Alex Loukas

Correction: Evaluation of real-time LAMP assay for detection of Entamoeba species in clinical stool samples from a tertiary care center in North India

Frontiers Production Office

Plasmodium falciparum putative Hsp90 functionally complements yeast Hsp90 and is inhibited in an isoform-specific manner

Shradha Ravindra Khamitkar, Monalisa Bag, Vaibhav R. Kini, Mansi Singh, Badal Kumar Sethi, Sunanda Bhattacharyya

Plasmodium falciparum Hsp90α has been proven to be an antimalarial target. However, high sequence conservation between PfHsp90α and HsHsp90α is an obstacle to developing selective inhibitors against the parasite chaperone. The parasite harbours an uncharacterised paralogue of Hsp90α, namely putative PfHsp90 (PF14_0417), which has low sequence conservation with PfHsp90α. A piggyBac transposon insertional mutagenesis study has indicated that putative PfHsp90 is essential for parasite survival. However, its poor sequence conservation with PfHsp90α raises concerns about its functionality. Here, we show that the putative isoform can complement a temperature-sensitive Schsp82 mutant, confirming its Hsp90-like activity. To identify selective inhibitors against this isoform, we developed a yeast-based assay system using isogenic Schsp82 temperature-sensitive Δpdr5 yeast strains, each harbouring Plasmodium Hsp90 isoforms. Utilising bona fide Hsp90 inhibitors, we measured their in silico affinities towards the available structure of putative PfHsp90 and categorised them in increasing order of binding affinities towards the putative isoform. The top-scoring inhibitors were tested within surrogate yeast systems. Our study indicates that only one compound, CCT018159, manifests selective inhibition of the putative PfHsp90 but remains ineffective against PfHsp90α. When tested in the asexual growth of the drug-sensitive and drug-resistant parasites, CCT018159 showed antiparasitic activity in the micromolar range. Together, our study underlines the importance of putative PfHsp90 in parasite survival and merits additional research.

Effect of urine storage conditions on circulating anodic antigen detection using the UCP-LF CAA test

Pytsje T. Hoekstra, Govert J. van Dam, Maureen Blokland-Flink, Danielle de Jong, Said M. Ali, Mohammed N. Ali, Naomi C. Ndum, Stefanie Knopp, Paul L.A.M. Corstjens, Lisette van Lieshout

Schistosomiasis is a parasitic neglected tropical disease that remains a major public health problem in many African countries. Accurate diagnosis is essential for control, surveillance and elimination efforts. Conventional parasitological methods have limited sensitivity, particularly in low-intensity infections commonly observed after treatment or in low-endemic settings. Circulating anodic antigen (CAA), released by live Schistosoma worms, is a highly sensitive and specific marker of active infection. The up-converting reporter particle lateral flow (UCP-LF) CAA test enables non-invasive urine-based diagnosis and is increasingly applied in low-endemic and near-elimination settings. For operational feasibility, urine samples may need to be stored before testing, but the effect of different storage conditions on CAA detection has not been systematically evaluated. We investigated the effect of freezing and non-frozen storage on urine CAA detection using the UCP-LF CAA test, compared with freshly tested urine. The study was conducted among school-aged children in a near-elimination Schistosoma haematobium setting on Pemba, Tanzania. A total of 272 urine samples were tested fresh and after freezing at -20 °C for 5-7 days. For a subset of 153 samples with sufficient urine available, an additional aliquot was stored under non-frozen conditions (4-25 °C) and tested approximately 5 weeks after collection. CAA positivity decreased from 44/272 (16.2%) in fresh urine to 35/272 (12.9%) after freezing. In the subset, positivity was 20/153 (13.1%) in fresh, 16/153 (10.5%) in frozen, and 24/153 (15.7%) in non-frozen stored urine. CAA concentrations showed strong correlation between storage conditions (Spearman’s ρ = 0.86–0.93, p<0.0001). Freezing was associated with a small but significant reduction in CAA positivity (p=0.004), while CAA concentrations showed a non-significant trend towards lower values after freezing. Non-frozen stored samples showed generally comparable results to fresh urine. In conclusion, these findings suggest that flexible urine storage strategies may be feasible for delayed centralized CAA testing, although freezing may result in loss of detection among samples with CAA concentrations close to the assay cut-off.

