Wriggly woes: Helminths stirring up T cell trouble.

Understanding determinants of immune response variation is central to developing treatment options. Even et al. show that naive CD4+ T cell transcriptional heterogeneity is altered by helminth infection leading to impaired immune responses independent of commensals.

A new superhero, the intraepithelial mast cell, joins the "Guardians of the Gut".

The intestinal epithelium interacts with immune cells to support tissue homeostasis and coordinate responses against pathogens. In this issue of Immunity, Yang et al. unveil a central role for mast cell-epithelial cell interactions in orchestrating protective type 2 immune responses following intestinal helminth infection.

Tuft cell acetylcholine is released into the gut lumen to promote anti-helminth immunity.

Upon parasitic helminth infection, activated intestinal tuft cells secrete interleukin-25 (IL-25), which initiates a type 2 immune response during which lamina propria type 2 innate lymphoid cells (ILC2s) produce IL-13. This causes epithelial remodeling, including tuft cell hyperplasia, the function of which is unknown. We identified a cholinergic effector function of tuft cells, which are the only epithelial cells that expressed choline acetyltransferase (ChAT). During parasite infection, mice with epithelial-specific deletion of ChAT had increased worm burden, fitness, and fecal egg counts, even though type 2 immune responses were comparable. Mechanistically, IL-13-amplified tuft cells release acetylcholine (ACh) into the gut lumen. Finally, we demonstrated a direct effect of ACh on worms, which reduced their fecundity via helminth-expressed muscarinic ACh receptors. Thus, tuft cells are sentinels in naive mice, and their amplification upon helminth infection provides an additional type 2 immune response effector function.

Beyond schistosomiasis: unraveling co-infections and altered immunity.

Schistosomiasis is a neglected tropical disease caused by the helminth Schistosoma spp. and has the second highest global impact of all parasites. Schistosoma are transmitted through contact with contaminated fresh water predominantly in Africa, Asia, the Middle East, and South America. Due to the widespread prevalence of Schistosoma, co-infection with other infectious agents is common but often poorly described. Herein, we review recent literature describing the impact of Schistosoma co-infection between species and Schistosoma co-infection with blood-borne protozoa, soil-transmitted helminths, various intestinal protozoa, Mycobacterium, Salmonella, various urinary tract infection-causing agents, and viral pathogens. In each case, disease severity and, of particular interest, the immune landscape, are altered as a consequence of co-infection. Understanding the impact of schistosomiasis co-infections will be important when considering treatment strategies and vaccine development moving forward.

Association of Intestinal Helminthiasis with Disseminated Leishmaniasis, Brazil.

Disseminated leishmaniasis is an emerging clinical form of Leishmania braziliensis infection. Evidence shows that co-infection by L. braziliensis and intestinal helminths does not affect clinical manifestations or response to therapy in cutaneous leishmaniasis patients. We evaluated whether co-infection was associated with those aspects in disseminated leishmaniasis patients in Brazil.

Modulation of intestinal epithelial permeability by chronic small intestinal helminth infections.

Increased permeability of the intestinal epithelial layer is linked to the pathogenesis and perpetuation of a wide range of intestinal and extra-intestinal diseases. Infecting humans with controlled doses of helminths, such as human hookworm (termed hookworm therapy), is proposed as a treatment for many of the same diseases. Helminths induce immunoregulatory changes in their host which could decrease epithelial permeability, which is highlighted as a potential mechanism through which helminths treat disease. Despite this, the influence of a chronic helminth infection on epithelial permeability remains unclear. This study uses the chronically infecting intestinal helminth Heligmosomoides polygyrus to reveal alterations in the expression of intestinal tight junction proteins and epithelial permeability during the infection course. In the acute infection phase (1 week postinfection), an increase in intestinal epithelial permeability is observed. Consistent with this finding, jejunal claudin-2 is upregulated and tricellulin is downregulated. By contrast, in the chronic infection phase (6 weeks postinfection), colonic claudin-1 is upregulated and epithelial permeability decreases. Importantly, this study also investigates changes in epithelial permeability in a small human cohort experimentally challenged with the human hookworm, Necator americanus. It demonstrates a trend toward small intestinal permeability increasing in the acute infection phase (8 weeks postinfection), and colonic and whole gut permeability decreasing in the chronic infection phase (24 weeks postinfection), suggesting a conserved epithelial response between humans and mice. In summary, our findings demonstrate dynamic changes in epithelial permeability during a chronic helminth infection and provide another plausible mechanism by which chronic helminth infections could be utilized to treat disease.

