Initiating the first rheumatic heart disease clinic in Cameroon: A descriptive study

Background and Aim

Rheumatic heart disease (RHD) is a significant cause of heart failure in sub-Saharan Africa. The causes of death from RHD are multiple, many of which can be prevented with appropriate follow-up of patients and effective secondary prophylaxis. An RHD Clinic was initiated to attempt a solution in Yaoundé, Cameroon. Over 6 months, its impact was evaluated.

Methods

Two echocardiography registers were accessed, and patients diagnosed with RHD between 2005 and 2018 were contacted. Consenting carers and patients pioneered the first RHD Clinic. Activities of the clinic comprised health education, medical visits, and benzylpenicillin G (BPG) injections. Text messages and phone calls were used to remind patients of their monthly appointments.

Results

Out of 1200 first-time cardiac ethnographies, 70 patients (5.83%) had been diagnosed with RHD. The case fatality rate of RHD was 16.67%. Twenty-three patients were successfully registered and followed-up by the clinic, 70% of whom were female. The age range was 4-22 years. Fifty-three percent had an NYHA score of 2 or more at the time of admission into the clinic. There was an increase in adherence to secondary prophylaxis with BPG from 42.9% at baseline to 87%-95% in the last 3 months.

Conclusion

Our short experience running an RHD Clinic was marked by increased treatment adherence among persons living with RHC.

Evaluation of the Antimicrobial Resistance Surveillance System in Sentinel Sites in Cameroon

Background The purpose of antimicrobial resistance (AMR) surveillance is to guide clinical decision-making, characterize trends in resistance infections, and provide epidemiological data to study the impact of AMR on health and the effectiveness of control measures in health facilities and the community. To do this, regular and relevant assessments of standardized AMR surveillance systems are essential to prioritize threats and improve their performance and cost-effectiveness. The scarcity of data and the absence of a local and national strategy on the surveillance of antibiotic resistance in Sub-Saharan Africa and even more so in Cameroon do not allow an effective response to be carried out against the scourge. This gap led us to conduct a study on the evaluation of the attributes of the antibiotic resistance surveillance system in Cameroon. Methodology We conducted a descriptive, cross-sectional study over a period of one year from January to December 2021. The study was conducted in the sentinel sites of surveillance in Cameroon, namely, those of the Centre, South-West, Littoral, and North regions. Using structured questionnaires and a pre-established and pre-tested interview guide, we collected data that allowed us to assess a surveillance system's quantitative and qualitative attributes according to the CDC guidelines. Scores were assigned based on the different questionnaires to assess the attributes of the AMR surveillance system. Results Of the evaluated attributes, it appears that although the system is useful (88.9%, i.e., a score of 2), and has good completeness of data transmission (98.9%, i.e., a score of 3), it is not simple (64.3%, i.e., a score of 1), not stable (58.6%, i.e., a score of 1), not acceptable (58.6%, i.e., a score of 1), and presents poor data quality (11.05%, a score of 1). Conclusions The AMR surveillance system in Cameroon is useful with good completeness. However, many other attributes have poor performance, indicating the importance of improving the antimicrobial surveillance system.

Viral suppression in the era of transition to dolutegravir-based therapy in Cameroon: Children at high risk of virological failure due to the lowly transition in pediatrics

This study aimed to compare viral suppression (VS) between children, adolescents, and adults in the frame of transition to dolutegravir (DTG)-based antiretroviral therapy (ART) in the Cameroonian context. A comparative cross-sectional study was conducted from January 2021 through May 2022 amongst ART-experienced patients received at the Chantal BIYA International Reference Centre in Yaounde-Cameroon, for viral load (VL) monitoring. VS was defined as VL < 1000 copies/mL and viral undetectability as VL < 50 copies/mL. Chi-square and multivariate binary logistic regression models were used to identify factors associated with VS. Data were analyzed using SPSS v.20.0 (SPSS Inc., Chicago, Illinois), with P < .05 considered significant. A total of 9034 patients (72.2% females) were enrolled. In all, there were 8585 (95.0%) adults, 227 (2.5%) adolescents, and 222 (2.5%) children; 1627 (18.0%) were on non-nucleoside reverse transcriptase-based, 290 (3.2%) on PI-based, and 7117 (78.8%) on DTG-based ART. Of those on DTG-based ART, only 82 (1.2%) were children, 138 (1.9%) adolescents, and 6897 (96.9%) adults. Median (interquartile range) duration on ART was 24 (12-72) months (24 months on Tenofovir + Lamivudine + Dolutegravir [TLD], 36 months on other first lines, and 84 months on protease inhibitors boosted with ritonavir-based regimens). Overall, VS was 89.8% (95% confidence interval: 89.2-90.5) and viral undetectability was 75.7% (95% confidence interval: 74.8-76.7). Based on ART regimen, VS on Non-nucleoside reverse transcriptase-based, protease inhibitors boosted with ritonavir-based, and DTG-based therapy was respectively 86.4%, 59.7%, and 91.8%, P < .0001. Based on ART duration, VS was respectively 51.7% (≤24 months) versus 48.3% (≥25 months), P < .0001. By gender, VS was 90.9% (5929) in females versus 87.0% (2183) in males, P < .0001; by age-range, VS moved from 64.8% (144) in children, 74.4% (169) adolescents, to 90.8% (7799) adults, P < .0001. Following multivariate analysis, VS was associated with adulthood, female gender, TLD regimens, and combination antiretroviral therapy duration > 24 months (P < .05). In Cameroon, ART response indicates encouraging rates of VS (about 9/10) and viral undetectability (about 3/4), driven essentially by access to TLD based regimens. However, ART response was very poor in children, underscoring the need for scaling-up pediatric DTG-based regimens.

Molecular detection of Sodalis glossinidius, Spiroplasma and Wolbachia endosymbionts in wild population of tsetse flies collected in Cameroon, Chad and Nigeria

Background Tsetse flies are cyclical vectors of African trypanosomiasis. They have established symbiotic associations with different bacteria, which influence certain aspects of their physiology. The vector competence of tsetse flies for different trypanosome species is highly variable and is suggested to be affected by various factors, amongst which are bacterial endosymbionts. Symbiotic interactions may provide an avenue for the disease control. The current study provided the prevalence of 3 tsetse symbionts in Glossina species from Cameroon, Chad and Nigeria. Results Tsetse flies were collected from five different locations and dissected. DNA was extracted and polymerase chain reaction PCR was used to detect the presence of Sodalis glossinidius , Spiroplasma sp and Wolbachia using specific primers. A total of 848 tsetse samples were analysed: Glossina morsitans submorsitans (47.52%), Glossina palpalis palpalis (37.26%), Glossina fuscipes fuscipes (9.08%) and Glossina tachinoides (6.13%). Only 95 (11.20%) were infected with at least one of the 3 symbionts. Among the infected, 6 (6.31%) were carrying mixed infection ( Wolbachia and Spiroplasma ). The overall symbiont prevalence was 0.88%, 3.66% and 11.00% respectively, for Sodalis , Spiroplasma and Wolbachia . Prevalence varied between countries and tsetse species. No Spiroplasma was detected in samples from Cameroon and no Sodalis was found in samples from Nigeria. Conclusion The present study revealed for the first time, the presence of infection by Spiroplasma in tsetse in Chad and Nigeria. These findings provide useful information to the repertoire of bacterial flora of tsetse flies and incite to more investigations to understand their implication in the vector competence of tsetse flies.

HIV Pre-exposure Prophylaxis Uptake and Continuation Among Key Populations in Cameroon: Lessons Learned From the CHAMP Program

INTRODUCTION

Pre-exposure prophylaxis (PrEP) is proven to be a highly effective HIV prevention method for key populations. However, its scale-up in resource-limited settings remains suboptimal. This paper seeks to describe PrEP initiation and continuation among key populations in Cameroon.

METHODOLOGY

From June 2019 through October 2020, we collected routine program data on PrEP uptake and continuation among female sex workers (FSWs) and men who have sex with men (MSM) in the Continuum of prevention, care and treatment of HIV/AIDS with Most-at-risk Populations (CHAMP) program in Cameroon. PrEP was offered to clients who tested negative for HIV and were assessed to potentially benefit from PrEP. Using survival analysis, we identified factors associated with PrEP discontinuation over time with significance set at 5%.

RESULTS

Overall, 27,750 clients were sensitized for PrEP of whom 3,138 persons were eligible to start PrEP and 1,409 (45%; FSW: 691 and MSM: 718) initiated PrEP. The PrEP continuation rate was 37% at 3 months, 28% at 6 months and 19% at 12 months. PrEP discontinuation was significantly higher among FSW than MSM [adjusted hazard ratio (aHR) 1.5 (95% CI: 1.2 to 1.9)] in Yaounde [aHR 1.5 (95% CI: 1.2 to 1.9)] and Bafoussam/Bertoua [aHR 3.1 (2.2-4.5)] relative to Douala. Discontinuation was lower among those with moderate [aHR 0.3 (0.3-0.4)] or good adherence [aHR 0.4 (0.3-0.6)] compared with poor adherence (all P < 0.001).

CONCLUSION

Differentiated approaches to deliver PrEP, create demand, and provide more intensive support for adherence and continuation may support scale-up of PrEP in Cameroon for equitable and prolonged impact on HIV prevention.

