A decontamination strategy for resolving SARS-CoV-2 amplicon contamination in a next-generation sequencing laboratory.

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) amplicon contamination was discovered due to next-generation sequencing (NGS) reads mapping in the negative controls. Environmental screening was undertaken to determine the source of contamination, which was suspected to be evaporation during polymerase chain reaction (PCR) assays while using the coronavirus disease 2019 (COVID-19) ARTIC protocol. A decontamination strategy is hereby documented to assist laboratories that may experience similar amplicon contamination. Routine molecular laboratory environmental screening as a quality control is highly recommended.

Whole Genome Analysis of Human Rotaviruses Reveals Single Gene Reassortant Rotavirus Strains in Zambia.

Rotarix® vaccine was implemented nationwide in Zambia in 2013. In this study, four unusual strains collected in the post-vaccine period were subjected to whole genome sequencing and analysis. The four strains possessed atypical genotype constellations, with at least one reassortant genome segment within the constellation. One of the strains (UFS-NGS-MRC-DPRU4749) was genetically and phylogenetically distinct in the VP4 and VP1 gene segments. Pairwise analyses demonstrated several amino acid disparities in the VP4 antigenic sites of this strain compared to that of Rotarix®. Although the impact of these amino acid disparities remains to be determined, this study adds to our understanding of the whole genomes of reassortant strains circulating in Zambia following Rotarix® vaccine introduction.

Molecular Characterisation of a Rare Reassortant Porcine-Like G5P[6] Rotavirus Strain Detected in an Unvaccinated Child in Kasama, Zambia.

A human-porcine reassortant strain, RVA/Human-wt/ZMB/UFS-NGS-MRC-DPRU4723/2014/G5P[6], was identified in a sample collected in 2014 from an unvaccinated 12 month old male hospitalised for gastroenteritis in Zambia. We sequenced and characterised the complete genome of this strain which presented the constellation: G5-P[6]-I1-R1-C1-M1-A8-N1-T1-E1-H1. The genotype A8 is often observed in porcine strains. Phylogenetic analyses showed that VP6, VP7, NSP2, NSP4, and NSP5 genes were closely related to cognate gene sequences of porcine strains (e.g., RVA/Pig-wt/CHN/DZ-2/2013/G5P[X] for VP7) from the NCBI database, while VP1, VP3, VP4, and NSP3 were closely related to porcine-like human strains (e.g., RVA/Human-wt/CHN/E931/2008/G4P[6] for VP1, and VP3). On the other hand, the origin of the VP2 was not clear from our analyses, as it was not only close to both porcine (e.g., RVA/Pig-tc/CHN/SWU-1C/2018/G9P[13]) and porcine-like human strains (e.g., RVA/Human-wt/LKA/R1207/2009/G4P[6]) but also to three human strains (e.g., RVA/Human-wt/USA/1476/1974/G1P[8]). The VP7 gene was located in lineage II that comprised only porcine strains, which suggests the occurrence of independent porcine-to-human reassortment events. The study strain may have collectively been derived through interspecies transmission, or through reassortment event(s) involving strains of porcine and porcine-like human origin. The results of this study underline the importance of whole-genome characterisation of rotavirus strains and provide insights into interspecies transmissions from porcine to humans.