A 14-year review (2007-2020) of helminthiasis epidemiology in a hospital in Southern Madrid, Spain.

PURPOSE: Vast majority of helminth diseases remain neglected tropical diseases (NTDs), causing significant morbidity. The widespread and periodic distribution of antiparasitic drugs, remains the cornerstone for controlling these diseases. In Spain, most helminthiasis cases are imported, and suspicion and diagnosis have become increasingly important. Our primary objective is to present the epidemiological landscape of helminthiasis diagnoses within our facility, while also detailing the demographic characteristics of the affected population. METHODS: A retrospective study was conducted at the Hospital Universitario Severo Ochoa (HUSO) from January 1, 2007, to December 31, 2020, encompassing all diagnosed cases of helminthiasis during this period. Comprehensive epidemiological, clinical, and microbiological data were gathered for all diagnosed patients. The study population comprised patients receiving treatment at the HUSO, as well as those receiving treatment at the Leganés and Fuenlabrada Primary Care Units. Subsequently, descriptive and comparative statistics were performed, comparing Spanish and foreign patients. RESULTS: During this period, a total of 952 patients were diagnosed with some form of helminthiasis. Among them, 495 were Spanish, and 457 were foreign. The total number of helminths identified, including patients with multiple infections, was 1,010. Significant differences were observed between Africans and Americans in terms of age distribution, with a higher prevalence among Africans in the 0-15 age range and among Americans in the 31-60 age range. Variations were noted in the distribution of helminths, with S. stercoralis significantly affecting Americans. For Spanish patients, the presence of Trichuris trichiura and S. stercoralis was significantly associated with eosinophilia, whereas among foreign patients, it was associated with Trichuris trichiura, Ascaris lumbricoides among others. Regarding symptoms, skin manifestations were more frequent among Spanish, while digestive were more common among foreigners. CONCLUSIONS: This study offers crucial epidemiological insights into helminth infections observed over time in a Madrid hospital. Although the prevalence of helminth infections has been decreasing, there is still a need for screening and diagnosing foreign patients.

Bacilli load in PTB- intestinal helminths co-infected and PTB non -infected patients at selected public health facilities in Jimma zone, Oromia, Ethiopia: comparative cross-sectional study.

BACKGROUND: Tuberculosis (TB) and intestinal helminths are diseases that pose a dual burden on public health in low-income countries. Previous studies have shown that helminths can affect the shedding of bacteria or the bacterial load in the sputum of active TB patients. However, there is limited information on bacterial load in TB patients with helminth infections. OBJECTIVE: This study aimed to compare bacterial load in helminths-infected and non-infected pulmonary tuberculosis patients at selected public health facilities in Jimma zone, Oromia, Ethiopia. METHODS: The study was conducted in Jimma Zone, Oromia, Ethiopia. A facility-based comparative cross-sectional study was employed from August 01, 2020, to January 2021. A total of 124 (55 intestinal helminths-infected and 69 non-infected) newly diagnosed smear-positive pulmonary tuberculosis (PTB) patients were included in the study. A convenience sampling technique was employed to recruit study participants, and a semi-structured questionnaire was used to collect data regarding socio-demographic characteristics and possible risk factors for intestinal helminths co-infection. Stool examination was performed using both wet mount and Kato Katz technique. Additionally, weight and height measurements, sputum, and blood samples were taken to determine body mass index, bacilli load, and diabetic mellitus, respectively. Data were entered into Epi-Data software version 3.1 and analyzed using Statistical Packages for Social Sciences (SPSS) Version 25. A statistically significant difference was defined as a P-value of less than 0.05. RESULTS: Intestinal helminths reduced bacilli load 3 times more than intestinal helminths non-infected PTB (AOR = 3.44; 95% CI; 1.52, 7.79; P = 0.003) However, diabetes mellitus, HIV, drinking alcohol and cigarette smoking were not associated with bacilli load. The rate of co-infection TB with intestinal helminths was 44%. The three most prevalent parasites detected were Trichuris trichiura 29 (66%), hookworm 19 (43%), and Ascaris lumbricoides 11(25%)). Among co-infected patients about 36 (81.8%) had a single parasite infection, and 19 (43.2%) had multiple infections. A body mass index < 18.5 (AOR = 3.26; 95% CI; 1.25, 8.56;P = 0.016) and untrimmed fingernail status (AOR = 3.63; 95%CI;1.32,9.93;P = 0.012) were significantly associated with PTB- intestinal helminth -co-infection. CONCLUSION: Helminth infection was associated with a lower bacilli load compared to helmenths non-infected PTB. The rate of co-infection TB with intestinal helminths was 44%. Trichuris trichiura was the most prevalent helminth. Untrimmed fingernail and a body mass index were associated with PTB-intestinal helminth co-infection.