Spatial meta-analysis of the occurrence and distribution of tsetse-transmitted animal trypanosomiasis in Cameroon over the last 30 years

In Cameroon, >90% of cattle are considered exposed to African animal trypanosomiasis (AAT) infection, with the presence of tsetse rendering cattle husbandry as a very difficult proposition. A systematic review of data on AAT and tsetse from 1990 to 2021 was conducted to develop a national atlas. The review identified 74 relevant scientific documents, with three pathogenic Trypanosoma species (Trypanosoma vivax , T. congolense and T. brucei s.l.) most frequently identified as causing AAT. Trypanosoma grayi , T. theileri , T. simiae and the human African trypanosomiasis causative agent T. brucei gambiense were also identified in a wide range of hosts. The tsetse fly fauna of Cameroon comprises nine species, with Glossina palpalis palpalis and G. fuscipes fuscipes the most widely distributed following their identification in seven and five of the 10 regions, respectively. Two species, Glossina nigrofusca and G. pallicera pallicera appeared to be rare and were restricted to both forest and protected areas. The presence of AAT is associated with the presence of tsetse in the livestock–human–wildlife interface of Cameroon. AAT occurs beyond the tsetse belts of the country where mechanical vectors are abundant. This study provides AAT and tsetse maps to support ongoing interventions in Cameroon.

Pseudo-pheochromocytoma due to obstructive sleep apnea: a case report

SUMMARY

Obstructive sleep apnea (OSA) is a condition of intermittent nocturnal upper airway obstruction. OSA increases sympathetic drive which may result in clinical and biochemical features suggestive of pheochromocytoma. We present the case of a 65-year-old male with a 2.9-cm left adrenal incidentaloma on CT, hypertension, symptoms of headache, anxiety and diaphoresis, and persistently elevated 24-h urine norepinephrine (initially 818 nmol/day (89-470)) and normetanephrine (initially 11.2 µmol/day (0.6-2.7)). He was started on prazosin and underwent left adrenalectomy. Pathology revealed an adrenal corticoadenoma with no evidence of pheochromocytoma. Over the next 2 years, urine norepinephrine and normetanephrine remained significantly elevated with no MIBG avid disease. Years later, he was diagnosed with severe OSA and treated with continuous positive airway pressure. Urine testing done once OSA was well controlled revealed complete normalization of urine norepinephrine and normetanephrine with substantial symptom improvement. It was concluded that the patient never had a pheochromocytoma but rather an adrenal adenoma with biochemistry and symptoms suggestive of pheochromocytoma due to untreated severe OSA. Pseudo-pheochromocytoma is a rare presentation of OSA and should be considered on the differential of elevated urine catecholamines and metanephrines in the right clinical setting.

LEARNING POINTS

Obstructive sleep apnea (OSA) is a common condition among adults. OSA may rarely present as pseudo-pheochromocytoma with symptoms of pallor, palpitations, perspiration, headache, or anxiety. OSA should be considered on the differential of elevated urine catecholamines and metanephrines, especially in patients with negative metaiodobenzylguanidine (MIBG) scan results.

Diagnostic performance of a colorimetric RT -LAMP for the identification of SARS-CoV-2: A multicenter prospective clinical evaluation in sub-Saharan Africa

BACKGROUND

Management and control of the COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus SARS-CoV-2 is critically dependent on quick and reliable identification of the virus in clinical specimens. Detection of viral RNA by a colorimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) is a simple, reliable and cost-effective assay, deployable in resource-limited settings (RLS). Our objective was to evaluate the intrinsic and extrinsic performances of RT-LAMP in RLS.

METHODS

This is a multicenter prospective observational study of diagnostic accuracy, conducted from October 2020 to February 2021 in four African Countries: Cameroon, Ethiopia, Kenya and Nigeria; and in Italy. We enroled 1657 individuals who were either COVID-19 suspect cases, or asymptomatic and presented for screening. RNA extracted from pharyngeal swabs was tested in parallel by a colorimetric RT-LAMP and by a standard real time polymerase chain reaction (RT-PCR).

FINDINGS

The sensitivity and specificity of index RT LAMP compared to standard RT-PCR on 1657 prospective specimens from infected individuals was determined. For a subset of 1292 specimens, which underwent exactly the same procedures in different countries, we obtained very high specificity (98%) and positive predictive value (PPV = 99%), while the sensitivity was 87%, with a negative predictive value NPV = 70%, Stratification of RT-PCR data showed superior sensitivity achieved with an RT-PCR cycle threshold (Ct) below 35 (97%), which decreased to 60% above 35.

INTERPRETATION

In this field trial, RT-LAMP appears to be a reliable assay, comparable to RT-PCR, particularly with medium-high viral loads (Ct < 35). Hence, RT-LAMP can be deployed in RLS for timely management and prevention of COVID-19, without compromising the quality of output.

Assessing the Potential Impact of Disruptions Due to COVID-19 on HIV Among Key and Lower-Risk Populations in the Largest Cities of Cameroon and Benin

BACKGROUND

The COVID-19 pandemic indirectly impacts HIV epidemiology in Central/West Africa. We estimated the potential impact of COVID-19-related disruptions to HIV prevention/treatment services and sexual partnerships on HIV incidence and HIV-related deaths among key populations including female sex workers (FSW), their clients, men who have sex with men, and overall.

SETTING

Yaoundé (Cameroon) and Cotonou (Benin).

METHODS

We used mathematical models of HIV calibrated to city population-specific and risk population-specific demographic/behavioral/epidemic data. We estimated the relative change in 1-year HIV incidence and HIV-related deaths for various disruption scenarios of HIV prevention/treatment services and decreased casual/commercial partnerships, compared with a scenario without COVID-19.

RESULTS

A 50% reduction in condom use in all partnerships over 6 months would increase 1-year HIV incidence by 39%, 42%, 31%, and 23% among men who have sex with men, FSW, clients, and overall in Yaoundé, respectively, and 69%, 49%, and 23% among FSW, clients, and overall, respectively, in Cotonou. Combining a 6-month interruption of ART initiation and 50% reduction in HIV prevention/treatment use would increase HIV incidence by 50% and HIV-related deaths by 20%. This increase in HIV infections would be halved by a simultaneous 50% reduction in casual and commercial partnerships.

CONCLUSIONS

Reductions in condom use after COVID-19 would increase infections among key populations disproportionately, particularly FSW in Cotonou, who need uninterrupted condom provision. Disruptions in HIV prevention/treatment services have the biggest impacts on HIV infections and deaths overall, only partially mitigated by equal reductions in casual/commercial sexual partnerships. Maintaining ART provision must be prioritized to minimize short-term excess HIV-related deaths.

Investigations of Kidney Dysfunction-Related Gene Variants in Sickle Cell Disease Patients in Cameroon (Sub-Saharan Africa)

Background

Renal dysfunctions are associated with increased morbidity and mortality in sickle cell disease (SCD). Early detection and subsequent management of SCD patients at risk for renal failure and dysfunctions are essential, however, predictors that can identify patients at risk of developing renal dysfunction are not fully understood.

Methods

In this study, we have investigated the association of 31 known kidney dysfunctions-related variants detected in African Americans from multi-ethnic genome wide studies (GWAS) meta-analysis, to kidney-dysfunctions in a group of 413 Cameroonian patients with SCD. Systems level bioinformatics analyses were performed, employing protein-protein interaction networks to further interrogate the putative associations.

Results

Up to 61% of these patients had micro-albuminuria, 2.4% proteinuria, 71% glomerular hyperfiltration, and 5.9% had renal failure. Six variants are significantly associated with the two quantifiable phenotypes of kidney dysfunction (eGFR and crude-albuminuria): A1CF-rs10994860 (P = 0.02020), SYPL2-rs12136063 (P = 0.04208), and APOL1 (G1)-rs73885319 (P = 0.04610) are associated with eGFR; and WNT7A-rs6795744 (P = 0.03730), TMEM60-rs6465825 (P = 0.02340), and APOL1 (G2)-rs71785313 (P = 0.03803) observed to be protective against micro-albuminuria. We identified a protein-protein interaction sub-network containing three of these gene variants: APOL1, SYPL2, and WNT7A, connected to the Nuclear factor NF-kappa-B p105 subunit (NFKB1), revealed to be essential and might indirectly influence extreme phenotypes. Interestingly, clinical variables, including body mass index (BMI), systolic blood pressure, vaso-occlusive crisis (VOC), and haemoglobin (Hb), explain better the kidney phenotypic variations in this SCD population.

Conclusion

This study highlights a strong contribution of haematological indices (Hb level), anthropometric variables (BMI, blood pressure), and clinical events (i.e., vaso-occlusive crisis) to kidney dysfunctions in SCD, rather than known genetic factors. Only 6/31 characterised gene-variants are associated with kidney dysfunction phenotypes in SCD samples from Cameroon. The data reveal and emphasise the urgent need to extend GWAS studies in populations of African ancestries living in Africa, and particularly for kidney dysfunctions in SCD.

Strengthening timely detection and reporting of unusual respiratory events from health facilities in Yaoundé, Cameroon

BACKGROUND

The International Health Regulations state that early detection and immediate reporting of unusual health events is important for early warning and response systems.

OBJECTIVE

To describe a pilot surveillance program established in health facilities in Yaoundé, Cameroon in 2017 which aimed to enable detection and reporting of public health events.

