Diagnostic Techniques of Soil-Transmitted Helminths: Impact on Control Measures

Recombinant multiepitope proteins expressed in Escherichia coli cells and their potential for immunodiagnosis

Recombinant multiepitope proteins (RMPs) are a promising alternative for application in diagnostic tests and, given their wide application in the most diverse diseases, this review article aims to survey the use of these antigens for diagnosis, as well as discuss the main points surrounding these antigens. RMPs usually consisting of linear, immunodominant, and phylogenetically conserved epitopes, has been applied in the experimental diagnosis of various human and animal diseases, such as leishmaniasis, brucellosis, cysticercosis, Chagas disease, hepatitis, leptospirosis, leprosy, filariasis, schistosomiasis, dengue, and COVID-19. The synthetic genes for these epitopes are joined to code a single RMP, either with spacers or fused, with different biochemical properties. The epitopes' high density within the RMPs contributes to a high degree of sensitivity and specificity. The RMPs can also sidestep the need for multiple peptide synthesis or multiple recombinant proteins, reducing costs and enhancing the standardization conditions for immunoassays. Methods such as bioinformatics and circular dichroism have been widely applied in the development of new RMPs, helping to guide their construction and better understand their structure. Several RMPs have been expressed, mainly using the Escherichia coli expression system, highlighting the importance of these cells in the biotechnological field. In fact, technological advances in this area, offering a wide range of different strains to be used, make these cells the most widely used expression platform. RMPs have been experimentally used to diagnose a broad range of illnesses in the laboratory, suggesting they could also be useful for accurate diagnoses commercially. On this point, the RMP method offers a tempting substitute for the production of promising antigens used to assemble commercial diagnostic kits.

Management of paediatric soil-transmitted helminthiasis in a non-endemic area: experience in a reference international health unit

Soil-transmitted helminth (STH) infections inflict disability worldwide, especially in the poorest communities. Current therapeutic options against STHs show limited efficacy, particularly against Trichuris trichiura. The empirical management of patients coming from high-prevalence areas has been suggested for non-endemic areas. This study aimed to describe the management of STH infections in a non-endemic setting using an individualised approach. We performed a retrospective, descriptive study of all patients up to 16 years of age with STH infections attended at an international health unit in a non-endemic area (2014-2018), including all T. trichiura, Necator americanus, Ancylostoma duodenale, and Ascaris lumbricoides infections diagnosed using a formol-ether concentration technique and direct visualisation. Patients were treated according to current international guidelines. Sixty-one stool samples from 48 patients testing positive for STHs were collected, with 96% (46/48) reporting a previous long-term stay in endemic areas. Cure rates with 3-day benzimidazole regimens were 72% for T. trichiura, 40% for hookworms, and 83% for A. lumbricoides. The results were not influenced by any reinfection risk due to the study being performed in a non-endemic area. Patients coming from STH-endemic areas should be evaluated with appropriate diagnostic tools and followed up until cure control results. Cure rates in our cohort were moderate to low, similar to those published in studies in endemic areas. The efficacy of current treatment options is insufficient to recommend a specific empirical approach in high-income countries' healthcare systems.

Seroprevalence and Potential Risk Factors of Toxocariasis among General Population in Southwest Iran: Implications on the One Health Approach

Toxocariasis is one of the most common zoonotic diseases distributed worldwide. This study aimed to estimate the seroprevalence of anti-Toxocara immunoglobulin G (IgG) antibodies and the associated risk factors among general populations living in urban and rural areas of Abadan and Khorramshahr cities in Khuzestan Province, Southwest Iran. This cross-sectional study was conducted between March and September 2022. There were 363 participants (190 females and 173 males) aged from <20 to ≥60 years old. Anti-Toxocara IgG antibodies in serum samples were measured using a commercially available enzyme-linked immunosorbent assay (ELISA). A structured questionnaire was employed to collect information regarding sociodemographic status and probable risk factors associated with toxocariasis. It was found that the seroprevalence rate in males (15.0%, 95% CI = 10.47-21.11) was higher than in females (10.5%, 95% CI = 6.92-15.70). Moreover, we observed that the seroprevalence was higher in participants at younger ages compared to other age ranges (COR = 2.55, 95% CI = 0.92-7.12, p =0.073). The findings of the univariate analysis revealed that residency in rural areas (p  < 0.001), using unpurified water (p  < 0.001), contact with dog (p =0.002), contact with soil (p  < 0.001), consumption of improperly washed vegetables (p  < 0.001), and history of drinking untreated water (p  < 0.001) were risk factors associated with toxocariasis. Further comprehensive studies with a focus on humans and animals should be designed in different areas of the Province. The data represented by the current study are useful to health policymakers to consider precise surveillance and effective prevention measures to control this zoonotic infection among general populations.

Epidemiology of soil-transmitted helminth infections and the differential effect of treatment on the distribution of helminth species in rural areas of Gabon

BACKGROUND

Soil-transmitted helminth (STH) infections are a public health concern in endemic areas. For efficient control, the epidemiology of the disease needs to be monitored. This report assesses the prevalence, incidence, post-treatment infection (PTI) rate, and risk factors for STH infections in two rural areas of Gabon.

METHOD

In this longitudinal and prospective study, participants aged six to 30 years from the vicinity of Lambaréné and selected households using a simple randomization process were included and followed in two consecutive periods of six and nine months. Stool samples were obtained at the beginning and the end of each follow-up phase (FUP). The Kato-Katz technique was used for the detection of STH eggs, while the Harada-Mori technique and coproculture were used for the detection of larvae in stool processed within a maximum of four hours of collection. Prevalence was determined at the three main time points of the study, incidence was assessed during the two study phases, and PTI was defined as an infection detected nine months post-treatment.

RESULTS

A total of 262 participants were included. The overall prevalence of STH infections was 42% (95%CI: 34-50) and 44% (95%CI: 37-51) at baseline for the six and nine month FUPs, respectively. Trichuris trichiura was the most prevalent species at each time point of assessment. The cumulative incidence of STH at the 6- and 9-month follow-ups was 18% (95%CI: 12-27) and 35% (95%CI: 27-43), respectively, while the incidence rates were 41 (95%CI: 28-55) and 56 (95%CI: 46-67) per 100 person-years, respectively. The PTI rates at the 9-month follow-up for T. trichiura, hookworm, and Ascaris lumbricoides were 58% (95%CI: 41-74), 31% (95%CI: 11-59) and 18% (95%CI: 5-40), respectively. The STH infection intensity was generally light.

