KIR2DL1 gene is a surrogate marker of protection against infection-related hospitalization among HIV-1 unexposed versus exposed uninfected infants in Cameroon.

BACKGROUND: HIV-exposed uninfected infants (HEU) appear more vulnerable to infections compared to their HIV-unexposed uninfected (HUU) peers, generally attributed to poor passive immunity acquired from the mother. This may be due to some genetic factors that could alter the immune system. We thus sought to determine the distribution of Killer Cell Immunoglobulin-Like Receptors (KIRs) genes in HEU versus HUU and study their associations with the occurrence of infection-related hospitalization. METHODS: A cohort study was conducted from May 2019 to April 2020 among HEU and HUU infants, including their follow-up at weeks 6, 12, 24, and 48, in reference pediatric centers in Yaoundé-Cameroon. The infant HIV status and infections were determined. A total of 15 KIR genes were investigated using the sequence-specific primer polymerase chain reaction (PCR-SSP) method. The KIR genes that were significantly associated with HIV-1 status (HEU and HUU) were analyzed for an association with infection-related hospitalizations. This was only possible if, and to the extent that, infection-related hospitalizations varied significantly according to status. Multivariate logistic regression analyses were conducted to determine the association between KIR gene content variants and HIV status, while considering a number of potential confounding factors. Furthermore, the risk was quantified using relative risk, odds ratio, and a 95% confidence interval. The Fisher exact test was employed to compare the frequency of occurrences. A p-value of less than 0.05 was considered statistically significant. RESULTS: In this cohort, a total of 66 infants participated, but only 19 acquired infections requiring hospitalizations (14.81%, 04/27 HUU and 38.46%, 15/39 HEU, p = 0.037). At week 48 (39 HEU and 27 HUU), the relative risk (RR) for infection-related hospitalizations was 2.42 (95% CI: 1.028-5.823) for HEU versus HUU with OR 3.59 (1.037-12.448). KIR2DL1 gene was significantly underrepresented in HEU versus HUU (OR = 0.183, 95%CI: 0.053-0.629; p = 0.003), and the absence of KIR2DL1 was significantly associated with infection-related hospitalization (p < 0.001; aOR = 0.063; 95%CI: 0.017-0.229). CONCLUSION: Compared to HUU, the vulnerability of HEU is driven by KIR2DL1, indicating the protective role of this KIR against infection and hospitalizations.

Effect of hepatitis B vaccination on HBV-infection among school children in Yaounde; ten years after the introduction of HBV vaccine into routine Immunization Program in Cameroon.

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

Immunoglobulin G (IgG) specific responses to recombinant Qß displayed MSP3 and UB05 in plasma of asymptomatic Plasmodium falciparum-infected children living in two different agro-ecological settings of Cameroon.

Introduction: in areas with intense perennial malaria transmission, limited data is available on the impact of environmental conditions especially rainfall on naturally acquired immunity against promising malaria vaccine candidates. For this reason, we have compared IgG antibody responses specific to Plasmodium spp. derived MSP3 and UB05 vaccine candidates, in plasma of children living in two areas of Cameroon differing in rainfall conditions. Methods: data about children less than 5 years old was collected during the years 2017 and 2018. Next malaria asymptomatic P. falciparum (Pf) infected children were selected following malaria test confirmation. MSP3 and UB05 specific IgG antibody responses were measured in participant´s plasma using enzyme-linked immunosorbent assay (ELISA). Results: interestingly, IgG antibody responses specific to UB05 were significantly higher (p<0.0001) in Pf-negative children when compared to their asymptomatic Pf-infected counterparts living in monomodal rainfall areas. In contrast, a significantly higher (p<0.0001) IgG response to MSP3 was observed instead in asymptomatic Pf-infected children in the same population. In addition, IgG responses specific to UB05 remained significantly higher in bimodal when compared to monomodal rainfall areas irrespective of children´s Pf infection status (p<0.0055 for Pf-positive and p<0.0001 for negative children). On the contrary, IgG antibody responses specific to MSP3 were significantly higher in bimodal relative to monomodal rainfall areas (P<0.0001) just for Pf-negative children. Conclusion: thus IgG antibody responses specific to UBO5 are a better correlate of naturally acquired immunity against malaria in Pf-negative Cameroonian children especially in monomodal rainfall areas.