Anthelmintic resistance in soil-transmitted helminths: One-Health considerations.

The One-Health approach recognizes the intricate connection between human, animal, and environmental health, and that cooperative effort from various professionals provides comprehensive awareness and potential solutions for issues relating to the health of people, animals, and the environment. This approach has increasingly gained appeal as the standard strategy for tackling emerging infectious diseases, most of which are zoonoses. Treatment with anthelmintics (AHs) without a doubt minimizes the severe consequences of soil-transmitted helminths (STHs); however, evidence of anthelmintic resistance (AR) development to different helminths of practically every animal species and the distinct groups of AHs is overwhelming globally. In this regard, the correlation between the application of anthelmintic drugs in both human and animal populations and the consequent development of anthelmintic resistance in STHs within the context of a One-Health framework is explored. This review provides an overview of the major human and animal STHs, treatment of the STHs, AR development and drug-related factors contributing towards AR, One-Health and STHs, and an outline of some One-Health strategies that may be used in combating AR.

Diagnosis of soil-transmitted helminth infections with digital mobile microscopy and artificial intelligence in a resource-limited setting.

BACKGROUND: Infections caused by soil-transmitted helminths (STHs) are the most prevalent neglected tropical diseases and result in a major disease burden in low- and middle-income countries, especially in school-aged children. Improved diagnostic methods, especially for light intensity infections, are needed for efficient, control and elimination of STHs as a public health problem, as well as STH management. Image-based artificial intelligence (AI) has shown promise for STH detection in digitized stool samples. However, the diagnostic accuracy of AI-based analysis of entire microscope slides, so called whole-slide images (WSI), has previously not been evaluated on a sample-level in primary healthcare settings in STH endemic countries. METHODOLOGY/PRINCIPAL FINDINGS: Stool samples (n = 1,335) were collected during 2020 from children attending primary schools in Kwale County, Kenya, prepared according to the Kato-Katz method at a local primary healthcare laboratory and digitized with a portable whole-slide microscopy scanner and uploaded via mobile networks to a cloud environment. The digital samples of adequate quality (n = 1,180) were split into a training (n = 388) and test set (n = 792) and a deep-learning system (DLS) developed for detection of STHs. The DLS findings were compared with expert manual microscopy and additional visual assessment of the digital samples in slides with discordant results between the methods. Manual microscopy detected 15 (1.9%) Ascaris lumbricoides, 172 (21.7%) Tricuris trichiura and 140 (17.7%) hookworm (Ancylostoma duodenale or Necator americanus) infections in the test set. Importantly, more than 90% of all STH positive cases represented light intensity infections. With manual microscopy as the reference standard, the sensitivity of the DLS as the index test for detection of A. lumbricoides, T. trichiura and hookworm was 80%, 92% and 76%, respectively. The corresponding specificity was 98%, 90% and 95%. Notably, in 79 samples (10%) classified as negative by manual microscopy for a specific species, STH eggs were detected by the DLS and confirmed correct by visual inspection of the digital samples. CONCLUSIONS/SIGNIFICANCE: Analysis of digitally scanned stool samples with the DLS provided high diagnostic accuracy for detection of STHs. Importantly, a substantial number of light intensity infections were missed by manual microscopy but detected by the DLS. Thus, analysis of WSIs with image-based AI may provide a future tool for improved detection of STHs in a primary healthcare setting, which in turn could facilitate monitoring and evaluation of control programs.

Using our understanding of interactions between helminth metabolism and host immunity to target worm survival.

