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Onchocerciasis (river blindness) is a debilitating tropical disease that causes significant eye and skin damage, afflicting millions worldwide. As global efforts shift from disease management to elimination, vaccines have become crucial supplementary tools. The Onchocerciasis Vaccine for Africa (TOVA) Initiative was established in 2015, to advance at least one vaccine candidate initially targeting onchocerciasis in infants and children below 5 years of age, through Phase I human trials by 2025. Notably, Ov-RAL-2 and Ov-103 antigens have shown great promise during pre-clinical development, however, the overall success rate of vaccine candidates during clinical development remains relatively low due to certain adverse effects and immunogenic limitations. This study, thus, aimed at predicting the safety and immunogenicity of Ov-RAL-2 and Ov-103 potential onchocerciasis vaccine candidates prior to clinical trials. Advanced molecular simulation models and analytical immunoinformatics algorithms were applied to predict potential adverse side effects and efficacy of these antigens in humans. The analyses revealed that both Ov-RAL-2 and Ov-103 demonstrate favourable safety profiles as toxicogenic and allergenic epitopes were found to be absent within each antigen. Also, both antigens were predicted to harbour substantial numbers of a wide range of distinct epitopes (antibodies, cytokines, and T- Cell epitopes) associated with protective immunity against onchocerciasis. In agreement, virtual vaccination simulation forecasted heightened, but sustained levels of primary and secondary protective immune responses to both vaccine candidates over time. Ov-103 was predicted to be non-camouflageable, as it lacked epitopes identical to protein sequences in the human proteome. Indeed, both antigens were able to bind with high affinity and activate the innate immune TLR4 receptor, implying efficient immune recognition. These findings suggest that Ov-RAL-2 and Ov-103 can induce sufficient protective responses through diverse humoral and cellular mechanisms. Overall, our study provides additional layer of evidence for advancing the clinical development of both vaccine candidates against onchocerciasis., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Nebangwa et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Occult hepatitis B infection (OBI) is characterized by the presence of hepatitis B virus (HBV) DNA at low levels in serum (<200 IU/mL) with a negative hepatitis B surface antigen (HBsAg) test. OBI remains a major challenge to blood safety, particularly in HBV-endemic regions like Cameroon, where HBV detection relies solely on HBsAg testing. This cross-sectional study aimed to investigate the actual incidence and genotype characteristics of OBI in Cameroonian blood donors., Methods: Between March and June 2023, samples were collected from 288 HBsAg-negative blood donors aged 18 to 55 years and analysed for antibodies against the HBV core (anti-HBc) and surface antigens (anti-HBs). Following DNA extraction from the serum samples, qualitative nested PCR and quantitative real-time PCR were used to detect HBV viral DNA and viral load respectively. For positive samples, sequencing of a fragment of the S gene was performed to identify the circulating HBV genotypes., Results: The findings revealed that 58% (n = 167/288) of blood donors tested positive for anti-HBc, 29% (n = 83/288) tested positive for anti-HBs, and 26% (n = 75/288) being positive for both anti-HBc and anti-HBs. Occult hepatitis was confirmed in 4.5% of the blood donors, all of whom belonged to either HBV genotypes A or E, which are predominant in Cameroon. The amino acid substitution sA184V associated with HBsAg detection failure in genotype E was observed in 70% of OBI sequences, and the HBsAg immune escape variants (sT131N and sS143L) implicated in OBI were also observed. The mutation rtN139K in the reverse transcriptase (RT) domain of the overlapping HBV polymerase (P) gene was present in 17% of OBI-positive sequences of genotype E, likely contributing to masking HBsAg secretion., Conclusion: The results suggest a considerable risk of transfusion-transmitted HBV in this region. Therefore, to ensure blood safety, nucleic acid testing (NAT) is recommended, as relying solely on HBsAg assays is insufficient to eliminate this risk., Competing Interests: The authors declare no conflict of interest., (Copyright: © 2024 Mbencho et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

In Cameroon, Aedes mosquitoes transmit various arboviruses, posing significant health risks. We aimed to characterize the Aedes virome in southwestern Cameroon and identify potential core viruses which might be associated with vector competence. A total of 398 Aedes mosquitoes were collected from four locations (Bafoussam, Buea, Edea, and Yaounde). Aedes albopictus dominated all sites except for Bafoussam, where Aedes africanus prevailed. Metagenomic analyses of the mosquitoes grouped per species into 54 pools revealed notable differences in the eukaryotic viromes between Ae. africanus and Ae. albopictus , with the former exhibiting greater richness and diversity. Thirty-seven eukaryotic virus species from 16 families were identified, including six novel viruses with near complete genome sequences. Seven viruses were further quantified in individual mosquitoes via qRT-PCR. Although none of them could be identified as core viruses, Guangzhou sobemo-like virus and Bafoussam mosquito solemovirus, were highly prevalent regionally in Ae. albopictus and Ae. africanus , respectively. This study highlights the diverse eukaryotic virome of Aedes species in southwestern Cameroon. Despite their shared genus, Aedes species exhibit limited viral sharing, with varying viral abundance and prevalence across locations. Ae. africanus , an understudied vector, harbors a rich and diverse virome, suggesting potential implications for arbovirus vector competence.

The global burden of Salmonella infections remains high due to the emergence of multidrug resistance to all recommended treatment antibiotics. Tetrahydroisoquinolines (THIQs) have demonstrated promising activity against multidrug-resistant (MDR) Salmonella Typhi. Hence, their interaction with treatment antibiotics was investigated for possible synergy. Twenty combinations of five THIQs ( 1 , 2 , 3 , 4, and 5 ) and four antibiotics were tested against each of 7 Salmonella isolates by the checkerboard method giving a total of 140 assays performed. Fractional inhibitory concentration indices (FICIs) were calculated, and isobolograms were plotted. In terms of FICI, synergism ranged from 0.078 to 0.5 and the highest magnitude (0.078) was recorded for chloramphenicol-THIQ 1 combination. In a total of 140 antibiotics-THIQs combination assays, 27 were synergistic (17%), 42 were additive (30%), 11 were antagonistic (7.8%), and 60 were indifferent (42%). The synergistic activity recorded for each antibiotic class in combination based on the total of 7 bacterial isolates tested ranged from 14.29% to 71.43%; the highest percentage was recorded for two combinations (chloramphenicol or sulphamethoxazole with THIQ 1 ). Ciprofloxacin-THIQ 1 combination showed additivity on all bacteria isolates tested (100%). Overall, THIQ 1 was the most synergistic and most additive in combination with three antibiotics (ampicillin, chloramphenicol, or sulphamethoxazole-trimethoprim). Some combinations of the THIQs and treatment antibiotics have shown high synergism which could potentially be efficacious against multidrug-resistant S. Typhi, hence this interaction should be further studied in vivo ., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2023 Rita Ayuk Ndip et al.)