METHODS

Cameroon's Ministry of Health, in partnership with the US Centers for Disease Control and Prevention, Cameroon Pasteur Center, and National Public Health Laboratory, implemented event-based surveillance (EBS) in nine Yaoundé health facilities. Four signals were defined that could indicate possible public health events, and a reporting, triage, and verification system was established among partner organizations. A pre-defined laboratory algorithm was defined, and a series of workshops trained health facilities, laboratory, and public health staff for surveillance implementation.

RESULTS

From May 2017 to January 2018, 30 signals were detected, corresponding to 15 unusual respiratory events. All health facilities reported a signal at least once, and more than three-quarters of health facilities reported ≥2 times. Among specimens tested, the pathogens detected included Klebsiella pneumoniae, Moraxella catarrhalis, Streptococcus pneumoniae, Haemophilus influenza, Staphylococcus aureus, Pneumocystis jiroveci, influenza A (H1N1) virus, rhinovirus, and adenovirus.

CONCLUSIONS

The events detected in this pilot were caused by routine respiratory bacteria and viruses, and no novel influenza viruses or other emerging respiratory threats were identified. The surveillance system, however, strengthened relationships and communication linkages between health facilities and public health authorities. Astute clinicians can play a critical role in early detection and EBS is one approach that may enable reporting of emerging outbreaks and public health events.

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.

Burnout as a correlate of depression among medical students in Cameroon: a cross-sectional study

OBJECTIVE

Burnout syndrome has been shown to mediate the pathway between job stress and depression. This study aims to assess the relationship between the various components of burnout syndrome and depression; and to determine the contribution of other sociodemographic variables to depression among medical students in Cameroon.

DESIGN

A cross-sectional study.

SETTING

Three of the five medical schools in Cameroon with students in both preclinical and clinical levels of studies.

PARTICIPANTS

The study included 413 consenting medical students.

PRIMARY OUTCOME MEASURE

Data were collected via a printed self-administered questionnaire. The primary outcome-depression was assessed using the Patient Health Questionnaire-9 (PHQ-9). Burnout was assessed using the Oldenburg Burnout Inventory. Multivariable linear regression was used to identify independent correlates of depression.

RESULTS

The overall prevalence of depression (PHQ-9 >4) and major depressive disorder (PHQ-9 >9) in these students was 66.34% and 23.00%, respectively. After multivariable linear regression analysis, four variables-total OLBI (beta=0.32; 95% CI 0.22 to 0.42; p<0.001); number of children (beta=-2.26; 95% CI -3.70 to -0.81; p=0.002); occurrence of a life-changing crises (beta=1.29; 95% CI 0.13 to 2.45; p=0.029) and presence of a chronic illness (beta=3.19; 95% CI 0.96 to 5.42; p=0.005) significantly predicted depression in these students and explained 32.4% of the variance (R²=32.4, F[14, 204]=6.98, p<0.001). The emotional exhaustion component (R²=17.4, F[1, 411]=86.39, p<0.001) explained more of the variance in depression than the disengagement component (R²=6.1, F[1, 411]=26.76, p<0.001) of burnout syndrome.

CONCLUSION

The prevalence of depression among medical students in Cameroon is high. It is important that correlates of depression are identified early in medical students to limit progress to depression.

Genetic characterization of influenza B virus in Cameroon and high frequency of reassortant strains

Influenza B is broadly divided into B/Victoria and B/Yamagata lineages based on its genetic and antigenic properties. We describe in this study the first report on genome characterization of type B influenza virus in the Cameroon National Influenza Center (NIC) between 2014 and 2017. Respiratory samples were collected as part of the influenza surveillance activity in the NIC. RNA products were tested for the presence of influenza using the CDC Influenza A/B typing panel. Thirty-five samples positive for influenza B were selected for sequencing three gene segments (HA, NA, and M) and phylogenetic trees were generated by MEGA version 6.0. Nucleotide phylogenetic analysis of the HA gene revealed the presence of three major clades among Cameroonian strains. All Victoria lineages grouped into B/Victoria clade 1A, while, Yamagata lineages grouped into Yamagata clade 2 (2014 strains) and Yamagata clade 3 (2015-2017). We observed a high frequency of reassortant viruses with Yamagata-like HA gene and Victoria-like NA gene (27.4%; 23/84). The results from this study confirm variations in the genome composition of type B influenza virus and emphasize on the relevance of molecular surveillance for spotting peculiar genetic variants of public health and clinical significance.

Predicted distribution and burden of podoconiosis in Cameroon

INTRODUCTION

Understanding the number of cases of podoconiosis, its geographical distribution and the population at risk are crucial to estimating the burden of this disease in endemic countries. We assessed each of these using nationwide data on podoconiosis prevalence in Cameroon.

METHODS

We analysed data arising from two cross-sectional surveys in Cameroon. The dataset was combined with a suite of environmental and climate data and analysed within a robust statistical framework, which included machine learning-based approaches and geostatistical modelling. The environmental limits, spatial variation of predicted prevalence, population at risk and number of cases of podoconiosis were each estimated.

RESULTS

A total of 214 729 records of individuals screened for podoconiosis were gathered from 748 communities in all 10 regions of Cameroon. Of these screened individuals, 882 (0.41%; 95% CI 0.38 to 0.44) were living with podoconiosis. High environmental suitability for podoconiosis was predicted in three regions of Cameroon (Adamawa, North West and North). The national population living in areas environmentally suitable for podoconiosis was estimated at 5.2 (95% CI 4.7 to 5.8) million, which corresponds to 22.3% of Cameroon's population in 2015. Countrywide, in 2015, the number of adults estimated to be suffering from podoconiosis was 41 556 (95% CI, 1170 to 240 993). Four regions (Central, Littoral, North and North West) contributed 61.2% of the cases.

CONCLUSION

In Cameroon, podoconiosis is more widely distributed geographically than was initially expected. The number of cases and the population at risk are considerable. Expanding morbidity management and follow-up of cases is of utmost necessity. Promotion of footwear use and regular foot hygiene should be at the forefront of any intervention plan.

Validation of Pediatric Weight Estimation Formulae in a Suburban Cameroonian Population: A Cross-sectional Study

We assessed the accuracy of the Nelson, Best Guess and Advanced Pediatric Life Support (APLS) formulae in estimating weight in a suburban Cameroonian pediatric population, by conducting a cross-sectional study using 544 children aged 1 month to 12 years. Agreement between measured and estimated weight was poor for Nelson [concordance correlation coefficient (CCC) 0.89 (95% confidence interval (CI) 0.87-0.90)] and Best Guess [CCC 0.88 (95% CI 0.86-0.90)] formulae, and moderate for the APLS formula [CCC 0.92 (95% CI 0.90-0.93)]. On Bland-Altman analysis, all three methods had limits of agreement (APLS -42.2 to -45.6%, Best Guess -42.7 to -55.1%, Nelson -36.4 to -42.4%) above the -10 to -10% set as criteria for clinical agreement. Conclusively, the accuracy of all three formulae was clinically unacceptable in our study population, suggesting the need for studies aimed at deriving more accurate formulae adapted for use in our context.

Floristic surveys of hydrocarbon-polluted sites in some Cameroonian cities (Central Africa)

Soils pollution with hydrocarbons is on the increase, especially in developing countries like Cameroon. Identifying plant species capable of growing on hydrocarbon-polluted soils remains an essential step in phytoremediation, a low cost, solar energy driven clean up technique in which living green plants are used. Here, we report floristic surveys conducted in 4 cities of Cameroon to identify plants with phytoremediation capacities. A total of 13 hydrocarbon-polluted sites were surveyed in each city using the quadrat method. Unpolluted sites served as the control. 106 species belonging to 76 genera and 30 families were identified on hydrocarbon-polluted sites. Plant diversity was shown to be higher (166 species contained in 125 genera and 50 families) in the control sites. Poaceae, Cyperaceae, Asteraceae and Amaranthaceae families have a higher taxonomic richness on polluted sites (16, 15, 10 and 8 taxa respectively). Shannon diversity index of the hydrocarbon-polluted sites (1.6 to 2.7 bits/ind.) were significantly lower than the control sites (2.7 to 3.2 bit/ind.). Based on a relative frequency > 10% and abundance > 7%, our results show that more than 15 plant species could be tested in preliminary trials to determine their phytoremediation/cleaning-up capacities on hydrocarbon-polluted soils in the tropics.

Seroprevalence of hepatitis C virus infection in Cameroon: a systematic review and meta-analysis

OBJECTIVE

Better knowledge of hepatitis C virus (HCV) seroprevalence at the national level can help to implement pertinent strategies to address the HCV-related burden. The aim of this paper was to estimate the seroprevalence of HCV infection in Cameroon.

DESIGN

Systematic review and meta-analysis.

PARTICIPANTS

People residing in Cameroon.

DATA SOURCES

Electronic databases including PubMed/MEDLINE, AJOL, WHO-Afro Library, Africa Index Medicus, National Institute of Statistics and National AIDS Control Committee, Cameroon from 1 January 2000 to 15 December 2016 were searched. English and French languages papers were considered. Two independent investigators selected studies. The methodological quality of the studies was assessed using the Newcastle-Ottawa scale.

