Search

Background: There has been a successful push towards parasitological diagnosis of malaria in Africa, mainly with rapid diagnostic tests (mRDTs), which has reduced over-prescribing of artemisinin-based combination therapies (ACT) to malaria test-negative patients. The effect on prescribing for test-positive patients has received much less attention. Malaria infection in endemic Africa is often most dangerous for young children and those in low-transmission settings. This study examined non-prescription of antimalarials for patients with malaria infection demonstrated by positive mRDT results, and in particular these groups who are most vulnerable to poor outcomes if antimalarials are not given., Methods: Analysis of data from 562,762 patients in 8 studies co-designed as part of the ACT Consortium, conducted 2007-2013 in children and adults, in Cameroon, Ghana, Nigeria, Tanzania, and Uganda, in a variety of public and private health care sector settings, and across a range of malaria endemic zones., Results: Of 106,039 patients with positive mRDT results (median age 6 years), 7426 (7.0%) were not prescribed an ACT antimalarial. The proportion of mRDT-positive patients not prescribed ACT ranged across sites from 1.3 to 37.1%. For patients under age 5 years, 3473/44,539 (7.8%) were not prescribed an ACT, compared with 3833/60,043 (6.4%) of those aged ≥ 5 years. The proportion of < 5-year-olds not prescribed ACT ranged up to 41.8% across sites. The odds of not being prescribed an ACT were 2-32 times higher for patients in settings with lower-transmission intensity (using test positivity as a proxy) compared to areas of higher transmission. mRDT-positive children in low-transmission settings were especially likely not to be prescribed ACT, with proportions untreated up to 70%. Of the 7426 mRDT-positive patients not prescribed an ACT, 4121 (55.5%) were prescribed other, non-recommended non-ACT antimalarial medications, and the remainder (44.5%) were prescribed no antimalarial., Conclusions: In eight studies of mRDT implementation in five African countries, substantial proportions of patients testing mRDT-positive were not prescribed an ACT antimalarial, and many were not prescribed an antimalarial at all. Patients most vulnerable to serious outcomes, children < 5 years and those in low-transmission settings, were most likely to not be prescribed antimalarials, and young children in low-transmission settings were least likely to be treated for malaria. This major public health risk must be addressed in training and practice., Trial Registration: Reported in individual primary studies. more...

In Cameroon, genome characterization of influenza virus has been performed only in the Southern regions meanwhile genetic diversity of this virus varies with respect to locality. The Northern region characterized by a Sudan tropical climate might have distinct genetic characterization. This study aimed to better understand the genetic diversity of influenza A(H3N2) viruses circulating in Northern Cameroon. Sequences of three gene segments (hemagglutinin (HA), neuraminidase (NA) and matrix (M) genes) were obtained from 16 A(H3N2) virus strains collected during the 2014 to 2016 influenza seasons in Garoua. The HA gene segments were analysed with respect to reference strains while the NA and M gene was analysed for reported genetic markers of resistance to antivirals. Analysis of the HA sequences revealed that majority of the virus strains grouped together with the 2016-2017 vaccine strain (3C.2a-A/Hong Kong/4801/2014) while 3/5 (60%) of the 2015 viral strains grouped together with the 2015-2016 vaccine strain 3C.3a-A/Switzerland/9715293/2013. Within clade 3C.2a, Northern Cameroon sequences mostly grouped in sub-clade A3 (10/16). Analysis of the coding regions of the NA and M genes showed that none had genetic markers of resistance to neuraminidase inhibitors but all strains possessed the S31N substitution of resistance to amantadine. Due to some discrepancies observed in this region with respect to the Southern regions of Cameroon, there is necessity of including all regions within a country in the sentinel surveillance of influenza. These data will enable to track changes in influenza viruses in Cameroon., (© 2019 Wiley Periodicals, Inc.) more...

Backround and Objective: Screening for diabetic retinopathy (DR) is cost-effective when compared with disability loss for those who go blind in the absence of a screening program. We aimed to evaluate the sensitivity and specificity of a smartphone-based device for the screening and detection of DR., Patients and Methods: A cross-sectional study of 220 patients with diabetes (440 eyes, all patients age 25 years or older) was completed. Tropicamide 0.5% was used for iris dilation followed by an indirect ophthalmoscopy using a 20-D lens. Retinal images were later obtained using a smartphone attached to an adaptable camera device. Retinal images permitted the visualization of the macular and papillary regions and were sent without compression via the internet to a retinal specialist for interpretation. Sensitivity and specificity were calculated for all cases and stages of DR., Results: Using our standard examination method, the prevalence of DR and macular edema were 13.6% and 6.4%, respectively. With the smartphone-based retinal camera, the prevalence of DR and macular edema were 18.2% and 8.2%, respectively. Sensitivity and specificity for the detection of all stages of DR was 73.3% and 90.5%, respectively. For the detection of macular edema, sensitivity was 77.8%, and specificity was 95%. For severe nonproliferative DR (NPDR), sensitivity and specificity were 80% and 99%, respectively; for proliferative DR (PDR), they were both 100%. In the early stages of DR, specificity was 89.8% for mild NPDR and 97.1% for moderate NPDR. Sensitivity was 57.1% and 42.9%, respectively., Conclusion: Screening for DR using a smartphone-based retinal camera has a satisfactory specificity at all DR stages. Its sensitivity seems to be high only in the stages of DR necessitating a specific therapeutic decision (eg, macular edema, severe NPDR, and PDR). A smartphone-based retinal camera may be a useful device to screen for DR in resource-limited settings. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:S18-S22.]., (Copyright 2019, SLACK Incorporated.) more...