Helminths can adapt to environmental conditions in the host, utilising anaerobic processes like fermentation and malate dismutation to produce energy from carbohydrate. Although targeting carbohydrate metabolism is an established therapeutic strategy to combat helminth infection, questions remain over the metabolic pathways they employ as adults to survive and evade host immunity. Helminths also use amino acid, polyunsaturated fatty acid (PUFA), and cholesterol metabolism, a possible strategy favouring the production of immunomodulatory compounds that may influence survival in the host. Here, we discuss the significance of these differing metabolic pathways and whether targeting of helminth metabolic pathways may allow for the development of novel anthelmintics.

Identifying opportunities to optimize mass drug administration for soil-transmitted helminths: A visualization and descriptive analysis using process mapping.

BACKGROUND: The control of soil-transmitted helminths (STH) is achieved through mass drug administration (MDA) with deworming medications targeting children and other high-risk groups. Recent evidence suggests that it may be possible to interrupt STH transmission by deworming individuals of all ages via community-wide MDA (cMDA). However, a change in delivery platforms will require altering implementation processes. METHODS: We used process mapping, an operational research methodology, to describe the activities required for effective implementation of school-based and cMDA in 18 heterogenous areas and over three years in Benin, India, and Malawi. Planned activities were identified during workshops prior to initiation of a large cMDA trial (the DeWorm3 trial). The process maps were updated annually post-implementation, including adding or removing activities (e.g., adaptations) and determining whether activities occurred according to plan. Descriptive analyses were performed to quantify differences and similarities at baseline and over three implementation years. Comparative analyses were also conducted between study sites and areas implementing school-based vs. cMDA. Digitized process maps were developed to provide a visualization of MDA processes and inspected to identify implementation bottlenecks and inefficient activity flows. RESULTS: Across three years and all clusters, implementation of cMDA required an average of 13 additional distinct activities and was adapted more often (5.2 adaptations per year) than school-based MDA. An average of 41% of activities across both MDA platforms did not occur according to planned timelines; however, deviations were often purposeful to improve implementation efficiency or effectiveness. Visualized process maps demonstrated that receipt of drugs at the local level may be an implementation bottleneck. Many activities rely on the effective setting of MDA dates and estimating quantity of drugs, suggesting that the timing of these activities is important to meet planned programmatic outcomes. CONCLUSION: Implementation processes were heterogenous across settings, suggesting that MDA is highly context and resource dependent and that there are many viable ways to implement MDA. Process mapping could be deployed to support a transition from a school-based control program to community-wide STH transmission interruption program and potentially to enable integration with other community-based campaigns. TRIAL REGISTRATION: NCT03014167.

Intestinal Helminths Infections as Infrequent Cause of Emergency Abdominal Surgery: A Retrospective Study in a University Hospital over 20 Years.

INTRODUCTION: All organs of any organism can be affected by helminths. They can be seen in a broad spectrum, from simple infestations to extensive, life-threatening involvement. Symptomatology is usually of chronic latent course. However, sometimes the presentation is acute and requires urgent surgical intervention. MATERIAL AND METHODS: We conducted a retrospective observational prospective recruitment study of patients undergoing emergency surgery for helminth infection from January 2000 to December 2019 at a university hospital. Sociodemographic and analytical variables, variables related to the clinical process, and the diagnostic test were analysed. Variables related to the surgical procedure and postoperative complications were also analysed. RESULTS: A total of 36 patients required emergency surgery for their helminth infection, which represented 0.26% of emergency abdominal surgeries. The mean age was 34.91 ± 21.5 years, with a predominance of men (69.4%). Most patients presented with pain in the right iliac fossa (69.4%), followed by symptoms compatible with intestinal obstruction (19.4%). The most frequent surgical interventions were appendectomy (38.9%) followed bowel resection (33.3%) and ileocecal resection (11.1%). Enterobious vermicularis and Anisakis simplex both together accounted for 75% of the sample. Statistically significant differences were identified in age (p < 0.001), diagnostic test performed (p = 0.032), intraoperative clinical diagnosis (p = 0.005) and surgical treatment received (p < 0.001). CONCLUSION: The frequency of emergency surgeries for intestinal helminth parasitism is decreasing. However, the majority of these are E. vermicularis and Anisakis simplex, which have distinctly different clinical presentations. Identification and recognition by physicians continue to be necessary for further postoperative management and possible complications.

