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Some serology assays demonstrated useful for post-treatment monitoring of Strongyloides stercoralis infection. Serology frequently has low specificity, which might be improved by the use of recombinant antigens. The Strongy Detect ELISA is based on 2 recombinant antigens (SsIR and NIE) and proved good accuracy. Aim of this study was to evaluate the performance of this test for the post-treatment monitoring of strongyloidiasis. We tested 38 paired sera, with matched fecal tests results, stored in our biobank and originating from a randomized controlled trial. At baseline, all patients tested positive for at least 1 fecal assay among PCR, direct stool microscopy and agar plate culture. Patients were re-tested with both serology and fecal assays 12 months after treatment. Primary outcome was the relative reduction in optical density (OD) between baseline and follow up. We observed that about 95% samples showed a reduction between pre and post-treatment OD, with a median relative reduction of 93.9% (IQR 77.3%–98.1%). In conclusion, the test proved reliable for post-treatment monitoring. However, some technical issues, including that the threshold for positivity has not be predefined, and that a substantial number of samples showed overflow signals, need to be fixed to permit use in routine practice.

Background Strongyloidiasis, a nematode infection which is mainly caused by Strongyloides stercoralis in humans, can lead to a fatal syndrome in immunocompromised individuals. Its diagnosis is challenging due to the absence of a diagnostic gold standard. The infection is highly prevalent in migrants from endemic countries in tropical and subtropical areas, and a rapid diagnostic test would be helpful for screening purposes. The aim of this study was to estimate the accuracy of a novel immunochromatographic test (ICT) for the diagnosis of S. stercoralis infection. Methods A single-centre diagnostic accuracy study was undertaken using well-characterized frozen sera available from the biobank of a referral hospital for parasitic diseases in Italy. The included sera were from migrants from sub-Saharan Africa, and matching results were available for agar plate culture and/or polymerase chain reaction for S. stercoralis ; moreover, the results of both a commercial enzyme-linked immunosorbent assay test and an in-house immunofluorescence test for strongyloidiasis were made available. Laboratory staff who read the ICT results were blinded as regards the results of the other tests. Two readers independently read the ICT, and a third one was involved when results were discrepant. The accuracy of the ICT was assessed both against the results of the panel of faecal tests and by latent class analysis (LCA). Results Agreement between the readers was excellent [Cohen’s κ = 92.7%, 95% confidence interval (CI) 88.3–97.1%]. When assessed against the results of the faecal tests, the sensitivity and specificity of the ICT were 82.4% (95% CI 75.7–89.0%) and 73.8% (95% CI 66.8–80.9%), respectively. According to the LCA, the sensitivity and specificity were 86.3% (95% CI 80.1–92.5%) and 73.9% (95% CI 67.0–80.8%), respectively. Conclusions The results of the ICT demonstrated ease of interpretation. The accuracy proved good, though the sensitivity might be further improved for screening purposes. Graphical Abstract

The host immune response has a prominent role in the progression and outcome of SARS-CoV-2 infection. Lymphopenia has been described as an important feature of SARS-CoV-2 infection and has been associated with severe disease manifestation. Lymphocyte dysregulation and hyper-inflammation have been shown to be associated with a more severe clinical course; however, a T cell subpopulation whose dysfunction correlate with disease progression has yet to be identify. We performed an immuno-phenotypic analysis of T cell sub-populations in peripheral blood from patients affected by different severity of COVID-19 (n=60) and undergoing a different clinical evolution. Clinical severity was established based on a modified WHO score considering both ventilation support and respiratory capacity (PaO2/FiO2 ratio). The ability of circulating cells at baseline to predict the probability of clinical aggravation was explored through multivariate regression analyses. The immuno-phenotypic analysis performed by multi-colour flow cytometry confirmed that patients suffering from severe COVID-19 harboured significantly reduced circulating T cell subsets, especially for CD4 T, Th1, and regulatory T cells. Peripheral T cells also correlated with parameters associated with disease severity, i.e., PaO2/FiO2 ratio and inflammation markers. CD4 T cell subsets showed an important significant association with clinical evolution, with patients presenting markedly decreased regulatory T cells at baseline having a significantly higher risk of aggravation. Importantly, the combination of gender and regulatory T cells allowed distinguishing between improved and worsened patients with an area under the ROC curve (AUC) of 82%. The present study demonstrates the association between CD4 T cell dysregulation and COVID-19 severity and progression. Our results support the importance of analysing baseline regulatory T cell levels, since they were revealed able to predict the clinical worsening during hospitalization. Regulatory T cells assessment soon after hospital admission could thus allow a better clinical stratification and patient management.

