Institut für Medizinische Mikrobiologie, Immunologie und Parasitologie (IMMIP)

Potential of Aframomum melegueta and Xylopia aethiopica Against Taenia spp.

2025-11-07T07:46:27Z

Potential of Aframomum melegueta and Xylopia aethiopica Against Taenia spp. Douti, Fekandine V.; Katawa, Gnatoulma; Arndt, Kathrin; Bara, Fagdéba D.; Awesso, Essimanam R.; Karou, Simplice D.; Hoerauf, Achim; Ritter, Manuel Background/Objectives: Taeniasis, a zoonotic infection, is a common foodborne disease. Niclosamide and praziquantel have proven to be effective in treating it, but the use of the same drugs can lead to resistance, so alternative drugs need to be explored. This study investigated the anthelmintic potential of derived fractions from hydroethanolic ex- tracts (HEs) of Aframomum melegueta (AM) and Xylopia aethiopica (XA), two medicinal plants known for their diverse bioactive properties. Methods: AM-HE fractions (dichloromethane fraction (DCMF), ether fraction (EF), aqueous fraction (AF)) and XA-HE fractions (chloroform fraction (CF), ether fraction (EF), and aqueous fraction (AF)) were used, and in vitro anthelmintic activity was assessed against Taenia spp. by using an adult motility assay for the worm's paralysis time determination. The parasiticidal and parasitostatic activity was also tested on Taenia spp. adult worms. Cell viability was further evaluated using propidium iodide (PI) staining, with albendazole (20 mg/mL) as the reference drug. Results: The three fractions of each plant exhibited significant, dose-dependent anthelmintic activity, with AM-HE and XA-CF showing the greatest effects at 20 mg/mL. AM-EF demonstrated significant activity at 0.4% and 0.8%. Irreversibility tests revealed that most of the treated worms remained paralysis, except those exposed to the AF of both plants. PI staining confirmed the dose-dependent mortality of Taenia cells treated with HE, DCMF, and AF of AM. Conclusions: These results underscore the potential of AM and XA extracts and fractions as alternative treatments for helminth infections. Further, in vivo studies are warranted to confirm their safety and therapeutic efficacy.

Robust COVID-19 Vaccine Responses Despite Filarial Co-Infection

2025-10-24T12:35:38Z

Robust COVID-19 Vaccine Responses Despite Filarial Co-Infection Meyer, Julia; Nadal, Jennifer; Batsa Debrah, Linda; Debrah, Alexander Yaw; Osei-Mensah, Jubin; Mensah, Derrick Adu; Korir, Patricia Jebett; Kuehlwein, Janina M.; Klarmann-Schulz, Ute; Hoerauf, Achim; Adjobimey, Tomabu Background/Objectives: Although the COVID-19 pandemic has largely concluded, the varied trajectories it has followed in different regions of the world remain incompletely understood. Intensive research is needed to fully grasp its course and the implications for future global health challenges. Notably, the milder trajectory of the COVID-19 pandemic in Sub-Saharan Africa has defied initial predictions. An emerging body of evidence suggests that, in addition to the continent’s younger average age and the lower prevalence of relevant comorbidities, co-infections with helminths may have also impressively shaped the pandemic’s milder trajectory in the region. Indeed, helminths are renowned for their ability to modulate human immune responses, which, while potentially beneficial in limiting excessive inflammation, could also diminish vaccine efficacy and impede viral clearance. This study investigated different aspects of the intricate interactions between COVID-19 and Lymphatic Filariasis (LF), a helminth infection caused by parasitic worms such as Wuchereria bancrofti, Brugia malayi, and Brugia timori and endemic to various regions in Sub-Saharan Africa and the tropics. Methods: For this purpose, samples of a larger and ongoing clinical trial (ethical approval codes: CHRPE/AP/525/17 and 325/21; trial registration number ISRCTN14042737) were collected from 222 individuals from endemic areas of Ghana, along with comprehensive clinical and demographic data. The samples include LF patients (n = 222) grouped according to their Lymphoedema (LE) stages, as well as COVID-19 vaccinated (n = 81) and non-vaccinated individuals (n = 141). All vaccinated participants received the COVID-19 vaccine ChAdOx1-S (also known as Vaxzevria) developed by the University of Oxford and AstraZenca. The expressions of SARS-CoV-2 and filarial-specific antibodies (IgG, IgA) were accessed using ELISA, while Luminex-based immunoassays were employed to measure the expression of SARS-CoV-2 variant-specific neutralizing antibodies. The interplay between vaccine responses and demographic factors was analyzed using group comparisons with the Kruskal-Wallis or Mann-Whitney U tests. Results: The results indicate that a remarkable portion of unvaccinated individuals (56% IgA seropositive, 39% IgG seropositive) developed antibodies against SARS-CoV-2 despite no confirmed infection. Notably, the study identified a robust antibody response to COVID-19 vaccination, which was independent of the degree of LF pathology or parasitic status. An important observation was the reduced SARS-CoV-2 antibody response in individuals seropositive for Ascaris lumbricoides (p = 0.0264), highlighting an interaction between roundworm infection and COVID-19. Conclusions: The study concludes that the ChAdOx1-S COVID-19 vaccine (AstraZeneca) triggers a strong immune response in LF patients; however, filarial and/or soil-transmitted helminth seropositivity might influence the COVID-19 infection-induced response. These findings emphasize the complexity of infectious disease dynamics in co-infected populations and the need to decipher parasite-induced immunomodulatory mechanisms on COVID-19 vaccination.

