.