Background: Several studies have demonstrated the role of meteorological parameters in the seasonality of influenza viruses in tropical and subtropical regions, most importantly temperature, humidity, and rainfall., Objectives: This study aimed to describe the influence of meteorological parameters in the seasonality of influenza viruses in Northern Cameroon, a region characterized by high temperatures., Methods: This was a retrospective study performed in Garoua Cameroon from January 2014 to December 2016. Monthly proportions of confirmed influenza cases from six sentinel sites were considered as dependent variables, whereas monthly values of mean temperature, average relative humidity, and accumulated rainfall were considered as independent variables. A vector error correction model was used to determine the relationship between influenza activity and the meteorological variables., Results and Conclusion: Analysis showed that there was a statistically significant association between overall influenza activity and influenza A activity with respect to average relative humidity. A unit increase in humidity within a given month leads to more than 85% rise in the overall influenza and influenza A activity 2 months later. Meanwhile, none of the three meteorological variables could explain influenza B activity. This observation is essential in filling the gap of knowledge and could help in the prevention and control strategies to strengthen influenza surveillance program in Cameroon., (© 2018 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.) more...

In 2009, Influenza A(H1N1)pdm09 caused the first influenza pandemic of the 21st century with high mortality rates of about 284 500 deaths. This virus, however, continues to circulate as a seasonal influenza virus and to cause illness and deaths worldwide. In this study, we describe the genetic diversity of A(H1N1)pdm09 viruses collected between 2014 and 2016 in Cameroon. Three gene segments (HA, NA and M) of Cameroon strains were studied. The phylogenetic tree of the coding nucleotide sequences was generated by MEGA version 6.0 using a Maximum Likelihood method. The NA and M protein coding sequences were analyzed for the reported genetic markers of resistance against neuraminidase inhibitors and adamantanes, while predicted vaccine efficacy was estimated using the Pepitope method. Overall 39 strains were obtained. Phylogenetic analysis of the HA gene of influenza A(H1N1)pdm09 showed that Cameroon strains belonged to two major clades. The 2014 Cameroon sequences belonged to clade 6C while all sequences collected between 2015 and 2016 belonged to clade 6B. Majority of the samples had some mutations in the NA gene notably: I117M, N248D, and N369K while the amantadine-resistant M mutant, S31N, was found to be absent only in the two sequences collected in 2014. Overall, A/California/07/2009 vaccine strain showed a predicted vaccine efficacy of 24.55% to 35.77% against Cameroon A(H1N1)pdm09 strains circulating between 2014 and 2016. Our findings confirms the fast evolution of A(H1N1)pdm09 since its first introduction and highlights on the importance of influenza vaccine in reducing the burden caused by influenza in the community., Competing Interests: The authors have declared that no competing interests exist. more...

In May 2016, highly pathogenic avian influenza virus of the subtype A/H5N1 was detected in Cameroon in an industrial poultry farm at Mvog-Betsi, Yaoundé (Centre region), with a recorded sudden increase of deaths among chickens, and an overall mortality rate of 75%. The virus spread further and caused new outbreaks in some parts of the country. In total, 21 outbreaks were confirmed from May 2016 to March 2017 (six in the Centre, six in the West, eight in the South and one in the Adamaoua regions). This resulted in an estimated total loss of 138,252 birds (44,451 deaths due to infection and 93,801 stamped out). Only domestic birds (chickens, ducks and geese) were affected in farms as well as in poultry markets. The outbreaks occurred in three waves, the first from May to June 2016, the second in September 2016 and the last wave in March 2017. The topology of the phylogeny based on the haemagglutinin gene segment indicated that the causative H5N1 viruses fall within the genetic clade 2.3.2.1c, within the same group as the A/H5N1 viruses collected in Niger in 2015 and 2016. More importantly, the gene constellation of four representative viruses showed evidence of H5N1/H9N2 intra-clade reassortment. Additional epidemiological and genetic data from affected countries in West Africa are needed to better trace the origin, spread and evolution of A/H5N1 in Cameroon. RESEARCH HIGHLIGHTS HPAI A/H5N1 was detected in May 2016 in domestic chickens in Yaoundé-Cameroon. Twenty-one outbreaks in total were confirmed from May 2016 to March 2017. The causative H5N1 viruses fall within the genetic clade 2.3.2.1c. The viral gene constellation showed evidence of H5N1/H9N2 intra-clade reassortment. more...

