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IDCases 2023Onchocerciasis or river blindness is a parasitic disease caused by transmitted to humans by the byte of a black fly of the species . This pathology, which is a part of...
Onchocerciasis or river blindness is a parasitic disease caused by transmitted to humans by the byte of a black fly of the species . This pathology, which is a part of the Neglected tropical Disease (NTDs), has been resurgent for some years in certain regions of Burkina Faso. We report a case of onchocercoma with the aim of describing the anatomopathological aspects of this pathology. These were two (02) biopsy fragments from a scalp nodule in an 8-year-old boy, received in the pathology laboratory for examination. In this case study, we recall that onchocerciasis is manifested mainly by skin lesions, subcutaneous nodules and ocular lesions. Histologically, the skin lesions present as a dermatitis with adult worms in the superficial dermis within a predominantly eosinophilic inflammatory infiltrate. Nodules or onchocercomas, usually subcutaneous, consist of fibrous, inflammatory tissue with a predominance of eosinophils and adult worms including females containing microfilariae. Ocular lesions begin with punctate keratitis with a snowflake image. Sclerosis with opacification of the cornea progressively sets in, causing blindness.
PubMed: 37273776
DOI: 10.1016/j.idcr.2023.e01811 -
PloS One 2023Life-style metabolic diseases are steadily rising, not only in developed countries, but also in low- and middle-income countries, presenting a global health problem....
The design and development of a study protocol to investigate Onchocerca volvulus, Loa loa and Mansonella perstans-mediated modulation of the metabolic and immunological profile in lean and obese individuals in Cameroon.
BACKGROUND
Life-style metabolic diseases are steadily rising, not only in developed countries, but also in low- and middle-income countries, presenting a global health problem. Metabolic disorders like type 2 diabetes and cardiovascular diseases are among the ten leading causes of death defined by the WHO in 2019. Results from animal and observational human studies suggest a connection between the decline in human helminth infections and rise of life-style-associated metabolic diseases in developing regions. This trial was designed to investigate filarial infections and their impact on metabolic diseases in Cameroon. We hypothesize that the induction of regulatory immune responses during filarial infection reduces obesity-induced low-grade inflammatory immune responses and thereby improves metabolic parameters, whereas anthelmintic treatment abolishes this protective effect.
METHODS/DESIGN
Participants infected with Mansonella perstans, Onchocerca volvulus and/or Loa loa being lean (BMI <25), overweight (BMI >25 and <30) or clinically obese (BMI ≥30) from Littoral regions of Cameroon will be evaluated for their parasitological, immunological, metabolic and biochemical profile before and after treatment of their parasitic infections. Anthropomorphic measurements and a detailed questionnaire will complement our analysis. The investigation will assess blood immune cell populations, serum adipokines and cytokines that could be influenced by the parasite infection and/or metabolic diseases. Further, parameters like blood glucose, homeostatic model assessment of insulin resistance (HOMA-IR), circulating lipids and circulating makers of liver function will be monitored. Parameters will be assessed before treatment, 12 and 18 months after treatment.
CONCLUSION
The focus of this study is to obtain a comprehensive metabolic profile of the participants in rural areas of Cameroon and to investigate the relationship between filarial immunomodulation and metabolic diseases. This study will elucidate the effect of anti-filarial treatment on the metabolic and immunological parameters that partake in the development of insulin resistance, narrowing in on a potential protective effect of filarial infections on metabolic diseases.
TRIAL REGISTRATION
doi.org/10.1186/ISRCTN43845142, ISRCTN43845142 February 2020 Trial title Effects of filarial parasite infection on type 2 diabetes Issue date: 27.10.22, V.1.
Topics: Animals; Humans; Mansonella; Onchocerca volvulus; Loa; Mansonelliasis; Cameroon; Diabetes Mellitus, Type 2; Insulin Resistance; Loiasis; Obesity
PubMed: 37267236
DOI: 10.1371/journal.pone.0285689 -
Heliyon May 2023Onchocerciasis caused by Leuckart, 1893 is the second-world infection responsible for human blindness. Except Ivermectin which has as targets the microfilariae of that...