Bowel function after anterior rectal resection for cancer: short and long-term prospective evaluation with low anterior rectal syndrome (LARS) score in a cohort of Cameroonian patients.

Introduction: bowel dysfunction is the most common and disabling complication after anterior rectal resection (ARR) for cancer. We aimed to evaluate these complications in a cohort of Cameroonian patients, using the low anterior rectal syndrome (LARS) score. Methods: we conducted a descriptive and analytical cross-sectional study, in two university hospitals of Yaoundé (Cameroon). Prospectively, we collected the records of all patients aged at least 18 years who had an ARR indicated for rectal cancer from January 2015 to March 2018. Alive patients among them were subsequently received in consultation at 1 and 3 years after surgery, for short and long-term assessment of their digestive function using the LARS score. Results: during the study period, 28 patients underwent anterior rectal resection for rectal cancers. Short-term bowel function was evaluated in 23 patients. Their mean age was 48.42 ± 12.2 years and 14 were males. LARS was present in 10 of them (43.47%) and classified as "minor" in the majority of cases (n=6). The commonest bowel dysfunction at this term was splitting of stool (56.53%). Long-term digestive function was evaluated in 11 patients; LARS was found in 3 of them (27,27%) and classified as minor in all cases. Perfect continence was significantly improved (p=0.003) in the long term compared to the short-term status. Continence (p=0.049) and urgency (p=0.048) were better in patients who had a low colorectal anastomosis compared to those who had a colo supra-anal anastomosis. Conclusion: after ARR for cancer, there is a high prevalence of LARS in the short term with an improvement in the long term.

Outcome of hospitalized patients with COVID-19 and predictors at the Buea Regional Hospital, South West region of Cameroon.

Introduction: there is a paucity of data on the epidemiology of COVID-19 infection in Cameroon with a few studies limited to big urban cities. The objective of this study was to describe the clinical characteristics and outcomes of hospitalized patients with COVID-19 at the Buea Regional Hospital, in the South West region of Cameroon. Methods: this was a retrospective cross-sectional study. The medical records of hospitalized patients with COVID-19 were reviewed from 2020 to 2021. Hospitalized patients with laboratory-confirmed COVID-19 were included. Binary logistic regression was used to identify factors associated with mortality. Results: two hundred and ten (210) patients were included in this cohort. There were 114 (54.7%) men. The mean age was 60±17.1 years. The common co-morbidities were hypertension (46.7%), diabetes mellitus (31%), and HIV infection (5.7%). The most common symptoms were dyspnea (93.3%), fatigue (93.8%), cough (77.6%), and fever (71.4%). The median oxygen saturation was 85% and the median respiratory rate was 24 cycles per minute. More than 80% had crackles on lung examination. Death occurred in 57 (27.1%) patients. In binary logistic regression, the factors independently associated with mortality were heart failure (aOR: 6.7, p=0.034), SBP < 100 mmHg (aOR: 8.1, p<0.001), RR > 24 cpm (aOR: 3, p=0.016), SaO2<90% (aOR: 6.2, p=0.031), blood glucose > 150mg/dL (aOR: 3.3, p=0.02), and CRP > 50 mg/L (aOR: 3.3, p=0.036). For every 1 mg/dL rise in blood glucose, the odds of death increased by 1% (p=0.011). For every 1 mg/L rise in the C-reactive protein (CRP), the odds of death increased by 1% (p=0.054). Conclusion: over half of hospitalized patients with laboratory-confirmed COVID-19 infection in the South West Region of Cameroon were males. Hypertension and diabetes were common co-morbidities. More than a quarter of these patients died. Furthermore, having heart failure, low systolic blood pressure (SBP), low oxygen saturation, elevated respiratory rate, high CRP and blood glucose levels on admission were associated with poor prognosis.

Frequency and determinants of phytotherapy use in patients with type 2 diabetes in the Dschang Health District, Cameroon: a cross-sectional study.