Onchocerciasis is an infectious disease of public health and socio-economic importance in most parts of Sub-Saharan Africa. The objective of this study was to evaluate the effects of the suspension of implementation activities towards combating onchocerciasis in the Bandjoun and Massangam health districts in the West Region of Cameroon as a consequence of the COVID-19 pandemic. Data on socio-demographic and clinical characteristics were obtained using a structured questionnaire. All participants in both health districts were examined for the presence of clinical manifestations of onchocerciasis. In addition, two skin snips were obtained from the knee of each participant and examined for the presence of microfilaria. All data were categorized, coded, entered in a database, and analysed using SPSS version 23.0. A total of 229 participants in the Bandjoun health district and 378 in the Massangam health district were recruited for the study. In both health districts, there was no significant difference between male and female participants in terms of the clinical manifestations of onchocerciasis. The prevalence of nodules was 8.7% in the Bandjoun health district and 20.6% in the Massangam health district while the prevalence of microfilaria carriers in Bandjoun and Massangam health districts was 3.5% and 3.7%, respectively. Except for the Tsesse and Lemgo communities in the Bandjoun health district, there was a reduction in the prevalence of microfilaria in the communities that were studied when compared to previous data obtained before the disruption of control programmes activities. Overall, in both health districts, elderly individuals bear the largest burden of onchocerciasis. Based on the results obtained, we conclude that the temporary suspension of Neglected Tropical Disease control programme activities by the World Head Organization as a result of COVID-19 may have resulted to recrudescence of O. volvulus transmission in hypoendemic communities in the Bandjoun health district., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: In respect of the WHO's commendation to incorporate traditional medicine (TM) in health care, the Cameroon government wants to promote the use of the traditional medicine and is resolute on encouraging the treatment of patients with alternative medicine from traditional sources. This study explores the use of herbal tea by Cameroonian adults to prevent or treat diseases and the socio-demographic determinants of tea use among participants., Methods: A cross-sectional survey was conducted among 307 Cameroonian adults (18-65 years) randomly selected within 4 hospitals and 4 communities in the Centre and Southwest regions of Cameroon between 04/01-20/04/2022, using interviewer administered semi-structured questionnaires. Binary logistic regression analysis was conducted to determine the association between variables., Results: Over four-fifth (89.3%) of participants had taken herbal teas at least once within the last 2 years prior to the survey, and most participants used the teas for the prevention and treatment of Covid-19 (67.9%), malaria (59.7%) and typhoid fever (35%). Most respondents took the teas warm (75%), and the treatment dosage used by most respondents (51%) was "one glass in the morning and evening for one to two weeks". The teas taken by 70% of users had bad or bitter taste and 52.2% of them were uncomfortable with the bad taste. However, the majority of users completed their treatment dosage (72%), 90.5% of them were willing to use teas for treatment if prescribed in health facilities in future, and 90.1% were in support that herbal teas should be prescribed in hospitals. There was no significant association (p ≥ 0.05) between sociodemographic characteristics of participants and herbal tea use. However, the major motivating factor for acceptability of herbal tea use was treatment effectiveness (52.7%)., Conclusion: There is high prevalence of herbal tea use among adults Cameroonians in the studied settings in the Centre and Southwest regions of Cameroon, with a positive opinion and willingness to use teas if prescribed in health facilities. Authorities must ensure the effectiveness and safety of traditional medicine served in health facilities, to enhance compliance and adequate use., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Malaria is the most widespread endemic disease in Cameroon, and asymptomatic Plasmodium (gametocyte) carriers (APCs) constitute more than 95% of infectious human reservoirs in malaria endemic settings. This study assesses the knowledge of asymptomatic malaria (ASM) among health care workers (HCWs) in health facilities (HFs) in the Centre Region of Cameroon and the acceptability of using Artemisia afra tea to treat APCs. A cross-sectional descriptive survey was conducted among 100 HCWs, in four randomly selected HFs in the Centre Region, in the period of 1-20 April 2022, using semi-structured self-administered questionnaires. Logistic regression analyses were performed to determine factors associated with knowledge. More than seven in eight (88%) respondents were aware of the existence of ASM, 83% defined ASM correctly, 75% knew how it was diagnosed, 70% prescribe ACTs for APCs, and 51.1% were informed about ASM transmission. The professional category of HCWs was significantly associated with their knowledge of the existence and transmission of ASM, and longevity of service was associated with knowledge of transmission ( p < 0.05). Two-thirds (67%) of respondents knew about Artemisia afra tea, 53.7% believed that it was effective in treating ASM, and 79% were willing to prescribe it if authorized. There was a fair level of knowledge of ASM among HCWs in the study settings.

There are over 500 species of the genus Artemisia in the Asteraceae family distributed over the globe, with varying potentials to treat different ailments. Following the isolation of artemisinin (a potent anti-malarial compound with a sesquiterpene backbone) from Artemisia annua , the phytochemical composition of this species has been of interest over recent decades. Additionally, the number of phytochemical investigations of other species, including those of Artemisia afra in a search for new molecules with pharmacological potentials, has increased in recent years. This has led to the isolation of several compounds from both species, including a majority of monoterpenes, sesquiterpenes, and polyphenols with varying pharmacological activities. This review aims to discuss the most important compounds present in both plant species with anti-malarial properties, anti-inflammatory potentials, and immunomodulating properties, with an emphasis on their pharmacokinetics and pharmacodynamics properties. Additionally, the toxicity of both plants and their anti-malaria properties, including those of other species in the genus Artemisia , is discussed. As such, data were collected via a thorough literature search in web databases, such as ResearchGate, ScienceDirect, Google scholar, PubMed, Phytochemical and Ethnobotanical databases, up to 2022. A distinction was made between compounds involved in a direct anti-plasmodial activity and those expressing anti-inflammatory and immunomodulating activities or anti-fever properties. For pharmacokinetics activities, a distinction was made between compounds influencing bioavailability (CYP effect or P-Glycoprotein effect) and those affecting the stability of pharmacodynamic active components.

Background: Plasmodium falciparum resistance to intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) continues to spread throughout sub-Saharan Africa. This study assessed the occurrence of microscopic and sub-microscopic P. falciparum parasitaemia, dihydropteroate synthase mutations associated with resistance to SP and maternal anaemia in the Mount Cameroon area., Methods: Consenting pregnant women living in semi-rural and semi-urban/urbanized settings were enrolled in this cross-sectional study. Socio-demographic, antenatal and clinical data were documented. Microscopic and sub-microscopic parasitaemia were diagnosed using peripheral blood microscopy and nested polymerase chain reaction (PCR) respectively. The dhps mutations were genotyped by restriction fragment length polymorphism analysis. The presence of A437G, K540E, and A581G was considered a marker for high-level resistance. Haemoglobin levels and anaemia status were determined., Results: Among the women, the prevalence of microscopic and sub-microscopic P. falciparum infection were 7.7% (67/874) and 18.6% (93/500) respectively. Predictors of microscopic infection were younger age (< 21 years) (AOR = 2.89; 95% CI 1.29-6.46) and semi-rural settings (AOR = 2.27; 95% CI 1.31-3.96). Determinants of sub-microscopic infection were the rainy season (AOR, 3.01; 95% CI 1.77-5.13), primigravidity (AOR = 0.45; 95% CI 0.21-0.94) and regular ITN usage (AOR = 0.49; 95% CI 0.27-0.90). Of the145 P. falciparum isolates genotyped, 66.9% (97) carried mutations associated with resistance to SP; 33.8% (49), 0%, 52.4% (76) and 19.3% (28) for A437G, K540E, A581G and A437G + A581G respectively. The A581G mutation was associated with ≥ 3 SP doses evident only among sub-microscopic parasitaemia (P = 0.027) and multigravidae (P = 0.009). Women with microscopic infection were more likely from semi-rural settings (AOR = 7.09; 95% CI 2.59-19.42), to report history of fever (AOR = 2.6; 95% CI 1.07-6.31), to harbour parasites with double resistant mutations (AOR = 6.65; 95% CI 1.85-23.96) and were less likely to have received 2 SP doses (AOR = 0.29; 95% CI 1.07-6.31). Microscopic infection decreased Hb levels more than sub-microscopic infection., Conclusion: The occurrence of sub-microscopic P. falciparum parasites resistant to SP and intense malaria transmission poses persistent risk of malaria infection during pregnancy in the area. ITN usage and monitoring spread of resistance are critical., (© 2023. The Author(s).)

In low- and middle-income countries, undernutrition often co-exists with intestinal parasites, especially Soil Transmitted Helminth (STH) infections in children. The collective impact of both conditions result in undernutrition and can exacerbate the general poor health status of children. A cross-sectional survey of 422 mother-child (12-59 months old) pairs from 14 villages in the District of Ndelele, East Region of Cameroon, was carried out to assess the magnitude and correlates of undernutrition and intestinal parasites. Socio-demographic data were collected from mothers and anthropometric data were collected from children. Parasitological assessment was performed using a combination of direct microscopy flotation, sedimentation and centrifugation techniques. Correlates of undernutrition and intestinal parasites were identified using multinomial logistic regression at individual and household levels. 83.77% of the children assessed for undernutrition were undernourished and 66.82% were positive for one or more intestinal parasites. It was not uncommon for the study participants to be concurrently infected with two or more intestinal parasites. The most common intestinal parasitic infections detected in the study were A. lumbricoides, E. histolytica/dispar and Hookworm infection. Multinomial logistic regression using Nutritional status as outcome showed that, children who were not exclusively breastfed were 106% (RR = 2.06; C.I = 1.12-3.80) more likely to be underweight compared to those who were exclusively breastfed. The household size of 4 to 6 persons also significantly impacted wasting (p-value = 0.007) at 7% (RR = 1.07, C.I = 0.49-2.32). Analysis by a logistic regression model with STH infection as outcome revealed that, Fingernail cleanness (p-value = 0.044; AOR = 1.75; CI = 1.09-2.78) and household size (p-value = 0.038; AOR = 0.55; CI = 0.32-0.92) were positively associated with intestinal parasite infection at the 5% significant level. This study reveals that intestinal helminthic parasitic infections (STH) and undernutrition are serious health problems in children below five in the study area. To address this dire situation, concerted efforts are needed to improve sanitation, hygiene education access, community deworming programs, and improve diets., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2022 Asa et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The onset and rapid spread of chloroquine resistance and the introduction of amodiaquine for the treatment of uncomplicated malaria in Cameroon have influenced the proportion of Plasmodium falciparum sensitive and resistant alleles related to 4-aminoquinoline drugs. This study was undertaken to determine the prevalence of resistance markers to antimalarial 4-aminoquinolines in Douala in the Littoral Region, and Buea in the South West Region in June 2020. Dry blood spots were prepared from malaria microscopy positive cases and used for parasite DNA extraction by chelex-100 method. Plasmodium species identification was carried out by PCR amplification/agarose gel electrophoresis of 18srRNA. The Pfcrt and Pfmdr1 genes were amplified by PCR followed by restriction digestion. The prevalence of single nucleotide polymorphisms (SNPs) was compared between study sites and with previous studies carried out between 2003-2005 and 2009-2011 using the Chi square test. The results showed that Plasmodium falciparum was the dominant species occurring as mono-infections (84.6%). The wild type K76 allele of the Pfcrt gene was found in 74.9% of isolates while the wild N86, Y184 and D1246 alleles of the Pfmdr1 gene were found respectively in 87.2%, 89.6% and 100% of field isolates. The results showed a significant reduction in the mutant alleles compared to results obtained in 2003-2005 and 2009-2013. The KNYD haplotype was observed to be the most prevalent. The results indicated that there is a gradual erosion of the mutant Pfcrt and Pfmdr1 genotype and a gradual return to the sensitive P. falciparum genotype in Cameroon.

