Serological surveillance reveals a high exposure to SARS-CoV-2 and altered immune response among COVID-19 unvaccinated Cameroonian individuals.

Surveillance of COVID-19/SARS-CoV-2 dynamics is crucial to understanding natural history and providing insights into the population's exposure risk and specific susceptibilities. This study investigated the seroprevalence of SARS-CoV-2 antibodies, its predictors, and immunological status among unvaccinated patients in Cameroon. A multicentre cross-sectional study was conducted between January and September 2022 in the town of Douala. Patients were consecutively recruited, and data of interest were collected using a questionnaire. Blood samples were collected to determine Immunoglobin titres (IgM and IgG), interferon gamma (IFN- γ) and interleukin-6 (IL-6) by ELISA, and CD4+ cells by flow cytometry. A total of 342 patients aged 41.5 ± 13.9 years were included. Most participants (75.8%) were asymptomatic. The overall crude prevalence of IgM and IgG was 49.1% and 88.9%, respectively. After adjustment, the seroprevalence values were 51% for IgM and 93% for IgM. Ageusia and anosmia have displayed the highest positive predictive values (90.9% and 82.4%) and specificity (98.9% and 98.3%). The predictors of IgM seropositivity were being diabetic (aOR = 0.23, p = 0.01), frequently seeking healthcare (aOR = 1.97, p = 0.03), and diagnosed with ageusia (aOR = 20.63, p = 0.005), whereas those of IgG seropositivity included health facility (aOR = 0.15, p = 0.01), age of 40-50 years (aOR = 8.78, p = 0.01), married (aOR = 0.21, p = 0.02), fever (aOR = 0.08, p = 0.01), and ageusia (aOR = 0.08, p = 0.01). CD4+, IFN-γ, and IL-6 were impaired in seropositive individuals, with a confounding role of socio-demographic factors or comorbidities. Although the WHO declared the end of COVID-19 as a public health emergency, the findings of this study indicate the need for continuous surveillance to adequately control the disease in Cameroon.

Exploring demographical, clinical, and dietary determinants of vitamin D deficiency among adults in Douala, Cameroon during the COVID-19 era.

Background and aim: Vitamin D deficiency (VDD) is a global public health problem in African populations. This study aimed at determining the prevalence, characteristics, and determinants of VDD in the era of SARS-CoV-2/COVID-19. This study was conducted from January to September 2022 in seven health facilities in Douala, Cameroon. Methods: A structured, pre-tested questionnaire was administered to each participant to collect participants' information. Molecular detection of the SARS-CoV-2 genome was done. A serum level of 25-hydroxyvitamin D < 20 ng/mL was used to diagnose VDD. Results: A total of 420 participants were included in the study. A Serum levels of 25(OH) vitamin D were reduced in SARS-CoV-2 (+) patients as compared to SARS-CoV-2 (-) patients (21.69 ± 5.64 ng/mL vs 42.09 ± 20.03 ng/mL, p < 0.0001). The overall prevalence of VDD was 10.2 %. SARS-CoV-2 (+) individuals had nearly two times more risk of being VDD compared to SARS-CoV-2 (-) individuals (aRR = 1.81, p < 0.0001). The risk of VDD was reduced by 46 % and 71 % in those consuming cocoa bean or powder regularly (aRR = 0.54, p = 0.03) and rarely (aRR = 0.29, p = 0.02) as compared to those never consuming it. Likewise, the risk of VDD was reduced by 59 % and 78 % in those consuming sardine fish regularly (aRR = 0.47, p = 0.002) and rarely (aRR = 0.22, p = 0.03). Overall, the association between VDD and SARS-CoV-2 infection was consistent, i.e., reduced risk of VDD in SARS-CoV-2 (-) individuals, after stratification for confounding variables. Conclusion: This study outlined a high burden of VDD, a strong link between VDD and SARS-CoV-2, and suggests the possible utility of vitamin D supplementation for COVID-19 patients in Cameroon.

Confounding role of comorbidities and COVID-19 vaccination uptake in clinical utility of hematological biomarkers in Cameroonian patients infected with SARS-CoV-2.

Objectives: To analyze variations in blood profile, the extent of hematological disorders, and the impact of comorbidities and COVID-19 vaccination on blood profile parameters and their clinical value for prognostic of SARS-CoV-2 infection. Methods: This cross-sectional study took place in Douala, Cameroon. A complete blood count and molecular detection of SARS-CoV-2 were performed on patients. Clinical value was appraised using area under the curve (AUC) analysis. Results: In total, 420 participants were included. A significant reduction of hematological parameters such as lymphocytes (p < 0.0001), red blood cells (P = 0.0025), mean corpuscular hemoglobin count (P < 0.0001), and platelets (P = 0.02) was seen in SARS-CoV-2 (+) patients. Anisocytosis was the main hematological disorder (95.5%). Normocytic normochromic anemia was predominant in SARS-CoV-2 (+) (35.3%) while microcytic normochromic anemia was more frequently seen in SARS-CoV-2 (-) (16.5%). Neutrophil-to-lymphocyte (NLR) consistently showed statistically significant AUC ∼0.75 upon stratification for age, gender, and comorbidities, with the exception of COVID-19 vaccination uptake. Conclusion: In a context where molecular detection methods are difficultly affordable in health facilities in developing countries such as Cameroon, NLR could be clinically interesting for identifying SARS-CoV-2 infected individuals, especially those with comorbidities.