Exploring extracellular vesicles in zoonotic helminth biology: implications for diagnosis, therapeutic and delivery.

Extracellular vesicles (EVs) have emerged as key intercellular communication and pathogenesis mediators. Parasitic organisms' helminths, cause widespread infections with significant health impacts worldwide. Recent research has shed light on the role of EVs in the lifecycle, immune evasion, and disease progression of these parasitic organisms. These tiny membrane-bound organelles including microvesicles and exosomes, facilitate the transfer of proteins, lipids, mRNAs, and microRNAs between cells. EVs have been isolated from various bodily fluids, offering a potential diagnostic and therapeutic avenue for combating infectious agents. According to recent research, EVs from helminths hold great promise in the diagnosis of parasitic infections due to their specificity, early detection capabilities, accessibility, and the potential for staging and monitoring infections, promote intercellular communication, and are a viable therapeutic tool for the treatment of infectious agents. Exploring host-parasite interactions has identified promising new targets for diagnostic, therapy, and vaccine development against helminths. This literature review delves into EVS's origin, nature, biogenesis, and composition in these parasitic organisms. It also highlights the proteins and miRNAs involved in EV release, providing a comprehensive summary of the latest findings on the significance of EVs in the biology of helminths, promising targets for therapeutic and diagnostic biomarkers.

The burden of intestinal parasitic infections in Antioquia, Colombia: Impact in childhood growth development and nutritional status.

Gastrointestinal protist (GP) and soil-transmitted helminth (STH) infections cause significant morbidity among children in poor-resource settings of tropical and sub-tropical countries including Colombia. Few prospective transversal studies investigating how GP and STH infections affect growth development and nutritional status during childhood have been conducted in this country, none of them in the Antioquia Department. This microscopy-based study estimated the prevalence of GP and helminth (including STH) infections in faecal samples from schoolchildren (n = 384) collected during April-May 2019 in three municipalities of the Antioquia Department. Demographic, epidemiological, and household data were elicited through face-to-face interviews. Parasite detection was carried out by direct microscopic examination of both fresh smears and concentrated faecal material. Children (aged 6-15 years) also had their haemoglobin (Hb) levels, height and weight data collected, and BMI estimated. Data were analysed using bivariate and multivariate logistic regression analysis. Overall, 60.7 % (233/384) of schoolchildren were infected by at least one intestinal parasitic species. Among GPs, Blastocystis sp. was the most common species found (47.7 %, 95 % CI: 42.6-52.8), followed by G. duodenalis (15.9 %, 95 % CI: 12.4-19.9). Cryptosporidium spp. and Cyclospora cayetanensis were sporadically identified (0.3 %, 95 % CI: 0.1-1.4 each). Among helminths, the most prevalent species found were Trichuris trichiura (6.0 %, 95 % CI: 3.8-8.9) and Enterobius vermicularis (1.0 %, 95 % CI: 0.3-2.6). Hookworms, Ascaris lumbricoides, and Strongyloides stercoralis were found at prevalence rates <1 %. Underweight, overweigh, or obese schoolchildren had 1.2 times greater chance of being infected with intestinal parasites than their counterparts with a healthy weight (P-value: 0.015). Variables significantly associated with an increased likelihood of being infected by intestinal parasites include living in a household with unfinished flouring, not wearing shoes, being in close proximity to rodents, and having improper waste disposal. Relatively simple interventional measures directed towards the improvement of household conditions, access to sanitary toilets, and promoting shoe wearing can significantly reduce childhood infections by GP and helminths in the Antioquia Department.

Transforming gastrointestinal helminth parasite identification in vertebrate hosts with metabarcoding: a systematic review.