CONCLUSION

The prevalence level of STH infection is moderate in the vicinity of Lambaréné, with T. trichiura being the most prevalent species. Our results reveal a rapid spread of the disease in the population mainly following intervention, particularly for trichuriasis, and therefore call for the full implementation of the World Health Organization's recommendations in the area. Trial registration clinicaltrials.gov Identifier NCT02769013. Registered 21 April 2016, https://clinicaltrials.gov/study/NCT02769013.

Sewerage as a protective factor for prevalence of hookworm infection in schoolchildren in Brazil: A multilevel ecological analysis of national prevalence surveys (1950-2018)

INTRODUCTION

The prevalence of hookworm infection in Brazil has decreased considerably in recent decades. However, there is no definitive consensus as to which changes have contributed to this reduction. A hypothesis is that improvements in environmental factors have contributed to lowering the parasite load and the level of host-parasite contact.

METHODS

This is an ecological study using unbalanced panel data from two Brazilian surveys (1947-1953 and 2010-2015), with municipalities as the analysis unit. The sample comprised 1428 municipalities, in which a total of 745,983 schoolchildren aged 7 to 14 were examined. Zero-inflated Poisson regression models, with fixed and random effects were estimated to evaluate the association of potential explanatory variables with the prevalence of hookworm infection at a significance level of 5 %.

RESULTS

We identified a significant decrease in the prevalence between the first and last analyzed periods (RR 0.096; CI 0.086-0.107); The following variables were found to have a protective effect: access to sanitary sewage systems (RR 0.984, CI 0.982-0.986), urbanization (RR 0.995, CI 0.993-0.997), and gross domestic product (RR 0.929, CI 0.912-0.945).

CONCLUSION

The findings of this study show a decrease in the prevalence of hookworm infections over six decades in schoolchildren in the Brazilian municipalities. Environmental, demographic, and economic factors were associated with this trend. A historical analysis indicates that interventions aimed at improving sanitation contributed to reducing the disease prevalence.

Evaluation of Kato-Katz and multiplex quantitative polymerase chain reaction performance for clinical helminth infections in Thailand using a latent class analysis

Using an appropriate diagnostic tool is essential to soil-transmitted helminth control and elimination efforts. Kato-Katz (KK) is the most commonly used diagnostic, but recently other tools, such as real-time quantitative polymerase chain reaction (multiplex qPCR), are starting to be employed more. Here, we evaluated the performance of these two diagnostic tools for five helminth species in Thailand. In the absence of a gold standard, diagnostic performance can be evaluated using latent class analysis. Our results suggest that in moderate to high prevalence settings above 2% multiplex qPCR could be more sensitive than KK, this was particularly apparent for Opisthorchis viverrini in the northeastern provinces. However, for low prevalence, both diagnostics suffered from low sensitivity. Specificity of both diagnostics was estimated to be high (above 70%) across all settings. For some specific helminth infection such as O. viverrini, multiplex qPCR is still a preferable choice of diagnostic test. KK performed equally well in detecting Ascaris lumbricoides and Taenia solium when the prevalence is moderate to high (above 2%). Neither test performed well when the prevalence of infection is low (below 2%), and certainly in the case for hookworm and Trichuris trichiura. Combination of two or more diagnostic tests can improve the performance although the cost would be high. Development of new methods for helminth surveillance at the pre-elimination phase is therefore very important. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.

Intestinal helminthic infections: a narrative review to guide the hepatogastroenterologist

Intestinal helminthic infections are not uncommon in Western Europe, mainly due to modern travel, emigration and globalization. Moreover, some helminthic infections are endemic in Western Europe and are part of the everyday clinical practice. The hepatogastroenterologist should therefore recognize and manage these patients or at least refer them to appropriate reference centers. Signs and symptoms are often unspecific or even absent. Discerning the disease at an early stage avoids expensive diagnostic testing, life-threatening complications and in some cases even further spread of the disease. This review article aims to guide the hepatogastroenterologist when suspecting a helminthic infection by addressing the most prevalent symptoms, summarizing the most probable associated helminthic entities, highlighting practical steps in diagnosis and available treatments.

Performance Evaluation of Three Diagnostic Methods for Soil-Transmitted Helminth Infections among Schoolchildren in Amhara Region, Northwest Ethiopia

Background

Soil-transmitted helminths are parasitic nematodes found in the intestine. They are more prevalent in the tropics and subtropics, including Ethiopia. However, low-sensitive direct wet mount microscopy fails to detect soil-transmitted helminths among infected cases. Therefore, more sensitive and cost-effective diagnostic methods are urgently needed to minimize soil-transmitted helminthiasis morbidity.

Objective

This study aimed to compare and evaluate the performance of diagnostic methods for soil-transmitted helminths against the "gold" standard.

Methods

An institution-based cross-sectional study was conducted among 421 schoolchildren from May to July, 2022 in the Amhara Region. Study participants were selected using a systematic random sampling technique. Stool samples were processed via Kato-Katz, McMaster, and spontaneous tube sedimentation techniques. Data were entered into epi-data version 3.1 and analyzed using SPSS version 25. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated against the combined result as a "gold" standard. The strength of agreement between the diagnostic methods was determined by the Kappa value.

Results

The overall prevalence of soil-transmitted helminths was 32.8% (95% CI: 28.2-37.8%) using a combination of methods. The detection rates of Kato-Katz, McMaster, and spontaneous tube sedimentation were 28.5% (95% CI: 24.2-33.2%), 30% (95% CI: 25.6-34.8%), and 30.5% (95% CI: 26.1-35.3%), respectively. Sensitivity and negative predictive values were 87.1% (95% CI: 80.2-92.3%) and 95.1% (95% CI: 92.6-96.8%) for Kato-Katz; 91.7% (95% CI: 85.6-95.6%) and 96.5% (95% CI: 94.1-98.0%) for McMaster; and 93.2% (95% CI: 87.5-96.8%) and 97.1% (95% CI: 94.7-98.4%) for spontaneous tube sedimentation. Kappa values of Kato-Katz, McMaster, and spontaneous tube sedimentation for the diagnosis of soil-transmitted helminths were 0.901, 0.937, and 0.948, respectively.

Conclusion

Kato-Katz, McMaster, and spontaneous tube sedimentation techniques had comparable sensitivity with almost perfect agreement for the detection of soil-transmitted helminths. Therefore, the spontaneous tube sedimentation technique can be used as an alternative diagnostic method for soil-transmitted helminth infections in endemic countries.

