High seroprevalence of SARS-CoV-2 in Burkina-Faso, Ghana and Madagascar in 2021: a population-based study.

BACKGROUND: The current COVID-19 pandemic affects the entire world population and has serious health, economic and social consequences. Assessing the prevalence of COVID-19 through population-based serological surveys is essential to monitor the progression of the epidemic, especially in African countries where the extent of SARS-CoV-2 spread remains unclear. METHODS: A two-stage cluster population-based SARS-CoV-2 seroprevalence survey was conducted in Bobo-Dioulasso and in Ouagadougou, Burkina Faso, Fianarantsoa, Madagascar and Kumasi, Ghana between February and June 2021. IgG seropositivity was determined in 2,163 households with a specificity improved SARS-CoV-2 Enzyme-linked Immunosorbent Assay. Population seroprevalence was evaluated using a Bayesian logistic regression model that accounted for test performance and age, sex and neighbourhood of the participants. RESULTS: Seroprevalence adjusted for test performance and population characteristics were 55.7% [95% Credible Interval (CrI) 49·0; 62·8] in Bobo-Dioulasso, 37·4% [95% CrI 31·3; 43·5] in Ouagadougou, 41·5% [95% CrI 36·5; 47·2] in Fianarantsoa, and 41·2% [95% CrI 34·5; 49·0] in Kumasi. Within the study population, less than 6% of participants performed a test for acute SARS-CoV-2 infection since the onset of the pandemic. CONCLUSIONS: High exposure to SARS-CoV-2 was found in the surveyed regions albeit below the herd immunity threshold and with a low rate of previous testing for acute infections. Despite the high seroprevalence in our study population, the duration of protection from naturally acquired immunity remains unclear and new virus variants continue to emerge. This highlights the importance of vaccine deployment and continued preventive measures to protect the population at risk.

Antimicrobial and Anti-Inflammatory Activities of Pterygota macrocarpa and Cola gigantea (Sterculiaceae).

Pterygota macrocarpa and Cola gigantea are African medicinal plants used in traditional medicine for the treatment of sores, skin infections, and other inflammatory conditions including pains. This study therefore aims at investigating the antimicrobial properties of ethanol leaf and stem bark extracts of P. macrocarpa and C. gigantea using the agar diffusion and the micro-dilution techniques and also determining the anti-inflammatory properties of the extracts of these plants in carrageenan-induced foot edema in seven-day old chicks. The minimum inhibitory concentration of both ethanol leaf and bark extracts of P. macrocarpa against the test organisms was from 0.125 to 2.55 mg/mL and that of C. gigantea extracts was 0.125 to 2.75 mg/mL. Extracts with concentration of 50 mg/mL were most active against the test organisms according to the agar diffusion method. All the extracts of P. macrocarpa and C. gigantea at 30, 100, and 300 mg/kg body weight except ethanol leaf extract of C. gigantea exhibited significant anti-inflammatory effects (P ≤ 0.001).

The burden of drug resistance tuberculosis in Ghana; results of the First National Survey.

Resistance to Tuberculosis drugs has become a major threat to the control of tuberculosis (TB) globally. We conducted the first nation-wide drug resistance survey to investigate the level and pattern of resistance to first-line TB drugs among newly and previously treated sputum smear-positive TB cases. We also evaluated associations between potential risk factors and TB drug resistance. Using the World Health Organization (WHO) guidelines on conducting national TB surveys, we selected study participants from 33 health facilities from across the country, grouped into 29 clusters, and included them into the survey. Between April 2016 and June 2017, a total of 927 patients (859 new and 68 previously treated) were enrolled in the survey. Mycobacterium tuberculosis complex (MTBC) isolates were successfully cultured from 598 (65.5%) patient samples and underwent DST, 550 from newly diagnosed and 48 from previously treated patients. The proportion of patients who showed resistance to any of the TB drugs tested was 25.2% (95% CI; 21.8-28.9). The most frequent resistance was to Streptomycin (STR) (12.3%), followed by Isoniazid (INH) (10.4%), with Rifampicin (RIF), showing the least resistance of 2.4%. Resistance to Isoniazid and Rifampicin (multi-drug resistance) was found in 19 (3.2%; 95% CI: 1.9-4.9) isolates. Prevalence of multidrug resistance was 7 (1.3%; 95% CI: 0.5-2.6) among newly diagnosed and 12 (25.0%; 95% CI: 13.6-39.6) among previously treated patients. At both univariate and multivariate analysis, MDR-TB was positively associated with previous history of TB treatment (OR = 5.09, 95% CI: 1.75-14.75, p = 0.003); (OR = 5.41, 95% CI: 1.69-17.30, p = 0.004). The higher levels of MDR-TB and overall resistance to any TB drug among previously treated patients raises concerns about adherence to treatment. This calls for strengthening existing TB programme measures to ensure a system for adequately testing and monitoring TB drug resistance.