RESULTS

31 studies including 36 407 individuals were finally considered. There was no national representative study. The overall pooled prevalence was 6.5% (95% CI 4.5% to 8.8%; I²=98.3%). A sensitivity analysis of individuals at low risk of HCV infection showed a pooled prevalence of 3.6% (95% CI 2.3% to 5.2%, I²=97.7%, 18 studies) among 22 860 individuals (general population, blood donors and pregnant women), which was higher than for a high-risk population (healthcare workers and people with other identified comorbidities), 12.2% (95% CI 4.9% to 22.2%; I²=98.3%, 13 studies); p=0.018. The prevalence was higher in the East region, in rural settings, and when using an enzyme immunoassay technique for detecting HCV antibodies. Sex, sites, study period, sample size, timing of data collection and methodological quality of studies were not sources of heterogeneity.

LIMITATION

One-third of studies (29.0%) had a low risk bias in their methodology and most were facility-based (87.1%).

CONCLUSION

The seroprevalence of HCV infection in Cameroon indicates the need for comprehensive and effective strategies to interrupt HCV transmission in the Cameroonian population. Specific attention is needed for the East region of the country, rural settings and high-risk populations. A national representative study is needed to provide better estimates.

Simulating the elimination of sleeping sickness with an agent-based model

Although Human African Trypanosomiasis is largely considered to be in the process of extinction today, the persistence of human and animal reservoirs, as well as the vector, necessitates a laborious elimination process. In this context, modeling could be an effective tool to evaluate the ability of different public health interventions to control the disease. Using the Cormas® system, we developed HATSim, an agent-based model capable of simulating the possible endemic evolutions of sleeping sickness and the ability of National Control Programs to eliminate the disease. This model takes into account the analysis of epidemiological, entomological, and ecological data from field studies conducted during the last decade, making it possible to predict the evolution of the disease within this area over a 5-year span. In this article, we first present HATSim according to the Overview, Design concepts, and Details (ODD) protocol that is classically used to describe agent-based models, then, in a second part, we present predictive results concerning the evolution of Human African Trypanosomiasis in the village of Lambi (Cameroon), in order to illustrate the interest of such a tool. Our results are consistent with what was observed in the field by the Cameroonian National Control Program (CNCP). Our simulations also revealed that regular screening can be sufficient, although vector control applied to all areas with human activities could be significantly more efficient. Our results indicate that the current model can already help decision-makers in planning the elimination of the disease in foci.

A phylogeny of Cichlidogyrus spp. (Monogenea, Dactylogyridea) clarifies a host-switch between fish families and reveals an adaptive component to attachment organ morphology of this parasite genus

BACKGROUND

Parasite switches to new host species are of fundamental scientific interest and may be considered an important speciation mechanism. For numerous monogenean fish parasites, infecting different hosts is associated with morphological adaptations, in particular of the attachment organ (haptor). However, haptoral morphology in Cichlidogyrus spp. (Monogenea, Dactylogyridea), parasites of African cichlids, has been mainly linked to phylogenetic rather than to host constraints. Here we determined the position of Cichlidogyrus amieti, a parasite of species of Aphyosemion (Cyprinodontiformes, Nothobranchiidae) in the phylogeny of its congeners in order to infer its origin and assess the morphological changes associated with host-switching events.

METHODS

The DNA of specimens of C. amieti isolated from Aphyosemion cameronense in Cameroon was sequenced and analyzed together with that of Cichlidogyrus spp. from cichlid hosts. In order to highlight the influence of the lateral transfer of C. amieti on the haptoral sclerotised parts we performed a Principal Component Analysis (PCA) to compare the attachment organ structure of C. amieti to that of congeners infecting cichlids.

RESULTS

Cichlidogyrus amieti was found to be nested within a strongly supported clade of species described from Hemichromis spp. (i.e. C. longicirrus and C. dracolemma). This clade is located at a derived position of the tree, suggesting that C. amieti transferred from cichlids to Cyprinodontiformes and not inversely. The morphological similarity between features of their copulatory organs suggested that C. amieti shares a recent ancestor with C. dracolemma. It also indicates that in this case, these organs do not seem subjected to strong divergent selection pressure. On the other hand, there are substantial differences in haptoral morphology between C. amieti and all of its closely related congeners described from Hemichromis spp..

CONCLUSIONS

Our study provides new evidence supporting the hypothesis of the adaptive nature of haptor morphology. It demonstrates this adaptive component for the first time within Cichlidogyrus, the attachment organs of which were usually considered to be mainly phylogenetically constrained.

Assessing the detection, reporting and investigation of adverse events in clinical trial protocols implemented in Cameroon: a documentary review of clinical trial protocols

BACKGROUND

International guidelines recommend ethical and scientific quality standards for managing and reporting adverse events occurring during clinical trials to competent research ethics committees and regulatory authorities. The purpose of this study was to determine whether clinical trial protocols in Cameroon are developed in line with national requirements and international guidelines as far as detecting, reporting and investigating of adverse events is concerned.

METHODS

It was a documentary review of all approved clinical trial protocols that were submitted at the Cameroon National Ethics Committee for evaluation from 1997 through 2012. Data were extracted using a preconceived and validated grid. Protocol review process targeted the title, abstract, objectives, methodology, resources, and the chapter on safety.

RESULTS

In total, 106 (4.9 %) clinical trial protocols were identified from 2173 protocols seen in the archive and 104 (4.8 %) included for review. Seventy six (73.1 %) trials did not include the surveillance of adverse events as part of their objective. A total of 91 (87.5 %) protocols did not budget for adverse event surveillance, 76 (73.1 %) did not have a data safety management board (DSMB), 11(10.6 %) included insurance for participants, 47 (45.2 %) did not include a case definition for serious adverse events, 33 (31.7 %) described procedures to detect adverse events, 33 (31.7 %) described procedure for reporting and 22 (21.2 %) described procedure for investigating adverse events.

DISCUSSIONS

Most clinical trial protocols in Cameroon are developed to focus on benefits and pay little attention to harms. The development of national guidelines can improve the surveillance of adverse events in clinical trial research conducted in Cameroon. Adverse events surveillance tools and a budget are critical for an adequate planning for adverse event surveillance when developing trial protocols.

CONCLUSION

Clinical trial protocols submitted in the Cameroon National Ethics Committee do not adequately plan to assess adverse events in clinical trial protocols. In order to improve on the safety of participants and marketed drug, there is a need to develop national guidelines for clinical trials by the government, and to improve evaluation procedures and monitoring of ongoing trials by the ethics committee.

Not every worm wrapped around a stick is a guinea worm: a case of Onchocerca volvulus mimicking Dracunculus medinensis

BACKGROUND

Despite being certified guinea worm free in 2007, Cameroon continues surveillance efforts to ensure rapid verification of any suspected reoccurrence. This includes the investigation of every rumor and confirmation of each suspicious expulsed worm. This paper presents fieldwork carried out to investigate a guinea worm rumor in Cameroon which turned out to be an Onchocerca volvulus mimicking Dracunculus medinensis.

METHODS

The investigation included a field visit to the subsistence farming community where the rumor was reported. During the visit, interviews were conducted with health staff who managed the case and the elderly farmer from whom the worm was retrieved. An investigation of any potential missed guinea worm cases was also conducted through interviews with community residents and reviews of the health facility's medical records. This was combined with laboratory analyses of water samples from the community's water sources and the retrieved worm which was removed from the patient via wrapping it around a stick.

RESULTS

Microscopy and molecular analyses of the retrieved worm revealed a female Onchocerca volvulus whose expulsion strongly mimicked guinea worm. In addition to presenting findings of our investigation, this paper discusses distinguishing elements between the two parasites and gives an overview of guinea worm eradication efforts in Cameroon as well as current challenges to the worm's eradication globally.

CONCLUSIONS

The investigation findings suggest the evolving Onchocerca volvulus worm tropisms' adaptive survival behavior worth further investigation. Strategies used to successfully control guinea worm in Cameroon could be adapted for Onchocerca volvulus control.

Cameroon public health sector: shortage and inequalities in geographic distribution of health personnel

INTRODUCTION

Cameroon is classified by the World Health Organization (WHO) as having a critical shortage of health personnel. This is further complicated by the geographic distributional inequalities of the national health workforce. This shortfall impedes Cameroons' progress of improving the human resources for health (HRH) to meet up with the Millennium Development Goals (MDGs) by 2015. However, it is unknown whether the health workforce of Cameroon is distributed equally across geographic regions. Additionally, indicators other than population levels have not been used to measure health care needs. This study aimed to assess the adequacy, evenness of distribution and challenges faced by the health workforce across the different regions of Cameroon.

METHODS

National health personnel availability and distribution were assessed by use of end-of-year census data for 2011 obtained from the MoPH data base. The inequalities and distribution of the workforce were estimated using Gini coefficient and Lorenz curve and linear regression was used to determine the relation between health personnel density and selected health outcomes. Alternative indicators to determine health care needs were illustrated using concentration curves.

RESULTS

Significant geographic inequalities in the availability of health workforce exist in Cameroon. Some regions have a higher number of physicians (per person) than others leading to poor health outcomes across the regions. 70 % of regions have a density of health personnel-to-population per 1,000 that is less than 1.5, implying acute shortage of health personnel. Poor working and living conditions, coupled with limited opportunities for career progress accounted for some documented 232 physicians and 205 nurses that migrated from the public sector. Significant distributional inequality was noticed when under-five infant mortality and malaria prevalence rate were used as indicators to measure health care needs.