The cuticle of C. elegans is impermeable to chemicals, toxins, and pathogens. However, increased permeability is a desirable phenotype because it facilitates chemical uptake. Surface lipids contribute to the permeability barrier. Here, we identify the lipid transfer protein GMAP-1 as a critical element setting the permeability of the C. elegans cuticle. A gmap-1 deletion mutant increases cuticular permeability to sodium azide, levamisole, Hoechst, and DiI. Expressing GMAP-1 in the hypodermis or transiently in the adults is sufficient to rescue this gmap-1 permeability phenotype. GMAP-1 protein is secreted from the hypodermis to the aqueous fluid filling the space between collagen fibers of the cuticle. In vitro , GMAP-1 protein binds phosphatidylserine and phosphatidylcholine while in vivo , GMAP-1 sets the surface lipid composition and organization . Altogether, our results suggest GMAP-1 secreted by hypodermis shuttles lipids to the surface to form the permeability barrier of C. elegans ., Competing Interests: The authors declare no competing interests., (© 2022 The Authors.)

African swine fever and swine erysipelas are two devastating diseases with similar manifestations ravaging the domestic pig industry. Only a single phylogenetic study has been carried out in Cameroon, and neither an extensive genotyping aimed at identifying the different serotypes nor has an appropriate differential diagnosis of different species of Erysipelothrix has been effected in ASF-infected animals. Of the 377 blood or tissue samples randomly collected from pig farms and slaughter slabs from January to August 2020, 120 were positive for ASFV (by PCR), giving a prevalence of 31.83%. Intragenomic resolution through sequencing divulged the presence of genotypes I, and Ia, two variants with 19 (ABNAAAACBNABTDBNAFA) and six (ABNAFA) tandem repeat sequences (TRS), serotype IV, and a single GGAATATATA repeat. The sole presence of E. tonsillarum (avirulent species) and not E. rhusiopathiae (virulent species) indicates that the severity observed during the 2020 ASF outbreak in the sampled regions was exclusively due to ASFV genotype I infection. Such characterisations are necessary for designing effective control measures and future potential vaccine candidates.

Onchocerciasis is a Neglected Tropical Disease that has a significant socioeconomic impact, especially in Sub-Saharan Africa. Numerous reports indicate that the Expanded Special Project for the Elimination of Neglected Tropical Diseases needs novel diagnostic tools before achieving its goal of successful elimination of onchocerciasis in Africa. The current diagnostic tests are either invasive, insensitive, or not applicable in the field and about 25% of persons infected cannot mount immune responses against the single antigen used in the only approved Ov-16 serological test. In the quest to identify novel biomarkers that can be used to certify that a patient is free from the disease, evaluate the progress of elimination programmes, and conduct post elimination surveillances, mass spectrometric analysis of Onchocerca volvulus crude extract revealed that 1392 proteins are expressed in the adult and microfilariae stages of the parasite. Computational analysis predicted six of the proteins as O. volvulus potential diagnostic targets. Linear B-epitopes were predicted from the six proteins and used to construct a multiepitope antigen (OvMCBL02). Serological analysis revealed that the OvMCBL02 test significantly differentiated between serum samples of onchocerciasis patients from the Kombone Health Area in the South West Region of Cameroon ( n = 63) and control serum samples from Rwanda ( n = 29) and Europe ( n = 26) as well as between serum samples from the onchocerciasis hyperendemic region of Kombone Health Area ( n = 63) and the hypoendemic region of Bandjoun Health District ( n = 54). Interestingly, the test did not cross-react with serum samples from patients suffering from related nematode infections, thereby suggesting that further characterization of the OvMCBL02 multiepitope antigen will render it an additional member of the diagnostic toolbox for the elimination of onchocerciasis.

The current serological test for human onchocerciasis relies on IgG4 reactivity against the parasite Ov-16 antigen, with reported sensitivities of only 60-80%. As control programs move from control to elimination, it is imperative to identify novel molecules that could improve the serodiagnosis reliability of this disease. In this study we compared the sensitivity of total IgG against OvMANE1-a chimeric antigen previously identified as a potential biomarker of human onchocerciasis-with that of an Ov-16 antibody test to detect an Onchocerca volvulus infection in persons presenting with microfilaria in skin snips. One hundred and ninety serum samples were obtained from persons with epilepsy in an onchocerciasis-endemic area at Ituri in the Democratic Republic of Congo where ivermectin has never been distributed. Fifty-nine (31.1%) samples were from individuals with a positive skin snip test; 41 (69.5%) of these 59 samples were positive with the OvMANE1 test and 41 (69.5%) with the Ov-16 test; 30 (50.8%) samples were positive for both tests and in 52 (88.1%) at least one of the tests was positive. Testing the 131 sera from persons with a negative skin snip result revealed that 63 (48.1%) were positive exclusively with the OvMANE1 test, 13 (9.9%) exclusively with the Ov-16 test and 25 (19.1%) with both tests. Nine European samples from individuals without past travel history in onchocerciasis endemic zones and 15 samples from Rwanda, a hypoendemic country for onchocerciasis were all negative for the OvMANE1 and Ov-16 tests. However, the specificity of both tests was difficult to determine due to the lack of a gold standard for antibody tests. In conclusion, the tandem use of OvMANE1 and Ov-16 tests improves the sensitivity of detecting Onchocerca volvulus seropositive individuals but, the OvMANE1 test needs to be further evaluated on samples from a population infected with other helminths to cautiously address its specificity.

Background: The Mount Cameroon area has experienced a 57.2% decline in confirmed malaria cases between 2006 and 2013 with the implementation of different control measures but, the disease is still of public health concern. The objective of the study was to assess the burden of asymptomatic and sub-microscopic Plasmodium infection, altitudinal influence on it, their effect on haematological parameters as well as identify the risk factors of infection., Methodology: A cross-sectional community-based survey involving 1319 children of both sexes aged 6 months to 14 years was conducted between July 2017 and May 2018. Malaria parasitaemia was confirmed by Giemsa-stained microscopy, sub-microscopic Plasmodium infection by 18S mRNA using nested PCR and full blood count analysis was done using an auto haematology analyser., Results: Malaria parasite, asymptomatic malaria parasitaemia and sub-microscopic Plasmodium infection and anaemia were prevalent in 36.4%, 34.0%, 43.8% and 62.3% of the children, respectively. The risk of having sub-microscopic Plasmodium infection was highest in children 5‒9 (OR = 3.13, P < 0.001) and 10‒14 years of age (OR = 8.18, P < 0.001), non-insecticide treated net users (OR = 1.69, P < 0.04) and those anaemic (OR = 9.01, P < 0.001). Children with sub-microscopic infection had a significantly lower mean haemoglobin (9.86 ± 1.7 g/dL, P < 0.001), red blood cell counts (4.48 ± 1.1 × 10 12 /L, P < 0.001), haematocrit (31.92%, P < 0.001), mean corpuscular haemoglobin concentration (313.25 ± 47.36, P = 0.035) and platelet counts (280.83 ± 112.62, P < 0.001) than their negative counterparts. Children < 5 years old (73.8%), having asymptomatic (69.8%) and sub-microscopic Plasmodium infection (78.3%) as well as resident in the middle belt (72.7%) had a higher prevalence of anaemia than their peers., Conclusion: The meaningful individual-level heterogeneity in the burden of asymptomatic and sub-microscopic Plasmodium infection in addition to its corollary on haematological variables among children in the different attitudinal sites of the Mount Cameroon Region accentuate the need for strategic context specific planning of malaria control and preventative measures., (© 2021. The Author(s).)

One of the most debilitating consequences of aging is the progressive decline in immune function, known as immunosenescence. This phenomenon is characterized by a shift in T-cell phenotypes, with a manifest decrease of naive T-cells-dealing with newly encountered antigens-and a concomitant accumulation of senescent and regulatory T-cells, leading to a greater risk of morbidity and mortality in older subjects. Additionally, with aging, several studies have unequivocally revealed an increase in the prevalence of onchocerciasis infection. Most lymphatic complications, skin and eye lesions due to onchocerciasis are more frequent among the elderly population. While the reasons for increased susceptibility to onchocerciasis with age are likely to be multi-factorial, age-associated immune dysfunction could play a key role in the onset and progression of the disease. On the other hand, there is a growing consensus that infection with onchocerciasis may evoke deleterious effects on the host's immunity and exacerbate immune dysfunction. Indeed, Onchocerca volvulus has been reported to counteract the immune responses of the host through molecular mimicry by impairing T-cell activation and interfering with the processing of antigens. Moreover, reports indicate impaired cellular and humoral immune responses even to non-parasite antigens in onchocerciasis patients. This diminished protective response may intensify the immunosenescence outcomes, with a consequent vulnerability of those affected to additional diseases. Taken together, this review is aimed at contributing to a better understanding of the immunological and potential pathological mechanisms of onchocerciasis in the older population.