Food Allergies and Parasites in Children

The dynamically growing incidence of food allergies forces the scientific community to develop new methods for their diagnosis, differentiation, and effective treatment. Parasitoses appear much less frequently in the scientific literature, as well as among the presumed causes of numerous conditions. The similarity of inflammatory mechanisms in allergies and parasitosis necessitates a revision of current diagnostic standards. A lack of specificity and the coincidence of symptoms at an early stage of disease can lead to misdiagnosis. In this paper, we attempted to perform a comparative analysis of the similarities and differences in symptoms for these two types of diseases. We described the molecular mechanisms and metabolic pathways of food allergy and parasitosis. We presented the available research methods and directions of ongoing studies aimed at implementing precise medical techniques for differential diagnosis. We discussed the allergenic properties of certain parasite proteins, using the example of myofibrillar tropomyosins from the nematode Anisakis simplex. The literature in the fields of allergology and parasitology leads to the conclusion that it is reasonable to run parallel allergological and parasitological diagnostics in patients with non-specific symptoms. This approach will facilitate accurate and early diagnosis and implementation of effective therapy.

Prevalence, intensity and associated risk factors of soil-transmitted helminth infections among individuals living in Bata district, Equatorial Guinea

BACKGROUND

Soil transmitted Helminths (STH) infections remain a public health concern worldwide, particularly in tropical and subtropical areas where these diseases are highly endemic. Knowing the prevalence and risk factors of the disease is crucial for efficient STH control strategies in endemic areas. The scarcity of epidemiological data on STH for Equatorial Guinea has motivated the decision to perform the present study.

METHODS

A cluster-based cross-sectional study was carried out in Bata district from November 2020 to January 2021. Stool samples were collected for the diagnostic of STH infections using Kato-Katz technique. Descriptive statistics was performed for determination of STH prevalence and intensity, while logistic regression models were used to assess the risk factors associated with STH infections.

RESULTS

A total of 340 participants were included in the study with a mean age of 24 years (SD = 23.7) and 1.2 female-to-male sex-ratio. The overall prevalence of any STH was 60% (95%CI: 55-65). The most prevalent species were Ascaris lumbricoides (43%, 95%CI: 37-48) and Trichuris trichiura (40%, 95%CI: 35-46). Intensity of infection were mainly light to moderate. A trend of association was observed between age and any STH infection (overall p-value = 0.07), with a significant difference observed between children aged 5-14 years as compared to those aged 1-4 (aOR 2.12; 95%CI: 1.02-4.43, p-value = 0.04), while locality was significantly associated with STH infection (overall p-value<0.001) with a higher odds observed for peri-urban area as compared to urban area (aOR 4.57; 95%CI: 2.27-9.60, p-value<0.001).

CONCLUSION

Bata district is a high STH transmission area, where school-aged children and peri-urban areas are associated with a higher risk of any STH infection. This situation calls for a full implementation of the WHO recommendations for STH control; mass drug administration of anthelminthic twice a year to the whole population with great attention to school age children, and prioritizing peri-urban areas where safe water, improve sanitation, and hygiene education should be implemented to achieve a better control.

Zoonotic Parasites in Playgrounds in Southern Spain: A One Health Approach

Zoonotic parasitic diseases are considered a global threat to public health. In this sense, canines and felines may be infected by different cosmopolitan parasites, with playgrounds serving as an important focus of infection for humans, as well as domestic or wild animals. Knowledge of the epidemiological situation of parasites in animal reservoirs integrated into the environment, identifying the spread pathways, is a key element for an effective response to this threat. Thus, the aim of this study was to assess the frequency of intestinal parasites with zoonotic potential in 120 playgrounds in the Malaga province (Spain). Samples were processed and analysed following standard parasitological procedures. Some 36.7% of playgrounds were parasite-positive with one or more zoonotic parasites. The most common parasites recovered were nematodes (60.0%), followed by protozoan species (33.3%) and cestodes (6.7%). In the parasite-positive playgrounds, Toxocara spp. (17.0 ± 3.5%) and Giardia duodenalis (17.0 ± 3.4%) were the most predominant parasites. In addition, 34.1% of playgrounds were infected with multiple parasites. Our results show a high presence of parasitic forms with zoonotic potential in playgrounds in Malaga, Spain. Due to the close contact between pets and humans in playgrounds, the potential zoonotic risk may increase if prevention and control measures are not designed.

Association of helminth infestation with childhood asthma: a nested case-control study

OBJECTIVES

The association between helminthiasis and asthma remains inconclusive but can only be investigated in counties where helminthiasis is transitioning from a high to low burden. We investigated this association using data from a childhood respiratory cohort in Sri Lanka.

METHODS

A case-control study was nested within a population-based cohort of children aged 6-14 years in Sri Lanka. The stool samples of 190 children with asthma and 190 children without asthma were analyzed to assess the burden of helminth infestation. Logistic regression models were fitted to investigate the association of gastrointestinal helminth species with asthma.

RESULTS

Helminthiasis in children with and without asthma was 23.3% (n = 44) and 15.3% (n = 23), respectively. Those with asthma were more likely to have helminthiasis (odds ratio 3.7; 95% confidence interval 1.7, 7.7; P = 0.001), particularly with Trichiuris trichura (odds ratio 4.5; 95% confidence interval 1.6, 12.3; P = 0.004). Helminth eggs per gram of feces were not associated with asthma (P >0.05).

CONCLUSION

Our findings demonstrate a positive association between T. trichura infestation and asthma and point to the need to fully characterize this association to understand the likely immunological mechanism that drives it. This association highlights an important public health intervention in countries where these infestations are still prevalent, affecting 24% of the population worldwide.

Imaging as a (pre)clinical tool in parasitology

Imaging of parasites is central to diagnosis of many parasitic diseases and has thus far played an important role in the development of antiparasitic strategies. The development of novel imaging technologies has revolutionized medicine in fields other than parasitology and has also opened up new avenues for the visualization of parasites. Here we review the role imaging technology has played so far in parasitology and how it may spur further advancement. We point out possibilities to improve current microscopy-based diagnostic methods and how to extend them with radiological imaging modalities. We also highlight in vivo tracking of parasites as a readout for efficacy of new antiparasitic strategies and as a source of fundamental insights for rational design.

Helminth species-specific effects on IFN-γ producing T cells during active and latent tuberculosis

BACKGROUND

Interferon-γ (IFN-γ) is a key cytokine inducing protective immune responses during tuberculosis (TB) infection. Helminth-induced immune responses may affect IFN-γ production by T cells, although its connection with disease severity and immune recovery during treatment is unexplored. We investigated the species-specific effect of helminths on the IFN-γ production by T cells in relation to disease severity during active and latent TB infection (LTBI).

