This week Waidid suggests to read "Twenty-nine Cases of Enterovirus-D68-associated Acute Flaccid Myelitis in Europe 2016: A Case Series and Epidemiologic Overview", an article available on the US National Library of Medicine- National Institutes of Health.

SUMMARY

Enterovirus-D68 (EV-D68) is a member of the genus Enterovirus, which belongs to the Picornaviridae family. These viruses are associated with a range of clinical symptoms, such as myocarditis, hand–foot–mouth disease, acute flaccid paralysis (AFP) and aseptic meningitis. The majority of EV replicate in the gastrointestinal tract and can be detected in stool samples. EV-D68 and rhinovirus, however, replicate in the upper airways and are best detected in respiratory samples.

Since 2014, EV-D68 has gained interest after causing a large respiratory disease outbreak in North America, and after being associated to acute flaccid myelitis (AFM).

The concurrent circulation of EV-D68 in Europe was shown by a joint effort of the European Society of Clinical Virology (ESCV) – European Centre for Disease Prevention and Control (ECDC) EV-D68 study group: 16,332 respiratory samples were screened for EV-D68 and 343 (2.1%) were positive.

During this 2014 epidemic, some cases of AFM in children were identified; subsequently, through an e-mail alert to the ESCV-ECDC EV-D68 study group network, more cases of EV-D68–related AFM were rapidly identified.

The authors present the clinical and virologic data of the 29 EV-D68 related AFM cases, that were identified through this network, between March and October 2016, after 21,875 EV tests reported by 16 European laboratories. For each case, information regarding age, gender, prodromal phase, neurologic abnormalities, virologic diagnostics, neurologic investigations (cerebrospinal fluid (CFS) analysis, magnetic resonance (MRI), electromyography (EMG)), and clinical follow-up was inquired.

Of these 29 EV-D68–related AFM cases, 26 were children (median age of 3.8 years), and 3 adults. EV-D68 was detected in a respiratory sample of 27 patients, in the feces of 8 patients and in the CSF of 2 patients. A prodromal phase with fever (n = 24) and/or respiratory symptoms (n = 26) preceded weakness by a median period of 2 days. Weakness was flaccid and usually asymmetric, with decreased or absent reflexes. Cranial nerve deficits were common (n =17). 19 patients needed ventilatory support. CSF analysis frequently showed a moderate pleocytosis. MRI was reported to be abnormal in 25 cases. Most patients were treated with intravenous immunoglobulins (n = 20), steroids (n = 17) or both (n = 15), with typically only partial recovery over time. Follow-up time ranged from 0.5 to 12 months. Two patients, who both showed EV-D68 in the CSF, died. 99% of EV-D68–positive samples were respiratory specimens.

Sequence analysis showed that most of the EV-D68 strains in 2014 clustered with clades A1, A2, B1 and B2. In 2016, however, nearly all strains belonged to subclade B3 in Europe as well as in the United States.

The authors concluded that the cases reported probably represent only the tip of the iceberg, due to the lack of non-polio AFP/AFM notification regulations. They highlighted the potential benefit of an e-mail alert system, by which clinicians and laboratories inform each other on the start of the EV season, the upsurge of rare types and on special EV-associated syndromes, such as AFM.

Read the full article here: https://www.ncbi.nlm.nih.gov/pubmed/30234793

AUTHORS: Brouwer OF, Helfferich J., Knoester M., Niesters HGM, Poelman R., Van Leer-Buter C.; 2016 EV-D68 AFM Working Group.