Low Circulation of Subclade A1 Enterovirus D68 Strains in Senegal during 2014 North America Outbreak

Abstract

To retrospectively investigate enterovirus D68 circulation in Senegal during the 2014 US outbreak, we retrieved specimens from 708 persons, mostly children, who had acute respiratory symptoms during September-December 2014. Enterovirus D68 was detected in 14 children (2.1%); most cases occurred in October. Phylogenetic analysis revealed that all strains clustered within subclade A1.

Keywords: ARI; EV-D68; ILI; SARI; Senegal; enterovirus; outbreak; respiratory infections; surveillance; viruses.

Figure 1

EV-D68 occurrence in Senegal, September–December 2014. A total of 708 nasopharyngeal samples were collected and tested for EV-68 during this period: 225 in September (0 positive), 218 in October (12 positive), 193 in November (1 positive), and 72 in December (1 positive). EV-D68, enterovirus D68.

Figure 2

Phylogenetic relationships among enterovirus D68 (EV-D68) strains detected in Senegal (blue) and other countries (black) during the US outbreak period, September–December 2014. The phylogenetic tree based on nucleotide sequences of partial viral protein 1 genomic regions of EV-D68 strains was generated using the neighbor-joining method in MEGA6 (http://www.megasoftware.net). Sequences are identified by GenBank accession number, country, and period of detection. The phylogenetic tree is rooted by the oldest EV-D68 sequence in GenBank, the Fermon strain (pink), collected in 1962 in California, USA. We performed 1,000 bootstrap replicates to determine the consensus tree; support for nodes present in >70% of the trees are annotated. Scale bar indicates nucleotide substitutions per site.