In a recent study published in medRxiv* Prepress server Researchers have determined the prevalence of circulating variants of coronavirus 2 (SARS-CoV-2) and the frequency of occurrence of coronavirus disease 2019 (COVID-19) and malaria in Burkina Faso, West Africa.
Low transmission of SARS-CoV-2 has been reported in Africa, which includes mostly asymptomatic cases, and lower associated death rates compared to developed countries. A greater proportion of youth, socio-ecological diversity (i.e. declining population, warmer weather, trained immune responses against infectious disorders) and immediate application of health measures such as government shutdowns could explain the lower infection rate.
Studies have documented that the COVID-19 pandemic affected some countries (such as Tunisia, Morocco, and South Africa) more significantly, demonstrating the region-specific spread of SARS-CoV-2; However, the results could be due to disproportionately low levels of diagnostic testing and monitoring measures.
Furthermore, malaria is endemic to Africa, and its cases increased during the initial COVID-19 wave, which may have been due to disruptions in malaria campaigns, diagnostic and testing capabilities during the initial epidemic wave.
In the current population-based study, researchers evaluated the frequency of COVID-19 and co-infection of malaria in the West African country of Burkina Faso.
The study was conducted on 998 asymptomatic volunteers residing in different rural or urban areas across 11 villages in the southern regions of Burkina Faso between August 22 and November 19, 2020. Blood samples were obtained from the participants and underwent microscopic examination for the malaria parasite, Plasmodium falciparum Detection (in the asexual and chorionic stages), and rapid diagnostic tests for the detection of SARS-CoV-2 based on the presence of serum immunoglobulins G (IgG), A and M against the SARS-CoV-2 nucleocapsid (N) protein.
The seroprevalence of SARS-CoV-2 was estimated as the fraction of participants with anti-SARS-CoV-2 N antibodies. In addition, nasopharyngeal swab Samples from study participants were obtained for quantitative analysis of reverse transcriptase-polymerase chain reaction (RT-qPCR), and cycle threshold (Ct) values were obtained. Furthermore, SARS-CoV-2 RNA (RNA) was extracted from samples of infected individuals with serum Ct values ≤35 (n = 19) and subjected to whole-genome sequencing (WGS) analysis, after which genome libraries were generated.
The sequences were also analyzed by comparative genomic and phylogenetic analyses, and the classification of PANGOLIN (Evolutionary Assignment of Named Global Outbreak Lineages) was used to identify SARS-CoV-2 strains and lines. Demographic and clinical data obtained from participants included sex, body temperature, and age.
Most participants (55%, n = 549) were women, and individuals were divided into the following age groups: five to 12 years, 13 to 20 years, 21 to 40 years, and over 40 years. The analysis showed a seroprevalence of SARS-CoV-2 of 3.2% (n = 32), positivity of 2.5% for SARS-CoV-2 RT-qPCR, and 22% of malaria cases (n = 219) with most infections detected. Common among children aged less than 12 years (42%) with no significant differences based on gender.
The highest seropositivity for SARS-CoV-2 (five percent) was reported in the urban city of Bobo Dioulasso in West Africa and was significantly higher among individuals over 40 years of age (seven percent), followed by those aged between 13 years and 20 years (three percent), five to 12 years (two percent), and 21 to 40 years (one percent). A marked rise in SARS-CoV-2 infection rates (six percent) was observed in November 2020; However, no significant sex-based differences were observed in SARS-CoV-2 seroprevalence and PCR positivity.
WGS analysis showed that there were 13 SARS-CoV-2 strains circulating in Burkina Faso during the study period, assigned to strains A.19, A.21, B.1, B.1.1.118 and B.1.1.404 clustered in 19B cables. and 20A and 20B. The strains circulating in Burkina Faso during the first wave of the epidemic were early strains derived from the Wuhan strain. Most of the previously reported strains have been described in Burkina Faso or neighboring countries. However, we also identified two less common strains (B.1.1.118 and B.1) that may have been imported into Burkina Faso from the USA or Europe.
Among the SARS-CoV-2 seropositive/RT-qPCR samples (n = 7), none showed malaria co-infection, while malaria and COVID-19 occurred in two (out of 17) negative/RT-qPCR- positive samples. Of the remaining individuals present in negative serum/RT-qPCR (n = 25), eight showed malaria co-infection. Therefore, two cases and eight cases of confirmed and suspected co-infection were detected, respectively, of which eight were under 14 years of age and two were over 40 years old. Only one (out of two) co-infected RT-qPCR samples were sequenced and assigned to the A.21 lineage.
Most of the age groups most affected by these two diseases did not show overlap. However, ten co-infections were observed among young adults. Serology tests measured total antibody titers (IgG, A, and M) against SARS-CoV-2, which makes it difficult to identify previous seropositive cases of current SARS-CoV-2 infection, and thus, whether the data suggest a recurrence of SARS-CoV-2 infection. Infection or co-infection can be clearly identified.
Similar to the observed time trends for COVID-19, malaria cases increased significantly from 5% at study start to 29% by the end of the study period, indicating a potential impact on malaria infection control due to the COVID-19 pandemic.
Study results showed a low frequency of COVID-19 and co-malaria infection (1%) in Burkina Faso. The authors believe this study is the first of its kind and provides data to estimate the true prevalence and generalization variables of SARS-CoV-2 infection in sub-Saharan Africa.
medRxiv publishes preliminary scientific reports that have not been peer-reviewed and therefore should not be considered conclusive, guide clinical practice/health-related behavior, or be treated as established information.