Performance characteristics of INDICAID antigen rapid diagnostic test on SARS-CoV-2 samples during the omicron wave in Cameroon.

Background: WHO recommends the use of COVID-19 antigen rapid diagnostic tests (Ag-RDT) with at least 80 % sensitivity and 97 % specificity. In the era of Omicron variants, we sought to ascertain the performance of the INDICAID™ Ag-RDT compared to real-time PCR (RT-PCR) as the gold standard. Methods: A laboratory-based study was conducted among consenting individuals tested for COVID-19 at the virology laboratory of the Chantal BIYA International Reference Centre, Yaoundé-Cameron. The samples were processed by INDICAID™ Ag-RDT and DaAn Gene real-time PCR according to the manufacturer's instructions, and PCR-results were interpreted as per cycle thresholds (CT). The sensitivity, specificity, positive and negative predictive values (PPV and NVP) of INDICAID™ Ag-RDT were evaluated according to PCR CT-values. Results: A total of 565 nasopharyngeal swabs were collected from participants (median age [IQR]: 40 [31-75]; M/F sex-ratio was 1.2 and 380 were vaccinated). Following PCR, overall COVID-19 positivity was 5.66 %. For CT < 37, INDICAID™ Ag-RDT sensitivity was 21.9 % (95%CI: [8.3-39.9]), specificity 100 % (95%CI: [99.3-100]); PPV 100 % (95%CI: [59.0-100]), NPV 95.5 % (95%CI: [93.4-97.1]) and kappa = 0.34 (95%CI: [0.19-0.35]). For CT < 25, sensitivity was 100 % (95%CI: [47.8-100.0]), specificity 99.6 % (95%CI: [98.7-99.9]); PPV 94.4 % (95%CI: [51.7-100]), NPV 100 % (95%CI: [99.3-100]) and kappa = 0.83 (95%CI: [0.6-1.0]). COVID-19 sequences generated were all Omicron BA.1 subvariants. Conclusion: For patients infected with high viral loads (CT < 25), INDICAID™ Ag-RDT has high intrinsic (sensitivity and specificity) and extrinsic (predictive values) performances for COVID-19 diagnosis. Due to its simplicity and short turnaround time, INDICAID™ Ag-RDT is, therefore a reliable tool to prevent the spread of COVID-19 at community level in the current era of Omicron subvariants.

Effect of Hepatitis B Vaccination on HBV-infection among school children in Yaounde ten years after its introduction of the HBV vaccine into routine Immunization Program in Cameroon

Introduction: since the introduction of the anti-HBV vaccine into the Expanded Program on Immunization (EPI) in 2005 in Cameroon, vaccination coverage has reached 99.0%. This coverage would indicate an increase the number of children immune to Hepatitis B Virus (HBV) and a decrease in susceptibility to HBV-infection. This study was conducted to evaluate the effect of the HBV vaccine on pediatric HBV-infection in Yaounde, Cameroon. Methods: this school based cross-sectional study was conducted from February to May 2016 among 180 children from Nkomo public school. The study population was stratified into two groups: vaccinated (n=95) versus (vs) unvaccinated (n=85). Screening for HBV biomarkers was done using a rapid panel test for detection (HBsAg, HBeAg and anti-HBc) and anti-HBs titer using enzyme linked immunosorbent assay (ELISA). Statistical analyses were done using SPSS v. 22 with p ≥0.05 considered significant. Results: the mean age was 9.65 years. HBsAg (p=0.019) and anti-HBc (p=0.001) rates were detected in children aged ≥10 years and children aged < 10 years (95.95% [71/74]) were vaccinated vs 22.64% (24/106) for those aged ≥10 years (OR: 80.86; 95% CI: 23.36%-279.87%, p < 0.0001). According to anti-HBV vaccination status, HBsAg rate varied from [9.41% (8/85) to 1.05% (1/95), p=0.025], HBeAg rate varied from [2.35% (2/85) to 0% (0/95), p= 0.42] and anti-HBc rate ranged from [12.94% (11/85) to 2.10% (2/95), p= 0.011]. Conclusion: despite the variability of the anti-HBs titer, vaccination against HBV has a positive effect on the reduction of HBV infection in children in tropical settings such as Cameroon.

Cryptococcal antigen carriage among HIV infected children aged 6 months to 15 years at Laquintinie Hospital in Douala.

