Access to and utilisation of antimicrobials among forcibly displaced persons in Uganda, Yemen and Colombia: a pilot cross-sectional survey.

OBJECTIVES: Identifying key barriers to accessing quality-assured and affordable antimicrobials among forcibly displaced persons in Uganda, Yemen and Colombia and investigating their (1) utilisation patterns of antibiotics, (2) knowledge about antimicrobial resistance (AMR) and (3) perception of the quality of antimicrobials received. DESIGN: Pilot cross-sectional survey. SETTING: Data were collected from five health facilities in the Kiryandongo refugee settlement (Bweyale, Uganda), three camps for internally displaced persons (IDPs) in the Dar Sad district (Aden, Yemen) and a district with a high population of Venezuelan migrants (Kennedy district, Bogotá, Colombia). Data collection took place between February and May 2021. The three countries were selected due to their high number of displaced people in their respective continents. PARTICIPANTS: South Sudanese refugees in Uganda, IDPs in Yemen and Venezuelan migrants in Colombia. OUTCOME MEASURE: The most common barriers to access to quality-assured and affordable antimicrobials. RESULTS: A total of 136 participants were enrolled in this study. Obtaining antimicrobials through informal pathways, either without a doctor's prescription or through family and friends, was common in Yemen (27/50, 54.0%) and Colombia (34/50, 68.0%). In Yemen and Uganda, respondents used antibiotics to treat (58/86, 67.4%) and prevent (39/86, 45.3%) a cold. Knowledge of AMR was generally low (24/136, 17.6%). Barriers to access included financial constraints in Colombia and Uganda, prescription requirements in Yemen and Colombia, and non-availability of drugs in Uganda and Yemen. CONCLUSION: Our multicentred research identified common barriers to accessing quality antimicrobials among refugees/IDPs/migrants and common use of informal pathways. The results suggest that knowledge gaps about AMR may lead to potential misuse of antimicrobials. Due to the study's small sample size and use of non-probability sampling, the results should be interpreted with caution, and larger-scale assessments on this topic are needed. Future interventions designed for similar humanitarian settings should consider the interlinked barriers identified.

Impact of helminth infections during pregnancy on maternal and newborn Vitamin D and on birth outcomes.

Poor birth outcomes in low- and middle income countries are associated with maternal vitamin D deficiency and chronic helminth infections. Here, we investigated whether maternal Schistosoma haematobium affects maternal or cord vitamin D status as well as birth outcomes. In a prospective cross-sectional study of pregnant women conducted in Lambaréné, Gabon, we diagnosed maternal parasitic infections in blood, urine and stool. At delivery we measured vitamin D in maternal and cord blood. S. haematobium, soil-transmitted helminths, and microfilariae were found at prevalences of 30.2%, 13.0%, and 8.8%, respectively. Insufficient vitamin D and calcium levels were found in 28% and 15% of mothers, and in 11.5% and 1.5% of newborns. Mothers with adequate vitamin D had lower risk of low birthweight babies (aOR = 0.11, 95% CI 0.02-0.52, p = 0.01), whilst offspring of primipars had low cord vitamin D levels, and low vitamin D levels increased the risk of maternal inflammation. Maternal filariasis was associated with low calcium levels, but other helminth infections affected neither vitamin D nor calcium levels in either mothers or newborns. Healthy birth outcomes require maintenance of adequate vitamin D and calcium levels. Chronic maternal helminth infections do not disrupt those levels in a semi-rural setting in sub-Saharan Africa.

Detection of hidden antibiotic resistance through real-time genomics.

Real-time genomics through nanopore sequencing holds the promise of fast antibiotic resistance prediction directly in the clinical setting. However, concerns about the accuracy of genomics-based resistance predictions persist, particularly when compared to traditional, clinically established diagnostic methods. Here, we leverage the case of a multi-drug resistant Klebsiella pneumoniae infection to demonstrate how real-time genomics can enhance the accuracy of antibiotic resistance profiling in complex infection scenarios. Our results show that unlike established diagnostics, nanopore sequencing data analysis can accurately detect low-abundance plasmid-mediated resistance, which often remains undetected by conventional methods. This capability has direct implications for clinical practice, where such "hidden" resistance profiles can critically influence treatment decisions. Consequently, the rapid, in situ application of real-time genomics holds significant promise for improving clinical decision-making and patient outcomes.

Epilepsy and nodding syndrome in association with an Onchocerca volvulus infection drive distinct immune profile patterns.