Large-scale production of Mansonella perstans infective larvae from engorged Culicoides milnei

2025-08-08T11:46:31Z

Large-scale production of Mansonella perstans infective larvae from engorged Culicoides milnei Kien, Chi Anizette; Ebai, Rene; Fombad, Fanny Fri; Esofi, Frederick; Ntuh, Anna Ning; Ouam, Emmanuel; Gandjui, Narcisse Victor Tchamatchoua; Chunda, Valerine Chawa; Ekanya, Relindis; Nietcho, Franck Noel; Foyet, Juluis Visnel; Nchang, Lucy Cho; Magha, Chefor; Njouendou, Abdel Jelil; Enyong, Peter; Hoerauf, Achim; Ritter, Manuel; Wanji, Samuel Background: Mansonella perstans is transmitted by Culicoides species and affects hundred millions of inhabitants in about 33 countries in sub-Saharan Africa. It is known that Mansonellosis due to Mansonella perstans do not result in a clear clinical picture, but down-regulates the immunity of patients predisposing them to other diseases like tuberculosis, HIV and malaria or damping vaccine efficacy. However, research about novel drugs against this filarial nematode is missing because of the lack of parasite material. Previous studies have developed in vitro culture systems using infective stage 3 larvae (L3), but these life stages are difficult to obtain and thus the performance of in vitro cultures is restricted and does not allow large-scale testing of drugs or even infection experiments in animal models. Therefore, we aim to establish a platform for the large-scale production of M. perstans infective larvae from engorged Culicoides milnei.
Methods: Culicoides species were caught in Yangom (Yabassi Health District) in the Littoral Region of Cameroon following a blood meal on six microfilariae-positive donors with different microfilaraemic loads over one year. Engorged midges were reared in the insectarium for up to 14 days and L3 were isolated from the different body parts.
Result: In summary, 13,658 engorged Culicoides were collected and reared in the laboratory. We observed an overall predicted survival of 78.5%. Out of the 8,123 survived midges, 7,086 midges belong to C. milnei, from which 2,335 were infected leading to a recovery of 6,310 L3. Moreover, we found the highest survival rates of midges during the early dry season in December with moderate temperatures (23-25°C) and low (2-4mm) or no rainfall. In addition, we observed that midges that fed on donors with high microfilarial loads showed increased mortality.
Conclusion: We revealed suitable conditions for the collection and maintenance of engorged Culicoides midges allowing the large-scale production of M. perstans L3. This procedure will provide a platform to produce sufficient parasite material that will facilitate in vitro cultures and the establishment of a murine model of M. perstans, which is important for in-depth investigation of the filarial biology and screening of novel drugs that are effective against this ivermectin-resistant nematode.