BACKGROUND: Gastrointestinal helminths are a very widespread group of intestinal parasites that can cause major health issues in their hosts, including severe illness or death. Traditional methods of helminth parasite identification using microscopy are time-consuming and poor in terms of taxonomic resolution, and require skilled observers. DNA metabarcoding has emerged as a powerful alternative for assessing community composition in a variety of sample types over the last few decades. While metabarcoding approaches have been reviewed for use in other research areas, the use of metabarcoding for parasites has only recently become widespread. As such, there is a need to synthesize parasite metabarcoding methodology and highlight the considerations to be taken into account when developing a protocol. METHODS: We reviewed published literature that utilized DNA metabarcoding to identify gastrointestinal helminth parasites in vertebrate hosts. We extracted information from 62 peer-reviewed papers published between 2014 and 2023 and created a stepwise guide to the metabarcoding process. RESULTS: We found that studies in our review varied in technique and methodology, such as the sample type utilized, genetic marker regions targeted and bioinformatic databases used. The main limitations of metabarcoding are that parasite abundance data may not be reliably attained from sequence read numbers, metabarcoding data may not be representative of the species present in the host and the cost and bioinformatic expertise required to utilize this method may be prohibitive to some groups. CONCLUSIONS: Overall, using metabarcoding to assess gastrointestinal parasite communities is preferable to traditional methods, yielding higher taxonomic resolution, higher throughput and increased versatility due to its utility in any geographical location, with a variety of sample types, and with virtually any vertebrate host species. Additionally, metabarcoding has the potential for exciting new discoveries regarding host and parasite evolution.

Estimating Prevalence and Infection Intensity of Soil-Transmitted Helminths Using Quantitative Polymerase Chain Reaction and Kato-Katz in School-Age Children in Angola.

Quantitative polymerase chain reaction (qPCR) is gaining recognition in soil-transmitted helminth (STH) diagnostics, especially for Strongyloides stercoralis and differentiating hookworm species. However, sample preservation and DNA extraction may influence qPCR performance. We estimated STH prevalence and infection intensity by using qPCR in schoolchildren from Huambo, Uige, and Zaire, Angola, and compared its performance with that of the Kato-Katz technique (here termed Kato-Katz). Stool samples from 3,063 children (219 schools) were preserved in 96% ethanol and analyzed by qPCR, of which 2,974 children (215 schools) had corresponding Kato-Katz results. Cluster-adjusted prevalence and infection intensity estimates were calculated by qPCR and Kato-Katz, with cycle threshold values converted to eggs per gram for qPCR. Cohen's kappa statistic evaluated agreement between qPCR and Kato-Katz. DNA extraction and qPCR were repeated on 191 (of 278) samples that were initially qPCR negative but Kato-Katz positive, of which 112 (58.6%) became positive. Similar prevalence for Ascaris lumbricoides (37.5% versus 34.6%) and Trichuris trichiura (6.5% versus 6.1%) were found by qPCR and Kato-Katz, respectively, while qPCR detected a higher hookworm prevalence (11.9% versus 2.9%). The prevalence of moderate- or high-intensity infections was higher by Kato-Katz than by qPCR. Agreement between qPCR and Kato-Katz was very good for A. lumbricoides, moderate for T. trichiura, and fair for hookworm. Strongyloides stercoralis prevalence was 4.7% (municipality range, 0-14.3%), and no Ancylostoma ceylanicum was detected by qPCR. Despite suboptimal performance, presumably due to fixative choice, qPCR was fundamental in detecting S. stercoralis and excluding zoonotic A. ceylanicum. Further evaluations on sample fixatives and DNA extraction methods are needed to optimize and standardize the performance of qPCR.

Regulation of host metabolic health by parasitic helminths.

Obesity is a worldwide pandemic and major risk factor for the development of metabolic syndrome (MetS) and type 2 diabetes (T2D). T2D requires lifelong medical support to limit complications and is defined by impaired glucose tolerance, insulin resistance (IR), and chronic low-level systemic inflammation initiating from adipose tissue. The current preventative strategies include a healthy diet, controlled physical activity, and medication targeting hyperglycemia, with underexplored underlying inflammation. Studies suggest a protective role for helminth infection in the prevention of T2D. The mechanisms may involve induction of modified type 2 and regulatory immune responses that suppress inflammation and promote insulin sensitivity. In this review, the roles of helminths in counteracting MetS, and prospects for harnessing these protective mechanisms for the development of novel anti-diabetes drugs are discussed.

Detection of soil-transmitted helminths and Schistosoma spp. by nucleic acid amplification test: Results of the first 5 years of the only international external quality assessment scheme.