Previous studies have described the association of onchocerciasis (caused by Onchocerca volvulus) with epilepsy, including nodding syndrome, although a clear etiological link is still missing. Cases are found in different African countries (Tanzania, South Sudan, Uganda, Democratic Republic of the Congo, Central African Republic and Cameroon). In our study we investigated immunological parameters (cytokine, chemokine, immunoglobulin levels) in individuals from the Mahenge area, Tanzania, presenting with either epilepsy or nodding syndrome with or without O. volvulus infection and compared them to O. volvulus negative individuals from the same endemic area lacking neurological disorders. Additionally, cell differentiation was performed using blood smears and systemic levels of neurodegeneration markers, leiomodin-1 and N-acetyltyramine-O, ß-glucuronide (NATOG) were determined. Our findings revealed that cytokines, most chemokines and neurodegeneration markers were comparable between both groups presenting with epilepsy or nodding syndrome. However, we observed elevated eosinophil percentages within the O. volvulus positive epilepsy/nodding syndrome patients accompanied with increased eosinophilic cationic protein (ECP) and antigen-specific IgG levels in comparison to those without an O. volvulus infection. Furthermore, highest levels of NATOG were found in O. volvulus positive nodding syndrome patients. These findings highlight that the detection of distinct biomarkers might be useful for a differential diagnosis of epilepsy and nodding syndrome in O. volvulus endemic areas. Trial-registration: NCT03653975.

Spectrum of Helminth Infections in Migrants from Sub-Saharan Africa to Europe: A Literature Review.

Sub-Saharan Africa (SSA) is endemic to numerous neglected tropical diseases, including many helminth diseases. With the migration of people from this part of the world to Europe, as has been happening on a large scale since 2015, these diseases are becoming more relevant to European physicians. This work aims to summarize the recent literature on this topic and to raise awareness of helminth diseases afflicting SSA migrants. The databases PubMed, Embase, and MEDLINE were screened for literature published in English and German between January 1, 2015 and December 31, 2020. In total, 74 articles were included in this review. The spectrum of helminth infections in migrants from SSA found in the literature review is broad; current research, however, is particularly focused on infections with Schistosoma spp. and Strongyloides stercoralis. Both diseases are often characterized by a long course, with few or no symptoms, with the risk of long-term organ damage. Successful and reliable screening for schistosomiasis and strongyloidiasis is strongly recommended. However, the current diagnostic methods lack sensitivity and specificity, rendering the diagnosis challenging and reliable assessment of disease prevalence difficult. Novel diagnostic methods and a greater awareness of these diseases are urgently needed.

Correction: A novel cell-free method to culture Schistosoma mansoni from cercariae to juvenile worm stages for in vitro drug testing.

[This corrects the article DOI: 10.1371/journal.pntd.0006590.].

Helminthic dehydrogenase drives PGE2 and IL-10 production in monocytes to potentiate Treg induction.

Immunoregulation of inflammatory, infection-triggered processes in the brain constitutes a central mechanism to control devastating disease manifestations such as epilepsy. Observational studies implicate the viability of Taenia solium cysts as key factor determining severity of neurocysticercosis (NCC), the most common cause of epilepsy, especially in children, in Sub-Saharan Africa. Viable, in contrast to decaying, cysts mostly remain clinically silent by yet unknown mechanisms, potentially involving Tregs in controlling inflammation. Here, we show that glutamate dehydrogenase from viable cysts instructs tolerogenic monocytes to release IL-10 and the lipid mediator PGE2 . These act in concert, converting naive CD4+ T cells into CD127- CD25hi FoxP3+ CTLA-4+ Tregs, through the G protein-coupled receptors EP2 and EP4 and the IL-10 receptor. Moreover, while viable cyst products strongly upregulate IL-10 and PGE2 transcription in microglia, intravesicular fluid, released during cyst decay, induces pro-inflammatory microglia and TGF-ß as potential drivers of epilepsy. Inhibition of PGE2 synthesis and IL-10 signaling prevents Treg induction by viable cyst products. Harnessing the PGE2 -IL-10 axis and targeting TGF-ß signaling may offer an important therapeutic strategy in inflammatory epilepsy and NCC.

Infection Control Measures and Prevalence of SARS-CoV-2 IgG among 4,554 University Hospital Employees, Munich, Germany.