Introduction: phytotherapy is widely used in Africa for the management of many diseases. Data on the use of phytotherapy in people with type 2 diabetes are scarce. We aimed to determine the frequency and factors associated with the consumption/use of phytotherapy products among patients with type 2 diabetes in the Dschang Health District. Methods: we conducted a cross-sectional study from January to May 2022, including community-dwelling or hospitalized patients with type 2 diabetes who had lived in the Dschang Health District for at least one year. Informed consent was obtained from all patients. Data were collected using a pre-designed questionnaire. Variables collected included socio-demographic characteristics, diabetes knowledge and practices, and perceptions of care. Results: we included 403 (249 women) patients with type 2 diabetes with a mean (SD) age of 63 (± 14.86) years). Among them, 240 (59.55%) used phytotherapy, either in combination with conventional treatment (168 (41.69%) participants) or not (72 (17.86%) participants), to treat diabetes. The most common reasons for using phytotherapy were easy accessibility and belief in its efficacy. Most patients used both treatments because they thought the combination was more effective. In univariable analysis, we observed a statistically significant association between level of education (p=0.003), socioeconomic level (p<0.001), place of residence (p=0.003), duration of diabetes (p=0.007), and use of phytotherapy. In multivariable analysis, only age between 51 and 60 years (OR: 0.50, 95% CI 0.298 - 0.8521; p=0.01) was associated with the use of phytotherapy. Conclusion: people living with T2D in the Dschang Health District frequently use phytotherapy as an antidiabetic remedy, especially those aged between 51 and 60 years, those with low education level, low socioeconomic level and medium duration of diabetes. There is a need to evaluate its effectiveness in treating diabetes and its adverse effects.

Structural barriers to maternity care in Cameroon: a qualitative study.

BACKGROUND: The maternal mortality and perinatal mortality rate in Cameroon are among the highest worldwide. To improve these outcomes, we conducted a formative qualitative assessment to inform the adaptation of a mobile provider-to-provider intervention in Cameroon. We explored the complex interplay of structural barriers on maternity care in this low-resourced nation. The study aimed to identify structural barriers to maternal care during the early adaptation of the mobile Medical Information Service via Telephone (mMIST) program in Cameroon. METHODS: We conducted in-depth interviews and focus groups with 56 key stakeholders including previously and currently pregnant women, primary healthcare providers, administrators, and representatives of the Ministry of Health, recruited by purposive sampling. Thematic coding and analysis via modified grounded theory approach were conducted using NVivo12 software. RESULTS: Three main structural barriers emerged: (1) civil unrest (conflict between Ambazonian militant groups and the Cameroonian government in the Northwest), (2) limitations of the healthcare system, (3) inadequate physical infrastructure. Civil unrest impacted personal security, transportation safety, and disrupted medical transport system. Limitations of healthcare system involved critical shortages of skilled personnel and medical equipment, low commitment to evidence-based care, poor reputation, ineffective health system communication, incentives affecting care, and inadequate data collection. Inadequate physical infrastructure included frequent power outages and geographic distribution of healthcare facilities leading to logistical challenges. CONCLUSION: Dynamic inter-relations among structural level factors create barriers to maternity care in Cameroon. Implementation of policies and intervention programs addressing structural barriers are necessary to facilitate timely access and utilization of high-quality maternity care.

Measuring HIV outcomes for adolescent girls and young women programs in Africa: Using the polling booth survey technique.

INTRODUCTION: Adolescent girls and young women (AGYW) remain highly vulnerable to the risk of acquiring HIV (Human immunodeficiency virus). This study was conducted to measure behavioral, biomedical and structural outcomes for the Global Fund funded AGYW programmes in five African countries with high burden of HIV including Botswana, Cameroon. Lesotho, Malawi and Namibia. METHODS: The study used a mixed methods approach to collect behavioral, structural and biomedical outcome data. Quantitative data were collected through 418 Polling Booth Survey (PBS) sessions from 4,581 AGYWs. Participants were recruited through a community-based multistage sampling technique using sampling weights for urban and rural communities. 23 Focus Group Discussions (FGD) were conducted to understand barriers to use of HIV prevention programme and community recommendations for improved coverage. Ethical approvals were obtained from the ethics review board in all five countries. RESULTS: More than 50% of the respondents from all five countries reported to be sexually active, and at least 30% or more of those who were sexually active had multiple sex partners. There were wide variations between the countries in condom use with a non-marital sexual partner which ranged between 66% in Namibia to 42% in Cameroon. Cameroon (44%) had high percentage of AGYWs with independent income source while school drop-outs were higher in Malawi (55.5%) and Lesotho (46.6%). Nearly 1/4th of AGYWs in all countries, except Namibia, reported experiencing intimate partner violence. Nineteen percent of the respondents were pregnant in the last 12 months, and 50% of those pregnancies were unplanned. Lesotho had the highest proportion of AGYW (90.5%) ever tested for HIV, followed by Malawi (87.5%), Botswana (75%), Cameroon (69%) and Namibia (62.6%). DISCUSSION: There is diversity across the countries, with country-wise and age-wise variations in results. In all countries, the AGYW programme will benefit from a more targeted approach to reach out to the most vulnerable AGYW, strengthening structural interventions, strengthening linkage to PrEP (Pre-Exposure Prophylaxis) and ART (Antiretroviral Therapy) for those who are living with HIV and a strong linkage with reproductive health services. The assessment helped countries to understand the gaps and opportunities to improve the HIV prevention programme with AGYW.

