Serological diagnosis of soil-transmitted helminth (Ascaris, Trichuris and hookworm) infections: A scoping review

BACKGROUND

The World Health Organization emphasizes the importance of integrated monitoring and evaluation in neglected tropical disease (NTD) control programs. Serological assays offer a potential solution for integrated diagnosis of NTDs, particularly for those requiring mass drug administration (MDA) as primary control and elimination strategy. This scoping review aims (i) to provide an overview of assays using serum or plasma to detect infections with soil-transmitted helminths (STHs) in both humans and animals, (ii) to examine the methodologies used in this research field and (iii) to discuss advancements in serological diagnosis of STHs to guide prevention and control programs in veterinary and human medicine.

METHODOLOGY

We conducted a systematic search in the Ovid MEDLINE, Embase and Cochrane Library databases, supplemented by a Google search using predefined keywords to identify commercially available serological assays. Additionally, we performed a patent search through Espacenet.

PRINCIPAL FINDINGS

We identified 85 relevant literature records spanning over 50 years, with a notable increased interest in serological assay development in recent years. Most of the research efforts concentrated on diagnosing Ascaris infections in both humans and pigs, primarily using ELISA and western blot technologies. Almost all records targeted antibodies as analytes, employing proteins and peptides as analyte detection agents. Approximately 60% of sample sets described pertained to human samples. No commercially available tests for Trichuris or hookworms were identified, while for Ascaris, there are at least seven different ELISAs on the market.

CONCLUSIONS

While a substantial number of assays are employed in epidemiological research, the current state of serological diagnosis for guiding STH prevention and control programs is limited. Only two assays designed for pigs are used to inform efficient deworming practices in pig populations. Regarding human diagnosis, none of the existing assays has undergone extensive large-scale validation or integration into routine diagnostics for MDA programs.

The effect of an injectable toltrazuril - gleptoferron (Forceris®) on Cystoisospora suis oocyst excretion and growth of neonatal piglets pre- and post-weaning

In this study the efficacy of an intramuscular formulation of toltrazuril combined with gleptoferron for the control of porcine cystoisosporosis caused by Cystoisospora suis was investigated. The study was carried out on three Belgian farms with a confirmed history of C. suis infections. As none of the farms implemented a standardized toltrazuril treatment regimen for their piglets, the presence of resistant C. suis strains seems improbable. In total 90 litters, representing 1249 piglets, were included in the study and randomly allocated to either the treatment or control group. Piglets in the treatment group received a single intramuscular injection, containing 45 mg toltrazuril and 200 mg gleptoferron, between 1 and 3 days of age. Piglets in the control group received a single injection with only 200 mg gleptoferron. The effect of treatment on oocyst excretion, expressed in oocysts per gram of feces (OPG), average daily weight gain (ADG) and mortality was determined both pre- and post-weaning. A significant decrease in OPG as well as a decrease in the number of litters (pre-weaning) and pens (post-weaning) that tested positive for cystoisosporosis, was observed in the treated animals compared to the controls. Furthermore, treatment resulted in an increased ADG during the period from day 1 to day 21 (p-value: 0.03881). There was no significant difference in mortality observed between the treatment group to the control group (p-value: 0.2167). To our knowledge, this is the first report on the effect of toltrazuril on oocyst excretion after weaning. This finding highlights the potential long-term benefits of the treatment beyond the initial administration.

Comparison of coproprevalence and seroprevalence to guide decision-making in national soil-transmitted helminthiasis control programs: Ethiopia as a case study

BACKGROUND

WHO recommends periodical assessment of the prevalence of any soil-transmitted helminth (STH) infections to adapt the frequency of mass drug administration targeting STHs. Today, detection of eggs in stool smears (Kato-Katz thick smear) remains the diagnostic standard. However, stool examination (coprology) has important operational drawbacks and impedes integrated surveys of multiple neglected tropical diseases. Therefore, the aim of the present study was to assess the potential of applying serology instead of coprology in STH control program decision-making.

