Diagnostic Performances of Commercial ELISA, Indirect Hemagglutination, and Western Blot in Differentiation of Hepatic Echinococcal and Non-Echinococcal Lesions: A Retrospective Analysis of Data from a Single Referral Centre

Ultrasound diagnosis of cystic echinococcosis: updates and implications for clinical management

The diagnosis of cystic echinococcosis (CE) is based on imaging. Detection of a focal lesion with morphological characteristics of Echinococcus granulosus sensu lato metacestode is the starting point for the diagnostic workup. In organs explorable with ultrasound (US), this is the method of choice for both aetiological diagnosis of CE and staging of the CE cyst. Staging in terms of lesion morphology is also needed when serology is added to the diagnostic workflow when imaging alone is inconclusive. Finally, staging guides the clinical management of uncomplicated CE, especially in the liver. This commentary provides an overview of the most up-to-date evidence backing the above-mentioned role of US in the diagnosis and clinical management of CE. Finally, we outline future perspectives for the improvement of CE diagnosis.

Head-to-Head Comparison of Nine Assays for the Detection of Anti-Echinococcus Antibodies: A Retrospective Evaluation

Background

Echinococcosis is a neglected tropical disease that is severely underdiagnosed in resource-limited settings. In developed countries, diagnosing echinococcosis is challenging, and reliable serological assays are urgently needed. In the Central European Alps, EM is more common than EG; however, data on the diagnostic performance of assays for EM cases are scarce. We evaluated the suitability of nine antibody assays for routine diagnostics.

Methods

Nine commercially available serological assays for detecting anti-Echinococcus antibodies were compared head-to-head using samples collected from 50 patients with echinococcosis and 50 age- and sex-matched control subjects. The assays are Anti-Echinococcus ELISA (IgG) (Euroimmun), Echinococcus IgG ELISA (DRG), Echinococcus IgG ELISA (IBL International), Echinococcus Western Blot IgG (LDBIO Diagnostics), EUROLINE WB (Euroimmun), Hydatidosis ELISA IgG (VirCell), Hydatidosis VIRCLIA IgG Monotest (VirCell), Ridascreen Echinococcus IgG (R-Biopharm), and Virapid Hydatidosis (VirCell). The cases were ranked according to the WHO-Informal Working Group on Echinococcosis (WHO-IWGE) criteria as confirmed, probable, or possible.

Results

The performance of the assays varied greatly, with overall sensitivities ranging between 50% and 88% and specificities between 62% and 100%. We observed a trend toward better performance with cases classified as "confirmed" using the WHO-IWGE criteria. Combined analysis with sequential screening and confirmatory testing resulted in a maximum sensitivity of 84% and specificity of 100%. Differentiation between EG and EM infections is clinically relevant but was found to be unreliable.

Conclusions

Echinococcus serological assays are highly variable in terms of sensitivity and specificity. Knowledge of the pre-test probability in the patient cohort is required to choose a suitable assay. A combined approach with screening and confirmatory assays may be the best diagnostic strategy in many situations.

Prevalence of cystic echinococcosis in relatives of patients undergoing surgery for hepatic cystic echinococcosis in an endemic region

BACKGROUND

Cystic echinococcosis (CE) is an endemic disease in southern Chile. The aim of this study was to ascertain the prevalence of CE among relatives of patients who underwent surgical intervention for this disease in Cautín, a province of southern Chile.

METHODOLOGY/PRINCIPAL FINDINGS

Cross-sectional study. Relatives of patients who underwent surgery for hepatic echinococcosis (HE), who lived at the same address, during the period 2000-2020 were studied. A total of 288 relatives of 322 patients who underwent surgery for HE participated in a CE screening. All these relatives were interviewed and underwent abdominal ultrasonography, chest X-ray and immunodiagnostic studies (relatives who had been diagnosed with or had undergone surgery for CE were excluded). Descriptive statistics were applied. Prevalence calculation, odds ratio (OR), and their respective 95% confidence intervals (95% CI) were determined. Abdominal or thoracic CE was verified in 42 relatives of subjects operated on for HE (mean age 41±8 years; 73.8% women; 38.1% of cases had two or more cysts), all of them new and asymptomatic cases. CE was detected in the lungs, liver, peritoneum, and spleen in 16.7%; 71.4%; 7.1%; and 4.8%, respectively. The overall prevalence of EQ during the studied time period was 14,6% (17.9% and 12.3% in relatives of first and second degree respectively (OR:1.56; CI 95%: 0.81; 3.01).

