First investigation of RH gene polymorphism in patients with sickle cell disease and associated blood donors in Cameroon, Central Africa.

BACKGROUND: Although genetic polymorphism of the RH blood group system is well known in sub-Saharan Africa, national/regional specificities still remain to be described precisely. For the first time in Cameroon, Central Africa, and in order to better characterize the molecular basis driving RH phenotype variability, as well as to identify the main antigens that may be potentially responsible for alloimmunization, we sought 1) to study the RH genes in a cohort of 109 patients with sickle cell disease; 2) to study the same genes in the corresponding donors whose red blood cells (RBCs) were transfused to the patients (108 donors in 98 patients); 3) to predict RH phenotype on the basis of the molecular data and compare the results with serologic testing; and 4) to identify retrospectively patients at risk for alloimmunization. MATERIALS AND METHODS: In order to generate an exhaustive dataset, the RH genes of all patient and donor samples were systematically investigated 1) by quantitative multiplex PCR of short fluorescent fragments (QMPSF) for characterization of RHD gene zygosity and potential structural variants (SVs), and 2) by Sanger sequencing for identification of single nucleotide variants (SNVs). Subsequent to molecular analysis, the genotypes and RH phenotype were deduced and predicted, respectively, from reference databases. RESULTS: In a total of 217 Cameroonian individuals, as many as 24 and up to 22 variant alleles were identified in the RHD and RHCE genes, respectively, in addition to the reference alleles. Interestingly, 65 patients with SCD (66.3%) were assumed to be exposed to one or more undesirable RH antigen(s) with varying degrees of clinical relevance. DISCUSSION: Beyond the comprehensive report of the nature and distribution of RH variant alleles in a subset of Cameroonian patients treated by transfusion therapy, this work highlights the need for an extensive review of current practice, including routine serologic typing procedures, preferably in the near future.

Partial spike gene sequencing for the identification of SARS-CoV-2 variants circulating in Cameroon in 2021.

INTRODUCTION: Global monitoring of severe acute respiratory syndrome related coronavirus 2 (SARS-CoV-2) genetic sequences and associated metadata is essential for coronavirus disease 2019 (COVID-19) response. Therefore, Sanger's partial genome sequencing technique was used to monitor the circulating variants of SARS-CoV-2 in Cameroon. METHODOLOGY: Nasopharyngeal specimen was collected from persons suspected of SARS-CoV-2 following the national guidelines between January and December 2021. All specimens with cycle threshold (Ct) below 30 after amplification were eligible for sequencing of the partial spike (S) gene of SARS-CoV-2 using the Sanger sequencing method. RESULTS: During the year 2021, 1481 real time reverse transcriptase polymerase chain reaction (RT-PCR) SARS-CoV-2 positive samples were selected for partial sequencing of the S gene of SARS-CoV-2. Amongst these, 878 yielded good sequencing products. A total of 231 probable variants (26.3%) were identified. The variants were mainly represented by Delta (70.6%), Alpha (15.6%), Omicron (7.4%), Beta (3.5%), Mu (1.7%) and Gamma (0.4%). Phylogenetic analysis of the probable variants from Cameroon with reference strains confirmed that all prior and current variants of concern (VOC) clustered with their respective reference sequences. CONCLUSIONS: The surveillance strategy implemented in Cameroon, based on partial sequencing of the S gene enabled identification of the major circulating variants and provided information on the distribution of these variants, which contributed to implementing public health measures to control disease spread in the country.

Analysis of chlorhexidine, antibiotics and bacterial community composition in water environments from Brazil, Cameroon and Madagascar during the COVID-19 pandemic.

