Caractérisation de la dynamique spatio-temporelle de la plaine inondable du Noun (Cameroun) à l’aide d’images satellites

In Cameroon, the pressure on wetlands, which cover nearly 70% of the national territory, appears to be increasing, whether for subsistence needs, firewood, grazing, logging or expansion of development projects. Currently, in terms of land use, forest has decreased by 619 km² and cultivated land has increased by 321 km². The surface area of degraded forests and land is estimated at around 12 million hectares, with a general trend towards an increase in the phenomenon due to both natural and anthropogenic factors. It is obvious that approaches in favour of wetlands are widely engaged in the different basins of Cameroon. However, the management strategies for these areas are based on knowledge that is certainly extensive, but still patchy. There is a serious lack of overview of the location of degraded lands, the intensity of this degradation and the way farmers are addressing this problem through sustainable land management.Goal and objectives:The objective of this study is to characterize the dynamics of land cover from multi-date satellite data in the Noun floodplain of Cameroon.MethodologyThe methodology relies on the use of remote sensing and GIS to identify spatial units and detect changes over a twenty-two year period (1999 to 2021). The land cover maps were produced from an unsupervised classification with maximum likelihood.Results:The results identified eight classes: herbaceous savannahs with shrubs, forest galleries, fields and plantations, herbaceous tannas, young fallows, mineralized and built-up soils, bare soils and surface waters. It appears that in 1999, the landscape was dominated by natural vegetation (72.6%) located from north to south of the Noun plain. However, since 2004, the landscape has been dominated by agricultural areas (56.8%). Natural formations have been progressively reduced in space over time. The evolution of the Noun floodplain landscape reveals that 14.3% of the space has remained stable. These are fields and plantations, young fallows, mineralized soils and surface water. This space has not migrated to other classes. While about 73.9% of the area has moved to higher classes, of which 35.6% to herbaceous tannas and 26% to fields and plantations. On the other hand, 72.6% of the area (herbaceous savannahs and forests gallery) has been heavily degraded. These results indicate that the landscape of the Noun floodplain is marked by a high level of agricultural activity, which is at the origin of the progressive degradation of the land.  They suggest an effective awareness of the level of land degradation and a better integrated management of land at the local level

Identification and Phenotype of MAIT Cells in Cattle and Their Response to Bacterial Infections

Mucosal-associated invariant T (MAIT) cells are a population of innate-like T cells that utilize a semi-invariant T cell receptor (TCR) α chain and are restricted by the highly conserved antigen presenting molecule MR1. MR1 presents microbial riboflavin biosynthesis derived metabolites produced by bacteria and fungi. Consistent with their ability to sense ligands derived from bacterial sources, MAIT cells have been associated with the immune response to a variety of bacterial infections, such as Mycobacterium spp., Salmonella spp. and Escherichia coli. To date, MAIT cells have been studied in humans, non-human primates and mice. However, they have only been putatively identified in cattle by PCR based methods; no phenotypic or functional analyses have been performed. Here, we identified a MAIT cell population in cattle utilizing MR1 tetramers and high-throughput TCR sequencing. Phenotypic analysis of cattle MAIT cells revealed features highly analogous to those of MAIT cells in humans and mice, including expression of an orthologous TRAV1-TRAJ33 TCR α chain, an effector memory phenotype irrespective of tissue localization, and expression of the transcription factors PLZF and EOMES. We determined the frequency of MAIT cells in peripheral blood and multiple tissues, finding that cattle MAIT cells are enriched in mucosal tissues as well as in the mesenteric lymph node. Cattle MAIT cells were responsive to stimulation by 5-OP-RU and riboflavin biosynthesis competent bacteria in vitro. Furthermore, MAIT cells in milk increased in frequency in cows with mastitis. Following challenge with virulent Mycobacterium bovis, a causative agent of bovine tuberculosis and a zoonosis, peripheral blood MAIT cells expressed higher levels of perforin. Thus, MAIT cells are implicated in the immune response to two major bacterial infections in cattle. These data suggest that MAIT cells are functionally highly conserved and that cattle are an excellent large animal model to study the role of MAIT cells in important zoonotic infections