Hospital staff are at high risk for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during the coronavirus disease (COVID-19) pandemic. This cross-sectional study aimed to determine the prevalence of SARS-CoV-2 infection in hospital staff at the University Hospital rechts der Isar in Munich, Germany, and identify modulating factors. Overall seroprevalence of SARS-CoV-2-IgG in 4,554 participants was 2.4%. Staff engaged in direct patient care, including those working in COVID-19 units, had a similar probability of being seropositive as non-patient-facing staff. Increased probability of infection was observed in staff reporting interactions with SARS-CoV-2‒infected coworkers or private contacts or exposure to COVID-19 patients without appropriate personal protective equipment. Analysis of spatiotemporal trajectories identified that distinct hotspots for SARS-CoV-2‒positive staff and patients only partially overlap. Patient-facing work in a healthcare facility during the SARS-CoV-2 pandemic might be safe as long as adequate personal protective equipment is used and infection prevention practices are followed inside and outside the hospital.

Hepatitis E, Schistosomiasis and Echinococcosis-Prevalence in a Cohort of Pregnant Migrants in Germany and Their Influence on Fetal Growth Restriction.

BACKGROUND: Infections, as well as adverse birth outcomes, may be more frequent in migrant women. Schistosomiasis, echinococcosis, and hepatitis E virus (HEV) seropositivity are associated with the adverse pregnancy outcomes of fetal growth restriction and premature delivery. METHODS: A cohort study of 82 pregnant women with a history of migration and corresponding delivery of newborns in Germany was conducted. RESULTS: Overall, 9% of sera tested positive for anti-HEV IgG. None of the patients tested positive for anti-HEV IgM, schistosomiasis, or echinococcus serology. Birth weights were below the 10th percentile for gestational age in 8.5% of the neonates. No association between HEV serology and fetal growth restriction (FGR) frequency was found. CONCLUSIONS: In comparison to German baseline data, no increased risk for HEV exposure or serological signs of exposure against schistosomiasis or echinococcosis could be observed in pregnant migrants. An influence of the anti-HEV serology status on fetal growth restriction could not be found.

Identification of hit compounds with anti-schistosomal activity on in vitro generated juvenile worms in cell-free medium.

BACKGROUND: Anthelminthic treatment options against schistosomiasis are limited. The current treatment relies almost exclusively on a single drug, praziquantel (PZQ). As a consequence, the development of resistance to PZQ and limited activity of PZQ against earlier development stages are respectively a risk and a limitation to achieving the goals of the new WHO roadmap towards elimination. For the discovery of new chemical starting points, the in vitro drug screening on Schistosoma mansoni (S. mansoni) against newly transformed schistosomula (NTS) is still the most predominant approach. The use of only NTS in the initial screening limits sensitivity to potential new compounds which are predominantly active in later developmental stages. Using our recently described highly standardized, straightforward and reliable culture method that generates high rates of juvenile worms, we aimed to repurpose a subset of the National Center for Advancing Translational Sciences (NCATS) Pharmaceutical Collection (340 compounds) to identify new hits with an in vitro worm culture assay. METHODOLOGY/PRINCIPAL FINDINGS: Cercariae were mechanically transformed into skin-stage (SkS) schistosomula and continuously cultured for 3-6 weeks to the liver stage (LiS). A commercial source of serum was identified, and decrease of NTS/well along with optimal drug testing conditions was established to test compounds on early and late LiS worms. The library was screened in 96-well format assays using praziquantel (PZQ) as a positive control. Primary screening allowed a 5.9% hit rate and generated two confirmed hits on adult worms; a prophylactic antianginal agent and an antihistaminic drug. CONCLUSION: With this standardized and reliable in vitro assay, important S. mansoni developmental stages up to LiS worms can be generated and cultured over an extended period. When exposed to a subset of the NCATS Pharmaceutical Collection, 3 compounds yielded a defined anti-schistosomal phenotype on juvenile worms. Translation of activity on perfused adult S. mansoni worms was achieved only for perhexiline (a prophylactic antianginal agent) and astemizole (an antihistaminic drug).

Host-Specific Serum Factors Control the Development and Survival of Schistosoma mansoni.

Introduction: Schistosomiasis is a neglected tropical disease (NTD) caused by blood-dwelling flatworms which develop from skin-penetrating cercariae, the freely swimming water-borne infective stage of Schistosoma mansoni, into adult worms. This natural course of infection can be mimicked in experimental mouse models of schistosomiasis. However, only a maximum of 20-30% of penetrated cercariae mature into fecund adults. The reasons for this are unknown but could potentially involve soluble factors of the innate immune system, such as complement factors and preexisting, natural antibodies. Materials and Methods: Using our recently developed novel serum- and cell-free in vitro culture system for newly transformed schistosomula (NTS), which supports long-term larval survival, we investigated the effects of mouse serum and its major soluble complement factors C1q, C3, C4 as well as preexisting, natural IgM in vitro and assessed worm development in vivo by infecting complement and soluble (s)IgM-deficient animals. Results: In contrast to sera from humans and a broad variety of mammalian species, serum from mice, surprisingly, killed parasites already at skin stage in vitro. Interestingly, the most efficient killing component(s) were heat-labile but did not include important members of the perhaps best known family of heat-labile serum factors, the complement system, nor consisted of complement-activating natural immunoglobulins. Infection of complement C1q and sIgM-deficient mice with S. mansoni as well as in vitro tests with sera from mice deficient in C3 and C4 revealed no major role for these soluble factors in vivo in regard to parasite maturation, fecundity and associated immunopathology. Rather, the reduction of parasite maturation from cercariae to adult worms was comparable to wild-type mice. Conclusion: This study reveals that not yet identified heat-labile serum factors are major selective determinants of the host-specificity of schistosomiasis, by directly controlling schistosomal development and survival.

