Influence of tillage systems and sowing dates on the incidence of leaf spot disease in Telfairia occidentalis caused by Phoma sorghina in Cameroon.

The production and leaf quality of Telfairia occidentalis in Cameroon are gravely threatened by leaf spot disease. A field study was conducted in July 2019 and 2020 to determine the influence of tillage systems and sowing dates on the incidence of Telfairia occidentalis leaf spot caused by Phoma sorghina. A randomized block design with three replications and four planting dates was used. The soil physicochemical properties were also determined. Data for disease incidence were registered once every two weeks and submitted to generalized linear model for statistical analysis. The means were separated by Duncan's multiple range test at a 95% confidence interval. Calculations for disease incidence and statistical analysis were conducted using the Microsoft Excel program and SPSS version 23, respectively. Statistical analysis revealed that the zero tilled field generally registered a lower leaf spot disease incidence than the tilled field, which was highly significant (p ≤ 0.05). In addition, the second sowing date in the zero tilled field proved to be better in terms of low disease incidence than other sowing dates employed in the study. Therefore, to minimize the devastating effects of leaf spot disease, zero tillage coupled with the second sowing date could be exploited.

Anti-V2 antibody deficiency in individuals infected with HIV-1 in Cameroon.

The results of the RV144 vaccine clinical trial showed a correlation between high level of anti-V1V2 antibodies (Abs) and a decreased risk of acquiring HIV-1 infection. This turned the focus of HIV vaccine design to the induction of elevated levels of anti-V2 Abs to increase vaccine efficacy. In plasma samples from HIV-1 infected Cameroonian individuals, we observed broad variations in levels of anti-V2 Abs, and 6 of the 79 plasma samples tested longitudinally displayed substantial deficiency of V2 Abs. Sequence analysis of the V2 region from plasma viruses and multivariate analyses of V2 characteristics showed a significant difference in several features between V2-deficient and V2-reactive plasma Abs. These results suggest that HIV vaccine immunogens containing a shorter V2 region with fewer glycosylation sites and higher electrostatic charges can be beneficial for induction of a higher level of anti-V2 Abs and thus contribute to HIV vaccine efficacy.

Viral load testing and the use of test results for clinical decision making for HIV treatment in Cameroon: An insight into the clinic-laboratory interface.

BACKGROUND: The viral load (VL) in patients receiving antiretroviral therapy (ART) is the best predictor of treatment outcome. The anticipated benefits of VL monitoring depend on the actual uptake of VL test results for clinical decisions. The objective of this study was to assess the uptake and utilization of VL test results for clinical decisions on HIV treatment in Cameroon, from 2013 to 2017. METHODS: This was a retrospective cohort analysis of data from files of patients receiving ART at Buea, Limbe, Bamenda and Bafoussam regional hospital HIV treatment centers. A simple random pick of six file blocks was performed in each shelf that corresponded to a year of initiation, and the contents of all selected files were reviewed and the information needed for the study entered a structured questionnaire. The data collected was recorded in Epi Info (version 7.1.5.2), and analyzed using SATA (version 12.1; StataCorp LP). RESULTS: Eight hundred and thirty files were reviewed. The mean duration on ART was 39.4±12 months. Viral load testing uptake was 24.33% and only one VL test had been done by all patients. Approximately 65% of the patients did the first VL after more than 24 months on ART. The median turnaround (TAT) time for VL testing was 6 days (Interquartile range (IQR) 3-7days). Among 201 patients who did a VL test, 94.55% had VL suppression (≤1000copies/mm3). Approximately 54% of the patients with virologic failure were switched to a second-line regimen. CONCLUSIONS: The uptake of viral load testing is low in North West, South West and West Regions of Cameroon. The current TAT for VL testing is plausible. The rate of switch to second line regimen is low. It is time to strengthen the scale up of VL testing and improve the rate of switch to second-line regimen in Cameroon.