Drug-induced hepatotoxicity and association with slow acetylation variants NAT2*5 and NAT2*6 in Cameroonian patients with tuberculosis and HIV co-infection.

BACKGROUND: Human immunodeficiency virus (HIV) and tuberculosis (TB) are major contributors to morbidity and mortality in sub-Saharan Africa including Cameroon. Pharmacogenetic variants could serve as predictors of drug-induced hepatotoxicity (DIH), in patients with TB co-infected with HIV. We evaluated the occurrence of DIH and pharmacogenetic variants in Cameroonian patients. METHODS: Treatment-naïve patients with HIV, TB or TB/HIV co-infection were recruited at three hospitals in Cameroon, between September 2018 and November 2019. Appropriate treatment was initiated, and patients followed up for 12 weeks to assess DIH. Pharmacogenetic variants were assessed by allele discrimination TaqMan SNP assays. RESULTS: Of the 141 treatment naïve patients, the overall incidence of DIH was 38% (53/141). The highest incidence of DIH, 52% (32/61), was observed among HIV patients. Of 32 pharmacogenetic variants, the slow acetylation variants NAT2*5 was associated with a decreased risk of DIH (OR: 0.4; 95%CI: 0.17-0.96; p = 0.038), while NAT2*6 was found to be associated with an increased risk of DIH (OR: 4.2; 95%CI: 1.1-15.2; p = 0.017) among patients treated for TB. Up to 15 SNPs differed in ≥ 5% of allele frequencies among African populations, while 25 SNPs differed in ≥ 5% of the allele frequencies among non-African populations, respectively. CONCLUSIONS: DIH is an important clinical problem in African patients with TB and HIV. The NAT2*5 and NAT2*6 variants were found to be associated with DIH in the Cameroonian population. Prior screening for the slow acetylation variants NAT2*5 and NAT2*6 may prevent DIH in TB and HIV-coinfected patients.

Ant-following behavior is correlated with plumage traits in African understory birds.

Ant-following behavior is a common phenomenon in birds of Neotropical and Afrotropical rainforests but yet little is known from Central Africa. We here report on the phenomenon in lowland rainforest in Cameroon, quantifying the strength of the interaction of different ant-following bird species with driver ants and test the hypothesis that higher levels of specialization in ant-following behavior are associated with dominance or aggression-dependent plumage and other morphological traits. Flock size varied between 1 and 11 individuals with a mean size of 5.34 ± 2.68 (mean ± SD) individuals occurring at the same time. The maximum number of species present during one raid observed was ten, whereas the minimum number was four with an overall species richness of 6.89 ± 2.1 species. The 21 attending bird species strongly varied in the degree of ant-following behavior. In an interspecific comparison, plumage traits such as the presence of a colored crown, eyespots, and bare skin around the eye, in combination with metatarsus length and weight, were significantly correlated with ant-following behavior. These results suggest that-in size and identity of species-ant-following bird assemblages in Central Africa are similar to those reported from East Africa. They also suggest that ant following favors the selection of traits that signal dominance in interactions between individuals struggling for valuable food resources in the forest understory.

A public health development intervention between acceptability and feasibility: descriptive-interpretive discussion of an example.