Strongyloides stercoralis is a neglected soil-transmitted helminth (STH) that leads to significant morbidity in endemic populations. Infection with this helminth has recently been recognised by the World Health Organization (WHO) as a major global health problem to be addressed with ivermectin preventive chemotherapy, and therefore, there is now, the need to develop guidelines for strongyloidiasis control that can be implemented by endemic countries. This study aimed to evaluate the impact of ivermectin preventive chemotherapy (PC) on S. stercoralis prevalence in endemic areas to generate evidence that can inform global health policy. This study was a systematic review and meta-analysis. We searched PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and LILACS for literature published between 1990 and 2022 and reporting prevalence of S. stercoralis before and after PC with ivermectin, administered either at school or at community level. The search strategy identified 933 records, eight of which were included in the meta-analysis. Data extraction and quality assessment were carried out by two authors. Meta-analysis of studies based on fecal testing demonstrated a significant reduction of S. stercoralis prevalence after PC: prevalence Risk Ratio (RR) 0.18 (95% CI 0.14-0.23), I2 = 0. A similar trend was observed in studies that used serology for diagnosis: RR 0.35 (95% CI 0.26-0.48), I2 = 4.25%. A sensitivity analysis was carried out for fecal tests where low quality studies were removed, confirming a post-intervention reduction in prevalence. The impact of PC could not be evaluated at different time points or comparing annual vs biannual administration due to insufficient data. Our findings demonstrate a significant decrease of S. stercoralis prevalence in areas where ivermectin PC has taken place, supporting the use of ivermectin PC in endemic areas.

Background Strongyloidiasis is a chronic parasitic disease that results in relevant human morbidity, caused by the nematode Strongyloides stercoralis . This nematode has a unique and complex life-cycle. There is so far no perfect test for this helminthiasis. Rapid immunochromatographic tests (RDTs) are of interest, specifically due to their feasibility for use in the field, where public health control of strongyloidiasis is recommended. The aim of this study was to evaluate two novel RDTs, one detecting immunoglobulin (Ig) G and the other detecting IgG4, based on a combination of recombinant antigens. The primary objective was to estimate the sensitivity and specificity of these RDTs, and the secondary objective was to assess ease of interpretation. Methods Serum samples stored in our biobank with available matched results for at least one fecal (i.e. agar plate culture or PCR) and one serology test (i.e. enzyme-linked immunosorbent assay [ELISA] or indirect immunofluorescent antibody test [IFAT]) for S. stercoralis , were selected for this study. Those with at least one positive result for the fecal test were considered to be true positives (irrespective of the serology), while true negatives were those with negative results for both the fecal and serology tests. The results of the RDTs were read independently by two laboratory technicians. When disagreement over the results occurred, a third reader was involved, and the final result for each test was based on consistent results from two readers. Estimates were reported along with the 95% confidence intervals (CI). Regarding the secondary objective, agreement between two independent readers was calculated with Cohen’s kappa statistic (κ). Results A total of 90 serum samples were tested. Sensitivity of the IgG- and the IgG4-RDTs was 91.1% (95% CI 78.8–97.5) and 77.3% (95% CI 62.2–88.5), respectively. Specificity was 91.1% (95% CI 78.8–97.5) for the IgG-RDT and 100% (95% CI 92.1–100) for the IgG4-RDT. Agreement between readers was excellent (Cohen’s κ = 0.96, 95% CI 0.86–1.08%). Conclusions The IgG-RDT demonstrated higher sensitivity and could hence be preferred for individual diagnosis, whereas the excellent specificity of the IgG4-RDT could be preferred for prevalence surveys in endemic areas. The results of both RDTs were easy to interpret based on excellent agreement between readers. Large prospective studies should follow to confirm these findings and to validate the use of either RDT for specific purposes/contexts. Graphical abstract