Onchocerciasis caused by Leuckart, 1893 is the second-world infection responsible for human blindness. Except Ivermectin which has as targets the microfilariae of that parasite, specific treatment for this disease does not exist and in developing countries, medicinal plants seem to remedy that health problem. For that, aqueous and hydro-ethanolic leaf, bark, and root extracts of and were evaluated , against the most popular bovine model, and the free-resistant nematode . microfilariae and adults extracted from the bovine nodules and skins as well as the free strains of were exposed to the various concentrations of the plant parts extracts and Ivermectin. In results, all the plant parts extracts were rich in tannins, saponins, alkaloids, flavonoids, phenols, coumarins, and glycosides. Phenols (175.45 ± 0.01 mg EGA/g DM), flavonoids (158.98 ± 0.05 mg EC/g DM), and tannins (89.98 ± 2.56 mg ETA/g DM) contents were high in the bark hydro-ethanolic extract of . The leaf hydro-ethanolic extract of induced high activity against microfilariae (CL = 0.13 mg/mL). The bark hydro-ethanolic extract of was also the most effective on adults and particularly on female adults (CL = 0.18 mg/mL). Against the parasite strain resistant to Ivermectin, leaf hydro-ethanolic extract appeared more active with CL = 0.13 mg/mL. Similarly, the bark hydro-ethanolic extract of was the most potent on the wild strain of . Thus, this study validates the use of these plants by traditional healers in the management of onchocerciasis and suggests a new source of isolation of the potential plant compounds against
PubMed: 37251817
DOI: 10.1016/j.heliyon.2023.e16379 -
PLoS Neglected Tropical Diseases May 2023Onchocerciasis, also known as "river blindness", is caused by the bite of infected female blackflies (genus Simuliidae) that transmit the parasite Onchocerca volvulus. A...
BACKGROUND
Onchocerciasis, also known as "river blindness", is caused by the bite of infected female blackflies (genus Simuliidae) that transmit the parasite Onchocerca volvulus. A high onchocerciasis microfarial load increases the risk to develop epilepsy in children between the ages of 3 and 18 years. In resource-limited settings in Africa where onchocerciasis has been poorly controlled, high numbers of onchocerciasis-associated epilepsy (OAE) are reported. We use mathematical modeling to predict the impact of onchocerciasis control strategies on the incidence and prevalence of OAE.
METHODOLOGY
We developed an OAE model within the well-established mathematical modelling framework ONCHOSIM. Using Latin-Hypercube Sampling (LHS), and grid search technique, we quantified transmission and disease parameters using OAE data from Maridi County, an onchocerciasis endemic area, in southern Republic of South Sudan. Using ONCHOSIM, we predicted the impact of ivermectin mass drug administration (MDA) and vector control on the epidemiology of OAE in Maridi.
PRINCIPAL FINDINGS
The model estimated an OAE prevalence of 4.1% in Maridi County, close to the 3.7% OAE prevalence reported in field studies. The OAE incidence is expected to rapidly decrease by >50% within the first five years of implementing annual MDA with good coverage (≥70%). With vector control at a high efficacy level (around 80% reduction of blackfly biting rates) as the sole strategy, the reduction is slower, requiring about 10 years to halve the OAE incidence. Increasing the efficacy levels of vector control, and implementing vector control simultaneously with MDA, yielded better results in preventing new cases of OAE.
CONCLUSIONS/SIGNIFICANCES
Our modeling study demonstrates that intensifying onchocerciasis eradication efforts could substantially reduce OAE incidence and prevalence in endemic foci. Our model may be useful for optimizing OAE control strategies.
Topics: Child; Animals; Female; Humans; Child, Preschool; Adolescent; Onchocerciasis; South Sudan; Onchocerciasis, Ocular; Ivermectin; Onchocerca volvulus; Epilepsy; Prevalence; Simuliidae; Blindness
PubMed: 37235598
DOI: 10.1371/journal.pntd.0011320 -
PLOS Global Public Health 2023Onchocerciasis transmission in the Ulanga District of Morogoro-Tanzania is still ongoing despite more than 20 years of Community Directed Treatment with Ivermectin...
Burden and factors associated with onchocerciasis transmission among school-aged children after more than 20 years of Community Directed Treatment with Ivermectin in Ulanga district, Tanzania: A school-based cross-sectional study.
Onchocerciasis transmission in the Ulanga District of Morogoro-Tanzania is still ongoing despite more than 20 years of Community Directed Treatment with Ivermectin (CDTI) in the area. Even though surveys conducted over the years in the area have revealed a decrease in the prevalence of onchocerciasis, the prevalence of comorbidities suggested to be associated with this filarial infection, as epilepsy, is rising in endemic regions. This fact suggests continued transmission of Onchocerca volvulus and emphasizes the need for the evaluation of factors associated with it among school aged children. Therefore, this study determined the current burden of onchocerciasis in children aged 6 to 12 years and factors associated with continued transmission despite more than 20 years of CDTI in Ulanga District, Morogoro Region-Tanzania. A school-based cross-sectional study was conducted among 270 children aged 6 to 12 years in Ulanga District. Participants were tested using the OV-16 IgG4 Rapid Test. An interview-administered questionnaire was used to assess disease-associated symptoms, knowledge of onchocerciasis, and factors associated with continued transmission of the disease among participants. Descriptive statistics, chi-square test, and logistic regression were performed during data analysis. The prevalence of onchocerciasis was 19.6% (53/270), with boys being more infected; prevalence increased with increasing age groups and was higher in rural areas. Sex (AOR = 2.2, 95% CI: 1.13-4.28), age group of 11-12 years (AOR = 31.45, 95% CI: 2.73-362.27), and not taking ivermectin (AOR = 3.17, 95% CI: 1.53-6.58) were the only significant factors identified to be associated with the transmission of onchocerciasis in this study. The high prevalence of onchocerciasis among school age children in Ulanga district suggests continued transmission in the area. Therefore, a need to integrate CDTI with health education on the importance of ivermectin uptake.