Introduction: the National Tuberculosis Control Program (NTP) in Cameroon participated between 2016 and 2018 in a multi-country operational study of the Union against Tuberculosis and Lung Disease (The UNION) aiming at demonstrating the efficiency and feasibility of systematic tuberculosis preventive treatment (TPT) with 3 months of an isoniazid/rifampicin (3RH) combination in under-five child contacts of bacilliferous TB patients. Cameroon was one of the participating countries of the study. Despite the promising results communicated following this study, the coverage of TPT with 3RH in Cameroon remains low. We explored the intervention under aspects of acceptability and perceived feasibility. Methods: key participants and stakeholders in this descriptive interpretative study in Cameroon were interviewed in five focus groups or individually (31 individuals). The Focus Group Discussion (FGD) and interview transcripts were analysed for different components of acceptability using a theoretical framework and the results discussed confronting them with the main objective of the study, i.e. demonstrating feasibility. Results: the children's parents expressed overall positive feelings about and acceptance of the intervention, emphasizing the unexpected empathy shown by the health staff. The involved field staff, too, showed unreserved acceptance. On the other hand, managers at the intermediate and central levels showed scepticism as to the process of initiation of the study as well as to its feasibility in the given context, neglecting aspects of resources necessary for a scaling-up and of prioritisation. Conclusion: the adoption of a public health strategy, also internationally recognized as an effective and efficient intervention, requires more than the demonstration of its acceptability or feasibility during the term of a showcase project introduced by an external development partner. Adoption is conditioned by adoption and circumspect planning involving at each stage the stakeholders on all levels of the program.

222Rn and 220Rn levels in drinking water, emanation, and exhalation assessment, and the related health implications in the U-bearing area of Poli-Cameroon.

The inherent radioactivity of radon gas presents potential exposure risks to human beings through ingestion and inhalation of its radioisotopes 222Rn (radon) and 220Rn (thoron) from water sources. Recent studies have been conducted to assess radon concentrations in different environmental matrices such as water, air, and soil, due to their detrimental impact on human health. As the main cause of lung cancer in non-smokers and an acknowledged contributor to stomach cancer when ingested, the present study aimed to preliminarily assess radon and thoron levels in the Uranium bearing area of Poli in the Faro division of Cameroon, known for its significant U-deposits. The assessment included measuring 220, 222Rn concentrations in drinking water, emanation, and exhalation, with a specific focus on evaluating the exposure of different age groups within the local population. The radon/thoron levels in water and their related exposure and cancer risk data indicated no immediate health hazards. However, continuous monitoring and prospective measures are deemed essential due to the area's abundant U-minerals. The emanation measurements showed sparsely distributed data with a singularity at Salaki, where the equipment recorded values of 8.14 × 1012 Bqm-3 and 3.27 × 1012 Bqm-3 for radon and thoron, respectively. Moreover, radon/thoron transfer coefficients from the soil to the air indicated levels below unity. While the calculated doses suggest minimum potential risk in line with WHO and UNSCEAR guidelines, the obtained results are expected to significantly contribute to the establishment of national standards for radon levels in drinking water, emanation, and exhalation. Furthermore, these findings can play a crucial role in monitoring radon/thoron levels to ensure public health safety.

Effect of COVID-19 on paediatric TB service delivery and patients' comfort receiving TB services in Cameroon and Kenya during COVID: a qualitative assessment.

BACKGROUND: The outbreak of COVID-19 has caused a setback to the gains achieved in tuberculosis (TB) control by impairing TB diagnosis, delaying treatment initiation and aggravating TB deaths. This study explored the effect of COVID-19 on paediatric TB services provided through the Catalysing Paediatric TB Innovations (CaP-TB) project among caregivers of children receiving TB services and healthcare workers (HCWs) providing TB services in Cameroon and Kenya. METHODS: From March to September 2021, in-depth interviews (44) were conducted with caregivers whose children under 5 years had gone through TB services and programme managers (10) overseeing the CaP-TB project. Focus group discussions were conducted with HCWs (07) and community health workers (04) supporting TB care services. Transcripts were coded and analysed by using MAXQDA V.12. RESULTS: The COVID-19 pandemic has caused fear and anxiety among HCWs and caregivers. This fear was motivated by stigma related to COVID-19 and affected the ability to screen patients for TB due to the similarity of symptoms with COVID-19. The health-seeking behaviour of patients was affected, as many caregivers avoided hospitals and those accessing the facilities concealed their sickness due to fear of testing positive or being vaccinated. In addition, COVID-19 mitigation strategies implemented by both government and health facilities to curb the spread of the virus limited patient access to paediatric healthcare services. These included temporary closure of health facilities due to COVID-19 infections among staff, transfer of services to other spaces, spacing out patient appointments and reduced time spent with patients. CONCLUSIONS: The outbreak of COVID-19 has induced fear and stigma that affected patients' health-seeking behaviour and provider attitudes towards paediatric TB service delivery. In addition, facility and governmental measures put in place to mitigate COVID-19 impact negatively affected paediatric service delivery. Training for health personnel, timely provision of personal protective equipments and appropriate communication strategies could help mitigate COVID-19 impact on paediatric TB service delivery.