The WHO recently issued guidelines for public health control of Strongyloides stercoralis in endemic areas. We aimed to evaluate the feasibility of implementing the WHO recommendations in Rwanda, and our secondary objective was to estimate S. stercoralis prevalence. We conducted a community-based cross-sectional study in two Rwandan districts (Gisagara and Rubavu) including a training session focused on diagnostics for S. stercoralis : parasitological assays (Baermann and agar plate culture, APC) and a novel rapid diagnostic test (RDT). Technicians’ perceptions of each assay were evaluated via a questionnaire; 1,415 individuals were screened. A critical aspect of the parasitological assays was the length of training, but there was no issues with RDT implementation. Based on the combination of Baermann and APC diagnostics, prevalence was 1.1% (95% CI 0.5–2.3) in Gisagara, and 3.9% (95% CI 2.6–5.7) in Rubavu, which was similar for the RDT. Overall, we found the implementation of S. stercoralis -specific tests was feasible, though intense training was crucial. Adding Strongyloides stercoralis diagnostics to Rwanda’s soil-transmitted helminth control program was evaluated. Following training, Baermann and stool culture tests were implemented successfully, with no reported issues with rapid testing.

Female Genital Schistosomiasis (FGS) is a neglected disease of the genital tract due to the inflammatory response to the presence of Schistosoma haematobium eggs in the genital tract. The WHO has prioritized the improvement of diagnostics for FGS and previous studies have explored the PCR-based detection of Schistosoma DNA on genital specimens, with encouraging results. This study aimed to determine the prevalence of FGS among women living in an endemic district in North-western Tanzania, using PCR on samples collected though cervical-vaginal swabs, and to compare the performance of self-collected and healthcare worker-collected (operator-collected) samples, and the acceptability of the different sampling methods. A cross-sectional study was conducted involving 211 women living in 2 villages in the Maswa district of North-western Tanzania. Urine, self-collected and operator-collected cervical-vaginal swabs were obtained from participants. A questionnaire was administered, focusing on the comfortability in undergoing different diagnostic procedures. Prevalence of urinary schistosomiasis, as assessed by eggs in urine, was 8.5% (95%CI 5.1-13.1). DNA was pre-isolated from genital swabs and transported at room temperature to Italy for molecular analysis. Prevalence of active schistosomiasis, urinary schistosomiasis, and FGS were 10.0% (95% CI 6.3-14.8), 8.5% (95%CI 5.1-13.1), and 4.7% (95%CI 2.3-8.5), respectively. When real-time PCR was performed after a pre-amplification step, the prevalence of active schistosomiasis increased to 10.4% (95%CI 6.7-15.4), and FGS to 5.2% (95%CI 2.6-9.1). Of note, more cases were detected by self-collected than operator-collected swabs. The vast majority of participants (95.3%) declared that they were comfortable/very comfortable about genital self-sampling, which was indicated as the preferred sampling method by 40.3% of participants. The results of this study show that genital self-sampling followed by pre-amplified PCR on room temperature-stored DNA is a useful method from both technical and acceptability point of views. This encourages further studies to optimize samples processing, and identify the best operational flow to allow integration of FGS screening into women health programmes, such as HPV screening.