Background: Genotyping is a powerful tool for investigating outbreaks of infectious diseases and it can provide useful information such as identifying the source and route of transmission, and circulating strains involved in the outbreak. Genotyping techniques based on variable number of tandem repeats (VNTR) are instrumental in detecting heterogeneity in Mycobacterium ulcerans (MU) and also for discriminating MU from other mycobacteria species. Here, we describe and map the distribution of MU genotypes in Buruli ulcer (BU) endemic communities of the Nyong valley in Cameroon. We also tested the hypothesis of whether the suspected animal reservoirs of BU that share the human microhabitat are shedding contaminated fecal matters and saliva into their surrounding environments., Methods: Environmental samples from suspected MU-risk factors and lesion swabs from human patients were sampled in BU-endemic communities and tested for the presence of MU by qPCR targeting three independent sequences (IS2404, IS2606, KR-B). Positive samples to MU were further genotyped by VNTR with confirmation by sequencing of four loci (MIRU1, Locus 6, ST1, Locus 19)., Results: MU was detected in environmental samples including water bodies (23%), biofilms (14%), detritus (10%), and in human patients (73%). MU genotypes D, W, and C were found both in environmental and human samples. The micro geo-distribution of MU genotypes from communities showed that genotype D is found both in environmental and human samples, while genotypes W and C are specific to environmental samples and human lesions, respectively. No obvious focal grouping of MU genotypes was observed at the community scale. An additional survey in the human microhabitat suggests that domestic and wild animals do not shed MU in their saliva and feces in sampled communities., Conclusions: VNTR typing uncovered different MU genotypes circulating in the endemic communities of the Akonolinga district. A MU environmental genotype was found in patients, yet the mechanism of contamination remains to be investigated; and recovering MU in culture from the environment remains key priority to enable a better understanding of the mode of transmission of BU. We also conclude that excretions from suspected animals are unlikely to be major sources of MU in the Nyong Valley in Cameroon.

African swine fever (ASF) is a hemorrhagic contagious porcine disease caused by the African swine fever virus. The disease poses enormous problems to the pork industry with pig mortality ranging from 30% to 100%, depending on the virulence of the virus circulating. Cameroon, situated in Central Africa is one of the countries in which the African swine fever virus (ASFV) has been endemic since its first outbreak in 1982. The disease is a major problem to the pig industry causing huge economic losses. A clear and concise review on ASF in Cameroon relating to the entry and current genotype of the virus, epidemiology, pathogenesis and economic impact is lacking. A thorough literature search revealed: (1) The virus entered the country in 1982 and caused the death of 80% of the pigs. (2) All isolates belong to serogroup I and only Genotype I is circulating in Cameroon principally in the domestic cycle as there are neither soft ticks nor warthog in the pig production regions sampled. (3) 70% of the pig farmers are involved in the traditional system of production with local and hybrid breeds of pigs with minimal input. (4) The country is endemic to the virus with huge economic losses. (5) So far, very little research has been effected on ASFV in Cameroon. This review gives a detailed overview of the situation of African swine fever virus (ASFV) in the country along with potential avenues for future research into ASFV in Cameroon.

: Onchocerciasis is a skin and eye disease that exerts a heavy socio-economic burden, particularly in sub-Saharan Africa, a region which harbours greater than 96% of either infected or at-risk populations. The elimination plan for the disease is currently challenged by many factors including amongst others; the potential emergence of resistance to the main chemotherapeutic agent, ivermectin (IVM). Novel tools, including preventative and therapeutic vaccines, could provide additional impetus to the disease elimination tool portfolio. Several observations in both humans and animals have provided evidence for the development of both natural and artificial acquired immunity. In this study, immuno-informatics tools were applied to design a filarial-conserved multi-epitope subunit vaccine candidate, (designated Ov-DKR-2) consisting of B-and T-lymphocyte epitopes of eight immunogenic antigens previously assessed in pre-clinical studies. The high-percentage conservation of the selected proteins and epitopes predicted in related nematode parasitic species hints that the generated chimera may be instrumental for cross-protection. Bioinformatics analyses were employed for the prediction, refinement, and validation of the 3D structure of the Ov-DKR-2 chimera . In-silico immune simulation projected significantly high levels of IgG1, T-helper, T-cytotoxic cells, INF-γ, and IL-2 responses. Preliminary immunological analyses revealed that the multi-epitope vaccine candidate reacted with antibodies in sera from both onchocerciasis-infected individuals, endemic normals as well as loiasis-infected persons but not with the control sera from European individuals. These results support the premise for further characterisation of the engineered protein as a vaccine candidate for onchocerciasis., Competing Interests: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

Background: Reducing the burden of malaria requires better understanding of vector populations, particularly in forested regions where the incidence remains elevated. Here, we characterized malaria vectors in a locality near the Yaoundé international airport, Cameroon, including species composition, abundance, Plasmodium infection rate, insecticide resistance profiles and underlying resistance mechanisms. Methods: Blood-fed adult mosquitoes resting indoors were aspirated from houses in April 2019 at Elende, a locality situated 2 km from the Yaoundé-Nsimalen airport. Female mosquitoes were forced to lay eggs to generate F 1 adults. Bioassays were performed to assess resistance profile to the four insecticides classes. The threshold of insecticide susceptibility was defined above 98% mortality rate and mortality rates below 90% were indicative of confirmed insecticide resistance. Furthermore, the molecular basis of resistance and Plasmodium infection rates were investigated. Results: Anopheles funestus s.s. was the most abundant species in Elende (85%) followed by Anopheles gambiae s.s. (15%) with both having similar sporozoite rate. Both species exhibited high levels of resistance to the pyrethroids, permethrin and deltamethrin (<40% mortality). An. gambiae s.s. was resistant to DDT (9.9% mortality) and bendiocarb (54% mortality) while susceptible to organophosphate. An. funestus s.s. was resistant to dieldrin (1% mortality), DDT (86% mortality) but susceptible to carbamates and organophosphates. The L119F-GSTe2 resistance allele (8%) and G119S ace -1 resistance allele (15%) were detected in An. funestus s.s. and An. gambiae s.s., respectively . Furthermore, the high pyrethroid/DDT resistances in An. gambiae corresponded with an increase frequency of 1014F kdr allele (95%). Transcriptional profiling of candidate cytochrome P450 genes reveals the over-expression of CYP6P5 , CYP6P9a and CYP6P9b. Conclusion: The resistance to multiple insecticide classes observed in these vector populations alongside the significant Plasmodium sporozoite rate highlights the challenges that vector control programs encounter in sustaining the regular benefits of contemporary insecticide-based control interventions in forested areas., Competing Interests: No competing interests were disclosed., (Copyright: © 2020 Nkemngo FN et al.)

Ageing is characterized by a low-grade chronic inflammation marked by elevated circulating levels of inflammatory mediators. This chronic inflammation occurring in the absence of obvious infection has been coined as inflammageing and represents a risk factor for morbidity and mortality in the geriatric population. Also, with ageing, important perturbations in the gut microbiota have been underlined and a growing body of literature has implicated age-related gut dysbiosis as contributing to a global inflammatory state in the elderly. Notwithstanding, very little attention has been given to how gut microbiota impact inflammageing. Here, we investigate the available evidence regarding the association between inflammageing and gut microbiota during ageing. PubMed, Web of Science and Scopus were systematically screened, and seven relevant articles in animals or humans were retrieved. The animal studies reported that Parabacteroides, Mucispirillum, Clostridium and Sarcina positively associate with the pro-inflammatory MCP-1 while Akkermansia, Oscillospira, Blautia and Lactobacillus negatively correlate with MCP-1. Furthermore, "aged"-type microbiota were associated with increased levels of IL6, IL-10, Th1, Th2, Treg, TNF-α, TGF-β, p16, SAMHD1, Eotaxin, and RANTES; activation of TLR2, NF-κB and mTOR; and with decreased levels of cyclin E and CDK2. On the other hand, the study on humans demonstrated that bacteria of the phylum Proteobacteria exhibited a positive correlation with IL-6 and IL-8, while Ruminococcus lactaris et rel. portrayed a negative correlation with IL-8. We conclude that changes in "aged"-type gut microbiota are associated with inflammageing., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The enormity of the public health burden of onchocerciasis motivated the creation of various large-scale control programs that have depended principally on mass treatment of endemic communities with ivermectin for the elimination of the disease. Parasitological evaluation of Onchocerca species in the West Region of Cameroon indicates significant progress in the interruption of parasite transmission in some communities under ivermectin treatment. However, to verify the complete elimination of onchocerciasis, entomological assessment through O-150 PCR poolscreen of black flies is mandatory. Thus, in the present study, we assessed transmission of Onchocerca species using an O-150 PCR technique to screen pools of black flies-in seven onchocerciasis endemic communities (Makouopsap, Bankambe, Lemgo, Tsesse, Ndionzou, Kouffen, and Bayon) in Cameroon. Two thousand black flies were assessed-in each community-for the presence of Onchocerca species DNA. Our results show that the frequency of infective flies was 0.6% in Makouopsap and 0.0% in the other communities. On the other hand, the frequency of infected flies was 0.8% in Makouopsap, 0.2% in Bankambe, 0.1% in Bayon, and 0.0% in Lemgo, Tsesse, Ndionzou, and Kouffen. These results provide entomologic evidence for continuous transmission of Onchocerca species in Makouopsap, risk of active transmission in Bankambe, and Bayon, and a suppressed transmission in the four other studied communities.