METHODS

In this study, 69 active pulmonary TB patients (PTB), 28 with LTBI and 66 healthy controls were included. Active TB was diagnosed using GenXpert MTB/RIF while QuantiFERON test (QFT) was used for the screening of healthy community controls (CCs) and for the diagnosis of LTBI. Helminth infection was identified by routine diagnosis whereas clinical disease severity was evaluated by the TB score. Intracellular IFN-γ production of T cells in stimulated peripheral blood mononuclear cells (PBMCs) was analyzed by flow cytometry using TB antigens (PPD), the polyclonal T cell activator staphylococcal enterotoxin B (SEB), or medium as unstimulated control.

RESULTS

Helminth infected CCs and LTBI subjects showed a significant reduction of IFN-γ+ CD4+ T cells by PPD-stimulation compared to non-helminth infected control groups. The significant reduction in the frequency of IFN-γ+ T cells in both latent and active PTB patients following SEB stimulation was mostly attributed to Schistosoma mansoni infection, whereas Ascaris lumbricoides, Schistosoma mansoni, and hookworm infection contributed equally in CCs. Following anti-helminthic and anti-TB treatment for 2 months, the frequency of IFN-γ+ CD4 T cells in helminth coinfected PTB was restored to levels of helminth negative PTB before treatment. Helminth coinfected PTB patients with an intermediate and severe clinical course had reduced capacity for production of IFN-γ+ T cells compared to the corresponding non-helminth infected PTB.

CONCLUSION

We found a reduction in IFN-γ producing T cells by helminth coinfection which was restored following anti-helminthic treatment. This reduction was helminth species-dependent in an exploratory sub-analysis and correlated to increased disease severity.

Soil-transmitted helminth surveillance in Benin: A mixed-methods analysis of factors influencing non-participation in longitudinal surveillance activities

BACKGROUND

Despite the significant success of deworming programs in reducing morbidity due to soil-transmitted helminth (STH) infections globally, efforts to achieve elimination of STH as a public health problem or to potentially interrupt transmission will require improving and intensifying surveillance. However, non-participation in surveillance threatens the ability of programs to adequately monitor program status and limited research has been conducted to investigate drivers of non-participation in stool-based surveillance.

METHODOLOGY/PRINCIPAL FINDINGS

This mixed-methods exploratory sequential study took place in Comé, Benin in association with the DeWorm3 Project. Six focus group discussions were conducted with individuals invited to participate in annual DeWorm3 stool surveillance. Thematic analysis was used to identify facilitators and barriers to participation and inform the quantitative analysis. A mixed-effects logistic regression model was built using baseline DeWorm3 survey data to identify factors associated with non-participation. Qualitative and quantitative findings were merged for interpretation. Among the 7,039 individuals invited to participate in baseline stool surveillance, the refusal rate was 8.1%. Qualitative themes included: community members weighing community-level benefits against individual-level risks, circulating rumors about misuse of stool samples, interpersonal communication with field agents, and cultural norms around handling adult feces. The quantitative analysis demonstrated that adults were significantly less likely to provide a stool sample than school-aged children (OR:0.69, 95%CI: 0.55-0.88), a finding that converged with the qualitative results. Individuals from areas in the highest quartile of population density were more likely to refuse to participate (OR:1.71, 95%CI:1.16-2.52). Several variables linked to community-affinity aligned with qualitative results; residing mainly in the community (OR:0.36, 95%CI:0.20-0.66) and having lived in the community for more than 10 years (OR:0.82, 95%CI:0.54-1.25) decreased likelihood of refusal.

CONCLUSIONS/SIGNIFICANCE

Optimizing STH surveillance will require that programs reimagine STH surveillance activities to address community concerns and ensure that no subpopulations are inadvertently excluded from surveillance data.

Molecular diagnostics for gastrointestinal helminths in equids: Past, present and future

This review is aimed to (i) appraise the literature on the use of molecular techniques for the detection, quantification and differentiation of gastrointestinal helminths (GIH) of equids, (ii) identify the knowledge gaps and, (iii) discuss diagnostic prospects in equine parasitology. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for systematic reviews, we retrieved 54 studies (horses: 50/54; donkeys and zebras: 4/54) from four databases. Polymerase chain reaction (PCR) was employed in all of the studies whereas PCR amplicons were sequenced in only 18 of them. Other techniques used (including modifications of PCR) were reverse line blot, quantitative (q)PCR, restriction fragment length polymorphism, nested-PCR, PCR-directed next-generation sequencing, Southern blotting, single strand conformation polymorphism, PCR-enzyme linked immunosorbent assay, matrix-assisted laser desorption/ionisation-time of flight and random amplification of polymorphic DNA. Most of the studies (53/54) used nuclear ribosomal RNA (including the internal transcribed spacers, intergenic spacer, 5.8 S, 18 S, 28 S and 12 S) as target loci while cytochrome c oxidase subunit 1 and random genomic regions were targeted in only three and one studies, respectively. Overall, to date, the majority of molecular studies have focused on the diagnosis and identification of GIHs of equids (i.e. species of Anoplocephala, Craterostomum, cyathostomins, Oesophagodontus, Parascaris, Strongylus, Strongyloides and Triodontophorus), with a recent shift towards investigations on anthelmintic resistance and the use of high-throughput nemabiome metabarcoding. With the increasing reports of anthelmintic resistance in equid GIHs, it is crucial to develop and apply techniques such as advanced metabarcoding for surveillance of parasite populations in order to gain detailed insights into their diversity and sustainable control. To the best of our knowledge, this is the first systematic review that evaluates molecular investigations published on the diagnosis and quantification of equid GIHs and provides useful insights into important knowledge gaps and future research directions in equid molecular parasitology.