PubMed: 37172010
DOI: 10.1371/journal.pgph.0001919 -
Seizure Apr 2023Onchocerciasis-associated epilepsy (OAE) is an important but neglected public health problem in onchocerciasis-endemic areas with insufficient or inadequate... (Review)
Review
Onchocerciasis-associated epilepsy (OAE) is an important but neglected public health problem in onchocerciasis-endemic areas with insufficient or inadequate onchocerciasis control. Hence, there is a need for an internationally accepted, easy-to-use epidemiological case definition of OAE to identify areas of high Onchocerca volvulus transmission and disease burden requiring treatment and prevention interventions. By including OAE as a manifestation of onchocerciasis, we will considerably improve the accuracy of the overall onchocerciasis disease burden, which is currently underestimated. Hopefully, this will lead to increased interest and funding for onchocerciasis research and control interventions, notably the implementation of more effective elimination measures and treatment and support for affected individuals and their families.
Topics: Humans; Onchocerciasis; Nodding Syndrome; Epilepsy; Public Health; Cost of Illness; Prevalence
PubMed: 37023626
DOI: 10.1016/j.seizure.2023.03.024 -
Frontiers in Immunology 2023Scientific findings have shown that Epstein-Barr virus (EBV) plays a key role in the development of some tumor diseases. Therefore, this study intends to take a...
BACKGROUND
Scientific findings have shown that Epstein-Barr virus (EBV) plays a key role in the development of some tumor diseases. Therefore, this study intends to take a practical step in controlling the pathogenicity of this virus by designing an effective vaccine based on the virus Capsid Envelope and Epstein-Barr nuclear immunogen (EBNA) Proteins Epitopes. Currently, there are no effective drugs or vaccines to treat or prevent EBV infection. So, we applied a computer-based strategy to design an epitope vaccine.
RESULTS
We designed a powerful multi-epitope peptide vaccine against EBV using in silico analysis. The vaccine is made up of 844 amino acids derived from three different types of proteins (Envelope, Capsid, EBNA) found in two different viral strains. responses. These epitopes have a high immunogenic capacity and are not likely to cause allergies. To enhance the vaccine immunogenicity, we used rOv-ASP-1, a recombinant Onchocerca volvulus activation associated protein-1, as an adjuvant and linked it to the vaccine's N and C terminus. The physicochemical and immunological properties of the vaccine structure were evaluated. The proposed vaccine was stable, with a stability index of 33.57 and a pI of 10.10, according to bioinformatic predictions. Docking analysis revealed that the vaccine protein binds correctly with immunological receptors.
CONCLUSION
Our results demonstrated that the multi-epitope vaccine might be potentially immunogenic and induce humoral and cellular immune responses against EBV. This vaccine can interact appropriately with immunological receptors Also, it has a high-quality structure and suitable characteristics such as high stability.
Topics: Humans; Herpesvirus 4, Human; Epstein-Barr Virus Infections; Epitopes; Viral Vaccines
PubMed: 36999015
DOI: 10.3389/fimmu.2023.1115345 -
Frontiers in Immunology 2023Parasitic nematodes responsible for filarial diseases cause chronic disablement in humans worldwide. Elimination programs have substantially reduced the rate of...
Parasitic nematodes responsible for filarial diseases cause chronic disablement in humans worldwide. Elimination programs have substantially reduced the rate of infection in certain areas, but limitations of current diagnostics for population surveillance have been pointed out and improved assays are needed to reach the elimination targets. While serological tests detecting antibodies to parasite antigens are convenient tools, those currently available are compromised by the occurrence of antibodies cross-reactive between nematodes, as well as by the presence of residual antibodies in sera years after treatment and clearance of the infection. We recently characterized the N-linked and glycosphingolipid derived glycans of the parasitic nematode and revealed the presence of various antigenic structures that triggered immunoglobulin G (IgG) responses in infected individuals. To address the specificity of IgG binding to these glycan antigens, we screened microarrays containing glycans with plasma from uninfected individuals and from individuals infected with , , and , four closely related filarial nematodes. IgG to a restricted subset of cross-reactive glycans was observed in infection plasmas from all four species. In plasma from and infected individuals, IgG binding to many more glycans was additionally detected, resulting in total IgG responses similar to the ones of infected individuals. For these infection groups, , and , we further studied the different IgG subclasses to glycans. In all three infections, IgG1 and IgG2 appeared to be the major subclasses involved in response to glycan antigens. Interestingly, in infected individuals, we observed a marked reduction in particular in IgG2 to parasite glycans post-treatment with anthelminthic, suggesting a promising potential for diagnostic applications. Thus, we compared the IgG response to a broad repertoire of glycans in individuals infected with various filarial nematodes. We identified broadly cross-reactive and more specific glycan targets, extending the currently scarce knowledge of filarial nematode glycosylation and host anti-glycan antibody response. We believe that our initial findings could be further exploited to develop disease-specific diagnostics as part of an integrated approach for filarial disease control.