Objective: Mycobacterium tuberculosis isolates that fail to hybridize to at least one rpoB wild-type or any mutation probe on the Genotype MTBDRplus strip are assumed to be rifampicin-resistant. However, the precise mutation(s) are unknown. We sought to identify the mutations in isolates with such hybridization patterns and determine if the mutations are associated with resistance to rifampicin., Methods: In this study, 275 M. tuberculosis isolates were screened with the Genotype MTBDRplus assay to identify isolates with the hybridization pattern. These isolates were sequenced and their minimum inhibitory concentrations (MIC) determined using the Bactec MGIT 960 system., Results: Among the 275 isolates tested, 15 (6%) isolates with the hybridization pattern were identified. Sequencing showed that failure to hybridize to rpoB wild-type probes resulted from the presence of 'disputed' rifampicin mutations, which are mutations not always associated with a rifampicin-resistant phenotype. All, except 3/15, isolates had a rifampicin-resistant phenotype (MIC > 1 μg/mL). One of the three isolates with a rifampicin-susceptible phenotype had the same mutation at position 526 (His526Leu) as another isolate that had a rifampicin-resistant phenotype., Conclusion: The recommendation of the Genotype MTBDRplus assay to assume rifampicin resistance based solely on failure to hybridize to rpoB wild-type probe allows the identification of important RIF-resistant isolates. About 20% (3/15) of such isolates could be missed by relying only on the standard MGIT 960 DST assay for drug susceptibility testing., (Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.) more...

Background: Hypertension holds a unique place in population health and health care because it is the leading cause of cardiovascular disease and the most common noncommunicable condition seen in primary care worldwide. Without effective prevention and control, raised blood pressure significantly increases the risk of stroke, myocardial infarction, chronic kidney disease, heart failure, dementia, renal failure, and blindness. There is an urgent need for stakeholders-including individuals and families-across the health system, researchers, and decision makers to work collaboratively for improving prevention, screening and detection, diagnosis and evaluation, awareness, treatment and medication adherence, management, and control for people with or at high risk for hypertension. Meeting this need will help reduce the burden of hypertension-related disease, prevent complications, and reduce the need for hospitalization, costly interventions, and premature deaths., Objective: This review aims to synthesize evidence on the epidemiological landscape and control of hypertension in Cameroon, and to identify elements that could potentially inform interventions to combat hypertension in this setting and elsewhere in sub-Saharan Africa., Methods: The full search process will involve several steps, including selecting relevant databases, keywords, and Medical Subject Headings (MeSH); searching for relevant studies from the selected databases; searching OpenGrey and the Grey Literature Report for gray literature; hand searching in Google Scholar; and soliciting missed publications (if any) from relevant authors. We will select qualitative, quantitative, or mixed-methods studies with data on the epidemiology and control of hypertension in Cameroon. We will include published literature in French or English from electronic databases up to December 31, 2016, and involving adults aged 18 years or older. Both facility and population-based studies on hypertension will be included. Two reviewers of the team will independently search, screen, extract data, and assess the quality of selected studies using suitable tools. Selected studies will be analyzed by narrative synthesis, meta-analysis, or both, depending on the nature of the data retrieved in line with the review objectives., Results: This review is part of an ongoing research program on disease prevention and control in the context of the dual burden of communicable and noncommunicable diseases in Africa. The first results are expected in 2017., Conclusions: This review will provide a comprehensive assessment of the burden of hypertension and control measures that have been designed and implemented in Cameroon. Findings will form the knowledge base relevant to stakeholders across the health system and researchers who are involved in hypertension prevention and control in the community and clinic settings in Cameroon, as a yardstick for similar African countries., Trial Registration: PROSPERO registration number: CRD42017054950; http://www.crd.york.ac.uk/PROSPERO/ display&#95;record.asp?ID=CRD42017054950 (Archived by WebCite at http://www.webcitation.org/6qYSjt9Jc)., (©Barthelemy Kuate Defo, Jean Claude Mbanya, Jean-Claude Tardif, Olugbemiga Ekundayo, Sylvie Perreault, Louise Potvin, Robert Cote, Andre Pascal Kengne, Simeon Pierre Choukem, Felix Assah, Samuel Kingue, Lucie Richard, Roland Pongou, Katherine Frohlich, Jude Saji, Pierre Fournier, Eugene Sobngwi, Valery Ridde, Marie-Pierre Dubé, Simon De Denus, Wilfred Mbacham, Jean-Philippe Lafrance, Dickson Shey Nsagha, Warner Mampuya, Anastase Dzudie, Lyne Cloutier, Christina Zarowsky, Agatha Tanya, Paul Ndom, Marie Hatem, Evelyne Rey, Louise Roy, Roxane Borgès Da Silva, Christian Dagenais, David Todem, Robert Weladji, Dora Mbanya, Elham Emami, Zakariaou Njoumemi, Laurence Monnais, Carl-Ardy Dubois. Originally published in JMIR Research Protocols (http://www.researchprotocols.org), 29.05.2017.) more...