Assessing the impact of neurosurgery and neuroanatomy simulation using 3D non-cadaveric models amongst selected African medical students

BackgroundLaboratory dissections are essential to acquire practical skills to perform neurosurgical procedures. Despite being traditionally done on cadavers, they are often unavailable and suffer from cultural barriers in the African context. Non-cadaveric UpSurgeOn neurosurgery models have been developed to bridge this barrier, providing an almost similar experience with the human body. This study aimed to assess the impact of the UpSurgeOn hands-on-touch non-cadaver model training amongst selected Cameroon medical students.MethodsAn anonymous 35-item questionnaire was distributed online using Google drive systems to medical students who attended UpSurgeOn's hands-on-touch non-cadaver model training course. These questions aimed to capture data on previous experience with neuroanatomy and neurosurgery practicals and the perception, attitudes, and impact of the UpSurgeOn neurosurgery tool.ResultsEighty-six students completed the survey. The mean age was 21.2 ± 1.868 years, 61.6% were males with 62.8% of respondents being medical students in preclinical years. Before the training, 29.4% had a fair knowledge of neuroanatomy. Textbooks and Youtube videos were the main sources of neuroanatomy and neurosurgery knowledge for more than half of the respondents. Up to 91.5% had no prior exposure to a neuroanatomy/neurosurgery cadaver laboratory dissection, and 22.6% and 17.6% had witnessed and performed at least one craniotomy before, respectively. There were 11.1%, 15.5%, and 31.3% of our respondents who had used a surgical microscope, a neurosurgical instrument, and the UpSurgeOn Neurosurgery tool before, respectively. The majority perceived the UpSurgeOn tool easy to use and felt they needed to learn just a few things before getting going with the box. Most thought of increasing the use of the UpSurgeOn Box and saw the need to be part of the training curriculum. Finally, the majority felt this tool helped to increase familiarity and acquire neurosurgical skills, and to develop the orientation skills needed during neurosurgical approaches.ConclusionUndergraduate exposure to traditional neurosurgery/neuroanatomy labs is limited in Cameroon. Neurosurgery/neuroanatomy practical skills are gained essentially using non-practical means. Most students found the UpSurgeOn tool user-friendly, saw the need to incorporate it as part of their training, and perceived it to be essential in getting acquainted with neurosurgical skills

Hepatitis E virus infection as a promoting factor for hepatocellular carcinoma in Cameroon: Preliminary Observations

Objectives: To determine the seroprevalence of hepatitis E virus (HEV) infection in patients with chronic hepatitis and/or hepatocellular carcinoma (HCC) and to assess its potential consequences for disease progression. Methods: We conducted a prospective case-control study on patients with HCC hepatitis B or C related and non-HCC patients including patients with CLD and patients without clinical evidence of liver disease. Anti-HEV IgG and IgM were tested by ELISA using commercially available kits. Liver damage was assessed by alanine aminotransferase, aspartate aminotransferase, platelets and prothrombin measurements. Results: We observed a significant anti-HEV IgG carriage in HCC patients compared to non-HCC subjects with CLD (41.8% vs 12.6%; P = 9.1 E-6; OR = 4.8, 95%CI: 2.3-10.6). HCC patients with HEV infection display more profound alterations of circulating liver enzymes, platelets count and prothrombin time than HCC patients without sero-reactivity to HEV. Conclusion: Overall, this study indicates a high prevalence of HEV infection in Cameroonian patients with CLD and HCC. These data suggest either that patients with liver tumors are more susceptible to hepeviral infection or that, in a tropical context, HEV might promote the progression of liver diseases towards tumor. Keywords: Hepatocellular carcinoma, Hepatitis E, Seroprevalence, Anti-HEV IgG, Anti-HEV Ig

The role of hepatitis C virus genotypes and core mutations in hepatocellular carcinoma in Cameroon