Background: Reducing the burden of malaria requires better understanding of vector populations, particularly in forested regions where the incidence remains elevated. Here, we characterized malaria vectors in a locality near the Yaoundé international airport, Cameroon, including species composition, abundance, Plasmodium infection rate, insecticide resistance profiles and underlying resistance mechanisms. Methods: Blood-fed adult mosquitoes resting indoors were aspirated from houses in April 2019 at Elende, a village located 2 km from the Yaoundé-Nsimalen airport. Female mosquitoes were forced to lay eggs to generate F 1 adult progeny. Bioassays were performed to assess resistance profile to insecticides. The threshold of insecticide susceptibility was defined above 98% mortality rate and mortality rates below 90% were indicative of confirmed insecticide resistance. Furthermore, the molecular basis of resistance and Plasmodium infection rates were investigated. Results: Anopheles funestus s.s. was most abundant species in Elende (85%) followed by Anopheles gambiae s.s. (15%) with both having a similar sporozoite rate. Both species exhibited high levels of resistance to pyrethroids (<40% mortality). An. gambiae s.s. was also resistant to DDT (9.9% mortality) and bendiocarb (54% mortality) while susceptible to organophosphate. An. funestus s.s. was resistant to dieldrin (1% mortality), DDT (86% mortality) but susceptible to carbamates and organophosphates. The L119F-GSTe2 resistance allele (8%) and G119S ace -1 resistance allele (15%) were detected in An. funestus s.s. and An. gambiae s.s., respectively . Furthermore, the high pyrethroid/DDT resistances in An. gambiae s.s. corresponded with an increase frequency of 1014F kdr allele (95%). Transcriptional profiling of candidate cytochrome P450 genes reveals the over-expression of CYP6P5 , CYP6P9a and CYP6P9b. Conclusion: The resistance to multiple insecticide classes observed in these vector populations alongside the high Plasmodium sporozoite rate highlights the challenges that vector control programs encounter in sustaining the regular benefits of contemporary insecticide-based control interventions in forested areas., Competing Interests: No competing interests were disclosed., (Copyright: © 2020 Nkemngo FN et al.)

The public health goal of onchocerciasis in Africa has advanced from control to elimination. In this light, accurate diagnosis is necessary to determine treatment endpoints and confirm elimination, as well as to conduct surveillance for the identification of any possible recrudescence of the disease. Currently, the monitoring of onchocerciasis elimination relies on the Ov-16 test. However, this test is unable to discriminate between past and active infections. Furthermore, about 15-25% of infected persons are reported to be negative for the Ov-16 test, giving a misleading sense of security to false-negative individuals who might continue to serve as reservoirs for infections. Therefore, we opted to design and validate a more sensitive and specific chimeric antigen (OvMANE1) for onchocerciasis diagnosis, using previously reported immunodominant peptides of O. volvulus, the parasite responsible for the disease. In silico analysis of OvMANE1 predicted it to be more antigenic than its individual peptides. We observed that OvMANE1 reacts specifically and differentially with sera from O. volvulus infected and non-infected individuals, as well as with sera from communities of different levels of endemicity. Moreover, we found that total IgG, unlike IgG4 subclass, positively responded to OvMANE1, strongly suggesting its complementarity to the Ov-16 diagnostic tool, which detects Ov-16 IgG4 antibodies. Overall, OvMANE1 exhibited the potential to be utilized in the development of specific diagnostic tools-based on both antibody capture and antigen capture reactions-which are indispensable to monitor the progress of onchocerciasis elimination programs.

Onchocerca volvulus is the nematode pathogen responsible for human onchocerciasis also known as "River blindness", a neglected tropical disease that affects up to 18 million people worldwide. Helminths Excretory Secretory Products (ESPs) constitute a rich repertoire of molecules that can be exploited for host-parasite relationship, diagnosis and vaccine studies. Here, we report, using a range of molecular techniques including PCR, western blot, recombinant DNA technology, ELISA, high performance thin-layer chromatography and mass spectrometry that the 28 KDa cysteine-rich protein (Ov28CRP) is a reliable component of the O. volvulus ESPs to address the biology of this parasite. We showed that (1) Ov28CRP is a putative ganglioside GM2 Activator Protein (GM2AP) conserved in nematode; (2) OvGM2AP gene is transcriptionally activated in all investigated stages of the parasitic life cycle, including larval and adult stages; (3) The full-length OvGM2AP was detected in in-vitro O. volvulus ESPs of adult and larval stages; (4) the mass expressed and purified recombinant OvGM2AP purified from insect cell culture medium was found to be glycosylated at asparagine 173 and lacked N-terminal signal peptide sequence; (5) the recombinant OvGM2AP discriminated serum samples of infected and uninfected individuals; (6) OvGM2AP competitively inhibits MUG degradation by recombinant β-hexosaminidase A but not MUGS, and could not hydrolyze the GM2 to GM3; (7) humoral immune responses to the recombinant OvGM2AP revealed a negative correlation with ivermectin treatment. Altogether, our findings suggest for the first time that OvGM2AP is an antigenic molecule whose biochemical and immunological features are important to gain more insight into our understanding of host-parasite relationship, as well as its function in parasite development at large., Competing Interests: The authors have declared no competing interests exist.

Recent studies in Cameroon after 20 years of implementation of the Community Directed Treatment with ivermectin (CDTI) strategy, revealed mixed results as regards community ownership. This brings into question the feasibility of Community Directed Interventions (CDI) in the country. We carried out qualitative surveys in 3 health districts of Cameroon, consisting of 11 individual interviews and 10 Focus Group Discussions (FGDs) with specific community members. The main topic discussed during individual interviews and FGDs was about community participation in health. We found an implementation gap in CDTI between the process theory in the 3 health districts. Despite this gap, community eagerness for health information and massive personal and financial adhesion to interventions that were perceived important, were indicators of CDI feasibility. The concept of CDI is culturally feasible in rural and semi-urban settlements, but many challenges hinder its actual implementation. In the view of community participation as a process rather than an intervention, these challenges include real dialogue with communities as partners, dialogue and advocacy with operational level health staff, and macroeconomic and political reforms in health, finance and other associated sectors.

Background: The global burden of onchocerciasis is the heaviest in sub-Saharan Africa. Studies have shown the importance of the role of Community-Directed Distributors (CDDs) and nurses in onchocerciasis control, but little is known about their experience in implementing onchocerciasis control programmes. Our aim was to document the barriers that CDDs and local health administrators face in implementing onchocerciasis control activities., Methods: We conducted a qualitative survey consisting of 16 in-depth interviews and 8 focus group discussions (FGDs) across three health districts of Cameroon. We interviewed a total of 9 local health officials at the district and Health Area levels, and 7 CDDs. Eight FGDs were conducted with CDDs and Health Committee members., Results: The major barriers to the implementation of Community Directed Treatment with Ivermectin that we identified were linked and interrelated. Examples of these barriers included: contextual factors (geographical and cultural background), top-to-bottom planning, insufficient human and material resources, and lack of transparency in the management of the programme's funds., Conclusions: The CDTI at operational level still faces many obstacles which negatively affect therapeutic coverages. This can lead to the non-adhesion of the communities to the programme, consequently jeopardizing the sustainability of the onchocerciasis elimination programme. We recommend that the national programme planners put in place a transparent management and planning system for onchocerciasis elimination activities, with better communication with local programme stakeholders.

Onchocerciasis is a parasitic disease with high socio-economic burden particularly in sub-Saharan Africa. The elimination plan for this disease has faced numerous challenges. A multi-epitope prophylactic/therapeutic vaccine targeting the infective L3 and microfilaria stages of the parasite's life cycle would be invaluable to achieve the current elimination goal. There are several observations that make the possibility of developing a vaccine against this disease likely. For example, despite being exposed to high transmission rates of infection, 1 to 5% of people have no clinical manifestations of the disease and are thus considered as putatively immune individuals. An immuno-informatics approach was applied to design a filarial multi-epitope subunit vaccine peptide consisting of linear B-cell and T-cell epitopes of proteins reported to be potential novel vaccine candidates. Conservation of the selected proteins and predicted epitopes in other parasitic nematode species suggests that the generated chimera could be helpful for cross-protection. The 3D structure was predicted, refined, and validated using bioinformatics tools. Protein-protein docking of the chimeric vaccine peptide with the TLR4 protein predicted efficient binding. Immune simulation predicted significantly high levels of IgG 1 , T-helper, T-cytotoxic cells, INF-γ, and IL-2. Overall, the constructed recombinant putative peptide demonstrated antigenicity superior to current vaccine candidates.