BACKGROUND: Infections with soil-transmitted helminths (STH) and schistosomiasis (SCH) result in a significant global health burden, particularly in rural communities in low and middle-income countries. While microscopy remains the primary diagnostic method for STH and SCH in resource-limited settings, nucleic acid amplification tests (NAATs) are gaining prominence as tools for evaluation of public health control programs in endemic countries, and individual diagnosis in high-income countries. Despite the high sensitivity and specificity of NAATs, previous research has highlighted inter-laboratory variations, both in technical and clinical performance, justifying the need for continuous proficiency testing. METHODOLOGY: Results from 5 rounds over a 5-year period of the so far only longitudinal international Helminth External Molecular Quality Assessment Scheme (HEMQAS), coordinated by the Dutch Foundation for Quality Assessment in Medical Laboratories (SKML), were examined in order to (i) assess the diagnostic proficiency of laboratories in detecting helminths in stool and (ii) identify potential factors contributing to variations in performance. OUTCOME AND CONCLUSIONS: Thirty-six laboratories, from 18 countries and 5 continents, participated in HEMQAS. The overall diagnostic performances were satisfying, with remarkably low numbers (<2%) of false-positive results. False-negative results were more often reported for stool (15%) than for DNA (5%) samples. False-negative results varied largely between targets (the highest number (29%) for Trichuris trichiura). Twenty-five laboratories provided a sufficient number of results for a robust comparison between participating laboratories, which confirmed substantial inter-laboratory variability in quantitative NAAT results (Cq-values). This variability likely arises from differences in pre-treatment, DNA isolation and DNA-target amplification procedures. This study emphasizes the complexity of molecular diagnosis for STH and SCH, highlighting the critical role of proper stool preparation and DNA isolation methods. The results underscore the necessity for laboratory professionals and public health decision-makers to recognize these complexities and continuously undertake external quality assessment schemes to ensure accurate and reliable performance in molecular diagnosis.

The enhancive effect of the 2014-2016 El Niño-induced drought on the control of soil-transmitted helminthiases without anthelmintics: A longitudinal study.

BACKGROUND: Soil-transmitted helminthiases (STHs) are common in tropical and subtropical regions. Southern Thailand experiences an extended rainy season, leading to persistently moist soil. This condition supports the life cycle of STHs, hindering effective control due to reinfection and low drug efficacy. We implemented a novel STH control strategy during the dry season aimed at decreasing reinfection rates without enhancing sanitation or hygiene practices. However, there were unexpected, prolonged droughts linked to El Niño events from 2014 to 2016. Additionally, we assessed the effects of these drought conditions on further control measures without the use of anthelmintics. METHODOLOGY/PRINCIPAL FINDINGS: A longitudinal study was conducted from 2012 to 2016. Stool samples collected from 299 participants were analyzed using the Kato-Katz and agar plate culture methods. Participants who tested positive for STHs received a single 400 mg dose of albendazole. The efficacy of the treatment was evaluated three weeks later. To confirm the control measures were implemented during the dry season, we monitored the number of rainy days following albendazole treatment for 52 days, of which 38 were without rain. Follow-up stool examinations were carried out in 2013 and 2016, with no additional doses of albendazole administered. Rainfall and rainy day data, which served as indicators of unexpected droughts due to El Niño, were collected from the nearest local meteorological stations. Before the drought, there was a decrease in STH prevalence in 2013-except for trichuriasis-attributable to the dry season control efforts. Despite these efforts, STH prevalence remained high. Remarkably, in 2016, following the drought period, the prevalence of trichuriasis, which had not changed previously, spontaneously declined without further albendazole treatment compared to 2013. Furthermore, the prevalence of strongyloidiasis remained unchanged likely due to its low susceptibility to drought conditions, as it can reproduce within hosts. Conversely, the prevalence of other STHs consistently declined. The drought and possible improvements in sanitation and hygiene practices contributed to this decrease by reducing rates of reinfection and new infection and by increasing the natural cure rate. Additionally, some participants infected with hookworms or Trichuris who were not cured by albendazole experienced natural remission. CONCLUSIONS/SIGNIFICANCE: Control measures implemented during the dry season, combined with a 14-month-long drought induced by the El Niño event of 2014-2016, and some improvements in sanitation and hygiene practices, contributed to a decrease in both the prevalence and intensity of STHs, except for S. stercoralis. Over time, S. stercoralis is likely to become the predominant species among the STHs.