Constitutive STAT3 phosphorylation and IL-6/IL-10 co-expression are associated with impaired T-cell function in tuberculosis patients.

T-cells critically contribute to protection against Mycobacterium tuberculosis infection, and impaired T-cell responses can lead to disease progression. Pro-inflammatory and immunosuppressive cytokines affect T-cells, and fine-tuned regulation of cytokine signaling via the Jak/STAT signaling pathways is crucial for appropriate T-cell function. Constitutive STAT3 phosphorylation as a consequence of aberrant cytokine signaling has been described to occur in pathognomonic T-cell responses in inflammatory and autoimmune diseases. We characterized blood samples from tuberculosis patients (n=28) and healthy contacts (n=28) from Ghana for M. tuberculosis-specific T-cell responses, constitutive cytokine production, and SOCS3 and pSTAT3 expression. Lentiviral modulation of primary CD4+ T-cells was performed to determine the effects of SOCS3 on T-cell functions. T-cells from tuberculosis patients expressed higher levels of IL-10 and IL-6 and lower levels of T helper type (TH)17 cytokines after M. tuberculosis-specific stimulation compared to healthy contacts. In addition, tuberculosis patients had higher IL-10 and IL-6 levels in the supernatants of non-stimulated immune cells and plasma samples compared to healthy contacts. Notably, aberrant cytokine expression was accompanied by high constitutive pSTAT3 levels and SOCS3 expression in T-cells. Multivariate analysis identified an IL-6/IL-10 co-expression-based principal component in tuberculosis patients that correlated with high pSTAT3 levels. SOCS3 contributed to a regulatory component, and tuberculosis patients with high SOCS3 expression showed decreased TH1 cytokine expression and impaired IL-2-induced STAT5 phosphorylation. SOCS3 over-expression in primary CD4+ T-cells confirmed the SOCS3 inhibitory function on IL-2-induced STAT5 phosphorylation. We conclude that constitutive pSTAT3 and high SOCS3 expression are influential factors that indicate impaired T-cell functions in tuberculosis patients.

Toxicity assessment of Erythrophleum ivorense and Parquetina nigrescens.

Erythrophleum ivorense and Parquetina nigrescens are found growing in tropical regions and they are used in African traditional medicine to treat various ailments including wounds, boils and anaemic conditions. Some species of plant in the Erythrophleum genus are also known to be poisonous and toxic to several livestock. However, there is no information on the toxicity of E. ivorense and P. nigrescens. This study is to determine the cytotoxicity and subchronic toxicity properties of methanol leaf extract (EIML) and methanol stem barks extract (EIMB) of E. ivorense and methanol leaf and aerial part extract of P. nigrescens (PNML). Concentrations from 0.1 to 100 µg/mL of the extracts were used to determine the influence of the extracts on the release of lactate dehydrogenase (LDH) from HaCaT keratinocytes. The EIML and EIMB extracts showed increase in LDH released from HaCaT keratinocytes at 0.1-10 µg/mL and 1-100 µg/mL for the PNML extracts (p > 0.05). Wistar rats were orally administered with 100, 300 and 1000 mg/kg body weight of the extracts (EIML, EIMB and PNML, respectively) for 35 days. Tissues from the kidney and liver of the rats treated with lower doses (100-300 mg/kg body weight) of EIML extract showed highly vascularized kidneys with numerous glomerular tufts, healthy hepatocytes and sinusoids in liver. However, there were persistent renal tissue inflammation and glomerular degeneration in kidney, and increased inflammatory infiltrates with few vacuolations and scarrings in liver in rats treated with higher extract dose of 1000 mg/kg body weight of rat. The rats treated with EIMB extract showed persistent renal and hepatocyte inflammations with glomerular and hepatocyte necrosis at all administered doses (100, 300 and 1000 mg/kg body weight) which are indications of renal and hepatic toxicities. Though rats administered with 100 and 300 mg/kg of PNML extract showed renal haemorrhage and inflammation and hepatic inflammation, the rats administered with 1000 mg/kg body weight showed restoring glomerular tufts and improved vasculature and liver with reduced inflammatory infiltrates with healthy hepatocytes. Phytochemical screening of EIML, EIMB and PNML extracts revealed the presence of alkaloids, tannins, flavonoids, sterols, cardiac glycosides and terpenoids.