Background: Despite recommendation from the World Health Organization that all malaria suspected patients undergo a parasitological confirmation using rapid diagnostic test or light microscopy prior to treatment, health facilities in remote malaria endemic settings sometimes resort to presumptive diagnosis of malaria for clinical management for various reasons. Following observation of this practice, we undertook a cross-sectional study aimed at comparing presumptive diagnosis based on axillary temperature, SD Bioline™ rapid test, and light microscopy as strategies for malaria diagnosis in the coastal region of Mutengene in the South West of Cameroon with the overall goal of supporting improved malaria diagnosis at local levels., Methodology: Venous blood from 320 participants was used to detect the presence of malaria parasite using SD Bioline™ mRDT and Giemsa stained microscopy or spotted on filter paper for PCR amplification of the 18s rRNA gene of Plasmodium sp following standard procedures. The axillary temperature of each participant was also measured. The sensitivity, specificity, and predictive values and their confidence intervals were determined for each of the methods with PCR as the reference. The area under the curve was used to estimate accuracy of diagnostic method and compared between test method using the X 2 test with P<0.05 considered significant., Results: The overall diagnostic sensitivities of presumptive diagnosis using axillary temperature, light microscopy, and SD Bioline™ were observed to be 74.30% (95%CI: 67.90-80.01), 94.86% (95%CI: 90.99-97.41), and 95.33% (95%CI: 91.57-97.74), respectively, and their respective diagnostic specificities were 53.77% (95%CI: 43.82-63.51), 94.34% (95%CI: 88.09-97.87), and 94.34%(95%CI: 88.09-97.89). SD Bioline™ had a diagnostic sensitivity of 91.80% [95%CI: 81.90-97.28] at a parasitaemia of less than 500 parasites/ μ l of blood but a sensitivity of 100% for parasite counts above 500 parasites/ μ l of blood. The predictive values of the positive test were highly comparable between light microscopy (90.09%, [95%CI: 83.61-94.18]) and SD Bioline™ mRDT (90.91%, [95%CI: 84.50-94.83]), P=0.98 with kappa values of 0.898 but lower for presumptive diagnosis (50.89%, [95%CI: 43.72-58.03]), P<0.0001, and kappa value of 0.277. Perfect agreement was observed between SD Bioline™ mRDT and light microscopy (Cohen kappa= 0.924)., Conclusions: The study showed that SD Bioline™ was as good as light microscopy in the diagnosis of malaria in remote areas of perennial transmission in South West Cameroon. This study equally revealed the limitations of presumptive diagnosis of malaria (as opposed to the use of RDTs or microscopy). Efforts should be made in such areas to promote parasitological confirmation of malaria using quality assured rapid tests or light microscopy for case management of malaria. The presence of nonnegligible levels of Plasmodium ovale in this study area indicate that treatment guidelines may require revision if same trend is proven in several other areas of same ecology.

Diarrhea remains one of the most common causes of deaths in children. A limited number of studies have investigated the prevalence of enteric pathogens in Cameroon, and as in many other African countries, the cause of many diarrheal episodes remains unexplained. A proportion of these unknown cases of diarrhea are likely caused by yet-unidentified viral agents, some of which could be the result of (recent) interspecies transmission from animal reservoirs, like bats. Using viral metagenomics, we screened fecal samples of 221 humans (almost all with gastroenteritis symptoms) between 0 and 89 years of age with different degrees of bat contact. We identified viruses belonging to families that are known to cause gastroenteritis such as Adenoviridae , Astroviridae , Caliciviridae , Picornaviridae , and Reoviridae Interestingly, a mammalian orthoreovirus, picobirnaviruses, a smacovirus, and a pecovirus were also found. Although there was no evidence of interspecies transmission of the most common human gastroenteritis-related viruses ( Astroviridae , Caliciviridae , and Reoviridae ), the phylogenies of the identified orthoreovirus, picobirnavirus, and smacovirus indicate a genetic relatedness of these viruses identified in stools of humans and those of bats and/or other animals. These findings points out the possibility of interspecies transmission or simply a shared host of these viruses (bacterial, fungal, parasitic, …) present in both animals (bats) and humans. Further screening of bat viruses in humans or vice versa will elucidate the epidemiological potential threats of animal viruses to human health. Furthermore, this study showed a huge diversity of highly divergent novel phages, thereby expanding the existing phageome considerably. IMPORTANCE Despite the availability of diagnostic tools for different enteric viral pathogens, a large fraction of human cases of gastroenteritis remains unexplained. This could be due to pathogens not tested for or novel divergent viruses of potential animal origin. Fecal virome analyses of Cameroonians showed a very diverse group of viruses, some of which are genetically related to those identified in animals. This is the first attempt to describe the gut virome of humans from Cameroon. Therefore, the data represent a baseline for future studies on enteric viral pathogens in this area and contribute to our knowledge of the world's virome. The studies also highlight the fact that more viruses may be associated with diarrhea than the typical known ones. Hence, it provides meaningful epidemiological information on diarrhea-related viruses in this area., (Copyright © 2019 Yinda et al.)

Onchocerciasis is a severely debilitating yet neglected tropical disease (NTD) that creates social stigma, generates and perpetuates poverty, and leads ultimately in some cases to irreversible unilateral or bilateral blindness if untreated. Consequently, the disease is a major impediment to socioeconomic development. Many control programs have been launched for the disease with moderate successes achieved. This mitigated hit is partially due to the lingering need for reliable, non-invasive and easily applicable tools for mapping endemic regions and post-elimination surveillance. In this work, bioinformatics analyses combined with immunological assays were applied in a bid to develop potential tools for diagnosis and assessing the success of drug treatment programs. We report that (i) the O. volvulus antigen, Ov58GPCR is a G-protein coupled receptor (GPCR) conserved in related nematodes, (ii) synthetic peptides predicted to be in the extracellular domain (ECD) of Ov58GPCR are indeed immunogenic epitopes in actively-infected individuals, (iii) synthetic peptide cocktails discriminate between actively-infected individuals, treated individuals and healthy African controls, (iv) polyclonal antibodies against one of the peptides or against the bacterially-expressed ECD reacted specifically with the native antigen of O. volvulus total and surface extracts, (v) Ov58GPCR is transcribed in both larvae and adult parasite stages, (vi) IgG and IgE responses to the recombinant ECD decline with ivermectin treatment. All these findings suggest that the extracellular domain and synthetic peptides of Ov58GPCR, as well as the specific immune response generated could be harnessed in the context of disease diagnosis and surveillance., Competing Interests: The authors have declared that no competing interests exist.

Background: After more than 15 years of community-directed treatment with ivermectin (CDTI) in the Centre 1, Littoral 2 and West CDTI projects in Cameroon, the epidemiological evaluation conducted in 2011 revealed that onchocerciasis endemicity was still high in some communities. To investigate the potential reasons explaining this high endemicity, a cluster coverage survey was conducted in April-May 2015 in three health districts (HD), to assess the implementation of the CDTI, the 2014 therapeutic coverage and the five-year adherence to treatment. A two-stage cluster design was considered during analyses, with data weighted proportionally to age and gender distribution in the population., Results: In the three HDs, 69 community leaders, 762 heads of households, 83 community drug distributors (CDD) and 2942 household members were interviewed. The CDTI organization and the involvement of heads of households were in average weak, with 84.0% (95% CI: 81.2-86.4%) of them who had not participated in activities during the 2014 mass drug administration (MDA). On average, six of ten community leaders declared that the period of treatment was decided by the health personnel while the CDDs selection was made during a community meeting for only 43.4% of them. The 2014 weighted therapeutic coverage was 64.1% (95% CI: 56.8-70.9%), with no significant difference in the three HDs. The survey coverages were lower than the reported coverages with a significant difference varying from 14.1% to 22.0%. Among those aged 10 years and above, 57.8% (95% CI: 50.2-65.1%) declared having taken the treatment each time during the last five MDAs with no significant difference among HDs, while 9.8% (95% CI: 7.5-12.8%) declared that they had never taken the drug. In multivariate analysis, the most important factors associated with the five-year adherence to treatment were high involvement in CDTI and age (40+ years)., Conclusions: Despite more than 15 years of CDTI, there was still weak community participation and ownership, a lower coverage than reported and an average five-year adherence in the surveyed HDs. The reinforcement of the community ownership by the Ministry of Public Health officials and the timely procurement of ivermectin as requested by the communities are some measures that should be implemented to improve the therapeutic coverage, adherence to treatment and hence achieve onchocerciasis elimination. Further anthropological and entomological studies would provide better insights into our understanding of the persistence of the disease in these three CDTI projects.