Multimethod Longitudinal HIV Drug Resistance Analysis in Antiretroviral-Therapy-Naive Patients.

The global intensification of antiretroviral therapy (ART) can lead to increased rates of HIV drug resistance (HIVDR) mutations in treated and also in ART-naive patients. ART-naive HIV-1-infected patients from Cameroon were subjected to a multimethod HIVDR analysis using amplification-refractory mutation system (ARMS)-PCR, Sanger sequencing, and longitudinal next-generation sequencing (NGS) to determine their profiles for the mutations K103N, Y181C, K65R, M184V, and T215F/Y. We processed 66 ART-naive HIV-1-positive patients with highly diverse subtypes that underlined the predominance of CRF02_AG and the increasing rate of F2 and other recombinant forms in Cameroon. We compared three resistance testing methods for 5 major mutation sites. Using Sanger sequencing, the overall prevalence of HIVDR mutations was 7.6% (5/66) and included all studied mutations except K65R. Comparing ARMS-PCR with Sanger sequencing as a reference, we obtained a sensitivity of 100% (5/5) and a specificity of 95% (58/61), caused by three false-positive calls with ARMS-PCR. For 32/66 samples, we obtained NGS data and we observed two additional mismatches made up of minority variants (7% and 18%) that might not be clinically relevant. Longitudinal NGS analyses revealed changes in HIVDR mutations in all five positive subjects that could not be attributed to treatment. In one of these cases, superinfection led to the temporary masking of a resistant virus. HIVDR mutations can be sensitively detected by ARMS-PCR and sequencing methods with comparable performances. Longitudinal changes in HIVDR mutations have to be considered even in the absence of treatment.

Monitoring HIV-1 Group M Subtypes in Yaoundé, Cameroon Reveals Broad Genetic Diversity and a Novel CRF02_AG/F2 Infection.

Broad HIV-1 genetic diversity in Cameroon provides a unique opportunity to monitor HIV-1 evolution and allows the detection of novel strains. We have genetically characterized the HIV-1 subtypes found in 156 samples from 90 drug-naive subjects in Yaoundé, Cameroon collected from 2011 to 2013, using phylogenetic analysis of regions in gag and pol. We identified subtypes CRF02_AG (64.9%), CRF22_01A1 (7.1%), D (4.5%), F2 (3.9%), G (3.2%), CRF18_cpx (3.2%), CRF37_cpx (3.2%), CRF11_cpx (2.6%), CRF13_cpx (1.9%), A1 (1.3%), CRF01_AE (1.3%), CRF09_cpx (1.3%), A2 (0.6%), and H (0.6%). Sequence data for both the gag and pol regions were obtained from 62 subjects; for 59 of these subjects the two regions were identified as the same viral subtype while three subjects were discordant, A1/CRF02_AG (subject MDC006), CRF02_AG/F2 (subject MDC179), and a dual infection with CRF02_AG/F2 (subject MDC131). Longitudinal sequence data were obtained for 28 of these 62 subjects and confirmed the cross-sectional results. These data update subtype information for this area and highlight the necessity of such studies due to the numerous circulating subtypes, the ongoing superinfection, and the risk of emerging novel recombinant viruses.

Hepatitis B and C Co-Infections in Some HIV-Positive Populations in Cameroon, West Central Africa: Analysis of Samples Collected Over More Than a Decade.

