Circulation of SARS-CoV-2 and co-infection with Plasmodium falciparum in Equatorial Guinea

The impact of COVID-19 in Africa has been a big concern since the beginning of the pandemic. However, low incidence of COVID-19 case severity and mortality has been reported in many African countries, although data are highly heterogeneous and, in some regions, like Sub-Saharan Africa, very scarce. Many of these regions are also the cradle of endemic infectious diseases like malaria. The aim of this study was to determine the prevalence of SARS-CoV-2, the diversity and origin of circulating variants as well as the frequency of co-infections with malaria in Equatorial Guinea. For this purpose, we conducted antigen diagnostic tests for SARS-CoV-2, and microscopy examinations for malaria of 1,556 volunteers at six health centres in Bioko and Bata from June to October 2021. Nasopharyngeal swab samples were also taken for molecular detection of SARS-COV-2 by RT-qPCR and whole genome viral sequencing. We report 3.0% of SARS-CoV-2 and 24.4% of malaria prevalence over the sampling in Equatorial Guinea. SARS-CoV-2 cases were found at a similar frequency in all age groups, whereas the age groups most frequently affected by malaria were children (36.8% [95% CI 30.9-42.7]) and teenagers (34.7% [95% CI 29.5-39.9]). We found six cases of confirmed co-infection of malaria and SARS-CoV-2 distributed among all age groups, representing a 0.4% frequency of co-infection in the whole sampled population. Interestingly, the majority of malaria and SARS-CoV-2 co-infections were mild. We obtained the genome sequences of 43 SARS-CoV-2 isolates, most of which belong to the lineage Delta (AY.43) and that according to our pandemic-scale phylogenies were introduced from Europe in multiple occasions (7 transmission groups and 17 unique introductions). This study is relevant in providing first-time estimates of the actual prevalence of SARS-CoV-2 in this malaria-endemic country, with the identification of circulating variants, their origin, and the occurrence of SARS-CoV-2 and malaria co-infection.We would like to thank all volunteers who participated in this study and the local authorities and communities in Equatorial Guinea for their support. We also thank the IPBLN and IBV core facilities for their support to project activitiesN

Therapeutic efficacy of artesunate-amodiaquine and artemether-lumefantrine and polymorphism in Plasmodium falciparum kelch13-propeller gene in Equatorial Guinea

International audienceBackground: Artesunate-amodiaquine (ASAQ) and artemether-lumefantrine (AL) are the currently recommended first-and second-line therapies for uncomplicated Plasmodium falciparum infections in Equatorial Guinea. This study was designed to evaluate the efficacy of these artemisinin-based combinations and detect mutations in P. falciparum kelch13-propeller domain gene (Pfkelch13). Methods: A single-arm prospective study evaluating the efficacy of ASAQ and AL at three sites: Malabo, Bata and Ebebiyin was conducted between August 2017 and July 2018. Febrile children aged six months to 10 years with confirmed uncomplicated P. falciparum infection and other inclusion criteria were sequentially enrolled first in ASAQ and then in AL at each site, and followed up for 28 days. Clinical and parasitological parameters were assessed. The primary endpoint was PCR-adjusted adequate clinical and parasitological response (ACPR). Samples on day-0 were analysed for mutations in Pfkelch13 gene. Results: A total 264 and 226 patients were enrolled in the ASAQ and AL treatment groups, respectively. Based on per-protocol analysis, PCR-adjusted cure rates of 98.6% to 100% and 92.4% to 100% were observed in patients treated with ASAQ and AL, respectively. All study children in both treatment groups were free of parasitaemia by day-3. Of the 476 samples with interpretable results, only three samples carried non-synonymous Pfkelch13 mutations (E433D and A578S), and none of them is the known markers associated with artemisinin resistance. Conclusion: The study confirmed high efficacy of ASAQ and AL for the treatment of uncomplicated falciparum infections as well as the absence of delayed parasite clearance and Pfkelch13 mutations associated with artemisinin resistance. Continued monitoring of the efficacy of these artemisinin-based combinations, at least every two years, along with molecular markers associated with artemisinin and partner drug resistance is imperative to inform national malaria treatment policy and detect resistant parasites early