CONCLUSION

Our results show an absolute shortage of public health personnel in Cameroon that is further complicated by the geographic distributional inequalities across the regions of the nation. Cameroon aims to achieve universal health coverage by 2035; to realize this objective, policies targeting training, recruitment, retention and effective deployment of motivated and supported health workforce as well as the development and improvement of health infrastructures remain the major challenge.

The pattern of neurological diseases in elderly people in outpatient consultations in Sub-Saharan Africa

BACKGROUND

Neurological diseases are frequent in older adults, affecting between 5% and 55% of people age 55 and older. They are associated with a high risk for adverse health outcomes, including mortality, disability, institutionalization and hospitalization. Little is known about the epidemiology and clinical pattern of neurological disorders of the elderly in developing countries. Although many studies have demonstrated the areas where the burden of neurological diseases lies, elderly patients in Sub-Saharan Africa have received little attention. We performed this descriptive study to understand the burden of disease faced by Cameroonian neurologists and geriatricians.

METHODS

The records of all out-patient neurological consultations from May 2005 to December 2011 were collected at the Clinique Bastos, the sole clinic with adult neurological consultations during the study period in Yaoundé, the political capital of Cameroon. All medical records were reviewed by a neurologist and neurological diagnoses were classified according to ICD-10.

RESULTS

Among a total of 912 patients, 187 (20.5%) were aged 60 and older. According to the ICD-10 classification, episodic and paroxysmal disorders were present in 18.7% of patients, extrapyramidal and movement disorders in 14.6%, and nerve, nerve root and plexus disorders in 13.3%. The most common neurological diseases of the elderly in this study were lumbar arthrosis (14%), dementia (Alzheimer's type, vascular) (12.4%), Parkinson's disease (10.2%), and polyneuropathy (9.1%).

CONCLUSION

Degenerative diseases like dementia and Parkinson's disease as well as strokes and headaches are frequently encountered neurological diseases in elderly patients in Sub-Saharan Africa. It is important that standard treatment regimes, often Ministry of Public Health based, are adhered to these diseases.

Primary care physicians' practice regarding diabetes mellitus diagnosis, evaluation and management in the West region of Cameroon

BACKGROUND

Primary care physicians (PCPs) are the main providers of diabetes care especially in resource-limited countries which experience extreme shortage of specialists. The present study aimed to evaluate PCPs' approach towards diabetes mellitus (DM) diagnosis, evaluation and management in Cameroon.

METHODS

We carried-out a cross-sectional survey in February 2012 in the West Region of Cameroon. Using a structured pretested questionnaire, we interviewed all PCPs working in the region who were present at their working place when the investigators visited, and volunteered to be enrolled in the study.

RESULTS

Sixty-six PCPs were interviewed. Their ages ranged from 24 to 56 years (mean 38.3, standard deviation 9.2 years). The levels of knowledge of PCPs regarding DM diagnosis were: 72.7%, 37.9%, 19.7% and 32.8% respectively obtained when using fasting plasma glucose, post-prandial glycemia, random glycemia and glycated hemoglobin as diagnostic tools. Only 6 PCPs (9.9%) prescribed the correct minimal work-up to evaluate diabetes patients at diagnosis. PCPs advised lifestyle modifications in 92.4% of cases, and thirty nine (53.1%) PCP's used to prescribe both generic and specialty oral anti-diabetic drugs in case of uncomplicated type 2 DM management. The two main classes of anti-diabetic drugs prescribed were biguanides (77.3%) and sulfonamides (60.6%). Nearly all PCPs (97%) used to give frequent follow-up appointments to their patients. Ninety eight point five percent of participants were willing to receive any further continuous training on DM management.

CONCLUSION

PCPs knowledge and practices towards diabetes mellitus diagnosis, evaluation and management were not optimal, stressing the need to improve their capacities regarding diabetes care. As such, more educational initiatives should be taken on, alongside regular upgrade and dissemination of clinical guidelines.

Delay in sputum smear conversion and outcomes of smear-positive tuberculosis patients: a retrospective cohort study in Bafoussam, Cameroon

BACKGROUND

In limited resource settings, sputum smear conversion at the end of the intensive phase of tuberculosis treatment is an indicator not only of patients' response to treatment, but also of anti-tuberculosis program performance. The objective of this study was to identify factors associated to sputum smear non-conversion at the end of the intensive phase of treatment, and the effect of smear non-conversion on the outcome of smear-positive pulmonary tuberculosis patients.

METHOD

This retrospective cohort study was carried out on data of patients treated in the Diagnostic and Treatment Centre of Baleng, West-Cameroon from 2006 to 2012. Logistic regression models were used to evaluate the association of socio-demographic and clinical factors with delay in sputum smear conversion, and the association of this delay with treatment outcomes.

RESULT

Out of 1425 smear-positive pulmonary tuberculosis patients treated during the study period, 1286 (90.2%) were included in the analysis. Ninety four (7.3% CI: 6.0- 8.9) patients were identified as non-converted at the end of the intensive phase of treatment. Pre-treatment smears graded 2+ and 3+ were independently associated to delay in smear conversion (p<0.01). Years of treatment ranging from 2009 to 2012 were also associated to delay in smear conversion (p<0.02). Delay in smear conversion was significantly associated to failure [Adjusted Odd Ratio (AOR):12.4 (Confidence Interval: CI 4.0- 39.0)] and death, AOR: 3.6 (CI 1.5- 9.0).

CONCLUSION

Heavy initial bacillary load and treatment years ranging from 2009 to 2012 were associated to sputum smear non-conversion at the end of the intensive phase of TB treatment. Also, delay in smear conversion was associated to unfavorable treatment outcomes. Patients with heavy initial bacillary load should thus be closely monitored and studies done to identify reasons for the high proportion of non-conversion among patients treated between 2009 and 2012.

Wildlife use and the role of taboos in the conservation of wildlife around the Nkwende Hills Forest Reserve; South-west Cameroon

BACKGROUND

Cameroon is known as Africa in miniature because of its multitude of ecosystems and associated biodiversity, cultures and traditions. The country also harbors very ancient human populations whose relationship with nature is very intimate and where animals play important roles for their livelihood. Located in the South-west region of Cameroon, the Nkwende Hills Forest Reserve (NHFR) represents an important wildlife conservation site because of its strategic position at the periphery of Korup National Park (KNP). The periphery of NHFR is inhabited by several ethnic groups amongst which are the Obang and Ngunnchang clans who share particular relationships with wildlife. The present paper studies these relationships and contributes to the growing trend of scientific ethnozoological studies across Africa.

METHOD

From August to December 2011, a questionnaire survey was addressed to 126 randomly chosen household respondents (HRs) in seven villages at the Northwest periphery of NHFR. In households, preference was given to parents, and to the eldest child in case the parents were absent. Questions related to the uses and local taboos on wildlife species were asked to HRs.

RESULTS

Both communities have accumulated knowledge on the use of 51 wildlife species of which 50.9% represent mammals, 21.6% birds, 15.7% reptiles, 7.8% fish and 3.9% invertebrates. Four main use categories of wildlife by both communities were identified, namely (1) Food, medicine and sales values (41.2%), (2) Ethnomusical animals and parts used as trophy (29.2%), (3) Decoration and jewelry making values (21.9%) and (4) Magico-religious and multipurpose values (7.8%). Regarding local taboos, species specific taboos (generation totems and acquired totems), habitat taboos (sacred forests), method and segment taboos still persist but are rarely respected among the youth mainly because of the scarcity of wildlife (65.3% of HRs).

CONCLUSION

Like other communities living around forest areas, the studied communities use wildlife in their culture and tradition. Wildlife is not only used for consumption, but also for traditional medicines, craft materials and spiritual purposes. But, threats to wildlife and their traditional uses are real and acculturation seems to be the main driver. High priority should be given to the reconciling conservation of species with high values for local communities and human needs.

Assessment of sex-related behaviours, human immunodeficiency virus (HIV) knowledge and sexually transmitted infections (STIs) among men of reproductive age in Cameroon

Sexually transmitted infections (STIs), including human immunodeficiency virus (HIV), are among the major public health challenges in Cameroon. This paper determined the effect of men's sex-related behaviors and HIV knowledge on reported STIs. The data came from the 2012 Cameroon's Demographic and Health Survey (DHS) that were collected from 7191 respondents in 2012. Descriptive and logistic regression methods were used for data analysis. Results showed that majority of the respondents were aware of STIs and Acquired Immune Deficiency Syndrome (AIDS), while 3.96% reported STIs. Also, 49.45% of the men had no wife, while 75.58% and 84.58% noted that condoms and keeping of one partner could be used to prevent HIV transmission, respectively. Wrong impressions that mosquito bites and sharing of food could lead to HIV infection were held by 31.94% and 12.44% of the men, respectively. Among those that reported STIs, 33.33%, 30.18% and 13.33% respectively used condom during sex with most recent partner, second to most recent partner and third to most recent partner, compared to 24.69%, 15.04% and 4.17% among those that did not report STIs. Logistic regression results showed that probability of STI increased significantly (p < 0.05) with condom use with third most recent partners, being married, wrong knowledge that mosquito bites cause HIV and being away for more than one month, while it significantly reduced (p < 0.05) with number of children, knowledge that having one partner prevents STIs. It was concluded that policy initiatives and programmes to enhance right sexual knowledge and behavior among men would go a long way in reducing STI incidence in Cameroon.