METHODOLOGY

An antibody-ELISA based on extract of Ascaris lung stage larvae (AsLungL3-ELISA) was applied in ongoing monitoring activities of the Ethiopian national control program against schistosomiasis and soil-transmitted helminthiasis. Blood and stool samples were collected from over 6,700 students (median age: 11) from 63 schools in 33 woredas (districts) across the country. Stool samples of two consecutive days were analyzed applying duplicate Kato-Katz thick smear.

PRINCIPAL FINDINGS

On woreda level, qualitative (seroprevalence) and quantitative (mean optical density ratio) serology results were highly correlated, and hence seroprevalence was chosen as parameter. For 85% of the woredas, prevalence based on serology was higher than those based on coprology. The results suggested cross-reactivity of the AsLungL3-ELISA with Trichuris. When extrapolating the WHO coproprevalence thresholds, there was a moderate agreement (weighted κ = 0.43) in program decision-making. Using the same threshold values would predominantly lead to a higher frequency of drug administration.

SIGNIFICANCE

This is the first time that serology for soil-transmitted helminthiasis is applied on such large scale, thereby embedded in a control program context. The results underscore that serology holds promise as a tool to monitor STH control programs. Further research should focus on the optimization of the diagnostic assay and the refinement of serology-specific program decision-making thresholds.

Longitudinal assessment of the exposure to Ascaris lumbricoides through copromicroscopy and serology in school children from Jimma Town, Ethiopia

Background

We previously demonstrated that serology holds promise as an alternative diagnostic tool to copromicroscopy to monitor and evaluate deworming programs targeting soil-transmitted helminths (STHs). Here we explored the dynamics of anti-Ascaris antibodies (Ab) and evaluated the Ab-isotype of choice to assess the longitudinal exposure to Ascaris in Ethiopian school children.

Methodology

Between October 2018 and February 2020, stool and blood samples were collected every four months from school children (4 to 6 years of age). Stool samples were analyzed by duplicate Kato-Katz to assess the presence and intensity of any STH infection. Plasma Ab-responses against the total extract of Ascaris suum lung third stage larvae were measured through in-house Ab-ELISA’s for seven different Ab-isotypes.

Principal findings

At baseline, 42.4% of the 66 children were excreting eggs of any STH, Trichuris (37.9%) being the most prevalent. The cumulative prevalence (proportion of children tested that positive at least once over the entire study period) was 56.1% for Trichuris and 31.8% for Ascaris. For Ascaris, re-infections were frequently observed, whereas for Trichuris, children often remained excreting eggs following drug administration. When measuring anti-Ascaris Ab-levels, the cumulative seroprevalence was generally higher (IgG4: 60.6%; IgG1: 50.0%; IgE: 36.4%). The individual anti-Ascaris IgG4 levels at baseline were positively associated with the fecal egg counts averaged over the study period, the rate of egg-appearance and the number of positive test results. There was no apparent cross-reactivity between the anti-Ascaris IgG4 Ab-ELISA and Trichuris.

Conclusions/Significance

We demonstrate that the children are exposed to STH before the age of four and that the exposure to Ascaris is underestimated when measured with copromicroscopy. Compared to other Ab-isotypes, IgG4 is the Ab-isotype of choice to measure Ascaris exposure in STH endemic settings. Finally, the results also highlight that measuring anti-Ascaris IgG4 levels holds promise as a tool to identify individuals at higher risk for continued exposure to this STH.

World-wide large-scale deworming programs are being implemented to control the morbidity attributable to intestinal worms. Our group has recently shown that diagnostic tools that detect anti-parasite antibodies hold promise as an alternative to the current diagnostic standard (detecting worm eggs in stool using microscopy) to monitor and evaluate the progress of these programs towards the set targets. In the present study, we further explored the potential of antibody-based assays by monitoring the exposure of Ethiopian school children during a 17-month period to worm infections. Our results indicated that children in this area are exposed to intestinal worms from an early age onwards and that, based on serological results, more children are exposed to worm infections than measured by the current diagnostic standard. In addition, we demonstrated that test results of the antibody assay at the start of the study were positively associated with mean egg counts averaged over the study period, the rate of egg-appearance and the number of positive stool tests, highlighting that such assay holds promise as a tool to identify individuals at higher high risk for continued exposure to worms, and ultimately improve control programs.