Background: In sub-Saharan Africa, intense perennial Plasmodium species transmission coincides with areas of high prevalence of the human immunodeficiency virus type 1 (HIV) infection. This implies that antiretroviral naïve HIV-infected people living within these regions are repeatedly exposed to Plasmodium species infection and consequently malaria. Natural killer (NK) cells are known to contribute to malaria immunity through the production of IFN-γ after exposure to Plasmodium falciparum -infected erythrocytes (infected red blood cells [iRBC]). However, in antiretroviral naïve HIV-1 infection, these functions could be impaired. In this study we assess the ability of NK cells from antiretroviral naïve HIV-1-infected people to respond to iRBC., Method: Magnetically sorted NK cells from antiretroviral naïve HIV-1-infected people were tested for their ability to respond to iRBC following in vitro coculture. NK cell IFN-γ production after coculture was measured through multiparametric flow cytometry analysis., Results: Our data show a significant reduction ( p = 0.03) in IFN-γ production by NK cells from antiretroviral naïve HIV-1-infected people after coculture with iRBCs. This was in contrast to the NK cell response from healthy controls, which demonstrated elevated IFN-γ production. NK cell IFN-γ production from untreated HIV-1-infected participants correlated inversely with the viral load ( r = -0.5, p = 0.02) and positively with total helper CD4 + T-cell count ( r = 0.4, p = 0.04). Thus, antiretroviral naïve HIV-1 infection can dampen NK cell-mediated immunity to P. falciparum infection in malaria-intense regions. This could in effect escalate morbidity and mortality in people chronically infected with HIV-1., (Copyright © 2017 by S. Karger AG, Basel.) more...

Objectives: The overuse of antimalarial drugs is widespread. Effective methods to improve prescribing practice remain unclear. We evaluated the impact of 10 interventions that introduced rapid diagnostic tests for malaria (mRDTs) on the use of tests and adherence to results in different contexts., Design: A comparative case study approach, analysing variation in outcomes across different settings., Setting: Studies from the ACT Consortium evaluating mRDTs with a range of supporting interventions in 6 malaria endemic countries. Providers were governmental or non-governmental healthcare workers, private retail sector workers or community volunteers. Each study arm in a distinct setting was considered a case., Participants: 28 cases from 10 studies were included, representing 148 461 patients seeking care for suspected malaria., Interventions: The interventions included different mRDT training packages, supervision, supplies and community sensitisation., Outcome Measures: Analysis explored variation in: (1) uptake of mRDTs (% febrile patients tested); (2) provider adherence to positive mRDTs (% Plasmodium falciparum positive prescribed/given Artemisinin Combination Treatment); (3) provider adherence to negative mRDTs (% P. falciparum negative not prescribed/given antimalarial)., Results: Outcomes varied widely across cases: 12-100% mRDT uptake; 44-98% adherence to positive mRDTs; 27-100% adherence to negative mRDTs. Providers appeared more motivated to perform well when mRDTs and intervention characteristics fitted with their own priorities. Goodness of fit of mRDTs with existing consultation and diagnostic practices appeared crucial to maximising the impact of mRDTs on care, as did prior familiarity with malaria testing; adequate human resources and supplies; possible alternative treatments for mRDT-negative patients; a more directive intervention approach and local preferences for ACTs., Conclusions: Basic training and resources are essential but insufficient to maximise the potential of mRDTs in many contexts. Programme design should respond to assessments of provider priorities, expectations and capacities. As mRDTs become established, the intensity of supporting interventions required seems likely to reduce., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.) more...

Background: Severe malaria is a leading cause of morbidity and mortality in under-fives in sub-Saharan Africa. Recently quinine has been replaced by artesunate as the first-line drug in the treatment of severe malaria in Cameroon. Artesunate has been shown to be cost-effective in African children, but whether these findings are transferable to Cameroonian children remains to be explored., Objectives: To conduct a cost-analysis of four different regimens used in the treatment from the perspective of the healthcare payer., Methods: An economic evaluation alongside a randomized comparative study was conducted in children aged 3 months to 15 years, admitted at the Ebolowa Regional Hospital with severe malaria due to Plasmodium falciparum. Patients were randomized to receive one of the four treatment alternatives. Group 1 (ARTES) received parenteral artesunate at 2.4 mg/kg at H 0 , H 12 , H 24 and then once daily; Group 2 (QLD) received a loading dose of quinine base at 16.6 mg/kg followed 8 h later by an 8-hourly maintenance dose of 8.3 mg/kg quinine base; Group 3 (QNLD3) received 8.3 mg/kg quinine base every 8 h, and Group 4 (QNLD2) received 12.5 mg/kg quinine base every 12 h. The main outcome measure for effectiveness of treatment was the parasite reduction rate. Based on a healthcare perspective, an evaluation of direct medical costs was done, including costs of anti-malarials, nursing care materials, adjuvant treatment, laboratory investigations, hospitalisation and professional fees. Guided by a cost minimalization approach, the relative costs of these treatment alternatives was compared and reported., Results: Overall cost was higher for ARTES group at $65.14 (95% CI $57.68-72.60) than for quinine groups ($52.49-$62.40), but the difference was not statistically significant. Cost of the anti-malarial drug was significantly higher for artesunate-treated patients than for quinine-treated patients, whereas cost of hospitalization was significantly lower for artesunate-treated patients than for quinine-treated patients. Incremental analysis of ARTES against QLD as a baseline resulted in an ICER of $46.8/PRR 24 and suggests ARTES as the most cost effective of all four treatment options., Conclusion: Artesunate is a cost effective malaria treatment option relative to quinine alternatives with the lowest incremental cost per unit of effectiveness. Trial registration clinicaltrials.gov identifier: NCT02563704. Registered 19 September 2015, retrospectively registered. more...