A systematic review of gastrointestinal parasites in Sus scrofa domesticus from Europe (2010 – 2026)

Alesia Cioacă, Diana Hoffman, Ioan Cristian Dreghiciu, Tiana Florea, Mirela Imre, Anamaria Plesko, Mălina Oprescu, Ion Oprescu, Gheorghe Dărăbuş, Marius Stelian Ilie

Gastrointestinal parasitic infections remain an important concern in European pig production due to their potential impact on animal health, productivity, and, in the case of zoonotic species, public health. This systematic review investigated the occurrence of gastrointestinal helminths and enteric protists in domestic pigs across Europe and analysed the factors associated with their prevalence. A total of 28 studies published between 2010 and 2026 were included, identified through a structured search strategy conducted in three scientific databases. The included studies reported a wide diversity of helminths and enteric protists in pigs raised under intensive, extensive, organic, and alternative production systems. Among helminths, Ascaris suum, Trichuris suis, and Oesophagostomum spp. were the most frequently identified species, whereas Balantioides coli, Cryptosporidium spp., Cystoisospora suis, and Blastocystis sp. represented the main enteric protists reported. Overall, gastrointestinal parasites and enteric protists remain widely distributed in domestic pigs across Europe, with prevalence influenced by production system, management practices, host age, and diagnostic methodology. The identification of species with zoonotic potential also underlines the importance of continuous epidemiological surveillance within the One Health framework.

Evaluation of real-time LAMP assay for detection of Entamoeba species in clinical stool samples from a tertiary care center in North India

Devyani Sharma, Usha Dutta, Divya Rattan, Upninder Kaur, Shinichi Inoue, Shinjiro Hamano, Ruby Jain, Kawaljeet Singh Sandha, Rakesh Sehgal, P. V. M. Lakshmi

Enteric protozoa infections contribute to diarrheal diseases in low and middle income countries, affecting those with limited access to clean water and sanitation. Entamoeba histolytica is an invasive water and food-borne parasite, associated with mucosal inflammation causing symptoms of amoebic colitis that can overlap with ulcerative colitis (UC). As conventional diagnostic methods such as microscopy cannot differentiate morphologically similar species, diagnostic challenges frequently arise. The present prospective study evaluated the clinical diagnostic performance of Real-Time Loop Mediated Isothermal Amplification Assay (LAMP) for detecting and differentiating Entamoeba species in clinical endemic settings, with a focus on patients with UC. The study was conducted at a tertiary care hospital in North India from January 2021 to January 2023. Stool samples (n=494) were collected across four groups: patients with UC (n=117), non-inflammatory bowel disease (IBD) diarrhea patients (n=177), community participants (n=100), and diseased controls (n=100). All samples were analyzed using microscopy, conventional PCR, real-time PCR, and real-time LAMP, followed by phylogenetic analysis for species confirmation. For real-time LAMP, the SREHP gene and LSU rRNA gene reactions were performed separately in single run to ensure accurate identification. Statistical evaluation was performed using Bayesian latent class analysis. The sensitivity of microscopy, conventional PCR, real-time PCR, and real-time LAMP was calculated to be 39.4% 84.3%, 99.3%, and 99.3%, respectively, with 99.4–100% specificity for real-time LAMP. Five samples missed by conventional PCR were successfully detected by both real-time PCR and real-time LAMP. The overall infection rate across was 6.7% (33/494), with differential detection of Entamoeba species. Samples positive for E. histolytica showed amplification of both SREHP and LSU rRNA genes, whereas E. dispar and E.moshkovskii showed amplification of the LSU rRNA gene only. Among patients with UC, those with active disease had a higher incidence of E. histolytica infection (13/88) than those in remission (4/29). Real-time LAMP demonstrated specificity and sensitivity of 99.3% (92.5–100) equivalent to that of real-time PCR with an added advantage of shorter turnaround time than conventional PCR and real-time PCR (60 minutes vs. 200 minutes vs 120 minutes), facilitating prompt differential diagnosis of Entamoeba species in patients with UC. These finding support considering molecular tests in microscopy-negative cases to improve detection and differentiation of Entamoeba species in high-incidence areas and among high-risk patients. However, cost effectiveness and downstream impact on clinical outcomes warrant further study.