In a longitudinal study in a first-level hospital in Luanda, Angola, we found rifampin-resistant and multidrug-resistant tuberculosis (TB) in 38 (8%, 95% CI 5.7-10.8) of 474 patients with no previous history of TB. Of note, 2 patients (0.4%, 95% CI 0.1-1.5) demonstrated pre-extensively drug-resistant TB.

Cystic echinococcosis (CE) is mainly described as a food/waterborne zoonosis. However, evidence about matrices contamination is scarce. Identifying main transmission routes could optimize health messages aiming to prevent ingestion of parasite eggs. We evaluated Echinococcus granulosus contamination of matrices in two areas of Chile and Peru. In stage 1, areas with high active CE prevalence were identified through cross-sectional ultrasound surveys. Stage 2 was a case-control study encompassing matrices sampling in public places and households with and without CE cases in these areas, followed by (stage 3), matrices processing by sequential sieving and E. granulosus detection by PCR. Bayesian multilevel mixed-effects logistic regression analysis was used to identify factors associated with risk of contamination. In households, soil (19%-42%); dogs' fur (10%-30%); shoes' soles (5%-33%); and dogs' feces (0-50%) were highly contaminated. In public areas, ~ 30% of fecal and soil samples were contaminated. Overall, matrices from public areas were more contaminated than those from households. When examining households, there was no difference in risk of contamination according to presence of CE cases, while CE-free households had lower risk when considering households and public areas. There was no difference in risk of contamination according to matrix. Vegetables were PCR-negative. Results suggest the need for a paradigm-shift towards considering CE an environmental-borne infection with a \"community risk\" to which people are exposed.

Background The diagnosis of strongyloidiasis is challenging. Serological tests are acknowledged to have high sensitivity, but issues due to cross-reactions with other parasites, native parasite antigen supply and intrinsic test variability do occur. Assays based on recombinant antigens could represent an improvement. The aim of this study was to assess the sensitivity and specificity of two novel immunoglobulin (Ig)G and IgG4 enzyme-linked immunosorbent assays (ELISAs) based on the recombinant antigens NIE/SsIR for the diagnosis of strongyloidiasis. Methods This was a retrospective diagnostic accuracy study. We included serum samples collected from immigrants from strongyloidiasis endemic areas for whom there was a matched result for Strongyloides stercoralis on agar plate culture and/or PCR assay, or a positive microscopy for S. stercoralis larvae. For the included samples, results were also available from an in-house indirect fluorescent antibody test (IFAT) and a commercial (Bordier ELISA; Bordier Affinity Products SA) ELISA. We excluded: (i) samples with insufficient serum volume; (ii) samples from patients treated with ivermectin in the previous 6 months; and (iii) sera from patients for whom only routine coproparasitology was performed after formol–ether concentration, if negative for S. stercoralis larvae. The performance of the novel assays was assessed against: (i) a primary reference standard, with samples classified as negative/positive on the basis of the results of fecal tests; (ii) a composite reference standard (CRS), which also considered patients to be positive who had concordant positive results for the IFAT and Bordier ELISA or with a single “high titer” positive result for the IFAT or Bordier ELISA. Samples with a single positive test, either for the IFAT or Bordier ELISA, at low titer, were considered to be “indeterminate,” and analyses were carried out with and without their inclusion. Results When assessed against the primary reference standard, the sensitivities of the IgG and IgG4 ELISAs were 92% (95% confidence interval [CI]: 88–97%) and 81% (95% CI: 74–87%), respectively, and the specificities were 91% (95% CI: 88–95%) and 94% (95% CI: 91–97%), respectively. When tested against the CRS, the IgG ELISA performed best, with 78% sensitivity (95% CI: 72–83%) and 98% specificity (95% CI: 96–100%), when a cut-off of 0.675 was applied and the indeterminate samples were excluded from the analysis. Conclusion The NIE-SsIR IgG ELISA demonstrated better accuracy than the IgG4 assay and was deemed promising particularly for serosurveys in endemic areas. Graphical abstract