The accuracy of nucleic acid amplification tests (NAATs) in detecting human intestinal nematode infections: A protocol for a systematic review and meta-analysis

Human intestinal nematode infections are a global public health issue as they can result in considerable morbidity in infected individuals, mainly in developing countries. These infections continue to go undiagnosed, as they tend to be mainly endemic in resource-poor communities where there is a shortage of experienced laboratory staff and relevant diagnostic technologies. This is further exacerbated by the nature of intermittent shedding of eggs and larvae by these parasites. Diagnostic methods range from simple morphological identification to more specialised high-throughput sequencing technologies. Microscopy-based methods, although simple, are labour-intensive and considerably less sensitive than molecular methods which are rapid and have high levels of accuracy. Molecular methods use nucleic acid amplification (NAA) to amplify the deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) fragments of the parasite to detect and determine its presence using different technologies (NAAT). They have increased the sensitivity of detection and quantitation of intestinal nematode infections, especially in low infection intensity settings. The absence of a gold standard test limits current diagnosis and, in turn, restricts intervention measures and effective control efforts. The objective of this review is to determine the accuracy of NAATs in detecting human intestinal nematode infections using Kato-Katz as the reference test for the most common soil-transmitted helminth (STH) infections and the scotch tape test for enterobiasis and Baermann method for strongyloidiasis. Relevant studies will be identified by searches in electronic databases. Two reviewers will independently screen the literature against eligibility criteria. The methodological quality of studies will then be appraised by two reviewers using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Discrepancies will be addressed by a third reviewer. The true positives, false positives, true negatives and false negatives of all the studies will be extracted into contingency tables. In paired forest plots, study-specific sensitivity and specificity with a 95 per cent confidence interval will be displayed. The systematic review of this protocol will report the diagnostic accuracy of currently available NAATs for the detection of human intestinal nematode infections. This will help healthcare providers and administrators determine the diagnostic method to be used in different clinical and preventive settings. Trial registration: PROSPERO registration number for this protocol is CRD42022315730.

Advantages and Limitations of Microscopy and Molecular Detections for Diagnosis of Soil-transmitted Helminths: An Overview

World Health Organization (WHO) reported that over 1.5 billion people are infected by soil-transmitted helminths (STH) worldwide in sub-Saharan Africa, the United States of America, China, and East Asia. Heavy infections and polyparasitism are associated with higher morbidity rates, and the patients are exposed to increased vulnerability to other diseases. Therefore, accurate diagnosis followed by mass treatment for morbidity control is necessary.STH diagnosis commonly involves the microscopic observation of the presence of the STH eggs and larvae in the faecal samples. Furthermore, molecular approaches are increasingly utilised in monitoring and surveillance as they show higher sensitivity. Their capability to differentiate hookworm species is an advantage over the Kato-Katz technique. This review discusses the advantages and limitations of microscopy and various molecular tools used for STH detection.

Comparison of Human Intestinal Parasite Ova Segmentation Using Machine Learning and Deep Learning Techniques

Helminthiasis disease is one of the most serious health problems in the world and frequently occurs in children, especially in unhygienic conditions. The manual diagnosis method is time consuming and challenging, especially when there are a large number of samples. An automated system is acknowledged as a quick and easy technique to assess helminth sample images by offering direct visibility on the computer monitor without the requirement for examination under a microscope. Thus, this paper aims to compare the human intestinal parasite ova segmentation performance between machine learning segmentation and deep learning segmentation. Four types of helminth ova are tested, which are Ascaris Lumbricoides Ova (ALO), Enterobious Vermicularis Ova (EVO), Hookworm Ova (HWO), and Trichuris Trichiura Ova (TTO). In this paper, fuzzy c-Mean (FCM) segmentation technique is used in machine learning segmentation, while convolutional neural network (CNN) segmentation technique is used for deep learning. The performance of segmentation algorithms based on FCM and CNN segmentation techniques is investigated and compared to select the best segmentation procedure for helminth ova detection. The results reveal that the accuracy obtained for each helminth species is in the range of 97% to 100% for both techniques. However, IoU analysis showed that CNN based on ResNet technique performed better than FCM for ALO, EVO, and TTO with values of 75.80%, 55.48%, and 77.06%, respectively. Therefore, segmentation through deep learning is more suitable for segmenting the human intestinal parasite ova.

Historical overview and geographical distribution of neglected tropical diseases amenable to preventive chemotherapy in the Republic of the Congo: A systematic review

Background

Neglected Tropical Diseases amenable to Preventive Chemotherapy (PC-NTDs) affect the poorest populations around the world, especially in Africa. Scientific information on the distribution and level of endemicity of these diseases in the Republic of the Congo (RoC) is scarce in the published literature. We sought to collect all available epidemiological data on PC-NTDs in the RoC to document the historical and current situation and identify challenges in reaching the elimination of NTDs.

Methods

We searched Medline and Horizon databases for studies published until to July 4^th, 2019, on onchocerciasis, lymphatic filariasis, soil-transmitted helminth infections, schistosomiasis, and trachoma in the RoC. Unpublished reports were also reviewed. We included all epidemiological studies containing community data and excluded case reports. Location, prevalence data, and dates of the studies were extracted.

Principal findings

We identified 933 records, of which 56 met the inclusion criteria. The articles published before 1960 mainly concerned onchocerciasis and schistosomiasis. Despite a low number over the studied period, since 2005 there has been a steady increase in the number of publications. Most of the studies were cross-sectional and conducted in the general population. Trachoma is endemic in the Sangha and Likouala departments (prevalence of trachomatous inflammation-follicular > 5% in some villages), and further mapping is essential to properly assess the burden of this disease in the country. While the prevalence of soil-transmitted helminths is still high (over 20%) in a large part of Congo, cases of lymphatic filariasis (based on Wuchereria bancrofti antigenaemia and/or microfilaraemia) and onchocerciasis are becoming rare and very focused. To achieve the elimination of PC-NTDs, further intervention is required.

Conclusions

Except for trachoma, whose epidemiological situation should be better evaluated, PC-NTDs are endemic in the RoC, and actions to control them have been taken by health authorities. To eliminate PC-NTDs, which are still present in some locations, new mapping surveys are needed, and increased investment in scientific research should be encouraged in the country.

For many years, the Republic of the Congo has implemented control programs to combat neglected tropical diseases that cause severe disabilities. By tracing the past and recent distribution of these diseases through the analysis of epidemiological studies, we show that most remaining NTDs are located in defined foci of infection, maintained depending on ecology and lifestyle habits. However, the small number of recent studies limits the production of new knowledge, which would be useful for a better understanding of epidemiological patterns and to accelerate NTD elimination.

Application of Ziehl Neelsen Staining Method for Taenia spp. Eggs Differentiation

BACKGROUND

Three of Taenia species, named Taenia saginata, T. solium and T. asiatica can be found in Indonesia, but only T. solium can lead to neurocysticercosis. The morphology of those 3 Taenia spp. egg is indistinguishable by standard parasitology procedure. We aimed to use Ziehl Neelsen staining for differentiation of eggs of T. saginata and T. solium.

METHODS

As many as 40 containers of stool samples from the positive helminthiasis patients in Jakarta, Indonesia were collected during the year 2018. From each container, 10 slides prepared for staining with Kato-Katz technique as the preliminary examination. From those stool samples with positive taeniasis, we then once again made 10 slides/container for Ziehl Neelsen staining.

