ABSTRACT
BackgroundMany SARS-CoV-2 seroprevalence surveys since the end of 2020 have disqualified the first misconception that Africa had been spared by the pandemic. Through the analysis of three SARS-CoV-2 seroprevalence surveys carried out in Benin as part of the ARIACOV project, we argue that the integration of epidemiological serosurveillance of the SARS-COV2 infection in the national surveillance package would be of great use to refine the understanding of the COVID-19 pandemic in Africa. MethodsThree repeated cross-sectional surveys have been carried out in Benin, two in Cotonou, the economic capital in March and May 2021, and one in Natitingou, a semi-rural city in North in August 2021. The global and by age-groups weighted seroprevalences have been estimated and the risk factors of the infection by SARS-COV-2 have been assessed by using logistic regression. ResultsIn Cotonou, a slight increase in overall age-standardized SARS-CoV-2 seroprevalence from 29.77% (95% CI: 23.12-37.41%) at the first survey to 34.86% (95% CI: 31.57-38.30%) at the second survey was observed. In Natitingou the global adjusted seroprevalence was 33.34% (95% CI: 27.75-39.44%), much higher than expected. Adults over 40 seemed to be more at risk than the youngest during the first survey in Cotonou but no longer in the second survey, showing the persistence of the SARS-COV-2 virus circulation outside the epidemic waves. ConclusionsA routine serological surveillance on strategic sentinel sites and / or populations could constitute a cost / effective compromise to better anticipate the onset of new waves and define public health strategies.
ABSTRACT
Investment in Africa over the past year with regards to SARS-CoV-2 genotyping has led to a massive increase in the number of sequences, exceeding 100,000 genomes generated to track the pandemic on the continent. Our results show an increase in the number of African countries able to sequence within their own borders, coupled with a decrease in sequencing turnaround time. Findings from this genomic surveillance underscores the heterogeneous nature of the pandemic but we observe repeated dissemination of SARS-CoV-2 variants within the continent. Sustained investment for genomic surveillance in Africa is needed as the virus continues to evolve, particularly in the low vaccination landscape. These investments are very crucial for preparedness and response for future pathogen outbreaks. One-Sentence SummaryExpanding Africa SARS-CoV-2 sequencing capacity in a fast evolving pandemic.
ABSTRACT
Information on severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spread in Africa is limited by fragile surveillance systems and insufficient diagnostic capacity. We assessed the coronavirus disease-19 (COVID-19)-related diagnostic workload in Benin, Western Africa, characterized SARS-CoV-2 genomes from 12 acute cases of COVID-19, used those together with public data to estimate SARS-CoV-2 transmission dynamics in a Bayesian framework, validated a widely used diagnostic dual target RT-PCR kit donated to African countries, and conducted serological analyses in 68 sera from confirmed COVID-19 cases and from febrile patients sampled before the predicted SARS-CoV-2 introduction. We found a 15-fold increase in the monthly laboratory workload due to COVID-19. Genomic surveillance showed introductions of three distinct SARS-CoV-2 lineages. SARS-CoV-2 genome-based analyses yielded an R0 estimate of 4.4 (95% confidence interval: 2.0-7.7), suggesting intense spread of SARS-CoV-2 in Africa. RT-PCR-based tests were highly sensitive but showed variation of internal controls and between diagnostic targets. Commercially available SARS-CoV-2 ELISAs showed up to 25% false-positive results depending on antigen and antibody types, likely due to unspecific antibody responses elicited by acute malaria according to lack of SARS-CoV-2-specific neutralizing antibody responses and relatively higher parasitemia in those sera. We confirm an overload of the diagnostic capacity in Benin and provide baseline information on the usability of genome-based surveillance in resource-limited settings. Sero-epidemiological studies needed to assess SARS-CoV-2 spread may be put at stake by low specificity of tests in tropical settings globally. The increasing diagnostic challenges demand continuous support of national and supranational African stakeholders. FundingThis work was supported by the Deutsche Gesellschaft fur Internationale Zusammenarbeit (GIZ) GmbH.
ABSTRACT
OBJECTIVE@#To evaluate the contribution of poses screen pre-impregnated (PSP) installed at openings and eaves of dwellings in the reduction of malaria transmission in the commune of Aguégués in Bénin.@*METHODS@#The PSP were manufactured from preimpregnated Olyset Net. They were installed at windows, eaves and doors of 70 dwellings. 320 children aged 6-59 months were treated and 311 children were recruited in the control zone. Variables measured are: plasmodic index (IP), gametocyte index, parasite density (PD), fever, hemoglobin, anemia.@*RESULTS@#The global IP was 16.62% with PSP and 72.20% without PSP. Gametocyte index did not differ significantly between the treated zone (27.8) and the control zone (29.1). The total geometric mean of DP was 309 in the treated zone and 600 in the control zone. Hemoglobin level is 8.7 in the control zone and 9.5 in the treated zone. We noted a predominance of anemia in the control zone compared to the treated zone.@*CONCLUSIONS@#The PSP have contributed to a significant reduction in morbidity in the commune of Aguégués.
Subject(s)
Animals , Child, Preschool , Female , Humans , Infant , Male , Anemia , Epidemiology , Parasitology , Benin , Epidemiology , Fever , Epidemiology , Parasitology , Hemoglobins , Metabolism , Insecticide-Treated Bednets , Malaria , Epidemiology , Parasitology , Parasitemia , Epidemiology , Parasitology , PrevalenceABSTRACT
INTRODUCTION: To overcome the problems of periodic re-impregnation of mosquito nets and low rates of treatment, the commune of Aguegues was chosen to evaluate the effects of Olyset(®) nets on malaria transmission and against An. gambiae. METHODS: 87 old Olyset(®) nets installed five years ago were identified in the village 'Akpadon'. 10 untreated nets were installed in 10 structures of type "a bedroom and parlour" in the village 'Akodji'. Four rooms without nets were identified in the village 'Donoukpa'. Entomological and epidemiological evaluations were conducted during the May to October 2011. 24 sessions of capture or 2088 men-nights resulted in the capture of 30,608 mosquitoes. RESULTS: The entrance of anopheles was significantly reduced in the village with Olyset(®) nets. 45% of mosquitoes captured inside rooms with Olyset(®) nets were found dead after 24 hrs of obser-vation. Overall, parasitemia was very low in the treated village (4.52%). 18 (4.64%) cases of malaria fever were from Akpadon with 7.5% positive blade smear, 29 (10.98%) were from Akodji with 8.37% positive blade smear, and 80 (95.23%) come from Donoukpa with 38.09% positive blade smear. The Olyset(®) nets and untreated net were adjusted hemoglobin levels. CONCLUSION: Olyset(®) net had a very high knock down effect and is an alternative in malaria control.