A report of two cases in Cameroon

We report two cases of ectopia cordis in two children aged one day and twenty months respectively. A one day old newborn had complete thoracic ectopia cordis associated with an internal cardiac defect and severe thoracic and abdominal wall malformations. Our centre does not have the facilities to manage complex congenital defects and prior to being transferred to a cardiac centre, the neonate died on the second day of admission. A 20-month old baby had partial ectopia of the heart and a defect in the abdominal wall. He had no major congenital cardiac defect and has remained clinically stable with no life threatening symptoms.

Health labour market policies in support of universal health coverage: a comprehensive analysis in four African countries

BACKGROUND

Progress toward universal health coverage in many low- and middle-income countries is hindered by the lack of an adequate health workforce that can deliver quality services accessible to the entire population.

METHODS

We used a health labour market framework to investigate the key indicators of the dynamics of the health labour market in Cameroon, Kenya, Sudan, and Zambia, and identified the main policies implemented in these countries in the past ten years to address shortages and maldistribution of health workers.

RESULTS

Despite increased availability of health workers in the four countries, major shortages and maldistribution persist. Several factors aggravate these problems, including migration, an aging workforce, and imbalances in skill mix composition.

CONCLUSIONS

In this paper, we provide new evidence to inform decision-making for health workforce planning and analysis in low- and middle-income countries. Partial health workforce policies are not sufficient to address these issues. It is crucial to perform a comprehensive analysis in order to understand the dynamics of the health labour market and develop effective polices to address health workforce shortages and maldistribution as part of efforts to attain universal health coverage.

Prevalence of HBsAg and knowledge about hepatitis B in pregnancy in the Buea Health District, Cameroon: a cross-sectional study

BACKGROUND

Although infection with Hepatitis B Virus (HBV) remains a global public health problem, little is known about its epidemiology in pregnancy in sub-Saharan Africa. This study sought to determine the prevalence of, and identify factors associated with hepatitis B surface antigen (HBsAg) positivity among pregnant women in the Buea Health District (BHD) in rural Cameroon. We also assessed pregnant women's knowledge about hepatitis B.

METHODS

A cross-sectional, descriptive study was undertaken. Participants were evaluated using a structured questionnaire with clinical examination and were then screened for HBsAg using a commercial rapid diagnostic test. Assessment of knowledge was done using a hepatitis B basic knowledge summary score.

RESULTS

Of the 176 pregnant women studied, 9.7% (95% CI: 5.7%, 15%) tested positive for HBsAg. None of the risk factors assessed was significantly associated with HBsAg positivity. The hepatitis B knowledge summary score ranged from 0 to 12 with a mean of 1.5 (SD = 3.14, median = 0, IQR = 0 to 0). Only 16% of participants had scores greater than 6/12. The knowledge summary score of the participants was associated with the educational level (p-value = 0.0037).

CONCLUSION

The high prevalence of HBsAg (9.7%) among women of child bearing age suggests that vertical transmission of HBV may be a public health problem in Buea Health District. Knowledge of HBV among pregnant women was poor. We recommend that all pregnant women ought to be routinely screened for HBV and that health education on HBV should be provided to pregnant women especially during antenatal visits.

Molecular typing reveals substantial Plasmodium vivax infection in asymptomatic adults in a rural area of Cameroon

BACKGROUND

Malaria in Cameroon is due to infections by Plasmodium falciparum and, to a lesser extent, Plasmodium malariae and Plasmodium ovale, but rarely Plasmodium vivax. A recent report suggested "Plasmodium vivax-like" infections around the study area that remained unconfirmed. Therefore, molecular and antigenic typing was used to investigate the prevalence of P. vivax and Duffy in asymptomatic adults resident in Bolifamba.

METHODS

A cross-sectional study was conducted from July 2008 to October 2009. The status of all parasite species was determined by nested PCR in 269 blood samples collected. The P. falciparum and P. vivax anti-MSP/CSP antibody status of each subject was also determined qualitatively by a rapid card assay. Parasite DNA was extracted from a sample infected with three parasite species, purified and sequenced. The Duffy antigen status of 12 subjects infected with P. vivax was also determined by sequencing. In silico web-based tools were used to analyse sequence data for similarities and matches to reference sequences in public DNA databases.

RESULTS

The overall malaria parasite prevalence in 269 individuals was 32.3% (87) as determined by PCR. Remarkably, 14.9% (13/87) of infections were caused either exclusively or concomitantly by P. vivax, established both by PCR and microscopic examination of blood smears, in individuals both positive (50%, 6/12) and negative (50%, 6/12) for the Duffy receptor. A triple infection by P. falciparum, P. vivax and P. malariae, was detected in one infected individual. Anti-MSP/CSP antibodies were detected in 72.1% (194/269) of samples, indicating high and continuous exposure to infection through mosquito bites.

DISCUSSION

These data provide the first molecular evidence of P. vivax in Duffy positive and negative Cameroonians and suggest that there may be a significant prevalence of P. vivax infection than expected in the study area. Whether the P. vivax cases were imported or due to expansion of a founder effect was not investigated. Notwithstanding, the presence of P. vivax may complicate control efforts if these parasites become hypnozoitic or latent as the liver stage.

CONCLUSIONS

These data strongly suggest that P. vivax is endemic to the south-west region of Cameroon and should be taken into account when designing malaria control strategies.

Crop yield gaps in Cameroon

Although food crop yields per hectare have generally been increasing in Cameroon since 1961, the food price crisis of 2008 and the ensuing social unrest and fatalities raised concerns about the country's ability to meet the food needs of its population. This study examines the country's potential for increasing crop yields and food production to meet this food security challenge. Fuzzy set theory is used to develop a biophysical spatial suitability model for different crops, which in turn is employed to ascertain whether crop production is carried out in biophysically suited areas. We use linear regression to examine the trend of yield development over the last half century. On the basis of yield data from experimental stations and farmers' fields we assess the yield gap for major food crops. We find that yields have generally been increasing over the last half century and that agricultural policies can have significant effects on them. To a large extent, food crops are cultivated in areas that are biophysically suited for their cultivation, meaning that the yield gap is not a problem of biophysical suitability. Notwithstanding, there are significantly large yield gaps between actual yields on farmers' farms and maximum attainable yields from research stations. We conclude that agronomy and policies are likely to be the reasons for these large yield gaps. A key challenge to be addressed in closing the yield gaps is that of replenishing and properly managing soil nutrients.

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.

Prevalence and correlates of depressive symptoms in HIV-positive patients: a cross-sectional study among newly diagnosed patients in Yaoundé, Cameroon

BACKGROUND

Depression is one of the most common neuropsychiatric complications of HIV disease, and in turn it is associated with worse HIV-related outcomes. Data on depression among HIV-infected patients in Cameroon are scarce. In this study, we report the prevalence and correlates of depressive symptoms among newly diagnosed HIV-infected patients in Yaoundé, Cameroon.

METHODS

Interviews were conducted with 100 newly diagnosed HIV-infected patients at three referral hospitals of Yaoundé. Depression was assessed using the nine-item Patient Health Questionnaire (PHQ-9). A positive depression screen was defined as PHQ-9 score greater than 9.

RESULTS

The overall prevalence of depressive symptoms was 63% (95% CI: 53.2 to 71.8), the majority having symptoms corresponding to moderate depression. Multiple logistic regression analysis showed that probable depressed patients were more likely than those who were not depressed to have had experience of alcohol abuse (OR: 19.03, 95% CI 3.11-375.85; p = 0.0083), and a 100 CD4 cells/mm3 fewer was associated with a 2.9 times increase of the odds of probable depression (95% CI 1.88-4.84; p < 0.0001).

CONCLUSIONS

Our findings indicate a high prevalence of depressive symptoms in newly diagnosed HIV-infected patients in our setting, and their association with alcohol abuse and severe immunosuppression. This study also highlights the necessity to integrate mental health interventions into routine HIV clinical care in Cameroon.

Multi-drug resistant toxigenic Vibrio cholerae O1 is persistent in water sources in New Bell-Douala, Cameroon

BACKGROUND

Cholera has been endemic in Douala, since 1971 when it was first recorded in Cameroon. Outbreaks have often started in slum areas of the city including New Bell. Despite the devastating nature of outbreaks, always resulting in high mortality and morbidity, a paucity of information exists on the reservoirs of the causative agent, V. cholerae, and factors maintaining its persistence. This has complicated disease prevention, resulting in frequent outbreaks of cholera. We investigated water sources in New Bell for contamination with V. cholerae O1 with pathogenic potential, to highlight their role in disease transmission. Antibiotic susceptibility pattern of isolates and the environmental factors maintaining its persistence were investigated.

METHOD

Water samples from various sources (taps, dug wells, streams) were analyzed for contamination with V. cholerae O1 using standard methods. Antibiotic susceptibility was determined by disc diffusion method. Pathogenic potential of isolates was determined by analyzing for genes for cholera toxin (ctx), toxin co-regulated pilus (tcpA), and zonula occludens toxin (zot) by PCR. Physico-chemical characteristics of water (pH, temperature and salinity) were investigated using standard methods. The Spearman's Rank correlation was used to analyze the relationship between physico-chemical factors and the occurrence of V. cholerae O1. Differences were considered significant at P≤0.05.