Epidemiological situation of SARS-CoV-2 infection in Douala, the most populated and highly heterogeneous town of Cameroon: a post-vaccination update.

This study aimed at providing an update of SARS-CoV-2 epidemiology in Douala, the most populated and highly heterogeneous town of Cameroon. A hospital-based cross sectional study was conducted from January to September 2022. A questionnaire was used to collect sociodemographic, anthropometric, and clinical data. Retrotranscriptase quantitative polymerase chain reaction was used to detect SARS-CoV-2 in nasopharyngeal samples. Of the 2354 individuals approached, 420 were included. The mean age of patients was 42.3 ± 14.4 years (range 21 - 82). The prevalence of SARS-CoV-2 infection was 8.1%. The risk of infection with SARS-CoV-2 was increased more than seven times in patients aged ≥ 70 years old (aRR = 7.12, p = 0.001), more than six times in married (aRR = 6.60, p = 0.02), more than seven times in those having completed secondary studies (aRR = 7.85, p = 0.02), HIV-positive patients (aRR = 7.64, p < 0.0001) and asthmatic patients (aRR = 7.60, p = 0.003), and more than nine times in those seeking health care regularly (aRR = 9.24, p = 0.001). In contrast, the risk of SARS-CoV-2 infection was reduced by 86% in patients attending Bonassama hospital (aRR = 0.14, p = 0.04), by 93% in patients of blood group B (aRR = 0.07, p = 0.04), and by 95% in COVID-19 vaccinated participants (aRR = 0.05, p = 0.005). There is need for ongoing surveillance of SARS-CoV-2 in Cameroon, given the position and importance of Douala.

Toxicological studies of stem bark extract from Schefflera barteri Harms (Araliaceae).

BACKGROUND: The use of herbal medicines as complements or alternatives to orthodox medicines has been on the increase. There has been the erroneous belief that these medicines are free from adverse effects. Schefflera barteri is popularly used in the West region of Cameroon for the treatment of various diseases such as diarrhea, spasm, pneumonia and animals bite. Considering the ethnopharmacological relevance of this plant, this study was designed to investigate the possible toxic effects of the stem bark extract of S. barteri. METHODS: The extract was prepared by maceration of stem bark dry powder in methylene chloride/methanol mixture. Phytochemical analysis was performed by chemical reaction method. Oral acute toxicity study was carried out by administering single geometric increasing doses (2 to 16 g/kg body weight) of plant extract to Swiss albino mice. For sub-acute toxicity study, repeated doses (100, 200, 400 and 800 mg/kg bw) of plant extract were given to Wistar albino rats for 28 consecutive days by oral route. At the end of the treatment period, hematological and biochemical parameters were assessed, as well as histopathological studies. RESULTS: Phytochemical analysis of stem bark extract of S. barteri revealed the presence of anthocyanins, anthraquinons and saponins. Acute toxicity results showed that the LD50 was greater than 16000 mg/kg. Sub-acute treatment significantly (P < 0.05) increased the level of serum transaminase, proteins and HDL cholesterol. On the other hand, the extract significantly (P < 0.05) reduced the level of leucocytes as well as neutrophils, basophils and monocytes in female. No significant variation of serum creatinine, LDL cholesterol, serum triglycerides as well as liver, spleen, testicles and ovaries proteins was noted. Histopathological analysis of organs showed vascular congestion, inflammation of peri-portal and vacuolization of hepatocytes at the level of the liver. Leucocytes infiltration of peri-portal veins were noticed on lungs and liver cells as well as inflammatory peri-bronchial and basal membranes seminar tube merely joined on lungs and testis respectively. CONCLUSION: The results suggest that acute administration of the stem bark extract of S. barteri is associated with signs of toxicity, administration over a long duration provokes hepatotoxicity, testes and lungs toxicities.

Antibacterial and Antioxidant Properties of the Methanolic Extract of the Stem Bark of Pteleopsis hylodendron (Combretaceae).

Pteleopsis hylodendron (Combretaceae) is used in Cameroon and West Africa folk medicine for the treatment of various microbial infections (measles, chickenpox, and sexually transmitted diseases). The antibacterial properties of the methanolic extract and fractions from stem bark of Pteleopsis hylodendron were tested against three Gram-positive bacteria and eight Gram-negative bacteria using Agar-well diffusion and Broth microdilution methods. Antioxidant activities of the crude extract and fractions were investigated by DPPH radical scavenging activity and ß-carotene-linoleic acid assays. The methanolic extract and some fractions exhibited antibacterial activities that varied between the bacterial species (ID = 0.00-25.00 mm; MIC = 781-12500 µg/mL and 0.24-1000 µg/mL). The activity of the crude extract is, however, very weak compared to the reference antibiotics (MIC = 0.125-128 µg/mL). Two fractions (F(E) and F(F)) showed significant activity (MIC = 0.97 µg/mL) while S. aureus ATCC 25922 was almost resistant to all the tested fractions. In addition, the crude extract and some fractions showed good antioxidant potential with inhibition values ranging from 17.53 to 98.79%. These results provide promising baseline information for the potential use of this plant as well as some of the fractions in the treatment of infectious diseases and oxidative stress.