As people infected with the human immunodeficiency virus (HIV) in Sub-Saharan Africa live longer due to availability of antiretroviral treatment (ART), so is the rise of associated infections with their burdens on patients. But reliable data on the prevalence of co-infection with hepatitis B (HBV) or C (HCV) still remains sparse and many individuals with HIV do not know their co-infection status. This study attempted to estimate the seroprevalence and identify risk factors associated with hepatitis B and/or C co-infections in HIV-infected individuals from five Regions of Cameroon by screening 531 HIV infected subjects for the presence of HBV surface antigen (HBsAg) and antibodies to HCV (HCV-Ab). A Screening and a confirmatory Enzyme linked immunosorbent assay were used to detect presence of markers of infection. CD4 count levels were also examined. The results indicate that of the 531 participants, 68% were females and 32% males. Mean CD4 count was ~400 cells/µl. Seroprevalence rates for HBsAg and HCV-Ab were 23.7%, and 7.2%, respectively. Associations assessed using logistic regression revealed that HBsAg but not HCV-Ab positivity was linked to age, lower CD4 count and residing in an urban rather than in a rural setting. This high prevalence of co-infection with HBV raises the urgent need to systematically screen all newly diagnosed HIV cases for co-infection in Cameroon and other regions of sub-Saharan Africa where HIV accounts for the majority of the global infection, so as to improve management strategies for HBV infection and ART implementation.

Use of amplification refractory mutation system PCR assay as a simple and effective tool to detect HIV-1 drug resistance mutations.

Access to genotyping assays to determine successful antiretroviral treatment (ART) is limited in resource-constrained settings by high cost, suggesting the need for a cost-effective and simplified method to identify HIV-1 drug resistance (HIVDR) mutations. In this study, an amplification refractory mutation system (ARMS)-PCR assay was developed and used to investigate the most frequent HIVDR mutations affecting first-line ART in settings where WHO ART guidelines are applied. Seventy-five HIV-positive (HIV(+)) samples from Cameroon were used to assess the performance of this assay. Sequencing of HIV-1 reverse transcriptase was simultaneously performed for comparison, and discordant samples were tested with a Trugene HIV-1 genotyping kit. The ARMS-PCR assay was able to detect M184V, T215Y/F, K103N, and Y181C mutations with sensitivities of 96.8%, 85.7%, 91.3%, and 70%, respectively, and specificities of 90.6%, 95%, 100%, 96.9%, respectively, compared with data on sequencing. The results indicated the highest positive predictive value for K103N (100%) and the highest negative predictive value for M184V (97.5%). ARMS-PCR's limits of detection for mutations M184V, T215Y/F, K103N, and Y181C were <75 copies/ml, 143 copies/ml, 143 copies/ml, and 836 copies/ml, respectively. ARMS-PCR efficiently identified mutations in individuals harboring different HIV-1 clades (CRF02_AG and non-CRF02_AG). In addition, this approach was more cost-effective than other genotyping assays. The high throughput, the cost-effectiveness, and the simplicity of the ARMS-PCR assay make it a suitable tool to monitor HIVDR patterns in resource-constrained settings with broad HIV-1 genetic diversity.

The evolution of HIV-1 group M genetic variability in Southern Cameroon is characterized by several emerging recombinant forms of CRF02_AG and viruses with drug resistance mutations.

The HIV epidemic in Cameroon is marked by a broad genetic diversity dominated by circulating recombinant forms (CRFs). Studies performed more than a decade ago in urban settings of Southern Cameroon revealed a dominance of the CRF02_AG and clade A variants in >90% of the infected subjects; however, little is known about the evolving viral variants circulating in this region. To document circulating HIV viral diversity, four regions of the viral genome (gag, PR, reverse transcriptase, env) in 116 HIV-1 positive individuals in Limbe, Southern Cameroon, were PCR-amplified. Sequences obtained at the RT and protease regions were analyzed for mutations that conferred drug resistance using the Stanford Drug Resistance Database. The present study reveals a broad genetic diversity characterized by several unique recombinant forms (URF) accounting for 36% of infections, 48.6% of patients infected with CRF02_AG, and the emergence of CRF22_01A1 in 7.2% of patients. Three out of 15 (20%) treated patients and 13 out of 93 (13.9%) drug naïve patients harbor drug resistance mutations to RT inhibitors, while 3.2% of drug naïve patients harbor drug resistance mutations associated with protease inhibitors. The high proportion (13.9%) of drug resistance mutations among the drug naïve patients reveals the ongoing transmission of these viruses in this region of Cameroon and highlights the need for drug resistance testing before starting treatment for patients infected with HIV-1.