RESULTS

Twenty-five V. cholerae O1 strains were isolated from stream and well samples in both dry and rainy seasons. Twenty-three (92%) isolates were multidrug resistant. All isolates had genes for at least one virulence factor. Cholera toxin gene was detected in 7 isolates. Of the 15 isolates positive for tcpA gene, two had Classical type tcpA while 13 had tcpA El Tor. All tcpA Classical positive isolates were positive for ctx gene. Isolates were grouped into nine genotypes based on the genes analyzed. pH and salinity significantly correlated with isolation of V. cholerae O1.

CONCLUSION

Multidrug resistant Vibrio cholerae O1 with pathogenic potential is present in some wells and streams in study area. pH and salinity are among the factors maintaining the persistence of the organism. Findings indicate an urgent need for potable water supply in study area and in addition, regular disinfection of water from contaminated sources to prevent outbreak of cholera.

Antiplasmodial activity of sesquiterpene lactones and a sucrose ester from Vernonia guineensis Benth. (Asteraceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Aqueous preparations of Vernonia guineensis Benth. (Asteraceae) are used in Cameroonian folk medicine as a general stimulant and to treat various illnesses and conditions including malaria, bacterial infections and helminthic infestations.

MATERIALS AND METHODS

Ten gram samples of the leaf and tuber powders of Vernonia guineensis were extracted separately using dichloromethane, methanol and distilled water. The extracts were dried in vacuo and used in bioassays. These extracts and three compounds previously isolated from Vernonia guineensis [vernopicrin (1), vernomelitensin (2) and pentaisovalerylsucrose (3)] were screened for antiplasmodial activity against chloroquine (CQ)-sensitive (Hb3) and CQ-resistant (Dd2) Plasmodium falciparum lines.

RESULTS

Crude extracts and pure compounds from Vernonia guineensis showed antiplasmodial activity against both Hb3 and Dd2. The IC50 values of extracts ranged from 1.64 to 27.2 µg/ml for Hb3 and 1.82-30.0 µg/ml for Dd2; those for compounds 1, 2 and 3 ranged from 0.47 to 1.62 µg/ml (1364-1774 nM) for Hb3 and 0.57-1.50 µg/ml (1644-2332nM) for Dd2. None of the crude extracts or pure compounds was observed to exert toxic effects on the erythrocytes used to cultivate the Plasmodium falciparum lines.

CONCLUSION

In Cameroonian folk medicine, Vernonia guineensis may be used to treat malaria in part due to the antiplasmodial activity of sesquiterpene lactones (1, 2), a sucrose ester (3) and perhaps other compounds present in crude plant extracts. Exploring the safety and antiplasmodial efficacy of these compounds in vivo requires further study.

Antibacterial constituents of three Cameroonian medicinal plants: Garcinia nobilis, Oricia suaveolens and Balsamocitrus camerunensis

BACKGROUND

Multidrug resistance is a worrying cause of treatment failure in bacterial infections. The search of bioactive constituents from medicinal plants against multidrug resistant (MDR) bacteria has significantly evolved in the two last decades. In the present study, twenty-two compounds (three terpenoids, eleven phenolics and eight alkaloids) isolated from three Cameroonian medicinal plants, namely Garcinia nobilis, Oricia suaveolens and Balsamocitrus camerunensis, as well as the crude extracts were tested for their antibacterial activities against Mycobacterium tuberculosis and Gram-negative bacteria amongst which were MDR active efflux pumps expressing phenotypes.

METHODS

The microplate alamar blue assay (MABA) and the broth microdilution methods were used to determine the minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) of the studied samples.

RESULTS

The results of the MIC determinations indicate that, the best crude extract was that from G. nobilis (GNB), its inhibitory effects being noted against 12 of the 14 tested bacteria. The extract of GNB also exhibited better anti-tuberculosis (MIC of 128 μg/ml M. tuberculosis against ATCC 27294 strain) and antibacterial (MIC of 64 μg/ml against Escherichia coli ATCC10536) activities compared to the extracts of O. suaveolens and B. camerunensis. Interestingly, 4-prenyl-2-(3,7-dimethyl-2,6-octadienyl)-1,3,5,8-tetrahydroxyxanthone (2), isolated from the most active extract GNB, also showed the best activity amongst compounds, inhibiting the growth of all the fourteen tested microorganisms. The lowest MIC value obtained with compound 2 was 8 μg/ml against M. tuberculosis ATCC 27294 and M. tuberculosis clinical MTCS2 strains. Other compounds showed selective activities with 11 of the 14 tested bacteria being sensitive to the xanthone, morusignin I (5) and the alkaloid, kokusaginine (13).

CONCLUSIONS

The results of the present investigation provide evidence that the crude extract from G. nobilis, O. suaveolens and B. camerunensis as well as some of their compounds, and mostly compound 2 (isolated from G. nobilis,) could be considered as interesting natural antibacterial products.

Bars to jars: bamboo value chains in Cameroon

Bamboo is a well know and versatile material, which is a common sight across Cameroon's diverse ecosystems, from dry to humid tropical and Afromontane forests. Its numerous uses range from storage jars to decorating restaurant-bars, beehives to knives, fences, fodder, and fuel. Responding to the paucity of data on species and uses, the value chain for bamboo in Cameroon was analyzed. Based on 171 interviews and field observations, two African indigenous species (alpine Yushania alpina and savannah Oxytenanthera abyssinica) and exotic (Bambusa vulgaris spp.) bamboos were identified as most utilized. They were tracked from major production zones to final consumers. The ecological, socio-economic, institutional, and governance contexts and impacts are described and analyzed. Issues for research, conservation, and development are highlighted. These include the ambiguous regulatory status, the relationship between tenure and management, threats and conservation of African species and options to increase the sustainable livelihoods for stakeholders dependent upon bamboo.

Trends and determining factors associated with adherence to antiretroviral therapy (ART) in Cameroon: a systematic review and analysis of the CAMPS trial

BACKGROUND

The benefits of antiretroviral therapy (ART) cannot be experienced if they are not taken as prescribed. Yet, not all causes of non-adherence are dependent on the patient. Having to pay for medication reduces adherence rates. Non- adherence has severe public health implications which must be addressed locally and globally. This paper seeks to describe the trends in adherence rates reported in Cameroon and to investigate the determinants of adherence to ART in the Cameroon Mobile Phone SMS (CAMPS) trial.

METHODS

We conducted a systematic review of electronic databases (PubMed, Google Scholar, Web of Science, CINAHL, EMBASE and PSYCINFO) for publications on adherence to ART in Cameroon (from January 1999 to May 2012) and described the trend in reported adherence rates and the factors associated with adherence. Data were extracted in duplicate. We used multivariable analyses on the baseline data for 200 participants in the CAMPS trial to determine the factors associated with adherence in four models using different measures of adherence (more than 90% or 95% on the visual analogue scale, no missed doses and a composite measure: 100% on the visual analogue scale, no missed doses and all pills taken on time).

RESULTS

We identified nine studies meeting our inclusion criteria. Adherence to ART in Cameroon has risen steadily between 2000 and 2010, corresponding to reductions in the cost of medication. The factors associated with adherence to ART in Cameroon are grouped into patient, medication and disease related factors. We also identified factors related to the health system and the patient-provider relationship. In the CAMPS trial, education, side effects experienced and number of reminder methods were found to improve adherence, but only using multiple reminder methods was associated with better adherence in all the regression models (Adjusted Odds Ratio [AOR] 4.11, 95% Confidence Interval [CI] 1.89, 8.93; p<0.001; model IV).

CONCLUSIONS

Reducing the cost of ART is an important aspect of ensuring adequate adherence rates. Using multiple reminder methods may have a cumulative effect on adherence to ART, but should be investigated further.

Cameroon mid-level providers offer a promising public health dentistry model

BACKGROUND

Oral health services are inadequate and unevenly distributed in many developing countries, particularly those in sub-Saharan Africa. Rural areas in these countries and poorer sections of the population in urban areas often do not have access to oral health services mainly because of a significant shortage of dentists and the high costs of care. We reviewed Cameroon's experience with deploying a mid-level cadre of oral health professionals and the feasibility of establishing a more formal and predictable role for these health workers. We anticipate that a task-shifting approach in the provision of dental care will significantly improve the uneven distribution of oral health services particularly in the rural areas of Cameroon, which is currently served by only 3% of the total number of dentists.

METHODS

The setting of this study was the Cameroon Baptist Convention Health Board (BCHB), which has four dentists and 42 mid-level providers. De-identified data were collected manually from the registries of 10 Baptist Convention clinics located in six of Cameroon's 10 regions and then entered into an Excel format before importing into STATA. A retrospective abstraction of all entries for patient visits starting October 2010, and going back in time until 1500 visits were extracted from each clinic.

RESULTS

This study showed that mid-level providers in BCHB clinics are offering a full scope of dental work across the 10 clinics, with the exception of treatment for major facial injuries. Mid-level providers alone performed 93.5% of all extractions, 87.5% of all fillings, 96.5% of all root canals, 97.5% of all cleanings, and 98.1% of all dentures. The dentists also typically played a teaching role in training the mid-level providers.

CONCLUSIONS

The Ministry of Health in Cameroon has an opportunity to learn from the BCHB model to expand access to oral health care across the country. This study shows the benefits of using a simple, workable, low-cost way to provide needed dental services across Cameroon, particularly in rural areas.