BACKGROUND: Up to 15% of deaths of people living with HIV is attributable to meningeal cryptococcosis, with nearly 75% occuring in sub-Saharan Africa. Although rare in children, it is a major cause of morbidity and mortality in people living with HIV. A strong association between cryptococcal antigenemia and the development of meningeal cryptococcosis has been shown in adults. Thus, in 2018, the World Health Organization published an updated version of its guidelines for the diagnosis, prevention and management of cryptococcal infection in adults, adolescents and the HIV-infected child. GOAL: To determine the prevalence of cryptococcal antigenemia and to identify its determinants in children infected with HIV. METHODS: An analytical cross-sectional study was carried out at the approved treatment center of Laquintinie hospital in Douala over a period of 4 months. Children were recruited consecutively after informed parental consent. Cryptococcal antigenemia and CD4 assay were performed using a Cryptops® immunochromatographic rapid diagnostic test and flow cytometry, respectively. The data collected included the socio-demographic, clinical and paraclinical variables of the children, as well as their antecedents. Data analysis was performed using Epiinfo software version 3.1 and SPSS 21.0. The significance threshold was set at 5%. RESULTS: A total of 147 children were enrolled. The mean age was 9.8 ± 4.09 years. The majority were on antiretroviral therapy (142, 96.60%). Only 13 (8.80%) were in severe immunosuppression. No child showed signs of meningeal cryptococcosis. The prevalence of cryptococcal antigenemia was 6.12%. Severe immunosuppression [OR: 10.03 (1.52-65.91), p = 0.016] and contact with pigeons [OR: 9.76 (1.14-83.65), p = 0.037] were independent factors significantly associated with the carriage of the cryptococcal antigen. CONCLUSION: We recommend screening for cryptococcal antigenemia and routine treatment with fluconazole of all HIV positive children with cryptococcal antigen whether symptomatic or not.

Serologic response to SARS-CoV-2 in an African population.

Official case counts suggest Africa has not seen the expected burden of COVID-19 as predicted by international health agencies, and the proportion of asymptomatic patients, disease severity, and mortality burden differ significantly in Africa from what has been observed elsewhere. Testing for SARS-CoV-2 was extremely limited early in the pandemic and likely led to under-reporting of cases leaving important gaps in our understanding of transmission and disease characteristics in the African context. SARS-CoV-2 antibody prevalence and serologic response data could help quantify the burden of COVID-19 disease in Africa to address this knowledge gap and guide future outbreak response, adapted to the local context. However, such data are widely lacking in Africa. We conducted a cross-sectional seroprevalence survey among 1,192 individuals seeking COVID-19 screening and testing in central Cameroon using the Innovita antibody-based rapid diagnostic. Overall immunoglobulin prevalence was 32%, IgM prevalence was 20%, and IgG prevalence was 24%. IgM positivity gradually increased, peaking around symptom day 20. IgG positivity was similar, gradually increasing over the first 10 days of symptoms, then increasing rapidly to 30 days and beyond. These findings highlight the importance of diagnostic testing and asymptomatic SARS-CoV-2 transmission in Cameroon, which likely resulted in artificially low case counts. Rapid antibody tests are a useful diagnostic modality for seroprevalence surveys and infection diagnosis starting 5-7 days after symptom onset. These results represent the first step towards better understanding the SARS-CoV-2 immunological response in African populations.

Point-of-care testing can achieve same-day diagnosis for infants and rapid ART initiation: results from government programmes across six African countries.

INTRODUCTION: Point-of-care (POC) early infant diagnosis (EID) testing has been shown to dramatically decrease turnaround times from sample collection to caregiver result receipt and time to ART initiation for HIV-positive infants compared to centralized laboratory testing. As governments in sub-Saharan Africa implement POC EID technologies, we report on the feasibility and effectiveness of POC EID testing and the impact of same-day result delivery on rapid ART initiation within national programmes across six countries. METHODS: This pre-/post-evaluation compared centralized laboratory-based (pre) with POC (post) EID testing in 52 facilities across Cameroon, Democratic Republic of Congo, Ethiopia, Kenya, Senegal and Zimbabwe between April 2017 and October 2019 (country-dependent). Data were collected retrospectively from routine records at health facilities for all infants tested under two years of age. Hazard ratios and 95% confidence intervals were calculated to compare time-to-event outcomes, visualized with Kaplan-Meier curves, and the Somers' D test was used to compare continuous outcomes. RESULTS: Data were collected for 2892 EID tests conducted on centralized laboratory-based platforms and 4610 EID tests on POC devices with 127 (4%) and 192 (4%) HIV-positive infants identified, respectively. POC EID significantly reduced the time from sample collection to caregiver result receipt (POC median: 0 days, IQR: 0 to 0 vs. centralized: 35 days, IQR: 26 to 56) and time from sample collection to ART initiation for HIV-positive infants (POC median: 1 day, IQR: 0 to 7 vs. centralized: 39 days, IQR: 26 to 57). With POC testing, 72% of infants received results on the same day as sample collection; HIV-positive infants with a same-day diagnosis had six times the rate of ART initiation compared to those diagnosed one or more days after sample collection (HR: 6.39; 95% CI: 3.44 to 11.85). CONCLUSIONS: Same-day diagnosis and treatment initiation for infants is possible with POC EID within routine government-led and -supported public sector healthcare facilities in resource-limited settings. Given that POC EID allows for rapid ART initiation, aligning to the World Health Organization's recommendation of ART initiation within seven days, its use in public sector programmes has the potential to reduce overall mortality for infants with HIV through early treatment initiation.

