Clade B transmission dynamics linked to acute flaccid myelitis risk

Enterovirus D68, a common cause of mild respiratory illness in children, has been quietly circulating in seasonal patterns for decades longer than previously recognised, according to a new phylodynamic analysis published in Nature Communications. Using a birth-death-sampling model applied to publicly available viral genetic sequences collected in Europe and North America from the 1990s through 2023, researchers reconstructed the transmission history of the virus without relying on case reports, which are unreliable because EV-D68 symptoms overlap with other common childhood respiratory infections. The analysis showed that seasonal transmission was well established long before the 2014 outbreak that first brought the virus to widespread international attention.

The study also addressed a more serious question: why outbreaks of acute flaccid myelitis, a rare but severe neurological condition that can cause permanent paralysis, have followed EV-D68 activity in some years but not others. By linking the reconstructed transmission dynamics of individual viral clades to recorded AFM case burden, the researchers found a strong association with one specific genetic lineage, clade B. No comparable association was observed for clades A or D, suggesting that biological differences between clades, rather than the sheer volume of EV-D68 transmission alone, drive the risk of neurological disease.

Phylodynamic approaches of this kind infer epidemiological parameters directly from pathogen genetic sequences, offering an alternative to case-based surveillance where clinical reporting is incomplete or confounded. For EV-D68, this matters particularly for the period before 2014, when the burden of transmission remained poorly understood because the virus was rarely distinguished from other causes of respiratory illness. The new reconstruction fills that gap, indicating that the virus had already established recurring seasonal circulation patterns well before clinicians and public health agencies recognised it as an emerging concern.

The clade-specific finding carries practical implications for surveillance and preparedness. If AFM risk depends on the circulation dynamics of clade B in particular, then genomic monitoring that tracks which clades are spreading, rather than simply detecting the presence of EV-D68, could help anticipate when neurological case burden is likely to rise. The authors suggest this could inform surveillance prioritisation and the timing of preparations for future burdens of neurological disease. The analysis rests on sequences from Europe and North America, and the association between clade B dynamics and AFM is observational, so the biological mechanisms underlying the clade-specific risk remain to be established. Even so, the work demonstrates how genetic sequence data can recover epidemiological history that case reporting cannot, and it sharpens the focus for monitoring this virus as it continues to circulate.

Subject of Research: Phylodynamic reconstruction of enterovirus D68 clade-specific transmission and its association with acute flaccid myelitis

Article Title: Clade-specific transmission dynamics of enterovirus D68 and their association with acute flaccid myelitis

Article References: Jorgensen, D., Lefrancq, N., Grassly, N. C., du Plessis, L., & Pons-Salort, M. (2026). Clade-specific transmission dynamics of enterovirus D68 and their association with acute flaccid myelitis. Nature Communications. https://doi.org/10.1038/s41467-026-78448-2

Image Credits: AI Generated

DOI: 10.1038/s41467-026-78448-2

Keywords: enterovirus D68, acute flaccid myelitis, phylodynamics, clade B, viral surveillance, birth-death-sampling model, genomic epidemiology, seasonal transmission, Nature Communications, children's respiratory illness, Clade-specific, transmission