Antidepressant study design affects patient expectancy: a pilot study

BACKGROUND

Response to antidepressant medication is higher in comparator versus placebo-controlled randomized controlled trials (RCTs). Patient expectancy is an important influence on clinical outcome in the treatment of depression and may explain this finding. The results are reported from a pilot RCT studying expectancy and depression outcome in placebo-controlled versus comparator treatment conditions.MethodOut-patients aged 18-65 years with major depressive disorder (MDD) were enrolled in this 8-week RCT. Subjects were randomized to placebo-controlled (escitalopram or placebo) or comparator (escitalopram or citalopram) administration of antidepressant medication. Subjects reported their expected likelihood and magnitude of depression improvement before and after randomization using questions from the Credibility and Expectancy Scale (CES). A regressed change model of post-randomization expectancy of improvement was fit to the data to determine whether subjects in the comparator group reported greater expectancies of improvement than subjects in the placebo-controlled group.

RESULTS

Twenty subjects with mean age 56.5+/-11.7 years, a baseline Hamilton Depression Rating Scale (HAMD) score of 24.2+/-5.3, baseline Beck Depression Inventory (BDI) score of 24.9+/-6.4 and baseline Clinical Global Impressions (CGI) - Severity score of 4.0+/-0.3 were enrolled in the study. Adjusting for other factors, the effect of group assignment on expected magnitude of improvement was significant and large (effect size 1.5). No group differences in expected likelihood of improvement were found.

CONCLUSIONS

Randomization to comparator versus placebo-controlled administration of antidepressant medication produced greater expectancies of how much patients would improve during the trial. This expectancy difference may explain the higher response and remission rates that are observed in comparator versus placebo-controlled trials.

Assessing the subjective experience of being a participant in psychiatric research

OBJECTIVE

To address both clinical and ethical concerns in psychiatric research, the study assessed the subjective experience of being a participant in a feasibility study of outcome in long-term psychodynamic psychotherapy and psychoanalysis.

METHOD

A questionnaire assessing positive and negative reactions to three typical research methodologies (self-report questionnaires, structured diagnostic interviews, and tape-recording of sessions) was administered to 23 patient-therapist pairs.

RESULTS

Patients reported that questionnaires and interviews were slightly to moderately helpful in promoting self-realization and facilitating therapy, and not at all to slightly intrusive and disruptive. Adjustment to audiotaping of sessions was rapid (within two sessions). Therapists significantly overestimated the negative effects and underestimated the positive benefit patients reported from participating in research.

CONCLUSIONS

Traditional objections to research in dynamic psychotherapy on the grounds that patients experience research procedures as significantly intrusive and disruptive appear to be unfounded.

Treatment of major depression with nortriptyline and paroxetine in patients with ischemic heart disease

OBJECTIVE

This study compared the efficacy, tolerability, and safety of paroxetine and nortriptyline in depressed patients with ischemic heart disease.

METHOD

After a 2-week, single-blind placebo lead-in phase, 81 outpatients with DSM-III-R-defined nonpsychotic unipolar major depression and ischemic heart disease were randomly assigned to double-blind treatment with paroxetine or nortriptyline for 6 weeks. Paroxetine was administered at a fixed-flexible dose of 20-30 mg/day. Nortriptyline dose was adjusted with the use of blood-level monitoring to reach a plasma concentration of 50-150 ng/ml.

RESULTS

Twenty-seven of the 41 patients who started treatment with paroxetine and 29 of the 40 patients who started treatment with nortriptyline had an improvement of at least 50% in their Hamilton Depression Rating Scale scores. Significantly more patients taking nortriptyline discontinued treatment prematurely (35% versus 10%), and more patients taking nortriptyline had adverse events resulting in termination (25% versus 5%).

CONCLUSIONS

Both treatments were efficacious. Sixty-three percent of all patients improved at least 50%, and of these, 90% met the criteria for remission. Paroxetine was better tolerated than nortriptyline and less likely to produce cardiovascular side effects.