Fetomaternal immune cross talk modifies T-cell priming through sustained changes to DC function.

BACKGROUND: Prenatal exposure to infections can modify immune development. These environmental disturbances during early life potentially alter the incidence of inflammatory disorders as well as priming of immune responses. Infection with the helminth Schistosoma mansoni is widely studied for its ability to alter immune responsiveness and is associated with variations in coinfection, allergy, and vaccine efficacy in endemic populations. OBJECTIVE: Exposure to maternal schistosomiasis during early life, even without transmission of infection, can result in priming effects on offspring immune responses to bystander antigenic challenges as related to allergic responsiveness and vaccination, with this article seeking to further clarify the effects and underlying immunologic imprinting. METHODS: Here, we have combined a model of chronic maternal schistosomiasis infection with a thorough analysis of subsequent offspring immune responses to allergy and vaccination models, including viral challenge and steady-state changes to immune cell compartments. RESULTS: We have demonstrated that maternal schistosomiasis alters CD4+ responses during allergic sensitization and challenge in a skewed IL-4/B-cell-dominant response to antigenic challenge associated with limited inflammatory response. Beyond that, we have uncovered previously unidentified alterations to CD8+ T-cell responses during immunization that are dependent on vaccine formulation and have functional impact on the efficacy of vaccination against viral infection in a murine hepatitis B virus model. CONCLUSION: In addition to steady-state modifications to CD4+ T-cell polarization and B-cell priming, we have traced these modified CD8+ responses to an altered dendritic cell phenotype sustained into adulthood, providing evidence for complex priming effects imparted by infection via fetomaternal cross talk.

Taenia larvae possess distinct acetylcholinesterase profiles with implications for host cholinergic signalling.

Larvae of the cestodes Taenia solium and Taenia crassiceps infect the central nervous system of humans. Taenia solium larvae in the brain cause neurocysticercosis, the leading cause of adult-acquired epilepsy worldwide. Relatively little is understood about how cestode-derived products modulate host neural and immune signalling. Acetylcholinesterases, a class of enzyme that breaks down acetylcholine, are produced by a host of parasitic worms to aid their survival in the host. Acetylcholine is an important signalling molecule in both the human nervous and immune systems, with powerful modulatory effects on the excitability of cortical networks. Therefore, it is important to establish whether cestode derived acetylcholinesterases may alter host neuronal cholinergic signalling. Here we make use of multiple techniques to profile acetylcholinesterase activity in different extracts of both Taenia crassiceps and Taenia solium larvae. We find that the larvae of both species contain substantial acetylcholinesterase activity. However, acetylcholinesterase activity is lower in Taenia solium as compared to Taenia crassiceps larvae. Further, whilst we observed acetylcholinesterase activity in all fractions of Taenia crassiceps larvae, including on the membrane surface and in the excreted/secreted extracts, we could not identify acetylcholinesterases on the membrane surface or in the excreted/secreted extracts of Taenia solium larvae. Bioinformatic analysis revealed conservation of the functional protein domains in the Taenia solium acetylcholinesterases, when compared to the homologous human sequence. Finally, using whole-cell patch clamp recordings in rat hippocampal brain slice cultures, we demonstrate that Taenia larval derived acetylcholinesterases can break down acetylcholine at a concentration which induces changes in neuronal signalling. Together, these findings highlight the possibility that Taenia larval acetylcholinesterases can interfere with cholinergic signalling in the host, potentially contributing to pathogenesis in neurocysticercosis.

Host immune responses during Taenia solium Neurocysticercosis infection and treatment.