RESULTS

The first 400 slides stained with Kato-Katz technique as preliminary test were all positive for Taenia spp. The second 400 slides, we got 244 slides that gave good results as we could distinguished between the eggs of T. saginata and T. solium, meanwhile the remainder 156 slides gave unconfirmed results. From those 244 slides, 154 slides showed T. saginata eggs with magenta colored and 90 slides showed T. solium eggs with blue/purple colored. The eggs of T. solium slightly smaller if compared to Taenia saginata and had round shape, meanwhile T. saginata eggs were oval in shape.

CONCLUSION

Ziehl Neelsen staining method can be used as an alternative parasitological method to differentiate the eggs of T. saginata and T. solium.

Immune Response (Serum Globulin) in BALB/c Mice after Hookworm Egg Protein Immunization as the Initial Stage of Developing Laboratory Diagnostics: An In Vivo Approach

BACKGROUND: Hookworm infestation is still high and requires practical laboratory diagnosis with high sensitivity and specificity. Meanwhile, there are several limitations associated with the existing method; hence, a new method is essentially needed. Furthermore, the principle of immunological reactions needs to be developed by identifying the extent of hookworm eggs suspension immune responses. The BALB/c mouse is among the most widely used inbred models used in biomedical research and is particularly utilized in immunology and infectious disease research. AIM: This study aims to determine whether the protein concentration of hookworm eggs stimulates antibodies formation (proteins) in the serum of BALB/c mice. METHODS: This is an experimental study with a post-test only control design approach. Egg protein was isolated by removing the contents using a mini drill to immunize BALB/c mice, while the antibody response was observed by spectrophotometer and agglutination methods. RESULTS: The Chi-square and Post hoc statistical tests showed a significance p ≤ 0.001 indicating a relationship between hookworm egg protein and agglutination results. The higher the antibody level, the more visible the agglutination and vice versa. CONCLUSION: These results are expected to form a basis for developing more practical and efficient diagnostic methods based on antigen-antibody reactions.

Current status of intestinal parasitosis among patients attending teaching hospitals in Zagazig district, Northeastern Egypt

Almost 80% of health problems in the developing world are due to malnutrition and infectious diseases, which are mainly parasitic. Updated records on the prevalence of parasitic infections and the potential risk factors are essential to enhancing control strategies. Therefore, this study was conducted to evaluate the current situation of intestinal parasitism among patients attending teaching hospitals in Zagazig district, Northeastern Egypt. The study involved five hundred cases. They were all subjected to faecal examination using direct smear measure and two commercial faecal concentrators: Mini-Parasep® solvent-free and Mini-FLOTAC procedures. Mini-FLOTAC was performed with two solutions (FS2: saturated sodium chloride and FS7: zinc sulphate). The overall prevalence of intestinal parasitic infections was 56%. Different species were identified, like Giardia lamblia (12.6%), Entamoeba histolytica/dispar (10%), Ascaris lumbricoides (8.8%) and Hymenolepis nana (8.6%). Data analyses revealed a significant association of intestinal parasitism with different socio-demographic features of the participants. Our results showed a better diagnostic performance of Mini-Parasep® in the overall recovery of intestinal parasites. It was more accurate than Mini-FLOTAC in diagnosing both helminths and protozoan infections. Mini-FLOTAC (FS2) exhibited a higher sensitivity than FS7 for helminth recovery (74.6% vs 53.4%), while FS7 was more sensitive for protozoan infections (50.6% vs 43.8%). Intestinal parasitosis remains a challenging health problem in Zagazig city, wherever reliable diagnostic approaches are limited. Thus, our study has proposed the value of the commercial concentrators (Mini-Parasep® and Mini-FLOTAC) as alternative techniques for diagnosing a large variety of parasite species in resource-constrained settings.

Worms and bugs of the gut: the search for diagnostic signatures using barcoding, and metagenomics-metabolomics

Gastrointestinal (GI) helminth infections cause significant morbidity in both humans and animals worldwide. Specific and sensitive diagnosis is central to the surveillance of such infections and to determine the effectiveness of treatment strategies used to control them. In this article, we: (i) assess the strengths and limitations of existing methods applied to the diagnosis of GI helminth infections of humans and livestock; (ii) examine high-throughput sequencing approaches, such as targeted molecular barcoding and shotgun sequencing, as tools to define the taxonomic composition of helminth infections; and (iii) discuss the current understanding of the interactions between helminths and microbiota in the host gut. Stool-based diagnostics are likely to serve as an important tool well into the future; improved diagnostics of helminths and their environment in the gut may assist the identification of biomarkers with the potential to define the health/disease status of individuals and populations, and to identify existing or emerging anthelmintic resistance.

Anthelmintic Effect of Leucaena leucocephala Extract and Its Active Compound, Mimosine, on Vital Behavioral Activities in Caenorhabditis elegans

Helminth infections continue to be a neglected global threat in tropical regions, and there have been growing cases of anthelmintic resistance reported towards the existing anthelmintic drugs. Thus, the search for a novel anthelmintic agent has been increasing, especially those derived from plants. Leucaena leucocephala (LL) is a leguminous plant that is known to have several pharmacological activities, including anthelmintic activity. It is widely known to contain a toxic compound called mimosine, which we believed could be a potential lead candidate that could exert a potent anthelmintic effect. Hence, this study aimed to validate the presence of mimosine in LL extract and to investigate the anthelmintic effect of LL extract and mimosine on head thrashing, egg-laying, and pharyngeal pumping activities using the animal model Caenorhabditis elegans (C. elegans). Mimosine content in LL extract was confirmed through an HPLC analysis of spiking LL extract with different mimosine concentrations, whereby an increasing trend in peak heights was observed at a retention time of 0.9 min. LL extract and mimosine caused a significant dose-dependent increase in the percentage of worm mortality, which produced LC50s of 73 mg/mL and 6.39 mg/mL, respectively. Exposure of C. elegans to different concentrations of LL extract and mimosine significantly decreased the head thrashing, egg-laying, and mean pump amplitude of pharyngeal pumping activity. We speculated that these behavioral changes are due to the inhibitory effect of LL extract and mimosine on an L-type calcium channel called EGL-19. Our findings provide evidential support for the potential of LL extract and its active compound, mimosine, as novel anthelmintic candidates. However, the underlying mechanism of the anthelmintic action has yet to be elucidated.