The World Health Organization (WHO) classifies snake bites as neglected public health problem affecting mostly tropical and subtropical countries. In Africa there are an estimated 1 million snake bites annually with about half needing a specific treatment. Women, children and farmers in poor rural communities in developing countries are the most affected. Case management of snake bites are not adequate in many health facilities in developing countries where personnel are not always abreast with the new developments in snake bite management and in addition, quite often the anti-venom serum is lacking. We report the case of a medical doctor bitten by a cobra in the rural area of Poli, Cameroon while asleep in his bedroom. Lack of facilities coupled with poor case management resulted in a fatal outcome., Competing Interests: The authors declare no competing interests. more...

Background: Artemisinin combination therapy (ACT) has been the first-line treatment for uncomplicated malaria in Cameroon since 2004 and Nigeria since 2005, though many febrile patients receive less effective antimalarials. Patients often rely on providers to select treatment, and interventions are needed to improve providers' practice and encourage them to adhere to clinical guidelines., Methods: Providers' adherence to malaria treatment guidelines was examined using data collected in Cameroon and Nigeria at public and mission facilities, pharmacies and drug stores. Providers' choice of antimalarial was investigated separately for each country. Multilevel logistic regression was used to determine whether providers were more likely to choose ACT if they knew it was the first-line antimalarial. Multiple imputation was used to impute missing data that arose when linking exit survey responses to details of the provider responsible for selecting treatment., Results: There was a gap between providers' knowledge and their practice in both countries, as providers' decision to supply ACT was not significantly associated with knowledge of the first-line antimalarial. Providers were, however, more likely to supply ACT if it was the type of antimalarial they prefer. Other factors were country-specific, and indicated providers can be influenced by what they perceived their patients prefer or could afford, as well as information about their symptoms, previous treatment, the type of outlet and availability of ACT., Conclusions: Public health interventions to improve the treatment of uncomplicated malaria should strive to change what providers prefer, rather than focus on what they know. Interventions to improve adherence to malaria treatment guidelines should emphasize that ACT is the recommended antimalarial, and it should be used for all patients with uncomplicated malaria. Interventions should also be tailored to the local setting, as there were differences between the two countries in providers' choice of antimalarial, and who or what influenced their practice., (Published by Oxford University Press in association with The London School of Hygiene and Tropical Medicine © The Author 2014.) more...

Background: Severe malaria is a medical emergency with high mortality in children below 5 years of age especially in sub-Saharan Africa. Recently, quinine has been replaced by artesunate as the first-line drug in the treatment of severe malaria in Cameroon. No local data are yet available on the efficacy of artesunate with respect to the different quinine regimens used in this setting. This study was undertaken at the Ebolowa Regional Hospital (ERH), which is located in a region of perennial transmission of malaria., Methods: This was a randomized, open-label trial in children aged 3 months to 15 years, admitted in the hospital with severe malaria due to Plasmodium falciparum confirmed on microscopy after informed parental consent. Patients were randomized into four groups. Group 1 (ARTES) received parenteral artesunate at 2.4 mg/kg at H0, H12, H24 and then once daily; Group 2 (QLD) received a loading dose of quinine base at 16.6 mg/kg followed 8 hours later by an eight-hourly maintenance dose of 8.3 mg/kg quinine base; Group 3 (QNLD3) received 8.3 mg/kg quinine base every 8 hours; and, Group 4 (QNLD2) received 12.5 mg/kg quinine base every 12 h. All patients invariably received a minimum of 24 h parenteral treatment, then, oral drugs were prescribed. The endpoints were fever clearance time, time to sit unsupported, time to eat, parasite clearance time, and parasitaemia reduction rate at H24. Survival analysis was used to compare the outcomes., Results: One-hundred and sixteen patients completed the study: 29 in ARTES arm, 28 in QLD arm, 30 in QNLD3 arm, and 29 in QNLD2 arm. There was no major differences in baseline characteristics in the treatment groups. On analysis of endpoints, fever clearance time and parasite clearance time were significantly shorter for artesunate-treated patients than for quinine-treated patients. Parasitaemia reduction rate at H24 was also significantly higher for artesunate. Time to sit unsupported and time to eat were shorter with artesunate, but the difference was not statistically significant., Conclusion: Artesunate is more effective than quinine in the treatment of severe malaria in Cameroonian children. more...

As the study of disease occurrence and health indicators in human populations, Epidemiology is a dynamic field that evolves with time and geographical context. In order to update African health workers on current epidemiological practices and to draw awareness of early career epidemiologists on concepts and opportunities in the field, the 3(rd) African Epidemiology Association and the 1st Cameroon Society of Epidemiology Conference was organized in June 2-6, 2014 at the Yaoundé Mont Febe Hotel, in Cameroon. Under the theme«Practice of Epidemiology in Africa: Stakes, Challenges and Perspectives», the conference attracted close to five hundred guest and participants from all continents. The two main programs were the pre-conference course for capacity building of African Early Career epidemiologists, and the conference itself, providing a forum for scientific exchanges on recent epidemiological concepts, encouraging the use of epidemiological methods in studying large disease burden and neglected tropical diseases; and highlighting existing opportunities. more...