International audienceBackground: Hepatitis C virus (HCV) infection is known to be an important risk factor for hepatocellular carcinoma (HCC) in Cameroon. However, the effect of HCV-related factors on HCC development still remains unknown in the Central Africa. In this study, we investigated the role of HCV genotypes and core mutations in HCC development in Cameroonian patients.Methods: A case-control study was conducted using patients with HCV-related HCC and matched controls individuals with chronic HCV infection but without HCC. HCV genotypes and mutations were determined using a hemi-nested amplification and sequencing analysis focus on the core and NS5B HCV regions.Results: We identify HCV genotype 1, 2 and 4 in both groups. Interestingly, genotype 4 was significantly more prevalent in HCC patients (53.3%). Overall, distribution of genotypes was very different between cases and controls (P = 4.2 E-7). The risk factors analysis showed that infection with HCV-4 is strongly associated with HCC development with odd ratio, 95% confidence interval and p-values of 7.4 (95% CI: 2.08-26.6; P = .001). Furthermore, the risk of developing HCC increased even more significantly in case of infection with HCV subtype 4f with the odd ratio of 20.8 (95% CI, 4.1-66.8; P < .001). Mutations K10R, T72E, K74R and G77A were significantly more frequent in patients with HCC. Remarkably, HCV-4f isolates from HCC patients carried significantly more mutations when compared to controls with HCV-4f or others genotypes (P = .0001).Conclusions: Our results indicate that patients infected with HCV-4f or with selected variants affecting HCV core gene are at increased risk to develop HC

MOESM1 of Dichotomous associations of liver pathology with hepatocellular carcinoma morphology in Middle Africa: the situation in Cameroon

Additional file 1. Microphotographs of the A: (H&E × 10) liver parenchyma within the limits of normal but showing a slight dilation of sinusoids; B: (H&E × 10) and C: (H&E × 20) chronic hepatitis with moderate activity characterized by ballonnisation, cellular clarification of moderate intensity and the presence of macrovascular steatosis less than 20%; the morphological variants of HCC. D: (H&E × 4) and E: (H&E × 20) Moderately differentiated HCC with trabecular/acinar pattern; F: Moderately differentiated HCC with moderately to severe steatosis pattern (H&E × 40). H&E Hematin-Eosin

Phthirus pubis Infestation of the Eyelids Presenting as Chronic Blepharoconjunctivitis in a 6-Year-Old Girl: A Case Report

Purpose: To report the case of Phthirus pubis infestation of the eyelashes presenting as chronic blepharoconjunctivitis. Case Report: A 6-year-old girl presented with a 2-month history of blepharoconjunctivitis unresponsive to topical antibiotics in the left eye. Slit-lamp examination revealed the presence of nits and adult parasites on the eyelashes. Parasitological examination confirmed adult forms and nits of Phthirus pubis. There was no evidence of infestation elsewhere. Outcome was favourable with mechanical removal and application of petroleum jelly. Conclusion: Careful slit-lamp examination of the eyelashes should be done in all patients presenting with ocular irritation symptoms

Partially absorbed cataractous lens in the anterior chamber revealing neglected severe ocular contusion: a case report

Abstract Background Ocular contusion can produce severe lesions, which if not treated appropriately and promptly, can lead to visual impairment. Ocular contusion in childhood may not be reported by children. Case presentation A 27 year old female presented with a partially absorbed cataractous lens that was dislocated into the anterior chamber of her left eye. There was mild anterior chamber reaction. She reported no history of ocular trauma; but associated findings and further investigations were in favour of a post-traumatic aetiology. Conclusion All ocular injuries require a detailed ophthalmological examination to assess vision and the extent of lesions

Differential Diagnosis of Skin Ulcers in a Mycobacterium ulcerans Endemic Area: Data from a Prospective Study in Cameroon

Clinical diagnosis of Buruli ulcer (BU) due to Mycobacterium ulcerans can be challenging. We aimed to specify the differential diagnosis of skin lesions in a BU endemic area