Metabolic syndrome in type 2 diabetes: comparative prevalence according to two sets of diagnostic criteria in sub-Saharan Africans

BACKGROUND

Available definition criteria for metabolic syndrome (MS) have similarities and inconsistencies. The aim of this study was to determine the prevalence of MS in a group of Cameroonians with type 2 diabetes, according to the International Diabetes Federation (IDF) and the National Cholesterol Education Programme Adult Treatment Panel III (NCEP-ATP III) criteria, and to assess the concordance between both criteria, and the implications of combining them.

METHODS

We collected clinical and biochemical data for 308 patients with type 2 diabetes (men 157) at the National Obesity Center of the Yaounde Central Hospital, Cameroon. Concordance was assessed with the use of the Kappa statistic.

RESULTS

Mean age (standard deviation) was 55.8 (10.5) years and the median duration of diagnosed diabetes (25th-75th percentiles) was 3 years (0.5-5.0), similarly among men and women. The prevalence of MS was 71.7% according to the IDF criteria and 60.4% according to NCEP-ATP III criteria. The prevalence was significantly higher in women than in men independently of the criteria used (both p < 0.001). Overall concordance between both definitions was low to average 0.51 (95% confidence interval: 0.41-0.61). Combining the two sets of criteria marginally improved the yield beyond that provided by the IDF criteria alone in men, but not in the overall population and in women.

CONCLUSIONS

The IDF and NCEP-ATP III criteria do not always diagnose the same group of diabetic individuals with MS and combining them merely increases the yield beyond that provided by the IDF definition alone. This study highlights the importance of having a single unifying definition for MS in our setting.

Pandemic A/H1N1/2009 influenza virus in swine, Cameroon, 2010

Although swine origin A/H1N1/2009 influenza virus (hereafter "pH1N1″) has been detected in swine in 20 countries, there has been no published surveillance of the virus in African livestock. The objective of this study was to assess the circulation of influenza A viruses, including pH1N1 in swine in Cameroon, Central Africa. We collected 108 nasal swabs and 98 sera samples from domestic pigs randomly sampled at 11 herds in villages and farms in Cameroon. pH1N1 was isolated from two swine sampled in northern Cameroon in January 2010. Sera from 28% of these herds were positive for influenza A by competitive ELISA and 92.6% of these swine showed cross reactivity with pandemic A/H1N1/2009 influenza virus isolated from humans. These results provide the first evidence of this virus in the animal population in Africa. In light of the significant role of swine in the ecology of influenza viruses, our results call for greater monitoring and study in Central Africa.

Notes on the blood-feeding behavior of Aedes albopictus (Diptera: Culicidae) in Cameroon

BACKGROUND

The invasive mosquito Aedes albopictus is often considered a poor vector of human pathogens, owing to its catholic feeding behavior. However, it was recently incriminated as a major vector in several Chikungunya epidemics, outside of its native range. Here we assessed two key elements of feeding behavior by Ae. albopictus females in Yaoundé, Cameroon, Central Africa. Host preference was explored and the human-biting activity of females was monitored over 24 h to determine periods of maximum bite exposure.

FINDINGS

Analysis of ingested blood in outdoor-resting females showed that Ae. albopictus preferentially fed on humans rather than on available domestic animals (95% of the blood meals contained human blood). Our results further showed that Ae. albopictus is a day-biting species in Yaoundé, with a main peak of activity in the late afternoon.

CONCLUSION

This is the first report on the feeding behavior of Ae. albopictus in Central Africa. The species is highly aggressive to humans and might therefore be involved in human-human virus transmission in this setting.

Does HIV services decentralization protect against the risk of catastrophic health expenditures?: some lessons from Cameroon

OBJECTIVE

Scaling up antiretroviral treatment (ART) through decentralization of HIV care is increasingly recommended as a strategy toward ensuring equitable access to treatment. However, there have been hitherto few attempts to empirically examine the performance of this policy, and particularly its role in protecting against the risk of catastrophic health expenditures (CHE). This article therefore seeks to assess whether HIV care decentralization has a protective effect against the risk of CHE associated with HIV infection. DATA SOURCE AND STUDY DESIGN: We use primary data from the cross-sectional EVAL-ANRS 12-116 survey, conducted in 2006-2007 among a random sample of 3,151 HIV-infected outpatients followed up in 27 hospitals in Cameroon. DATA COLLECTION AND METHODS: Data collected contain sociodemographic, economic, and clinical information on patients as well as health care supply-related characteristics. We assess the determinants of CHE among the ART-treated patients using a hierarchical logistic model (n = 2,412), designed to adequately investigate the separate effects of patients and supply-related characteristics.

PRINCIPAL FINDINGS

Expenditures for HIV care exceed 17 percent of household income for 50 percent of the study population. After adjusting for individual characteristics and technological level, decentralization of HIV services emerges as the main health system factor explaining interclass variance, with a protective effect on the risk of CHE.

CONCLUSION

The findings suggest that HIV care decentralization is likely to enhance equity in access to ART. Decentralization appears, however, to be a necessary but insufficient condition to fully remove the risk of CHE, unless other innovative reforms in health financing are introduced.

[Booster doses outside of the Expanded Program on Immunization in two schools in basic education in Yaounde, Cameroon]

Introduction

L'absence des rappels vaccinaux est problématique dans les pays en développement où certaines maladies évitables par la vaccination font encore des victimes chez les enfants en raison d'une immunisation incomplète. L'identification des raisons de non rappel vaccinaux permettrait de proposer des solutions adaptées afin d'améliorer le statut vaccinal des enfants au-delà de 12 mois.

Méthodes

Cette étude descriptive transversale avait pour objectif d’évaluer le taux de rappels vaccinaux des enfants au-delà de la cible du programme élargi de vaccination (PEV). Elle s'est déroulée de Septembre à Novembre 2009 dans deux écoles d’éducation de base de Yaoundé. L’échantillonnage était consécutif et limité aux élèves âgés de deux à sept ans possédant des carnets de vaccination. Par souci d'uniformité, nous n'avons pas analysé les rappels des vaccins contre l'hépatite B et l'haemophilus introduits tardivement au Cameroun.

Résultats

L’étude a porté sur 310 élèves. La tranche d’âge de 2 à 4 ans représentait 69%. Seul 223 enfants (71,9%) étaient correctement vaccinés. Quant aux rappels vaccinaux diphtérie-tétanos-coqueluche et poliomyélite, les couvertures étaient insignifiantes (2,7% et 0% respectivement pour la première et la deuxième dose). Les raisons évoquées étaient l'absence de sensibilisation des parents (50%), le prix élevé des vaccins (48,69%) et la désinformation (1,31%).

Conclusion

Le recyclage du personnel de santé sur la vaccination est une nécessité. Les parents doivent être informés sur le déroulement, les prix et les lieux des rappels vaccinaux. La réduction des prix de vaccins faciliterait l'accès à une large tranche de la population.

Chromosomal inversions, natural selection and adaptation in the malaria vector Anopheles funestus

Chromosomal polymorphisms, such as inversions, are presumably involved in the rapid adaptation of populations to local environmental conditions. Reduced recombination between alternative arrangements in heterozygotes may protect sets of locally adapted genes, promoting ecological divergence and potentially leading to reproductive isolation and speciation. Through a comparative analysis of chromosomal inversions and microsatellite marker polymorphisms, we hereby present biological evidence that strengthens this view in the mosquito Anopheles funestus s.s, one of the most important and widespread malaria vectors in Africa. Specimens were collected across a wide range of geographical, ecological, and climatic conditions in Cameroon. We observed a sharp contrast between population structure measured at neutral microsatellite markers and at chromosomal inversions. Microsatellite data detected only a weak signal for population structuring among geographical zones (F(ST) < 0.013, P < 0.01). By contrast, strong differentiation among ecological zones was revealed by chromosomal inversions (F(ST) > 0.190, P < 0.01). Using standardized estimates of F(ST), we show that inversions behave at odds with neutral expectations strongly suggesting a role of environmental selection in shaping their distribution. We further demonstrate through canonical correspondence analysis that heterogeneity in eco-geographical variables measured at specimen sampling sites explained 89% of chromosomal variance in A. funestus. These results are in agreement with a role of chromosomal inversions in ecotypic adaptation in this species. We argue that this widespread mosquito represents an interesting model system for the study of chromosomal speciation mechanisms and should provide ample opportunity for comparative studies on the evolution of reproductive isolation and speciation in major human malaria vectors.

Suffering for water, suffering from water: access to drinking-water and associated health risks in Cameroon

Although many African countries, along the equator, receive a great amount of rainfall and possess a dense hydrographic network, access to drinking-water remains a great challenge. In many households, water is used for various purposes, including domestic and crafts activities. According to the World Health Organization, an estimated four billion cases of diarrheoa occurs worldwide, of which 88% are ascribed to unsafe drinking-water. This study aimed at evaluating health risks in the usage of contaminated drinking-water and its relationship with the prevalence of diarrhoeal diseases in Yaound6, Cameroon. In this cross-sectional epidemiological design, 3,034 households with children aged less than five years were investigated. Households were selected from among 20 representative neighbourhoods out of 105 that made up the city. The study revealed a diarrheoa prevalence of 14.4% (437 diarrheoa cases out of 3,034 children tested). Among various risk factors examined, water-supply modes and quality of drinking-water were statistically associated with diarrheoa cases. Moreover, levels of diarrheoa attacks varied considerably from one neighbourhood to the other. The spatial analysis helped determine neighbourhoods of higher and lower prevalence of diarrheoa in the city.