Seed germination, morphology and fruit phenology insight of Cylicomorpha solmsii (Urb.) Urb: a step towards sustainable restoration planning.

Cylicomorpha solmsii (Urb.) Urb (Caricaceae) is a wild relative of domesticated Carica papaya native to the humid tropical forest of Cameroon. C. solmsii is becoming extinct due to rapid urbanization of its habitat. There is currently no restoration planning, no available data on seed germination, details on morphological description and fruit phenology. We investigated the effects of light and soil on seed germination, updated its morphological description and provided cues of its fruit phenology. In two series of experiments, a germination test was first conducted under light and dark conditions with three seed pre-treatments (scarification, drying and cold). Secondly, pre-treated seeds were sown in native soils of C. solmsii habitat collected at Eloumden I and II, two ex-situ and mixtures soil with sand. Qualitative and quantitative data were collected on different part of the plant and analyzed using R package version 4.3.2. Our findings showed that C. solmsii seeds can germinate only under light. The seeds manifested a physiological embryonic dormancy. The native soils showed the highest germination percentage and seedling establishment. The dioicy of C. solmsii was clearly described with incomplete staminate and pistillate unisexual flower whorls. C. solmsii was observed to produce fruits throughout the year at varying intensity. This information is a vital cue to species restoration and policy makers towards C. solmsii conservation.

Genetic analysis of the circumsporozoite gene in Plasmodium falciparum isolates from Cameroon: Implications for efficacy and deployment of RTS,S/AS01 vaccine.

Current understanding of genetic polymorphisms and natural selection in Plasmodium falciparum circumsporozoite (PfCSP), the leading malaria vaccine, is crucial for the development of next-generation vaccines, and such data is lacking in Africa. Blood samples were collected among Plasmodium-infected individuals living in four Cameroonian areas (Douala, Maroua, Mayo-Oulo, Pette). DNA samples were amplified using nested PCR protocols, sequenced, and BLASTed. Single nucleotide polymorphisms (SNPs) were analysed in each PfCSP region, and their impact on PfCSP function/structure was predicted in silico. The N-terminal region showed a limited polymorphism with four haplotypes, and three novel SNPs (N68Y, R87W, K93E) were found. Thirty-five haplotypes were identified in the central region, with several variants (e.g., NVNP and KANP). The C-terminal region was also highly diverse, with 25 haplotypes and eight novel SNPs (N290D, N308I, S312G, K317A, V344I, D356E, E357L, D359Y). Most polymorphic codon sites were mainly observed in the Th2R subregion in isolates from Douala and Pette. The codon site 321 was under episodic positive selection. One novel (E357L) and three known (K322I, G349D, D359Y) SNPs show an impact on function/structure. This study showed extensive genetic diversity with geographical patterns and evidence of the selection of Cameroonian PfCSP central and C-terminal regions.

Modelling onchocerciasis-associated epilepsy and the impact of ivermectin treatment on its prevalence and incidence.

Retrospective cohort studies in Cameroon found an association between Onchocerca volvulus microfilarial load in childhood (measured in 1991-1993) and risk of developing epilepsy later in life (measured in 2017). We parameterised and integrated this relationship (across children aged 3-15 years) into the previously published, stochastic transmission model, EPIONCHO-IBM, for Simulium damnosum sensu lato-transmitted onchocerciasis. We simulated 19 years (1998-2017) of annual ivermectin mass drug administration (MDA) reflecting coverage in the study area, and modelled epilepsy prevalence and incidence. Scenario-based simulations of 25 years of (annual and biannual) MDA in hyper- and holoendemic settings, with 65% and 80% therapeutic coverage, were also conducted. EPIONCHO-IBM predicted 7.6% epilepsy prevalence (compared to 8.2% in the Cameroon study) and incidence of 317 cases/100,000 person-years (compared to 350). In hyperendemic areas, 25 years of biannual MDA (80% coverage) eliminated onchocerciasis-associated epilepsy (OAE) and protected untreated under-fives from its development. Strengthening onchocerciasis programmes, implementing alternative strategies, and evaluating treatment for under-fives and school-age children are crucial to prevent OAE in highly-endemic settings.