The widespread of chlorhexidine and antibiotics in the water bodies, which grew during the global COVID-19 pandemic, can increase the dispersion of antibiotic resistance. We assessed the occurrence of these pharmaceutical compounds as well as SARS-CoV-2 and analysed the bacterial community structure of hospital and urban wastewaters from Brazil, Cameroon, and Madagascar. Water and wastewater samples (n = 59) were collected between January-June 2022. Chlorhexidine, azithromycin, levofloxacin, ceftriaxone, gentamicin and meropenem were screened by Ultra-High-Performance Liquid Chromatography coupled with mass spectrometer. SARS-CoV-2 was detected based on the nucleocapsid gene (in Cameroon and Madagascar), and envelope and spike protein-encoding genes (in Brazil). The total community-DNA was extracted and used for bacterial community analysis based on the 16S rRNA gene. To unravel likely interaction between pharmaceutical compounds and/or SARS-CoV-2 with the water bacterial community, multivariate statistics were performed. Chlorhexidine was found in hospital wastewater effluent from Brazil with a maximum concentration value of 89.28 µg/L. Additionally, antibiotic residues such as azithromycin and levofloxacin were also present at concentrations between 0.32-7.37 µg/L and 0.11-118.91 µg/L, respectively. In Cameroon, azithromycin was the most found antibiotic present at concentrations from 1.14 to 1.21 µg/L. In Madagascar instead, ceftriaxone (0.68-11.53 µg/L) and levofloxacin (0.15-0.30 µg/L) were commonly found. The bacterial phyla statistically significant different (P < 0,05) among participating countries were Proteobacteria, Patescibacteria and Dependentiae which were mainly abundant in waters sampled in Africa and, other phyla such as Firmicutes, Campylobacterota and Fusobacteriota were more abundant in Brazil. The phylum Caldisericota was only found in raw hospital wastewater samples from Madagascar. The canonical correspondence analysis results suggest significant correlation of azithromycin, meropenem and levofloxacin with bacteria families such as Enterococcaceae, Flavobacteriaceae, Deinococcaceae, Thermacetogeniaceae and Desulfomonilaceae, Spirochaetaceae, Methanosaetaceae, Synergistaceae, respectively. Water samples were also positive for SARS-CoV-2 with the lowest number of hospitalized COVID-19 patients in Madagascar (n = 7) and Brazil (n = 30). Our work provides new data about the bacterial community profile and the presence of pharmaceutical compounds in the hospital effluents from Brazil, Cameroon, and Madagascar, whose limited information is available. These compounds can exacerbate the spreading of antibiotic resistance and therefore pose a risk to public health.

Prevalence and risk factors associated with Haemophilus ducreyi cutaneous ulcers in Cameroon.

Epidemics of yaws-like cutaneous ulcers are regularly documented in children in the tropics. They occur mainly in poor and remote communities without access to health facilities. The integration of molecular tools into yaws control efforts has made it possible to describe Haemophilus ducreyi (HD) as a major cause of cutaneous ulcers. The objective of this study was to determine the prevalence of HD as cause of cutaneous ulcers, investigate its presence in asymptomatic individuals and identify associated risk factors. A cross-sectional study was conducted in yaws endemic districts of Cameroon. Participants included people presenting yaws-like ulcers and asymptomatic individuals. Swab samples were collected from each participant and tested for HD and Treponema pallidum (TP) using an established qPCR method. Additionally, demographic, habitat, proximity, and hygiene characteristics were collected using a structured questionnaire. A total of 443 individuals participated in the study, including 271 ulcer cases and 172 asymptomatic contacts. The prevalence of HD in ulcers was 30.3% (Confidence Interval (CI) 95% [24.8-35.7]) and the prevalence of asymptomatic HD carriage was 8.6% (CI95% [4.5-12.9]). TP was also detected in our sample among ulcer cases but in lower proportion (5.2% CI95% [2.5-7.8]) compared to HD. The adjusted logistic regression model showed that women were as much at risk of having HD cutaneous ulcer as men regardless of age. Physical proximity to a confirmed ulcer case was the major factor identified favouring HD transmission. HD ulcers were more likely to be present on Bantu individuals compared to Baka as well as HD colonization. These findings highlight HD as the most common cause of cutaneous ulcers in yaws-endemic communities in Cameroon. The exact implications of detecting HD on intact skin are not yet clear. Further studies are needed to understand the significance of this carriage in the spread dynamics of the disease.

