Enterovirus D Research Articles

Clinical application of phage immunoprecipitation sequencing to diagnose enterovirus D68 as the underlying etiology in a case of Gullain-Barré syndrome.

Gullain-Barré syndrome (GBS) is an acute peripheral neuropathy often preceded by respiratory or gastrointestinal infections, though molecular testing of cerebrospinal fluid (CSF) is often inconclusive. In a recent case of severe pediatric GBS in British Columbia, Canada, we detected CSF antibodies against enterovirus D (EV-D) to link GBS with prior EV-D68 respiratory infection.

Genetic and phenotypic characterization of recently discovered enterovirus D type 111.

Members of the species Enterovirus D (EV-D) remain poorly studied. The two first EV-D types (EV-D68 and EV-D70) have regularly caused outbreaks in humans since their discovery five decades ago but have been neglected until the recent occurrence of severe respiratory diseases due to EV-D68. The three other known EV-D types (EV-D94, EV-D111 and EV-D120) were discovered in the 2000s-2010s in Africa and have never been observed elsewhere. One strain of EV-D111 and all known EV-D120s were detected in stool samples of wild non-human primates, suggesting that these viruses could be zoonotic viruses. To date, EV-D111s are only known through partial genetic sequences of the few strains that have been identified so far. In an attempt to bring new pieces to the puzzle, we genetically characterized four EV-D111 strains (among the seven that have been reported until now). We observed that the EV-D111 strains from human samples and the unique simian EV-D111 strain were not phylogenetically distinct, thus suggesting a recent zoonotic transmission. We also discovered evidences of probable intertypic genetic recombination events between EV-D111s and EV-D94s. As recombination can only happen in co-infected cells, this suggests that EV-D94s and EV-D111s share common replication sites in the infected hosts. These sites could be located in the gut since the phenotypic analysis we performed showed that, contrary to EV-D68s and like EV-D94s, EV-D111s are resistant to acid pHs. We also found that EV-D111s induce strong cytopathic effects on L20B cells, a cell line routinely used to specifically detect polioviruses. An active circulation of EV-D111s among humans could then induce a high number of false-positive detection of polioviruses, which could be particularly problematic in Central Africa, where EV-D111 circulates and which is a key region for poliovirus eradication.

Surveillance for enteroviruses in healthy children in Yunnan Province from 2014 to 2015

Objective To investigate the enterovirus (EV)-carrying status and the circulating serotypes in healthy children from inner and border areas of Yunnan Province in 2014 and 2015 and to analyze the genetic characteristics of echovirus 6 (ECHO6), ECHO25 and ECHO11 strains. Methods Stool samples were collected from children less than 15 years old living in 6 to 7 counties of 3 inner prefectures/cities and 8 to 9 counties of border prefectures/cities. Altogether 921 samples were collected including 453 samples in 2014 (213 samples in inner counties and 240 samples in border counties) and 468 samples in 2015 (195 samples in inner counties and 273 samples in border counties). Viruses were isolated from the stool samples and their serotypes were identified by gene sequencing. Results The numbers of EV strains isolated from the samples collected in inner counties and border counties in 2014 were 20 (isolating rate: 9.39%, 20/213) and 16 (isolating rate: 6.67%, 16/240), respectively. The overall isolating rate for 2014 was 7.95% (36/453). The predominant species was enterovirus B, accounting for 88.89% of all isolated strains (32/36), followed by enterovirus A species (11.11%, 4/36). No strains of enterovirus species C (including poliovirus) and D was detected in 2014. In total, 46 EV strains were isolated in 2015 with an overall isolating rate of 9.83% (46/468), including 13 strains in inner counties (isolating rate: 6.67%, 13/195) and 33 strains in border counties (isolating rate: 12.09%, 33/273). Most of the strains were enterovirus B species, accounting for 78.26% (36/46), followed by enterovirus C species (19.57%, 9/46) and enterovirus A species (2.17%, 1/46). Altogether 82 EV strains were isolated in 2014 and 2015 with an isolating rate of 8.90% (82/921), of which 33 strains were isolated in inner counties (8.09%, 33/408) and 49 strains were isolated in border counties (9.55%, 49/513). Among the 82 EV strains, 9 strains were polioviruses (0.98%, 9/921) and all of them were Sabin-like polioviruses. The rest of the strains were non-polio enterovirus (7.93%, 73/921). Conclusion In 2014, the EV isolating rate in inner counties (9.39%) was higher than that in border counties (6.67%). However, the EV isolating rate in border counties (12.09%) was higher than that in inner counties (6.67%) in 2015. Enterovirus B was the predominant species in both 2014 and 2015. No wild type polioviruses and enterovirus D species were detected. Polio-free status was maintained well in Yunnan Province. Key words: Enterovirus; Healthy children; Border areas; Serotyping by gene sequencing