Background: Malaria rapid diagnostic tests (RDTs) are a valid alternative to malaria testing with microscopy and are recommended for the testing of febrile patients before prescribing an antimalarial. There is a need for interventions to support the uptake of RDTs by health workers., Objective: To evaluate the cost-effectiveness of introducing RDTs with basic or enhanced training in health facilities in which microscopy was available, compared with current practice., Methods: A three-arm cluster randomized trial was conducted in 46 facilities in central and northwest Cameroon. Basic training had a practical session on RDTs and lectures on malaria treatment guidelines. Enhanced training included small-group activities designed to change health workers' practice and reduce the consumption of antimalarials among test-negative patients. The primary outcome was the proportion of febrile patients correctly treated: febrile patients should be tested for malaria, artemisinin combination therapy should be prescribed for confirmed cases, and no antimalarial should be prescribed for patients who are test-negative. Individual patient data were obtained from facility records and an exit survey. Costs were estimated from a societal perspective using project reports and patient exit data. The analysis used bivariate multilevel modeling and adjusted for imbalance in baseline covariates., Results: Incremental cost per febrile patient correctly treated was $8.40 for the basic arm and $3.71 for the enhanced arm. On scale-up, it was estimated that RDTs with enhanced training would save $0.75 per additional febrile patient correctly treated., Conclusions: Introducing RDTs with enhanced training was more cost-effective than RDTs with basic training when each was compared with current practice., (Copyright © 2014 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.) more...

As agents for their patients, providers often make treatment decisions on behalf of patients, and their choices can affect health outcomes. However, providers operate within a network of relationships and are agents not only for their patients, but also other health sector actors, such as their employer, the Ministry of Health, and pharmaceutical suppliers. Providers' stated preferences for the treatment of uncomplicated malaria were examined to determine what factors predict their choice of treatment in the absence of information and institutional constraints, such as the stock of medicines or the patient's ability to pay. 518 providers working at non-profit health facilities and for-profit pharmacies and drug stores in Yaoundé and Bamenda in Cameroon and in Enugu State in Nigeria were surveyed between July and December 2009 to elicit the antimalarial they prefer to supply for uncomplicated malaria. Multilevel modelling was used to determine the effect of financial and non-financial incentives on their preference, while controlling for information and institutional constraints, and accounting for the clustering of providers within facilities and geographic areas. 69% of providers stated a preference for artemisinin-combination therapy (ACT), which is the recommended treatment for uncomplicated malaria in Cameroon and Nigeria. A preference for ACT was significantly associated with working at a for-profit facility, reporting that patients prefer ACT, and working at facilities that obtain antimalarials from drug company representatives. Preferences were similar among colleagues within a facility, and among providers working in the same locality. Knowing the government recommends ACT was a significant predictor, though having access to clinical guidelines was not sufficient. Providers are agents serving multiple principals and their preferences over alternative antimalarials were influenced by patients, drug company representatives, and other providers working at the same facility and in the local area. Efforts to disseminate drug policy should target the full range of actors involved in supplying drugs, including providers, employers, suppliers and local communities., (Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.) more...

Background: Modelling is widely used to inform decisions about management of malaria and acute febrile illnesses. Most models depend on estimates of the probability that untreated patients with malaria or bacterial illnesses will progress to severe disease or death. However, data on these key parameters are lacking and assumptions are frequently made based on expert opinion. Widely diverse opinions can lead to conflicting outcomes in models they inform., Methods and Findings: A Delphi survey was conducted with malaria experts aiming to reach consensus on key parameters for public health and economic models, relating to the outcome of untreated febrile illnesses. Survey questions were stratified by malaria transmission intensity, patient age, and HIV prevalence. The impact of the variability in opinion on decision models is illustrated with a model previously used to assess the cost-effectiveness of malaria rapid diagnostic tests. Some consensus was reached around the probability that patients from higher transmission settings with untreated malaria would progress to severe disease (median 3%, inter-quartile range (IQR) 1-5%), and the probability that a non-malaria illness required antibiotics in areas of low HIV prevalence (median 20%). Children living in low transmission areas were considered to be at higher risk of progressing to severe malaria (median 30%, IQR 10-58%) than those from higher transmission areas (median 13%, IQR 7-30%). Estimates of the probability of dying from severe malaria were high in all settings (medians 60-73%). However, opinions varied widely for most parameters, and did not converge on resurveying., Conclusions: This study highlights the uncertainty around potential consequences of untreated malaria and bacterial illnesses. The lack of consensus on most parameters, the wide range of estimates, and the impact of variability in estimates on model outputs, demonstrate the importance of sensitivity analysis for decision models employing expert opinion. Results of such models should be interpreted cautiously. The diversity of expert opinion should be recognised when policy options are debated. more...

Background: Although the molecular basis of resistance to a number of common antimalarial drugs is well known, a geographic description of the emergence and dispersal of resistance mutations across Africa has not been attempted. To that end we have characterised the evolutionary origins of antifolate resistance mutations in the dihydropteroate synthase (dhps) gene and mapped their contemporary distribution., Methods and Findings: We used microsatellite polymorphism flanking the dhps gene to determine which resistance alleles shared common ancestry and found five major lineages each of which had a unique geographical distribution. The extent to which allelic lineages were shared among 20 African Plasmodium falciparum populations revealed five major geographical groupings. Resistance lineages were common to all sites within these regions. The most marked differentiation was between east and west African P. falciparum, in which resistance alleles were not only of different ancestry but also carried different resistance mutations., Conclusions: Resistant dhps has emerged independently in multiple sites in Africa during the past 10-20 years. Our data show the molecular basis of resistance differs between east and west Africa, which is likely to translate into differing antifolate sensitivity. We have also demonstrated that the dispersal patterns of resistance lineages give unique insights into recent parasite migration patterns. more...