Factors associated with non-adherence to antiretroviral therapy among HIV-infected adolescents aged 15-19 years: a snapshot from the Mother and Child Center in Yaounde, Cameroon.

INTRODUCTION: non-adherence to antiretroviral therapy (ART) constitutes the main cause of therapeutic failure among HIV-infected adolescents, especially in the aged group 15 to 19 years. We aimed to determine factors associated with this non-adherence in this specific population. METHODS: we conducted a cross-sectional study at the Mother and Child Center in Yaounde from August to October 2018. Delayed clinic appointment was referred to as defaulters. Non-adherence was measured during the 3 days preceding inclusion by self-reported method following quantitative (missing dosage of ART), qualitative (ART taken with a delay of more than 2 hours) and combined measure. A threshold of non-adherence > 20% was considered high, with p<0.05 statistically significant. RESULTS: overall, 195 out of 251 (77.7%) eligible adolescents were included, of which 56.9% were girls (sex-ratio = 4/3). The mean age was 16.8 ± 1.5 years. The rate of defaulters was 21.0%. Following quantitative approach, 33.8% were non-adherent. Using combined approach, we had 41.0%. This non-adherence was associated with duration on ART > 5 years (adjusted Odds Ratio [aOR]: 2.33;95% Confidence Interval [CI]: 1.08-5.00; p:0.030), defaulters (aOR: 2.56;95% CI: 1.12-5.82; p:0.025) and HIV Viral Load (VL) ≥ 40 copies/ml (aOR: 0.42; 95% CI: 0.21-0.83; p:0.013). CONCLUSION: at this reference pediatric center, 4 out of 10 adolescents aged 15-19 years on ART are non-adherent, driven by missing dosage of drug intake. Strategies for enhanced adherence for late age adolescents are therefore warranted, by prioritizing interventions on defaulters and duration on ART > 5 years.

Coding-Complete Genome Sequence and Phylogenetic Relatedness of a SARS-CoV-2 Strain Detected in March 2020 in Cameroon.

We describe the coding-complete genome sequence of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strain obtained in Cameroon from a 58-year-old French patient who arrived from France on 24 February 2020. Phylogenetic analysis showed that this virus, named hCoV-19/Cameroon/1958-CMR-YAO/2020, belongs to lineage B.1.5 and is closely related to an isolate from France.

Evaluation of a mobile health approach to improve the Early Warning System of influenza surveillance in Cameroon.

BACKGROUND: Rapid reporting of surveillance data is essential to better inform national prevention and control strategies. OBJECTIVES: We compare the newly implemented smartphone-based system to the former paper-based and short message service (SMS) for collecting influenza epidemiological data in Cameroon. METHODS: Of the 13 sites which collect data from persons with influenza-like illness (ILI), six sites send data through the EWS, while seven sites make use of the paper-based system and SMS. We used four criteria for the comparison of the data collection tools: completeness, timeliness, conformity and cost. RESULTS: Regarding the different collection tools, data sent by the EWS were significantly more complete (97.6% vs 81.6% vs 44.8%), prompt (74.4% vs n/a vs 60.7%) and of better quality (93.7% vs 76.1% vs 84.0%) than data sent by the paper-based system and SMS, respectively. The average cost of sending a datum by a sentinel site per week was higher for the forms (5.0 USD) than for the EWS (0.9 USD) and SMS (0.1 USD). The number of outpatient visits and subsequently all surveillance data decreased across the years 2017-2019 together with the influenza positivity rate from 30.7% to 28.3%. Contrarily, the proportion of influenza-associated ILI to outpatient load was highest in the year 2019 (0.37 per 100 persons vs 0.28 and 0.26 in the other 2 years). CONCLUSION: All sentinel sites and even other disease surveillance systems are expected to use this tool in the near term future due to its satisfactory performance and cost.