Describing the intestinal microbiota of Holstein Fasciola-positive and -negative cattle from a hyperendemic area of fascioliasis in central Colombia

The ability to identify compositional changes in the intestinal microbiota of parasitized hosts is important for understanding the physiological processes that may affect animal productivity. Within the field of host–parasite interactions, many studies have suggested that helminths can influence the microbial composition of their hosts via their immunomodulatory effects. Bovine fascioliasis is a helminthiasis widely studied by immunologists, but with little information available regarding gut microbial communities. Thus, we aimed to describe the composition of the intestinal microbiota of Holstein Fasciola-positive and -negative cattle using parasitological methods and ELISA (enzyme-linked immunosorbent assay). Bovine fecal samples (n = 65) were obtained from livestock slaughter plants in the Cundi-Boyacense Colombian highlands (a hyperendemic region for bovine fascioliasis) and studied by amplicon-based next-generation 16S-rRNA and 18S-rRNA gene sequencing. From these samples, 35 were Fasciola hepatica-negative and, 30 were F. hepatica-positive in our detection analysis. Our results showed a reduction in the relative abundance of Bacteroidetes and Ascomycota in the Fasciola-positive samples, along with decreased relative abundances of the commensal taxa previously associated with fermentation and digestion processes. However, metabolomic approaches and functional analyzes of the intestinal microbiota are necessary to support these hypothesis. These findings are a small first step in the development of research aimed at understanding how microbial populations in bovines are modulated in liver helminth infections.

Fasciola hepatica, a liver parasite, infects a wide variety of hosts, mostly ruminants. Ruminant infections with this parasite cause economic losses worldwide, mainly in livestock. Given its importance, much research has been carried out on this parasite, a lot of which has focused on its ability to alter the immune responses of its host. However, little is known about the numerous other interactions it has with the host and how they might affect the host’s intestinal microbiota. Here, we observed a reduction in the abundance of microorganisms associated with the fermentation and digestion of vegetable fiber, two important processes in animal health and productivity. Therefore, it is possible that F. hepatica, in addition to the previously documented liver alterations, also generates changes in the intestinal microbiota that may impact its bovine host. These findings are a small first step in the research of microbial populations in cattle infected with liver helminths which open the door to further research aimed at identifying alternative treatments for parasites such as F. hepatica.

How should Indonesia consider its neglected tropical diseases in the COVID-19 era? Hopes and challenges (Review)

During the coronavirus disease 2019 (COVID-19) pandemic, some countries, including Indonesia, have faced a double burden with regards to disease control. As Indonesia is a tropical country, it serves as a suitable host for disease vectors and multiple microorganisms of causative agents of disease. In total, five of the neglected tropical diseases (NTDs) should be a consideration in Indonesia during the COVID-19 pandemic, including leprosy, yaws, filariasis, soil-transmitted helminths and schistosomiasis. The present review summarises the preparedness of Indonesia in facing NTDs during the COVID-19 pandemic. Strengthening government leadership will be a valuable factor for combating NTDs in Indonesia. For instance, strong leadership can lead to precise management, by increasing the number of health facilities, engaging in active case identification, conducting health campaigns and instituting new regulations to prevent the stigmatization faced by patients. Preventive medicine in the first level of health facilities can be prioritized and presented to the community via health campaigns, health advocacy and improvement in follow-up after active case surveillance. Government-supported integrated management is also a key component in eliminating NTD. Moreover, healthy lifestyle campaigns that include social distancing, wearing a mask and regularly washing hands should be promoted continuously to reduce the transmission of COVID-19, which is potentially associated with a poor outcome in individuals with NTDs. This review concluded that the Indonesian government should strengthen their efforts toward NTD control using alternative methods, such as involving key citizens in the collaboration of the detection of new cases and introducing mobile health as a means of detecting health problems or following up on patient progress. To reduce the transmission of COVID-19, testing, tracing and treatment must be improved, so that the gap between suspected cases and confirmed cases of COVID-19 can be closed. If the transmission of COVID-19 can be decreased, case detection and efforts toward NTD control can be conducted effectively.

Exploratory analysis of the effect of helminth infection on the immunogenicity and efficacy of the asexual blood-stage malaria vaccine candidate GMZ2

Background

Helminths can modulate the host immune response to Plasmodium falciparum and can therefore affect the risk of clinical malaria. We assessed here the effect of helminth infections on both the immunogenicity and efficacy of the GMZ2 malaria vaccine candidate, a recombinant protein consisting of conserved domains of GLURP and MSP3, two asexual blood-stage antigens of P. falciparum. Controlled human malaria infection (CHMI) was used to assess the efficacy of the vaccine.

Methodology

In a randomized, double-blind Phase I clinical trial, fifty, healthy, lifelong malaria-exposed adult volunteers received three doses of GMZ2 adjuvanted with either Cationic Adjuvant Formulation (CAF) 01 or Alhydrogel, or a control vaccine (Rabies) on days (D) 0, D28 and D56, followed by direct venous inoculation (DVI) of 3,200 P. falciparum sporozoites (PfSPZ Challenge) approximately 13 weeks after last vaccination to assess vaccine efficacy. Participants were followed-up on a daily basis with clinical examinations and thick blood smears to monitor P. falciparum parasitemia for 35 days. Malaria was defined as the presence of P. falciparum parasites in the blood associated with at least one symptom that can be associated to malaria over 35 days following DVI of PfSPZ Challenge. Soil-transmitted helminth (STH) infection was assessed by microscopy and by polymerase chain reaction (PCR) on stool, and Schistosoma infection was assessed by microscopy on urine. Participants were considered as infected if positive for any helminth either by PCR and/or microscopy at D0 and/or at D84 (Helm+) and were classified as mono-infection or co-infection. Total vaccine-specific IgG concentrations assessed on D84 were analysed as immunogenicity outcome.

Main findings

The helminth in mono-infection, particularly Schistosoma haematobium and STH were significantly associated with earlier malaria episodes following CHMI, while no association was found in case of coinfection. In further analyses, the anti-GMZ2 IgG concentration on D84 was significantly higher in the S. haematobium-infected and significantly lower in the Strongyloides stercoralis-infected groups, compared to helminth-negative volunteers. Interesting, in the absence of helminth infection, a high anti-GMZ2 IgG concentration on D84 was significantly associated with protection against malaria.

Conclusions

Our results suggest that helminth infection may reduce naturally acquired and vaccine-induced protection against malaria. Vaccine-specific antibody concentrations on D84 may be associated with protection in participants with no helminth infection. These results suggest that helminth infection affect malaria vaccine immunogenicity and efficacy in helminth endemic countries.