Schistosomiasis–Microbiota Interactions

2025-08-08T11:16:27Z

Schistosomiasis–Microbiota Interactions Afful, Philip; Abotsi, Godwin Kwami; Adu-Gyamfi, Czarina Owusua; Benyem, George; Katawa, Gnatoulma; Kyei, Samuel; Arndts, Kathrin; Ritter, Manuel; Asare, Kwame Kumi Introduction: Schistosomiasis, a tropical disease affecting humans and animals, affected 251.4 million people in 2021. Schistosoma mansoni, S. haematobium, S. intercalatum, and S. japonicum are primary human schistosomes, causing tissue damage, granulomas, ulceration, hemorrhage, and opportunistic pathogen entry. The gut and urinary tract microbiota significantly impact a host’s susceptibility to schistosomiasis, disrupting microbial balance; however, this relationship is not well understood. This systematic review and meta-analysis explores the intricate relationship between schistosomiasis and the host’s microbiota, providing crucial insights into disease pathogenesis and management. Methods: This systematic review used PRISMA guidelines to identify peer-reviewed articles on schistosomiasis and its interactions with the host microbiome, using multiple databases and Google Scholar, providing a robust dataset for analysis. The study utilized Meta-Mar v3.5.1; descriptive tests, random-effects models, and subgroups were analyzed for the interaction between Schistosomiasis and the microbiome. Forest plots, Cochran’s Q test, and Higgins’ inconsistency statistic (I²) were used to assess heterogeneity. Results: The human Schistosoma species were observed to be associated with various bacterial species isolated from blood, stool, urine, sputum, skin, and vaginal or cervical samples. A meta-analysis of the interaction between schistosomiasis and the host microbiome, based on 31 studies, showed 29,784 observations and 5871 events. The pooled estimates indicated a significant association between schistosomiasis and changes in the microbiome of infected individuals. There was considerable heterogeneity with variance effect sizes (p < 0.0001). Subgroup analysis of Schistosoma species demonstrated that S. haematobium was the most significant contributor to the overall heterogeneity, accounting for 62.1% (p < 0.01). S. mansoni contributed 13.0% (p = 0.02), and the coinfection of S. haematobium and S. mansoni accounted for 16.8% of the heterogeneity (p < 0.01), contributing to the variability seen in the pooled analysis. Similarly, praziquantel treatment (RR = 1.68, 95% CI: 1.07–2.64) showed high heterogeneity (Chi² = 71.42, df = 11, p < 0.01) and also indicated that Schistosoma infections in males (RR = 1.46, 95% CI: 0.00 to 551.30) and females (RR = 2.09, 95% CI: 0.24 to 18.31) have a higher risk of altering the host microbiome. Conclusions: Schistosomiasis significantly disrupts the host microbiota across various bodily sites, leading to increased susceptibility to different bacterial taxa such as E. coli, Klebsiella, Proteus, Pseudomonas, Salmonella, Staphylococcus, Streptococcus, and Mycobacterium species (M. tuberculosis and M. leprae). This disruption enables these bacteria to produce toxic metabolites, which in turn cause inflammation and facilitate the progression of disease. The impact of schistosomiasis on the vaginal microbiome underscores the necessity for gender-specific approaches to treatment and prevention. Effective management of female genital schistosomiasis (FGS) requires addressing both the parasitic infection and the resulting microbiome imbalances. Additionally, praziquantel-treated individuals have different microbiome compositions compared to individuals with no praziquantel treatment. This suggests that combining praziquantel treatment with probiotics could potentially decrease the disease severity caused by an altered microbiome.