Most human emerging infectious diseases originate from wildlife and bats are a major reservoir of viruses, a few of which have been highly pathogenic to humans. In some regions of Cameroon, bats are hunted and eaten as a delicacy. This close proximity between human and bats provides ample opportunity for zoonotic events. To elucidate the viral diversity of Cameroonian fruit bats, we collected and metagenomically screened eighty-seven fecal samples of Eidolon helvum and Epomophorus gambianus fruit bats. The results showed a plethora of known and novel viruses. Phylogenetic analyses of the eleven gene segments of the first complete bat rotavirus H genome, showed clearly separated clusters of human, porcine, and bat rotavirus H strains, not indicating any recent interspecies transmission events. Additionally, we identified and analyzed a bat bastrovirus genome (a novel group of recently described viruses, related to astroviruses and hepatitis E viruses), confirming their recombinant nature, and provide further evidence of additional recombination events among bat bastroviruses. Interestingly, picobirnavirus-like RNA-dependent RNA polymerase gene segments were identified using an alternative mitochondrial genetic code, and further principal component analyses suggested that they may have a similar lifestyle to mitoviruses, a group of virus-like elements known to infect the mitochondria of fungi. Although identified bat coronavirus, parvovirus, and cyclovirus strains belong to established genera, most of the identified partitiviruses and densoviruses constitute putative novel genera in their respective families. Finally, the results of the phage community analyses of these bats indicate a very diverse geographically distinct bat phage population, probably reflecting different diets and gut bacterial ecosystems.

Although it is generally agreed that an effective vaccine would greatly accelerate the control of malaria, the lone registered malaria vaccine Mosquirix™ has an efficacy of 30%-60% that wanes rapidly, indicating a need for improved second-generation malaria vaccines. Previous studies suggested that immune responses to a chimeric Plasmodium falciparum antigen UB05-09 are associated with immune protection against malaria. Herein, the preclinical efficacy and immunogenicity of UB05-09 are tested. Growth inhibition assay was employed to measure the effect of anti-UB05-09 antibodies on P. falciparum growth in vitro. BALB/c mice were immunized with UB05-09 and challenged with the lethal Plasmodium yoelii 17XL infection. ELISA was used to measure antigen-specific antibody production. ELISPOT assays were employed to measure interferon-gamma production ex vivo after stimulation with chimeric UB05-09 and its constituent antigens. Purified immunoglobulins raised in rabbits against UB05-09 significantly inhibited P. falciparum growth in vitro compared to that of its respective constituent antigens. A combination of antibodies to UB05-09 and the apical membrane antigen (AMA1) completely inhibited P. falciparum growth in culture. Immunization of BALB/c mice with recombinant UB05-09 blocked parasitaemia and protected them against lethal P. yoelii 17XL challenge infection. These data suggest that UB05-09 is a malaria vaccine candidate that could be developed further and used in conjunction with AMA1 to create a potent malaria vaccine., (© 2017 The Authors. Parasite Immunology Published by John Wiley & Sons Ltd.)

Background: The fight against onchocerciasis in Africa has boomed thanks to the Community Directed Treatment with Ivermectin (CDTI) program. However, in Cameroon, after more than 15 years of mass treatment, onchocerciasis prevalence is still above the non-transmission threshold. This study aimed to explore a possible association between people's beliefs/perceptions of onchocerciasis and of CDTI program, and their adherence to ivermectin in three regions of Cameroon., Methodology/principal Findings: A cross sectional survey was carried out in three health districts with persistent high onchocerciasis prevalence. Participants were randomly selected in 30 clusters per district. Adherence to ivermectin was comparable between Bafang and Bafia (55.0% and 48.8%, respectively, p>0.05) and lower in Yabassi (40.7%). Among all factors related to program perceptions and disease representations that were studied, perceptions of the program are the ones that were most determinant in adherence to ivermectin. People who had a "not positive" opinion of ivermectin distribution campaigns were less compliant than those who had a positive opinion about the campaigns (40% vs 55% in Bafang, and 48% vs 62% in Bafia, p<0.01), as well as those who had a negative appreciation of community drug distributors' commitment (22% vs 53% in Bafang, 33% vs 59% in Bafia, 27% vs 47% in Yabassi; p<0.01). The most common misconception about onchocerciasis transmission was the lack of hygiene, especially in Bafia and Yabassi. In Bafang, high proportions of people believed that onchocerciasis was due to high consumption of sugar (31% vs less than 5% in Bafia and Yabassi, p<0.001)., Conclusion/significance: There are still frequent misconceptions about onchocerciasis transmission in Cameroon. Perceptions of ivermectin distribution campaigns are more strongly associated to adherence. In addition to education/sensitisation on onchocerciasis during the implementation of the CDTI program, local health authorities should strive to better involve communities and more encourage community distributors' work.

Background: After more than a decade of community-directed treatment with ivermectin (CDTI) in the West Region of Cameroon, epidemiological evaluation conducted in 2011 showed that onchocerciasis endemicity was still high in some communities. The conceptual framework for onchocerciasis elimination recommends in such case, to conduct additional phase 1A surveys at intervals of three to four years. Therefore, to assess the progress made towards the elimination of onchocerciasis in the West CDTI projects, we conducted a cross-sectional survey in May 2015 in 15 unevaluated communities where the highest baseline endemicity level were found in 1996. All volunteers living for at least five years in the community, aged five years or more, underwent clinical and parasitological examinations. Individual adherence to ivermectin treatment was also assessed. Analyses of data were weighted proportionally to age and gender distribution in the population., Results: The mean age was 28.4 ± 22.2 years and there were 55% of women among the 2058 individuals examined. The weighted prevalences were 5.5%, 2.1% and 1.7% for microfilaridermia, nodule and cutaneous signs, respectively. The weighted microfilaridermia prevalences varied from 4.0 in 5-9 years old to 11.6% in 40-49 years old. In the 30 children under 10 years examined in Makouopsap, the weighted prevalences were 49.9% for microfilaridermia and 13.3% for nodule. In surveyed communities, the weighted prevalences varied from 0 to 41.6% for microfilaridermia, with 11 (73.3%) communities having <5%. Except Makouopsap which had 41.6%, all the surveyed communities were below 15% for microfilaridermia prevalence. The community microfilarial load (CMFL) expressed in microfilariae/skin snip (mf/ss), also significantly dropped by 98-100%, from 3.75-33.16 mf/ss in 1996 to 0-0.94 mf/ss in 2015. The weighted therapeutic coverage in 2014 was 69.4% and the 5 years' adherence was only 39.3% among participants., Conclusions: After more than 15 years of CDTI, there is an important progress towards the elimination of onchocerciasis in the communities surveyed. Innovative strategy like semi-annual ivermectin treatment plus vector control or the adjunction of a vector control strategy to the current annual treatment should be implemented in the bordering districts of the Centre and West Regions, as well as in other parts of the country with persistent high prevalences in the sight of onchocerciasis elimination.

Sapoviruses (SaVs) belong to the Sapovirus genus, in the family Caliciviridae. They have been associated with gastroenteritis in humans and in pigs but not in other animals. In addition, some strains from pigs, chimpanzees and rodents show close sequence identity with human SaVs thereby suggesting the possibility of interspecies transmissions. Bats are known to be a major reservoir of zoonotic viruses, however, very little is known about the genetic diversity of SaVs in bats. To explore the genetic diversity of bat SaVs, fecal samples of Eidolon helvum and Epomophorus gambianus were treated according to the NetoVIR protocol and sequenced by Illumina technology. Nearly complete genome sequences of six highly divergent SaVs and one partial SaV (only VP1 region) were identified in Eidolon helvum and based on sequence identities and phylogenetic analysis, they potentially represent two novel genogroups, only distantly related to known SaVs. Furthermore, comparing these sequences with currently used screening primers and probes indicated that the novel SaVs would not be detected in routine epidemiological screening studies in humans in case an interspecies transmission would occur. Therefore, we designed and validated new primers that can detect both human and bat SaVs. In this study, we identified multiple novel bat SaVs, however, further epidemiological studies in humans are needed to unravel their potential role in gastroenteritis.

Background: The order Picornavirales represents a diverse group of positive-stranded RNA viruses with small non-enveloped icosahedral virions. Recently, bats have been identified as an important reservoir of several highly pathogenic human viruses. Since many members of the Picornaviridae family cause a wide range of diseases in humans and animals, this study aimed to characterize members of the order Picornavirales in fruit bat populations located in the Southwest region of Cameroon. These bat populations are frequently in close contact with humans due to hunting, selling and eating practices, which provides ample opportunity for interspecies transmissions., Results: Fecal samples from 87 fruit bats (Eidolon helvum and Epomophorus gambianus), were combined into 25 pools and analyzed using viral metagenomics. In total, Picornavirales reads were found in 19 pools, and (near) complete genomes of 11 picorna-like viruses were obtained from 7 of these pools. The picorna-like viruses possessed varied genomic organizations (monocistronic or dicistronic), and arrangements of gene cassettes. Some of the viruses belonged to established families, including the Picornaviridae, whereas others clustered distantly from known viruses and most likely represent novel genera and families. Phylogenetic and nucleotide composition analyses suggested that mammals were the likely host species of bat sapelovirus, bat kunsagivirus and bat crohivirus, whereas the remaining viruses (named bat iflavirus, bat posalivirus, bat fisalivirus, bat cripavirus, bat felisavirus, bat dicibavirus and bat badiciviruses 1 and 2) were most likely diet-derived., Conclusion: The existence of a vast genetic variability of picorna-like viruses in fruit bats may increase the probability of spillover infections to humans especially when humans and bats have direct contact as the case in this study site. However, further screening for these viruses in humans will fully indicate their zoonotic potential.