Helminths, mainly because of their immune regulatory effects, are able to impact the response induced by vaccines. In the context of clinical trial designs that measure accrual of natural infections during follow up or outcome of controlled human malaria infection (CHMI), their effect on vaccine efficacy can be measured. Indeed, most of such clinical trials on malaria vaccine candidates conducted in Africa, especially where the prevalence of helminths is high, have shown a certain limit in their efficacy and immunogenicity, as compared to results observed in European and U.S volunteers. The present analysis assessed the effect of helminths on GMZ2, a malaria vaccine candidate. We found a high level of anti-GMZ2 antibodies among volunteers not infected with helminths and protected against CHMI, indicating efficacy of the candidate vaccine in this population. We found a species-dependent effect of helminths on the level of post-immunization GMZ2-specific IgG concentration, and an association of helminths with an early onset of malaria in CHMI. Our findings reveal that helminths are associated with immunogenicity and may decrease the protective effect of antibodies induced by vaccination. Helminth infection status shall be determined when measuring the immunogenicity and efficacy of malaria vaccine candidates in helminth endemic countries.

Prevalence of Soil-transmitted Helminths Infection in Students of Klungkung, Bali, after Mass Treatment with AlbendazolePrevalence of Soil-transmitted Helminths Infection in Students of Klungkung, Bali, after Mass Treatment with Albendazole

The success of the anti-helminth mass treatment use Albendazole makes detection of soil transmitted helminth infections even more difficult to do microscopically. It is hoped that the molecular method was able to help increase the detectability of Soil Transmitted Helminth infection. The research aimed is to evaluate effectiveness of Albendazole administration in Bali, to identify the presence of β-tubulin gene as molecular diagnosis of STHs infection among children who treated by Albendazole. This study is a cross-sectional study that recruits elementary school children aged 6-12 years as subjects. Stool examination was carried out using the Kato-Katz technique, then followed by a molecular method using the B-tubulin gene as the target gene. The results showed that only 1 sample out of 140 examined using Kato-Katz was positive for Trichuris trichiura. 30 samples were then extracted from the faeces and performed Polymerase Chain Reaction. A total of 4 positive samples detected the B-tubulin Ascaris lumbricoides gene and 1 positive sample of the B-tubulin Trichuris trichiura gene. In conclusion, albendazole is still effective to treat STH infection, the molecular method has a higher detectability than the microscopic method.

Haematological changes in Schistosoma haematobium infections in school children in Gabon

Background

Schistosomiasis is a parasitic disease affecting the blood cell. As a chronic disease, schistosomiasis particularly impacts on the human host’s haematological profile. We assessed here the impact of urogenital schistosomiasis on the full blood counts (FBC) as proxy diagnostic tool for schistosomiasis.

Methods

A cross-sectional study was conducted among school children living in Lambaréné, Gabon. Schistosomiasis status was determined using urine filtration technique. EDTA blood samples were analysed using a Pentra ABX 60^® analyzer.

Results

Compared to their infection-free counterparts, school children infected with Schistosoma haematobium displayed an altered FBC profile, with changes in all three blood cell lines. Adjusted for praziquantel intake, soil-transmitted helminthic infections and Plasmodium falciparum infection status, schistosomiasis was independently associated with a decreasing trend of mean haemoglobin (β = − 0.20 g/dL, p-value = 0.08) and hematocrit (β = − 0.61%, p-value = 0.06) levels, a lower mean MCV (β = − 1.50µm³, p-value = 0.02) and MCH (β = − 0.54 pg, p-value = 0.04), and higher platelet (β = 28.2 10³/mm³, p-value = 0.002) and leukocyte (β = 1.13 10³/mm³, p-value = 0.0003) counts, respectively.

Conclusions

Schistosomiasis is associated with a characteristic FBC profile of schoolchildren living in Lambaréné, indicating the necessity to consider schistosomiasis as a single cause of disease, or a co-morbidity, when interpreting FBC in endemic areas.

Prevalence, risk factors, challenges, and the currently available diagnostic tools for the determination of helminths infections in human

Soil transmitted helminthes (STH) are among the major public health issues in tropical and sub-tropical countries infecting more than 2 billion humans worldwide. STH causes considerable morbidity in children, affecting their cognitive development and physical growth. Endemic areas with poor sanitation and limited access to good quality water supply have the highest burden of STH infection. Various approaches to reduce and control the worm infections include the intermittent deworming of children with anti-helminthic drugs. Individual patient management and population based studies can only be successful upon using the diagnostic techniques with high accuracy. The lack of reliable tools for the provision of correct diagnostic results about the status and intensity of infection is a major challenge, as these factors varies considerably in areas of low infection intensities. The techniques currently available for the diagnosis of parasitic infections show limited specificity and sensitivity and as such several techniques in combination are normally used in diagnosing the variety of parasite species infection. This review article was planned to study the prevalence, risk factors, and the available diagnostic techniques for soil and water transmitted helminthes infections in humans. This article also discussed the challenges in diagnosis, treatment, and management of worm infections particularly helminthes. The articles available online on important portals like google scholar, PubMed, Digital Libraries, PakMediNet, Science direct, and the Directory of Open Access Journals (DOAJ) were searched for inclusion of the data in this review study. Duplicate studies and irrelevant reports describing the general aspects of parasite infections were excluded. This review study provides a comprehensive report on the prevalence, accurate diagnostic, and chemotherapeutic protocols to reduce the burden of worms infections. WHO suggests the chemotherapy for worm infections as feasible and cost effective strategy in schools due to the lack of proper policy for the prevention of intestinal worms.

Impact of Helminth Infections during Pregnancy on Vaccine Immunogenicity in Gabonese Infants

Helminth infections are common in sub-Saharan Africa. Besides direct clinical effects, a bias towards a T helper type 2 (Th2) cell immune response is observed. The consequences of parasite infection during pregnancy for the mother and particularly for the fetus and the newborn can be severe and may include impaired immune response during acute infection and vaccination. Here, we present data of immune responses to vaccines given within the expanded program on immunization (EPI) of infants born to helminth infected or non-infected mothers. The study was conducted in Lambaréné and surroundings, Gabon. Maternal helminth infection was diagnosed microscopically using the Kato-Katz method for soil-transmitted helminths (STH), urine filtration for Schistosoma haematobium infections and the saponin-based method for filarial infections. Plasma antibody levels to different vaccine antigens were measured in mothers and their offspring by enzyme-linked immunosorbent assay (ELISA) at different timepoints. We found 42.3% of the mothers to be infected with at least one helminth species. Significantly lower anti-tetanus toxoid immunoglobulin (Ig) G was detected in the cord blood of infants born to helminth infected mothers. Following vaccination, immune responses of the infants to EPI vaccines were similar between the two groups at nine and 12 months. Even though infection with helminths is still common in pregnant women in Gabon, in our setting, there was no evidence seen for a substantial effect on infants’ immune responses to vaccines given as part of the EPI.