Occupational exposure to blood, hepatitis B vaccine knowledge and uptake among medical students in Cameroon.

BACKGROUND: Hepatitis B virus (HBV) is the most contagious blood borne pathogen. The risk of occupational exposure to HBV among health care workers is a major concern, especially medical trainees. In this study we describe the knowledge of risk factors for HBV infection, history of accidental exposure to blood, awareness of HBV vaccine and the vaccination status among medical students in Cameroon. METHODS: In April 2012, a cross-sectional survey was carried out using a pretested self-administered questionnaire among 111 medical students. RESULTS: Sixty-two students (55.9%) had had at least one accidental exposure to blood since the beginning of their medical training, with a median of 2 (IQR, 1-3) exposures. There was a good knowledge of the risk factors for HBV infection and awareness of HBV vaccine among participants. However, only 20 (18%) participants had completed the three doses of primary HBV vaccination. Furthermore, only 2 of the 20 (10%) adequately vaccinated participants had a post-vaccination test to confirm a good immune response and thus an effective protection against HBV infection. The main reason for not being vaccinated was lack of money to pay for the vaccine (45.6%). Forty seven (42.3%) participants had been sensitized by their training institutions about the importance of HBV vaccination. These were more likely to be vaccinated compared to those who had not been sensitized (p<0,001). CONCLUSION: There is a high rate of accidental exposure to blood and a very low HBV vaccination uptake in medical students in Cameroon, leading to a high occupational risk of HBV infection. HBV vaccination should be strongly recommended for medical students and the vaccine made available free of charge at the beginning of their training.

Protease mutations in HIV-1 non-B strains infecting drug-naive villagers in Cameroon.

To describe the presence of protease inhibitor (PI) resistance-associated mutations and subtype distribution in drug-naive villagers of six provinces of Cameroon, we sequenced the protease (PR) gene (297 bp) of 128 viruses. Secondary PI resistance-associated mutations were identified at five sites: L10I/V (16%), K20R (8%), M36I (98%), L63P (13%), and V77I (6%). No primary mutation in the PR was identified. Of the 128 specimens analyzed, subtypes A (11%), C(2%), D (6%), F2 (3%), G (6%), H (0.8%), J (6%), and CRF02_AG (60%) were identified. The mutations identified were not characteristic to any particular subtype. The absence of primary mutations, in addition to the few secondary mutations, gives good perspectives for PI treatment interventions in these rural areas.

Genetic and biological properties of HIV type 1 isolates prevalent in villagers of the Cameroon equatorial rain forests and grass fields: further evidence of broad HIV type 1 genetic diversity.

To understand the evolution of HIV-1, the genetic and biological characteristics of viruses that infect persons living in regions in which the virus has been evolving for several decades must be studied. Thus, we investigated teh genetic subtypes, coreceptor usage, and syncytium-inducing ability of viruses in 47 HIV-1-infected blood samples from individuals living in rural villages in the equatorial rain forest and grass field regions in Cameroon. Heteroduplex mobility analysis (HMA) of gag (part of p24 and p7) and env (C2V5) or sequence and phylogenetic analysis of gag (part of p24 and p7), pol (protease), and env (C2V5), revealed a broad HIV-1 group M genetic diversity. Subtype analysis revealed genetic evidence of seven subtypes (A, C, D, F, G, H, and J) and three circulating recombinant froms (CRFs) (CRF01_AE, CRF02_AG, and CRF11_cpx). Only 15 (32%) of the 47 samples analyzed revealed a concordant subtype in all three genes (gag, pol, and env), while discordant subtypes and CRFs were identified for the remaining 32 (68%) samples. Two patterns of HIV-1 diversity could be discerned in two provinces. While more concordant subtypes in gag, pol, and env genes were identified in villages of South province (10 of 13, 77%), the HIV-1 diversity in the West province was characterized by intersubtype recombinants (63%). Five new intersubtype recombinants were identified including Agag Jpol Genv, Ggag Upol Aenv, AGgag Jpol Aenv, Agag AGpol Henv, and Cgag AGpol AGenv. All of the 40 viruses tested used the R5 coreceptor, of which four also used the X4 coreceptor. Four viruses were able to induce syncytia in MT-2 cells, however, syncytium induction did not correlate with coreceptor usage. This study further reveals the complexity of HIV-1 infection in rural Cameron and points to the future of the global epidemic, which may be characterized by more genetically diverse viruses.

