Sensitive poliovirus detection using nested PCR and nanopore sequencing: a prospective validation study.

Timely detection of outbreaks is needed for poliovirus eradication, but gold standard detection in the Democratic Republic of the Congo takes 30 days (median). Direct molecular detection and nanopore sequencing (DDNS) of poliovirus in stool samples is a promising fast method. Here we report prospective testing of stool samples from suspected polio cases, and their contacts, in the Democratic Republic of the Congo between 10 August 2021 and 4 February 2022. DDNS detected polioviruses in 62/2,339 (2.7%) of samples, while gold standard combination of cell culture, quantitative PCR and Sanger sequencing detected polioviruses in 51/2,339 (2.2%) of the same samples. DDNS provided case confirmation in 7 days (median) in routine surveillance conditions. DDNS enabled confirmation of three serotype 2 circulating vaccine-derived poliovirus outbreaks 23 days (mean) earlier (range 6-30 days) than the gold standard method. The mean sequence similarity between sequences obtained by the two methods was 99.98%. Our data confirm the feasibility of implementing DDNS in a national poliovirus laboratory.

Use of Mpox Multiplex Serology in the Identification of Cases and Outbreak Investigations in the Democratic Republic of the Congo (DRC).

Human Mpox cases are increasingly reported in Africa, with the highest burden in the Democratic Republic of Congo (DRC). While case reporting on a clinical basis can overestimate infection rates, laboratory confirmation by PCR can underestimate them, especially on suboptimal samples like blood, commonly used in DRC. Here we used a Luminex-based assay to evaluate whether antibody testing can be complementary to confirm cases and to identify human transmission chains during outbreak investigations. We used left-over blood samples from 463 patients, collected during 174 outbreaks between 2013 and 2022, with corresponding Mpox and VZV PCR results. In total, 157 (33.9%) samples were orthopox-PCR positive and classified as Mpox+; 124 (26.8%) had antibodies to at least one of the three Mpox peptides. The proportion of antibody positive samples was significantly higher in Mpox positive samples (36.9%) versus negative (21.6%) (p < 0.001). By combining PCR and serology, 66 additional patients were identified, leading to an Mpox infection rate of 48.2% (223/463) versus 33.9% when only PCR positivity is considered. Mpox infections were as such identified in 14 additional health zones and 23 additional outbreaks (111/174 (63.8%) versus 88/174 (50.6%)). Our findings highlight the urgent need of rapid on-site diagnostics to circumvent Mpox spread.

SARS-CoV2 mutations and impact on mortality: observational study in a sub-saharan Africa hospital.

BACKGROUND: One year after the coronavirus disease 2019 (COVID-19) pandemic, the focus of attention has shifted to the emergence and spread of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) variants of concern (VOCs). The aim of the study was to assess the frequency of VOCs in patients followed for COVID-19 at Kinshasa university hospital (KUH) during the 3rd and 4th waves of the pandemic in Kinshasa. Hospital mortality was compared to that of the first two waves. METHOD: The present study included all patients in whom the diagnosis of SARS-CoV-2 infection was confirmed by the polymerase chain reaction (PCR). The laboratory team sequenced a subset of all SARS-CoV-2 positive samples with high viral loads define as Ct < 25 to ensure the chances to generate complete genome sequence. RNA extraction was performed using the Viral RNA Mini Kit (Qiagen). Depending on the platform, we used the iVar bioinformatics or artic environments to generate consensus genomes from the raw sequencing output in FASTQ format. RESULTS: During the study period, the original strain of the virus was no longer circulating. The Delta VOC was predominant from June (92%) until November 2021 (3rd wave). The Omicron VOC, which appeared in December 2021, became largely predominant one month later (96%) corresponding the 4th wave. In-hospital mortality associated with COVID-19 fell during the 2nd wave (7% vs. 21% 1st wave), had risen during the 3rd (16%) wave before falling again during the 4th wave (7%) (p < 0.001). CONCLUSION: The Delta (during the 3rd wave) and Omicron VOCs (during the 4th wave) were very predominant among patients followed for Covid-19 in our hospital. Contrary to data in the general population, hospital mortality associated with severe and critical forms of COVID-19 had increased during the 3rd wave of the pandemic in Kinshasa.

Emergence and spread of SARS-CoV-2 lineage B.1.620 with variant of concern-like mutations and deletions.

Distinct SARS-CoV-2 lineages, discovered through various genomic surveillance initiatives, have emerged during the pandemic following unprecedented reductions in worldwide human mobility. We here describe a SARS-CoV-2 lineage - designated B.1.620 - discovered in Lithuania and carrying many mutations and deletions in the spike protein shared with widespread variants of concern (VOCs), including E484K, S477N and deletions HV69Δ, Y144Δ, and LLA241/243Δ. As well as documenting the suite of mutations this lineage carries, we also describe its potential to be resistant to neutralising antibodies, accompanying travel histories for a subset of European cases, evidence of local B.1.620 transmission in Europe with a focus on Lithuania, and significance of its prevalence in Central Africa owing to recent genome sequencing efforts there. We make a case for its likely Central African origin using advanced phylogeographic inference methodologies incorporating recorded travel histories of infected travellers.