Background: Pseudomonas aeruginosa is a ubiquitous gram-negative pathogen with a propensity to cause opportunistic infections in humans. Different strains of the organism could colonise patients heralding a wide spectrum of P. aeruginosa infections in the environment., Objective: To analyse isolates of P. aeruginosa from clinical and environmental samples using the Polymerase Chain Reaction (PCR) to establish strain relatedness., Methods: Fifty-two strains of the organism were isolated from wound swabs, urine, sputum of patients and environmental samples from the hospital environment using standard microbiological techniques and ethical consideration. Genomic DNA of the isolates was amplified with primers AF1 (5'-AGA GTT TGA TCC TGG CTCA-3') and 1541R (5'-AAG GAG GTG ATC CAG CC-3')., Results: At least two bands were observed in all isolates typed and band sizes ranged from 0.07 - 1.5kb. The strains were genetically diverse, displaying profiles of 2 - 6 bands between 0.07 - 1.5kb., Conclusion: The study demonstrates that strain diversity could be discerned between strains of P. aeruginosa, circulating in the environment of Buea, a finding which has important epidemiological and clinical significance bearing in mind that this pathogen is highly incriminated in nosocomial infections with attendant social implications. This therefore calls for more attention in the diagnosis and management of P. aeruginosa infections in the environment of Buea, Cameroon. more...

Molecular markers or gene mutations that are associated with resistance have been the recent focus for an attempt to promptly determine the establishment of resistance to known and currently used antimalaria drugs. For control managers, the effective management of malaria would involve strategies of interruption of the malaria transmission and/or improved therapeutic management of malaria. To place molecular markers within the context of control programs requires that one recognises the two data pools necessary for effective evidence-based policy change. These include data on socio-economic determinants on the one hand and biomedical data on the other. The markers for clinical efficacy of drugs have principally been genes either associated with transport or metabolism of the drug. In malaria those that have been the most characterised are the Pfcrt, Pfmdrl for the quinolines and the dhfr and dhps genes for the anti-folates. The PfATPase has been suggested to be involved in the recently developed artermisinine based combination therapies (ACT). To consider changes in drug policy, a control manager needs to address: efficacy, transmissibility, disease dynamics, safety, epidemics, tolerability and compliance. Except for safety and tolerability/compliance, molecular markers do provide useful information. However these markers still have to be validated alongside in vitro studies and in many different ecological settings and shown to be stable over time or associated with changing drug efficacy situations. Besides the evidence provided with these tools, the government will be required to ensure a mass education of the population and care providers, and fight against illicit street vendors. The governments will therefore still wary on the resources necessary to occasion an effective switch in drug policy especially at the district level and in the rural areas where meaningful, cost-effective programs are most needed. more...

Objectives: To determine the prevalence of tuberculosis (TB) in Fako health District, to assess the effects of seasonal variation on the incidence of TB in the study area and to use sentinel analysis to predict areas of greatest infection., Design: A prospective cross sectional study based on laboratory investigations., Setting: Fako health District, South Western Cameroon., Results: The prevalence of TB was 23.3%. Tuberculosis was significantly more prevalent in males (12.6%) as compared with females (10.7%) (P = 0.034). TB prevalence was significantly different between age groups, with the highest number of cases recorded in the age group 21-30 (P = 0.002). When the health areas were compared, TB prevalence varied significantly (P = 0.001), with Limbe Town recording the highest number of TB cases. We recorded more TB cases in the wet season compared with the dry season and the difference was statistically significant (P = 0.000). There was a significant drop in the prevalence of TB over the study period (P = 0.000)., Conclusion: This study is the first to report on the effects of season on the prevalence of TB in Cameroon. These findings will therefore provide additional useful base line data for setting up TB control strategies in Cameroon. more...

Transmission of malaria depends on the successful development of the sexual stages of the parasite within the midgut of the mosquito vector. The differentiation process leading to the production of the sexual stages is delineated by several developmental switches. Arresting the progression through this sexual differentiation pathway would effectively block the spread of the disease. The successful development of such transmission-blocking agents is hampered by the lack of a detailed understanding of the program of gene expression that governs sexual differentiation of the parasite. Here we describe the isolation and functional characterization of the Plasmodium falciparum pfs16 and pfs25 promoters, whose activation marks the developmental switches executed during the sexual differentiation process. We have studied the differential activation of the pfs16 and pfs25 promoters during intraerythrocytic development by transfection of P. falciparum and during gametogenesis and early sporogonic development by transfection of the related malarial parasite P. gallinaceum. Our data indicate that the promoter of the pfs16 gene is activated at the onset of gametocytogenesis, while the activity of the pfs25 promoter is induced following the transition to the mosquito vector. Both promoters have unusual DNA compositions and are extremely A/T rich. We have identified the regions in the pfs16 and pfs25 promoters that are essential for high transcriptional activity. Furthermore, we have identified a DNA-binding protein, termed PAF-1, which activates pfs25 transcription in the mosquito midgut. The data presented here shed the first light on the details of processes of gene regulation in the important human pathogen P. falciparum. more...