Negative Association of Interleukin-33 Plasma Levels and Schistosomiasis Infection in a Site of Polyparasitism in Rural Cameroon.

Background: This study aimed to investigate the association of plasma levels of IL-33, a mucosal alarmin known to elicit type-2 immunity, with infection and liver fibrosis profiles of school children from an endemic area for Schistosoma mansoni, malaria and hepatitis (B & C) in rural Cameroon. Methods: A cross-sectional study enrolling schoolchildren from 5 public schools was conducted. Single schistosomiasis, malaria and hepatitis infections or co-infections were assessed by kato katz, microscopy, and rapid diagnostic tests, respectively. Hepatic fibrosis was assessed by ultrasound according to WHO Niamey guidelines and plasma levels of Interleukin 33 were determined by ELISA. All statistics were performed using R studio software. Principal findings: We found a prevalence of 13.5% (37/275), 18.2% (50/275), and 8% (22/275), respectively for schistosomiasis, malaria and hepatitis (B or C) single infections. Only 7.6% (21/275) of co-infections were reported. Although Plasma IL-33 showed a minimal negative risk for schistosomiasis infection (AOR 0.99; 95% CI 0.97-1.01), S. mansoni infected participants had lower levels of plasma IL-33 (p = 0.003) which decreased significantly as eggs burdens increased (p = 0.01) with a negative Pearson coefficient of r = -0.22. Hepatic fibrosis occurred in 47.3% (130/275) of our study population independently from plasma levels of IL-33 (AOR 1.00; 95% CI 0.99-1.01). Conclusion/Significance: Our data failed to show an association between plasma IL-33 levels and liver disease but convincingly report on a negative association between plasma IL-33 levels and schistosomiasis infection and egg burden in school children from a polyparasitic schistosomiasis endemic area.

Rate of viral load change and adherence of HIV adult patients treated with Efavirenz or Nevirapine antiretroviral regimens at 24 and 48 weeks in Yaoundé, Cameroon: a longitudinal cohort study.

BACKGROUND: HIV-load decrease and suppression over time is associated with consistent adherence to antiretroviral therapy (ART). Our study aimed to evaluate the difference in viral load and adherence of patients treated with a combination of either Tenofovir (TDF), Lamivudine (3TC) and Efavirenz (EFV) or TDF / Zidovudine (AZT), 3TC and Nevirapine (NVP) regimens at 24 and 48 weeks. METHODS: A longitudinal study was conducted from May 2016 to June 2017 among 256 HIV infected adult patients who were enrolled at two approved treatment hospitals in Yaoundé, before the start of first-line ART. Whole blood samples were collected using standard operating procedures. HIV-loads were determined by a quantitative RealTime PCR assay. Adherence was evaluated by pharmacy refill data records. Statistical analyses were performed using the PRISM 5.0 software. RESULTS: Off the 256 HIV infected patients enrolled, 180 (70%) patients completed the study and 76 (30%) patients were lost to follow-up. The success rate in achieving viral load < 40 copies/ml was 1.8 times higher with the EFV regimen at 24 weeks and was 1.2 times higher in the NVP regimen at 48 weeks. At 48 weeks the treatment failure rate was 12.0 and 40.0% in patients on EFV and the NVP regimen, respectively. The rate of adherence varied in both ART based regimens with 84.0 to 74.0% for EFV and 65.5 to 62.5% for NVP, at 24 and 48 weeks respectively. CONCLUSION: In our study and setting, the rate of viral load decrease was higher in the NVP based regimen than with the EFV regimen. The adherence rate to ART was higher in the EFV regimen, compared to the NVP regimen. This adds to evidence that the EFV regimen is the preferred ART combination for non-nucleoside reverse transcriptase inhibitors (NNRTIs).

Chronic obstructive pulmonary disease (COPD): neutrophils, macrophages and lymphocytes in patients with anterior tuberculosis compared to tobacco related COPD.

