Acute Flaccid Paralysis/Myelitis (AFM/AFP) - Results from National Enterovirus Surveillance

Backround: In 2018, an upsurge of cases of acute flaccid paresis (AFP) of unclear genesis has been reported in the United States. Magnetic resonance imaging (MRI) revealed spinal cord lesions that were largely confined to the gray matter and spanned one or more segments of the spine. Since >90% of affected patients complained of cold symptoms and/or fever before paralysis, a viral disease seems to be the most likely cause. In addition to poliovirus, other enteroviruses (non-polio enteroviruses, NPEV) can infect the central nervous system (CNS) and cause AFP. Other neurotropic viruses such as West Nile-, Japanese encephalitis- or even Zika-Virus have also been described to cause AFP. In 2014, the first increase in AFM cases has been reported in the US. At the same time, there was a nationwide outbreak of a severe respiratory disease caused by Enterovirus D68 (EV-D68). Since then, a possible association has been discussed; although only in four of 563 cases Enteroviruses (EV) have been detected (CV-A16, EV-A71 and EV-D68, no polioviruses) [1]. Such cases have also been described in some European countries. In 2016, the "EV-D68 Working Group" was established. Virologists and clinicians from across Europe collected clinical and virological information on EV-D68 cases. Accordingly, 29 AFP/AFM cases occurred in Europe in 2016 in which EV-D68 was detected. The detection was most successful from respiratory samples (96%). Stool or cerebrospinal fluids (CSF) were far less suitable as sample material [2]. In Germany, more AFP/AFM cases have been reported in 2016, too. Polioviruses could also be excluded. However, NPEV has been detected in some patients [3, 4].

Methods: As part of the nationwide Enterovirus Surveillance (EVSurv), in Germany a free enterovirus diagnostics is offered to all pediatric and neurological clinics for patients with suspicion of viral meningitis or encephalitis, or AFP.

Results: The data show that the overall number of AFP cases (27–78 per year) and the rates of enterovirus positive samples (6.5% and 14%) in the last 9 years (2010–2018) have not increased. Also, the detected serotypes (n = 19) were diverse, so that no causal relationship with a particular enterovirus was detectable.

Conclusion: In patients with AFP, stool samples should preferentially be tested since enteroviruses are shed for at least 14 days after onset of symptoms. In order to be able to reliably detect EV-D68 in AFP/AFM cases, the additional examination of a respiratory sample is recommended for patients with previous respiratory symptoms. The analysis is carried out free of charge in every LaNED laboratory

References

1. https://www.cdc.gov/acute-flaccid-myelitis/afm-surveillance.html

2. Knoester M, et al. Pediatr Infect Dis J 2019

3. Hübner J, et al. Dtsch Arztebl Int 2017

4. Böttcher S, et al. Neuropädiatrie in Klinik und Praxis. 2017

No conflict of interest has been declared by the author(s).