A match made in heaven? A pilot study of patient-therapist match

The authors report on a study of patient-therapist match in 50 psychodynamic psychotherapy dyads. Sixty-six percent of patients and therapists agreed about the quality of the match, with 58% of patients and 56% of therapists reporting that the match was positive. Positive match correlated with positive patient and therapist assessments about the progress and process of therapy, but not with perceived similarity of personal characteristics. Patients' and therapists' perceptions about their similarities and differences from one another did not correlate. This study suggests it is both possible and important to gather data from both patient and therapist when studying match.

The definition and assessment of analytic process: can analysts agree?

Although analytic process (AP) is a core concept in psychoanalytic theory and practice and has emerged as an important variable in outcome studies, there is no consensus regarding its definition and operationalisation. This paper describes the development and validation of the Columbia Analytic Process Scale (CAPS), a rating scale developed to evaluate the presence or absence of AP in a single psychoanalytic session transcript for purposes of an outcome study. Definitions of interrater reliability and construct validity are reviewed and two studies designed to evaluate these important aspects of the CAPS are presented. The results demonstrate that the CAPS has adequate interrater reliability (kappa = .5). To establish construct validity the plan was to compare the CAPS rating of AP to clinical consensus. However, when a group of ten senior training and supervising analysts at Columbia were asked to rate five psychoanalytic session transcripts, no clinical consensus could be established. Statistical analysis of the pattern of the analysts' clinical ratings showed that the largest portion of the variance was accounted for by the error term of a two-way ANOVA. The implication of this finding is that the construct of AP itself is ill-defined. The results of this study suggest that the commonly used term AP has less consensually held meanings than analysts tend to believe; the impact of lack of definition of key terms on clinical and research pursuits within psychoanalysis is discussed.

The fate of training cases

The authors regard the treatment of analytic patients as a crucial, formative and ultimately integrative experience in a candidate's development that has received remarkably little direct attention as an aspect of analytic education. From 1983 to 1992 a questionnaire was sent to all graduates of the Columbia University Psychoanalytic Center for Training and Research asking for information on training cases, both those terminated before graduation and those still ongoing at the time of graduation. The authors report data on pre-graduation candidate case experience, treatment duration of training cases, the impact of graduation on the course of analysis and on a global assessment of the outcome. 70 per cent of the 71 who graduated between 1983 and 1992 returned the questionnaire. The survey showed that before graduation the average candidate had a cumulative nine-year experience of treating training cases. 35 per cent of cases terminated before graduation and were invariably considered to have an unsuccessful outcome. Thus the 'failed case' was a common event and should be anticipated as part of a candidate's education. There was no evidence of precipitous termination of cases after graduation; in fact the data suggest that graduation has no discernible effect on the timing of termination. The vast majority of candidates at Columbia continue to be supervised after graduation, which suggests that graduation is only a marker in the training of an analyst, rather than the point of completion. With respect to outcome, 23 per cent of the 151 terminated cases were rated successful. Though this finding is consistent with previous reports, the methodological limitations of this study limit the confidence in this result. One of the important issues raised by these results is the impact of training requirements on the candidate's education and the Fate of Training Cases.

Design for polarizing holographic optical elements

We present results of the application of a three-dimensional rigorous-vector coupled-wave theory to the design of polarizing holographic optical elements. Two different cases have been selected giving rise to two types of element, one of which is completely original. Experimental realizations were performed. The recording material was dichromated gelatin because of its outstanding performance related to diffraction efficiency. A fair agreement between the theoretical previsions and the experimental results was achieved.

Computer-originated polarizing holographic optical element recorded in photopolymerizable layers

The photosensitive system that is used in most cases to produce holographic optical holograms is dichromated gelatin. Other materials may be used, in particular, photopolymerizable layers. In the present investigation, we set out to use the polymer developed in the Laboratoire de Photochimie Générale in Mulhouse in order to duplicate a computer-generated hologram. Our technique is intended to generate polarizing properties. We took into account the fact that no wet chemistry processing is required; grating fringe spacings are not distorted through chemical development.