OBJECTIVE: The inflammatory profile of chronic obstructive pulmonary disease (COPD) related to tobacco is known in certain studies while that of the post tuberculosis form is not yet known. This study aimed to evaluate the levels of neutrophils, macrophages and lymphocytes cells in sputum of COPD patients with history of smoking or anterior tuberculosis. Enumeration of cells in samples was analyzed using standard microscopy. RESULTS: We enrolled 92 participants, 46 (50%) were COPD subjects comprising 22 (47.83%) smokers and 24 (52.17%) with anterior tuberculosis while 46 (50%) healthy persons constituted the control group. The levels of neutrophils, lymphocytes and monocytes were statistically higher in COPD patients compared to the control group with p-values of 0.0001 respectively. Neutrophils levels were higher in COPD patients with history of tobacco than in COPD patients with anterior tuberculosis with a mean rate of 4.72 × 106/ml and 2.48 × 106/ml respectively (p = 0.04). The monocytes and lymphocytes levels were not statistically different between the two sub-groups of COPD patients with p-value of 0.052 and 0.91 respectively. Neutrophils are the only inflammatory cells that were significantly higher in COPD patients with history of smoking as compared to COPD patients with anterior tuberculosis.

A Cross Sectional Study of the Impact of Human Immunodeficiency Virus, Hepatitis B Virus and Hepatitis C Virus on Rheumatoid Factor Production.

OBJECTIVES: This study aims to investigate how human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV) affect the production of immunoglobulin M (IgM)-rheumatoid factor (RF). PATIENTS AND METHODS: The study included 405 voluntary participants (139 males, 266 females; mean age 39.4±17.9 years; range 3 to 88 years) randomly recruited by a consecutive sampling technique in the main health facilities of the Center, East, Far North, Littoral and West regions of Cameroon. We excluded persons under treatment or hospitalized for any form of primary autoimmune disease. Blood samples were collected and used for serological analyses. We sought for the HIV antibodies (Ab); the core antibody (HBcAb), the surface antigen (HBsAg), and the replicative antigen (HBeAg) of the HBV; HCVAb of HCV and the IgM-RF. RESULTS: The prevalence of HIVAb was 7.61%, 38.7% for HBcAb, 5.43% for HBsAg, 1.26% for HBeAg and 6.41% for IgM-RF in the study population. The Far North region had the highest prevalence of IgM-RF (9.8%) and the Littoral region had the lowest prevalence (3.2%). The prevalence of RF was 6.7% and 5.7% for females and males, respectively (sex ratio of 2.25). The IgM-RF prevalence was 9.7%, 8.9%, 9.1%, and 27.8% in participants with positive serological results for HIVAb, HBcAb, HBsAg, and HCV, respectively. CONCLUSION: Infection by HIV and HBV showed to poorly stimulated IgM-RF production. However, IgM-RF was highly produced in HCV infected participants. Increased IgM-RF production may contribute to cytotoxicity in tissues or organs of HCV-infected patients, leading to the onset of autoimmune diseases.

Evidence of Co and Triple Infections of Hepatitis B and C amongst HIV Infected Pregnant Women in Buea; Cameroon

OBJECTIVES. Little data is available on the prevalence of HIV; Hepatitis B and C; Co-and or triple infection during pregnancy in Cameroon as well as many other resource limited settings. HIV and Hepatitis B and C are major public health concerns world wide. Our study aimed at assessing the seroprevalence of Hepatitis B and C amongst HIV infected pregnant women in Buea; located in the Southwest region of Cameroon. METHODS. A cross-sectional study of consented pregnant women were conducted from March 2015 to August 2015. HIV-1 infections were detected using the national HIV-1 test algorithms. Hepatitis B surface antigen (HBsAg); anti-HBe and anti- Hepatitis C (anti-HCV) were detected using Enzyme linked Immunosorbent Assays (ELISAs). RESULTS. Our study group had an HIV prevalence rate of 7.8% (N = 97 / 1230). Of the HIV-1 positive group; 14 women (17.5%; N = 97) were co-infected with HBV and 11 (11.3%; N = 97) were co-infected with HCV. 8 (8.2%; N = 97) were triple infected with HIV; HBV and HCV. Anti-HBe was detected in all 14 HBV-infected pregnant women (100% N= 14) (14/14;(95%CI: 65.8; 100%). CONCLUSION. Co- and triple infections of HIV;Hepatitis B and C were present amongst pregnant women in Buea. Epidemiological data generated from this study are limited due to the existence of triple infected. It will nevertheless serve as a guide to the government policies to reinforce screening; treatment and prevention strategies; through its Mother-to-Child-transmission (pMTCT) Programme nationwi

evaluation de la phase pre-analytique dans quelques laboratoires d'analyses medicales de la ville de Yaounde