HIV type 1 group M clades infecting subjects from rural villages in equatorial rain forests of Cameroon.

Though the HIV-1 subtypes infecting patients living in urban and semi-urban areas in Cameroon have been reported, information on the subtypes infecting patients in rural villages is lacking. To begin to understand the diversity of the HIV-1 group M subtypes infecting persons living in rural villages in the equatorial rain forest regions of Cameroon, 49 plasma samples from 14 rural villages in four provinces of Cameroon were analyzed using heteroduplex mobility analysis (HMA), DNA sequencing, and phylogenetic tree analysis on the basis of env C2V5, gag, or pol regions. Sixty-one percent of the group M infections were clade A or CRF02_AG-like as subtyped by env and gag. Of the remaining group M infections, 12% were either A or CRF02_AG-like or CRF01_AE-like in recombination with other clades; 25% were infections that were entirely non-A or non-CRF02_AG-like; and 2% were CRF11_cpx. The HIV-1 group M clades identified included A, D, F (F2), G, and H. The CRF strains identified were CRF02_AG-like, CRF01_AE-like, and CRF11_cpx. Two new intersubtype recombinant infections, H/G and A/F2, were identified. This study suggests that the HIV-1 diversity in rural villages in the equatorial rain forest of Cameroon is at least as broad as has been observed in major cities of Cameroon and that multiple HIV-1 group M subtypes are infecting persons living in the countryside of Cameroon.

HIV infection in rural villages of Cameroon.

OBJECTIVE: To evaluate HIV-1 antibody seroprevalence and risk factors for HIV seropositivity in rural areas of Cameroon. METHOD: The prevalences of HIV antibodies in 53 villages in rural Cameroon visited during May-October 2000 were determined with an HIV1/2 rapid assay, standard ELISA, and western blot. Demographic data and risk factors were elicited via face-to-face interviews with a structured questionnaire. RESULTS: HIV seroprevalence was 5.8% (243/4156, 95% confidence interval [CI] = 5.1-6.6) overall, 6.3% (151/2394, 95% CI = 5.4-7.4) among females and 5.2% (92/1762, 95% CI = 4.3-6.4) among males. HIV seroprevalence among persons aged 15 - 70 years did not differ significantly by province (5.6% in Center, 4.5% in East, 6.9% in South, and 5.8% in South-West) ( =.10). Analysis of age- and gender-standardized prevalence by village across provinces indicated a near-significant difference (nonparametric Wilcoxon signed rank test, =.06), with highest prevalence in South-West, followed by South, Center, and East. Multivariate analysis revealed that single women were significantly more likely to be HIV seropositive than were married or widowed women. Women with a history of sexual relations while traveling were at significantly increased risk of HIV seropositivity (OR adjusted for age and marital status = 2.4, 95% CI = 1.4-9.7). Among men, those who reported ever having a sexually transmitted disease were at significantly increased risk of HIV-seropositivity (OR adjusted for age = 1.8, 95% CI = 1.1-2.8). CONCLUSION: We have documented a wide range of HIV prevalences among rural villages of Cameroon. Age, marital status (in women) and sexual risk factors appear to be associated with HIV infection in this setting.