Topics: Humans; Animals; Filariasis; Antibodies, Helminth; Brugia malayi; Antigens; Immunoglobulin G
PubMed: 36949937
DOI: 10.3389/fimmu.2023.1102344 -
African Health Sciences Sep 2022Despite 20 years of ivermectin mass distribution in the Mahenge area, Tanzania, the prevalence of onchocerciasis and epilepsy has remained high in rural villages.
BACKGROUND
Despite 20 years of ivermectin mass distribution in the Mahenge area, Tanzania, the prevalence of onchocerciasis and epilepsy has remained high in rural villages.
OBJECTIVES
We investigated the efficacy of ivermectin in reducing Onchocerca volvulus microfilariae and predictors for parasitic load following ivermectin treatment in persons with (PWE) and without epilepsy (PWOE).
METHODS
Between April and September 2019, 50 PWE and 160 randomly selected PWOE from Msogezi and Mdindo villages participated in a follow-up study. Skin snips were obtained pre (baseline) and three months post-ivermectin treatment.
RESULTS
The overall prevalence of positive skin snips at baseline was 49% (103/210), with no significant difference between PWE (58.0%) and PWOE (46.3%); p=0.197. The overall mean microfilarial density was significantly higher at baseline 1.45(95%CI:0.98-2.04)) than three-month post-ivermectin treatment (0.23(95%CI:0.11-0.37), p<0.001. Three months after ivermectin, the microfilarial density had decreased by ≥80% in 54 (81.8%, 95%CI: 72.3-91.4) of the 66 individuals with positive skin snips at baseline. High microfilarial density at baseline was the only significant predictor associated with higher microfilarial density in the post-ivermectin skin snips.
CONCLUSION
Our study reports a decrease in microfilarial density following ivermectin treatment in most individuals. Optimizing ivermectin coverage will address the ongoing onchocerciasis transmission in Mahenge.
Topics: Animals; Humans; Epilepsy; Follow-Up Studies; Ivermectin; Microfilariae; Onchocerca volvulus; Onchocerciasis; Prevalence; Tanzania; Treatment Outcome
PubMed: 36910370
DOI: 10.4314/ahs.v22i3.65 -
Frontiers in Tropical Diseases Mar 2023Filariae are vector borne parasitic nematodes, endemic in tropical and subtropical regions causing avoidable infections ranging from asymptomatic to stigmatizing and...
Filariasis research - from basic research to drug development and novel diagnostics, over a decade of research at the Institute for Medical Microbiology, Immunology and Parasitology, Bonn, Germany.
Filariae are vector borne parasitic nematodes, endemic in tropical and subtropical regions causing avoidable infections ranging from asymptomatic to stigmatizing and disfiguring disease. The filarial species that are the major focus of our institution's research are causing onchocerciasis (river blindness), and spp. causing lymphatic filariasis (elephantiasis), causing loiasis (African eye worm), and spp causing mansonellosis. This paper aims to showcase the contribution of our institution and our collaborating partners to filarial research and covers decades of long research spanning basic research using the animal model to development of drugs and novel diagnostics. Research with the model has been extensively useful in elucidating protective immune responses against filariae as well as in identifying the mechanisms of filarial immunomodulation during metabolic, autoimmune and infectious diseases. The institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany has also been actively involved in translational research in contributing to the identification of new drug targets and pre-clinical drug research with successful and ongoing partnership with sub-Saharan Africa, mainly Ghana (the Kumasi Centre for Collaborative Research (KCCR)), Cameroon (University of Buea (UB)) and Togo (Laboratoire de Microbiologie et de Contrôle de Qualité des Denrées Alimentaires (LAMICODA)), Asia and industry partners. Further, in the direction of developing novel diagnostics that are sensitive, time, and labour saving, we have developed sensitive qPCRs as well as LAMP assays and are currently working on artificial intelligence based histology analysis for onchocerciasis. The article also highlights our ongoing research and the need for novel animal models and new drug targets.
PubMed: 38655130
DOI: 10.3389/fitd.2023.1126173