Objectifs: Les pratiques pre-analytiques conditionnent la reussite des autres phases du systeme d'assurance qualite par l'obtention de l'echantillon dont l'analyse fournira l'information demandee par le prescripteur. Notre etude avait pour but d'evaluer les pratiques pre-analytiques dans les laboratoires d'analyses medicales de la ville de Yaounde.Methodologie : Une etude transversale descriptive a ete menee aupres des laboratoires d'analyses medicales de la ville de Yaounde. Le questionnaire confectionne a cet effet; a ete rempli par l'enqueteur a travers l'interview avec le responsable du laboratoire enquete et les observations journalieres du deroulement de la phase pre-analytique dans ce dernier. Les reponses aux questions; avec leurs cotations; ont permis de determiner les pratiques pre-analytiques avec leur score d'evaluation . Resultats : Nous avons enquete dans 8 laboratoires d'analyses medicales dont 6 dans le secteur public et 2 dans le secteur prive. Nous avons observe une insuffisance d'informations sur les prescriptions d'analyses; un defaut d'individualisation entre les salles d'accueil et de prelevement majoritairement dans le secteur public ; une absence du manuel de prelevement dans la quasi-totalite de ces laboratoires ; un materiel de transport des echantillons n'assurant pas leur integrite et la securite du personnel implique ; une absence de procedure de reception des echantillons. Les scores d'evaluation obtenus etaient inferieurs a 40 pour le secteur prive

Importance of bacterial resistance in streptococcus pneumoniae and streptococcus pyogenes in the center region in Cameroon

Respiratory tract infections are a real public health problem; and the few studies of African data make difficult the definition of a probabilistic rational therapeutic approach. The present study from May 2006 to June 2007 included 107 strains of Streptococcus pneumoniae and 94 strains of Streptococcus pyogenes. A single isolate was collected by topic; and the minimum inhibitory concentration (MIC) has been made by the E test method; 201 strains from 115 adults and 86 children were included in the study. From 107 strains of S. pneumoniae; 24 were from children; and from 94 strains of S. pyogenes; 62 came from child. From antibiotics susceptibility of S. pyogenes; 100% were sensitive to penicillin G; with MIC between 0.064 and 0.128; 20 were resistant to erythromycin; and 100% were sensitive to levofloxacin; chloramphenicol; amoxicillin; cefotaxime; and ceftriaxone. From S. pneumoniae; 95.3% were sensitive to penicillin G and 4.7% were intermediate; 19.3% were resistant to erythromycin; 100% were sensitive to levofloxacin; cefotaxime amoxicillin; and ceftriaxone

Plasma concentrations of soluble Fas receptors (Fas) and Fas ligands (FasL) in relation to CD4+ cell counts in HIV-1 positive and negative patients in Yaounde, Cameroon.

BACKGROUND: Though documented that HIV infection progresses with the depletion of CD4+ cells, the exact mechanisms by which these cell depletions occur are not clearly understood. This study aimed at evaluating the plasma levels of soluble Fas receptors and ligands in HIV-infected and uninfected patients in Yaounde, Cameroon, a population with a known diversity of HIV in whom this has not been previously assessed. FINDINGS: In a cross-sectional study, 39 antiretroviral naïve HIV-1 positive and negative participants were recruited in Yaounde, Cameroon. CD4+ lymphocyte cell counts were quantified from whole blood using an automated FACScount machine (Becton-Dickinson, Belgium). Plasma samples obtained were analyzed for soluble Fas receptors and Fas ligands in both HIV-1 positive and negative samples using two different quantitative sandwich ELISA kits (Quantikine®, R&D Systems , UK).Plasma levels of Fas receptors were higher in HIV-1 positive patients (median = 1486pg/ml IQR = 1193, 1830pg/ml) compared to HIV-negative controls (median = 1244pg/ml, IQR = 1109, 1325pg/ml), p-value <0.001. Plasma levels of Fas ligands were also higher in HIV-1 positive patients (median = 154pg/ml, IQR = 111, 203pg/ml) compared to HIV-negative controls (median = 51pg/ml, IQR = 32, 88pg/ml), p-value = 0.005. Plasma concentrations of soluble fas receptors and ligands tended to be negatively correlated with the CD4+ cell counts of HIV-positive patients; the correlation coefficients were -0.34 (value = 0.78) and-0.3 (p-value = 0.51) respectively. CONCLUSIONS: In this population of patients in Cameroon, plasma concentrations of Fas receptors and Fas ligands tend to be higher in HIV-positive patients. The Fas pathway of apoptosis may have a role in the depletion of CD4+ cell counts.