Five murine monoclonal antibodies raised against Onchocerca volvulus cuticular extracts and termed MOVs (1-4 and 6) were selected based on reactivity with O. volvulus cryosections, and non-reactivity with cryosections of human skin and/or nodular tissue. Two others MOVs 5 and 7 reacted with both. Using the peroxidase-anti- peroxidase (PAP) histochemical method, the target epitopes of MOV 1 were located in the cuticle's basal and cortical layers, those of MOV 2 in the cortical layer; whilst MOV 3-7 stained the basal layer. A sandwich ELISA was then developed. The trapping polyclonal antibody was raised in rabbits utilising the same antigens as for preparation of the MOVs. Once captured on microtiter plates, target antigens were identified by the sequential binding of a MOV, followed by a goat anti-mouse globulin/peroxidase or alkaline phosphatase conjugate that catalysed a colorimetric reaction in the presence of appropriate substrates. In this system, MOV 1 emerged as the most specific and potent reagent capable of recognizing antigens of Onchocerca sp. with a minimal detection limit of 78 ng per test. MOV 1, failed to react with extracts of Loa Loa, Ascaris lumbricoides and Ascaris suum in the test. The developed assay relied on the use of MOV 1, required only 1 ml of urine or 0.05 ml serum. About 97.8% of the 47 urines and 50% of the 20 sera from patients studied gave positive results. Only 1 (3%) of 32 control urines and up to 80% of the 10 control sera studied tested positive, suggesting urine as a better specimen source.(ABSTRACT TRUNCATED AT 250 WORDS) more...

The surface polypeptide antigens of third-stage infective larvae (L3) and adult males of Onchocerca volvulus have been compared after iodogen-catalysed radioiodination, separation by sodium dodecyl sulphate-polyacrylamide gel electrophoresis in beta-mercaptoethanol followed by autoradiography. L3 surfaces contained polypeptides with apparent molecular weights of 14, 18.5, 26, 34, 51, 68 and 130 kDa, whereas the adults contained 14, 19, 26, 34, 37.5 and 68 kDa components. By immunoprecipitation with patient's sera, only the 14 and 18.5 kDa components were shown to be antigenic on the L3, the other components being unreactive with patients' antibodies. Under similar conditions, 4 of the 6 adult male polypeptides reacted with patients' antisera, confirming their antigenic nature. Lentil lectin and immunosorbent chromatography of the surface components revealed the 18.5 kDa and 68 kDa antigens of L3 and adult males respectively to be glycoproteins. The apparently weak reactivity of L3 surface components with host antibody may be part of an escape mechanism that favours the establishment of O. volvulus in human hosts. more...

By using radioiodination methods which are thought to label preferentially the surface followed by SDS-PAGE and autoradiography, components of different developmental stages of O. volvulus have been identified. Between 2 and 10 polypeptide antigens were revealed on infective larvae (L3), females, males, eggs, nodular and skin microfilariae by using immunoblotting assays with human onchocerciasis sera. Antigen recognition did not vary with the density of skin microfilariae in the patients from whom the sera were obtained. Some of the antigens seemed to be stage specific; for example, antigens of 31 kDa which were detected only on skin microfilariae, or the 67.5 and 25 kDa components that occurred on the adult females, but were absent from adult males. Some of these antigens were also identified as glycoproteins. A 68 kDa glycoprotein was found in adult females, males and nodular microfilariae. Two glycoproteins of 74 and 45 kDa were found on egg shells, and a 18.5 kDa glycoprotein was recovered from L3. Type VI collagen was found with a specific antiserum on skin microfilariae, but not on eggs and females. Laminin was found on nodular mf. It is concluded that the changing antigenic profiles of the worm stages and the coating of these worms with connective tissue epitopes contribute to the evasion of host immunity. more...

A preparation of the cuticle of Onchocerca volvulus was obtained by extracting worm fragments in an series of buffers with 1.5% Triton-X-100 and 3% Sodium dodecyl sulfate (SDS). Electron micrographs of worm fragments, treated with the detergents or collagenase showed that our methods had been effective in isolating the cuticle from the other organs of the parasite. The cuticular preparation was found to contain 19 different amino acids with glycine (23.4%); proline (11.23%); hydroxyproline (10%); and glutamic acid (9.4%) being the most abundant. Hydroxylysine was present in small amounts (0.04%). Total reducing sugar was determined to be 5.3 mg per gram dry weight of the preparation. The cuticular preparation was solubilized by boiling in 2-mercaptoethanol and shown by SDS-PAGE to contain at least 10 different polypeptides in the Mr range 17,000-163,000. Five of these polypeptides with apparent Mr respectively of 33,000; 67,000; 74,000, 88,500 and 114,000 were isolated by preparative gel electrophoresis and their amino acid compositions shown to be similar to that of invertebrate collagens. We conclude that the cuticle of O. volvulus contains collagen-like proteins held together by disulfide bridges. more...