Indoor residual spraying of experimental huts in Cameroon highlights the potential of Fludora® Fusion to control wild pyrethroid-resistant malaria vectors.

Elevated resistance to pyrethroids in major malaria vectors has led to the introduction of novel insecticides including neonicotinoids. There is a fear that efficacy of these new insecticides could be impacted by cross-resistance mechanisms from metabolic resistance to pyrethroids. In this study, after evaluating the resistance to deltamethrin, clothianidin and mixture of clothianidin + deltamethrin in the lab using CDC bottle assays, the efficacy of the new IRS formulation Fludora® Fusion was tested in comparison to clothianidin and deltamethrin applied alone using experimental hut trials against wild free-flying pyrethroid-resistant Anopheles funestus from Elende and field An. gambiae collected from Nkolondom reared in the lab and released in the huts. Additionally, cone tests on the treated walls were performed each month for a period of twelve months to evaluate the residual efficacy of the sprayed products. Furthermore, the L1014F-kdr target-site mutation and the L119F-GSTe2 mediated metabolic resistance to pyrethroids were genotyped on a subset of mosquitoes from the EHT to assess the potential cross-resistance. All Anopheles species tested were fully susceptible to clothianidin and clothianidin + deltamethrin mixture in CDC bottle assay while resistance was noted to deltamethrin. Accordingly, Fludora® Fusion (62.83% vs 42.42%) and clothianidin (64.42% vs 42.42%) induced significantly higher mortality rates in EHT than deltamethrin (42.42%) against free flying An. funestus from Elende in month 1 (M1) and no significant difference in mortality was observed between the first (M1) and sixth (M6) months of the evaluation (P > 0.05). However, lower mortality rates were recorded against An. gambiae s.s from Nkolondom (mortality rates 50%, 45.56% and 26.68%). In-situ cone test on the wall showed a high residual efficacy of Fludora® Fusion and clothianidin on the susceptible strain KISUMU (> 12 months) and moderately on the highly pyrethroid-resistant An. gambiae strain from Nkolondom (6 months). Interestingly, no association was observed between the L119F-GSTe2 mutation and the ability of mosquitoes to survive exposure to Fludora® Fusion, whereas a trend was observed with the L1014F-kdr mutation. This study highlights that Fludora® Fusion, through its clothianidin component, has good potential of controlling pyrethroid-resistant mosquitoes with prolonged residual efficacy. This could be therefore an appropriate tool for vector control in several malaria endemic regions.

Molecular detection of trypanosomes of the Trypanosoma livingstonei species group in diverse bat species in Central Cameroon.

Bats are hosts for diverse Trypanosoma species, including trypanosomes of the Trypanosoma cruzi clade. This clade is believed to have originated in Africa and diversified in many lineages worldwide. In several geographical areas, including Cameroon, no data about trypanosomes of bats has been collected yet. In this study, we investigated the diversity and phylogenetic relationships of trypanosomes of different bat species in the central region of Cameroon. Trypanosome infections were detected in six bat species of four bat families, namely Hipposideridae, Pteropodidae, Rhinolophidae, and Vespertilionidae, with an overall prevalence of 29% and the highest infection rate in hipposiderid bat species. All trypanosomes were identified as belonging to the Trypanosoma livingstonei species group with one clade that might represent an additional subspecies of T. livingstonei. Understanding the prevalence, distribution, and host range of parasites of this group contributes to our overall knowledge of the diversity and host specificity of trypanosome species that phylogenetically group at the base of the T. cruzi clade.

Aedes Mosquito Virome in Southwestern Cameroon: Lack of Core Virome, But a Very Rich and Diverse Virome in Ae. africanus Compared to Other Aedes Species.

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.