Taenia solium cysticercosis and taeniasis (TSCT), caused by the tapeworm T. solium, is a foodborne and zoonotic disease classified since 2010 by WHO as a neglected tropical isease. It causes considerable impact on health and economy and is one of the leading causes of acquired epilepsy in most endemic countries of Latin America, Sub-Saharan Africa, and Asia. There is some evidence that the prevalence of TSCT in high-income countries has recently increased, mainly due to immigration from endemic areas. In regions endemic for TSCT, human cysticercosis can manifest clinically as neurocysticercosis (NCC), resulting in epileptic seizures and severe progressive headaches, amongst other neurological signs and/or symptoms. The development of these symptoms results from a complex interplay between anatomical cyst localization, environmental factors, parasite's infective potential, host genetics, and, especially, host immune responses. Treatment of individuals with active NCC (presence of viable cerebral cysts) with anthelmintic drugs together with steroids is usually effective and, in the majority, reduces the number and/or size of cerebral lesions as well as the neurological symptoms. However, in some cases, treatment may profoundly enhance anthelmintic inflammatory responses with ensuing symptoms, which, otherwise, would have remained silent as long as the cysts are viable. This intriguing silencing process is not yet fully understood but may involve active modulation of host responses by cyst-derived immunomodulatory components released directly into the surrounding brain tissue or by the induction of regulatory networks including regulatory T cells (Treg) or regulatory B cells (Breg). These processes might be disturbed once the cysts undergo treatment-induced apoptosis and necrosis or in a coinfection setting such as HIV. Herein, we review the current literature regarding the immunology and pathogenesis of NCC with a highlight on the mobilization of immune cells during human NCC and their interaction with viable and degenerating cysticerci. Moreover, the immunological parameters associated with NCC in people living with HIV/AIDS and treatments are discussed. Eventually, we propose open questions to understand the role of the immune system and its impact in this intriguing host-parasite crosstalk.

Author Correction: Placental gene expression and antibody levels of mother-neonate pairs reveal an enhanced risk for inflammation in a helminth endemic country.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Dynamic, Helminth-Induced Immune Modulation Influences the Outcome of Acute and Chronic Hepatitis B Virus Infection.

BACKGROUND: Chronic hepatitis B develops more frequently in countries with high prevalence of helminth infections. The crosstalk between these 2 major liver-residing pathogens, Schistosoma mansoni and hepatitis B virus (HBV), is barely understood. METHODS: We used state-of-the-art models for both acute and chronic HBV infection to study the pathogen-crosstalk during the different immune phases of schistosome infection. RESULTS: Although liver pathology caused by schistosome infection was not affected by either acute or chronic HBV infection, S mansoni infection influenced HBV infection outcomes in a phase-dependent manner. Interferon (IFN)-γ secreting, HBV- and schistosome-specific CD8 T cells acted in synergy to reduce HBV-induced pathology during the TH1 phase and chronic phase of schistosomiasis. Consequently, HBV was completely rescued in IFN-γ-deficient or in TH2 phase coinfected mice demonstrating the key role of this cytokine. It is interesting to note that secondary helminth infection on the basis of persistent (chronic) HBV infection increased HBV-specific T-cell frequency and resulted in suppression of virus replication but failed to fully restore T-cell function and eliminate HBV. CONCLUSIONS: Thus, schistosome-induced IFN-γ had a prominent antiviral effect that outcompeted immunosuppressive effects of TH2 cytokines, whereas HBV coinfection did not alter schistosome pathogenicity.

Placental gene expression and antibody levels of mother-neonate pairs reveal an enhanced risk for inflammation in a helminth endemic country.

In utero exposure to environmental factors can modify the development of allergies later in life whereby the mechanisms of the feto-maternal crosstalk still remain largely unknown. Murine studies revealed that inflammatory maternal signals elicited by chronic helminth infection within the placenta imprint a distinct gene expression profile related to the Vitamin-D-receptor (VDR)-inflammation-axis. We thus investigated whether pro- or anti- inflammatory immune responses as well as VDR and related gene expression within the placenta differ between women from helminth-endemic and non-endemic areas. A prospective pilot study was conducted in Munich, Germany (helminth non-endemic) and Lambaréné, Gabon (helminth-endemic). At delivery, clinical information alongside placenta tissue samples and maternal and cord blood were obtained for further laboratory analysis. Schistosoma haematobium infection was detected in 13/54 (23%) Gabonese women. RT PCR revealed significantly lower gene expression of VDR, Cyp27b1, Foxp3 and IL10 in Gabonese compared to German placentae as well as significantly lower levels of plasma IgG4 in newborns resulting in a significantly higher IgE/IgG4 ratio. These findings demonstrate that exposure in utero to different environments alters placental gene expression and thus possibly plays a role in the development and modulation of the immune system of the offspring.