A number of PVs have been described in bats but to the best of our knowledge not from feces. Using a previously described NetoVIR protocol, Eidolon helvum pooled fecal samples (Eh) were treated and sequenced by Illumina next generation sequencing technology. Two complete genomes of novel PVs (EhPV2 and EhPV3) and 3 partial sequences (BATPV61, BATPV890a and BATPV890b) were obtained and analysis showed that the EhPV2 and EhPV3 major capsid proteins cluster with and share 60-64% nucleotide identity with that of Rousettus aegyptiacus PV1, thus representing new species of PVs within the genus Psipapillomavirus . The other PVs clustered in different branches of our phylogenetic tree and may potentially represent novel species and/or genera. This points to the vast diversity of PVs in bats and in Eidolon helvum bats in particular, therefore adding support to the current concept that PV evolution is more complex than merely strict PV-host co-evolution., (© 2016 The Authors.)

Bats are an important reservoir for zoonotic viruses. To date, only three RVA strains have been reported in bats in Kenya and China. In the current study we investigated the genetic diversity of RVAs in fecal samples from 87 straw-colored fruit bats living in close contact with humans in Cameroon using viral metagenomics. Five (near) complete RVA genomes were obtained. A single RVA strain showed a partial relationship with the Kenyan bat RVA strain, whereas the other strains were completely novel. Only the VP7 and VP4 genes showed significant variability, indicating the occurrence of frequent reassortment events. Comparing these bat RVA strains with currently used human RVA screening primers indicated that most of the novel VP7 and VP4 segments would not be detected in routine epidemiological screening studies. Therefore, novel consensus screening primers were developed and used to screen samples from infants with gastroenteritis living in close proximity with the studied bat population. Although RVA infections were identified in 36% of the infants, there was no evidence of zoonosis. This study identified multiple novel bat RVA strains, but further epidemiological studies in humans will have to assess if these viruses have the potential to cause gastroenteritis in humans.

Background: Malaria remains a major global health burden despite the intensification of control efforts, due partly to the lack of an effective vaccine. Information on genetic diversity in natural parasite populations constitutes a major impediment to vaccine development efforts and is limited in some endemic settings. The present study characterized diversity by investigating msp1 block 2 polymorphisms and the relationship between the allele families with ethnodemographic indices and clinical phenotype., Method: Individuals with asymptomatic parasitaemia (AP) or uncomplicated malaria (UM) were enrolled from rural, semi-rural and semi-urban localities at varying altitudes along the slope of mount Cameroon. P. falciparum malaria parasitaemic blood screened by light microscopy was depleted of leucocytes using CF11 cellulose columns and the parasite DNA genotyped by nested PCR., Results: Length polymorphism was assessed in 151 field isolates revealing 64 (5) and 274 (22) distinct recombinant and major msp1 allelic fragments (genotypes) respectively. All family specific allelic types (K1, MAD20 and RO33) as well as MR were observed in the different locations, with K1 being most abundant. Eighty seven (60 %) of individuals harbored more than one parasite clone, with a significant proportion (p = 0.009) in rural compared to other settings. AP individuals had higher (p = 0.007) K1 allele frequencies but lower (p = 0.003) mean multiplicity of genotypes per infection (2.00 ± 0.98 vs. 2.56 ± 1.17) compared to UM patients., Conclusions: These results indicate enormous diversity of P. falciparum in the area and suggests that allele specificity and complexity may be relevant for the progression to symptomatic disease.

The maternal-zygotic transition (MZT) is an embryonic event that overlaps with and plays key roles in primary germ layer specification in vertebrates. During MZT, maternally supplied mRNAs are degraded while zygotic transcripts are synthesized to either reinforce the already specified cell fate or to trigger new cell identity. Here, we show that forced expression of the RNA-binding protein, XSeb4R, in animal pole blastomeres of Xenopus embryos, inappropriately stabilizes transcripts there, including maternal Sox3. This leads to the impaired ability of the ectodermal progenitors to respond to factors regulating brain patterning and their eventual loss by apoptosis. XSeb4R protein binds specifically to the 3'UTR of Sox3 mRNA. XSeb4R gain-of-function in ectodermal explants reveals increased stability of the maternal Sox3 transcripts, associated with a robust Sox3 protein production. Conversely, whereas XSeb4R depletion abolishes VegT expression, the amount of the maternal Sox3 mRNA is rather increased but without augmentation in the amount of Sox3 protein. Moreover, XSeb4R protein knockdown leads to the modification of the ectoderm-mesoderm boundary, marked by expanded/shifted expression of the mesodermal marker genes such as Xbra and Apod, followed by an expression inhibition of Epi. K., an ectodermal marker. Overall, our data suggest XSeb4R as a novel player in gene expression regulation, acting at the posttranscriptional level during ectoderm specification in Xenopus., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Activation of Wnt/beta-catenin target genes is regulated by a heterodimer of beta-catenin and the high mobility group box transcription factors of the lymphoid enhancer factor (LEF)/T-cell factor (TCF) family. In vertebrates, four LEF/TCF family members have been identified. They all contain a conserved beta-catenin-binding motif at the N terminus and a highly conserved high mobility group box for DNA binding. The core sequence between these motifs is less conserved and contributes to the specific properties of the individual family members. To identify interacting proteins that allocate specific functions to the individual LEF/TCF transcription factors, we performed a yeast two-hybrid screen using the less conserved core sequence as bait. We isolated the murine LIM protein HIC-5 (hydrogen peroxide-induced clone 5; also termed ARA-55 (androgen receptor activator of 55 kDa)) and cloned the highly conserved Xenopus homolog. In addition, we report that the LIM domain-containing C-terminal half of HIC-5 binds to a conserved alternatively spliced exon in LEF/TCF transcription factors. Our functional analyses revealed that HIC-5 acts as negative regulator of a subset of LEF/TCF family members, which have been characterized as activators in reporter gene analyses and in the Xenopus axis induction assay. In addition, we observed a repressive interference of LEF/TCF family members with HIC-5-mediated activation of glucocorticoid-driven transcription, which again could be allocated to specific LEF/TCF subtypes. With the characterization of HIC-5 as a binding partner of the alternatively spliced exon in LEF/TCF transcription factors, we identified a novel molecular mechanism in the dialog of steroid and canonical Wnt signaling that is LEF/TCF subtype-dependent.

Objective: To determine the role of an immunodominant antigen OvPG-1 in human onchocerciasis., Design: Cross-sectional study of subjects living in three onchocerciasis endemic areas., Setting: Mbonge and Tubah divisions of Western Cameroon and in Esmeralda Province of Ecuador., Subjects: There were 94 and 99 subjects from the Cameroon rain forest and savannah respectively, and 83 endemic residents from Ecuador., Results: The IgG2 anti-OvPG-1 responses of visually impaired and microfiladermic patients were significantly higher than for their age and sex matched counterparts with normal vision and no microfiladermia (p=0.024). Furthermore, the isotype specificity of anti-OvPG-I responses varied for the various onchocerciasis endemic zones. IgG1, IgG2, IgG3 and IgE levels correlated with the presence of microfilariae in Cameroon, but not in Ecuador., Conclusion: Increased IgG and IgE levels to the antigen OvPG-1 seem to correlate with the development of onchocercal eye pathology. The present results suggest that the OvPG1 is a dominant antigen of Onchocerca volvulus with a significant role in the pathogenesis of onchocerciasis.

The expression and characterization of a recombinant antigen termed Ov-47 are described. Ov-47 was identified and isolated from a lambda gt-11 cDNA expression library derived from adult female Onchocerca volvulus mRNA using rabbit antiserum raised against the surface proteins of O. volvulus female worms. The antiserum was earlier found to mediate, in vitro, cytoadherence and cytotoxicity reactions to microfilariae in the presence of heat-labile serum factors. The deduced amino acid sequence of the gene was assigned the EMBL GenBank Accession No. Y15993. The open reading frame (1077 bp) of the gene was then subcloned into pQE-60 and expressed in Escherichia coli JM109 cells. The gene encodes a protein with an apparent molecular weight of 47,000 Da as revealed by SDS-PAGE. Up to 100 micrograms/ml pure Ov-47 recombinant protein could be isolated from E. coli cultures by Ni-agarose affinity chromatography. The 47-kDa protein was recognized by sera from both infected and endemic normal subjects. The parent protein was found to have a molecular weight of 60 kDa. IgG3 subclass responses to Ov-47 were significantly higher in endemic normals than in infected subjects (P < 0.05). In contrast, IgG4 responses were higher in infected subjects than in endemic normals (P < 0.05). IgG2 response exhibited marked age dependency with lower responses in younger patients, which rose to higher levels in elderly patients. IgG1, IgG3, and IgG4 responses did not show any age dependency. This study clearly shows that Ov-47 is a dominant antigen of O. volvulus adult worms with an important role in the host-parasite-interplay.