CONCLUSION/SIGNIFICANCE

There is a high prevalence of CE in relatives of patients undergoing surgery by this disease in the province of Cautín, Chile.

'No cyst, no echinococcosis': a scoping review update on the diagnosis of cystic echinococcosis after the issue of the WHO-IWGE Expert Consensus and current perspectives

PURPOSE OF REVIEW

In 2010, the WHO-Informal Working Group on Echinococcosis (IWGE) published an Expert Consensus on the diagnosis and treatment of echinococcal infections. We provide an update on the diagnosis of cystic echinococcosis through a scoping review of the literature published after the release of the WHO-IWGE document.

RECENT FINDINGS

Ultrasound accurately and reliably depicts the pathognomonic signs of cystic echinococcosis (CE) stages compared with other imaging techniques. Among these, T2-wighted MRI is to be preferred to computed tomography, which has poor performance for the etiological diagnosis of CE. A negative serology cannot exclude the diagnosis of CE, while a positive serology, applied after the visualization of a CE-compatible lesion, may confirm a CE diagnosis. Serology alone must not be used to define 'CE' nor as 'screening' tool for infection. Other imaging and laboratory techniques did not show clinically applicable performances.

SUMMARY

In the absence of a focal lesion compatible with a CE cyst, no diagnosis of CE should be attempted. There is urgent need to achieve univocal CE case definitions and consensus diagnostic algorithm, as well as standardization of diagnostic methods and issue of a Target Product Profile of CE diagnostics, as advocated by the WHO in the 2021-2030 roadmap for neglected tropical diseases (NTDs).

Palliative Treatment for the Management of Advanced Pelvic Hydatid Bone Disease

Hydatid bone disease is a zoonotic parasitic infection that is caused primarily by the tapeworm Echinococcus granulosus, and it continues to be a major public health concern in pastoral regions. The reconstruction of limb function after limb salvage surgery remains a challenge for clinicians. The purpose of this study was to determine the clinical efficacy of palliative treatment of the management of advanced pelvic hydatid bone disease. From March 2005 to December 2018, medical records and images of patients with advanced pelvic hydatid bone disease treated with surgery combined with antiparasitic chemotherapy were evaluated retrospectively. The Enneking classification was applied to determine the location of the lesion, and the Musculoskeletal Tumor Society score system was used for outcome evaluation. Fifteen patients who met the criteria were included in this study, with a mean follow-up of 4.40 ± 1.76 years. All patients received treatment with surgery combined with antiparasitic chemotherapy. The mean number of surgical interventions per patient for pelvic cystic echinococcosis was 5.3 (range, 2-9 interventions per patient). Recurrence of pelvic hydatid bone disease occurred in 5 patients and was managed successfully through repeated debridement procedures. Palliative treatment with limb salvage surgery was an effective and practical approach to the management of advanced pelvic hydatid bone disease. Standard antiparasitic chemotherapy, which included albendazole at a dose of 10 mg/kg/day administered in two daily doses for 3 to 6 months, was also considered an essential part of the overall treatment strategy.

Circulating Small RNA Profiling of Patients with Alveolar and Cystic Echinococcosis

Alveolar (AE) and cystic (CE) echinococcosis are two parasitic diseases caused by the tapeworms Echinococcus multilocularis and E. granulosus sensu lato (s. l.), respectively. Currently, AE and CE are mainly diagnosed by means of imaging techniques, serology, and clinical and epidemiological data. However, no viability markers that indicate parasite state during infection are available. Extracellular small RNAs (sRNAs) are short non-coding RNAs that can be secreted by cells through association with extracellular vesicles, proteins, or lipoproteins. Circulating sRNAs can show altered expression in pathological states; hence, they are intensively studied as biomarkers for several diseases. Here, we profiled the sRNA transcriptomes of AE and CE patients to identify novel biomarkers to aid in medical decisions when current diagnostic procedures are inconclusive. For this, endogenous and parasitic sRNAs were analyzed by sRNA sequencing in serum from disease negative, positive, and treated patients and patients harboring a non-parasitic lesion. Consequently, 20 differentially expressed sRNAs associated with AE, CE, and/or non-parasitic lesion were identified. Our results represent an in-depth characterization of the effect E. multilocularis and E. granulosus s. l. exert on the extracellular sRNA landscape in human infections and provide a set of novel candidate biomarkers for both AE and CE detection.

Seropositivity Pattern of Human Cystic Echinococcosis at a Tertiary Care Hospital of India

Cystic echinococcosis (CE), even after several control measures, causes significant morbidity throughout the world. Besides imaging investigation technology, the serological tests are essential for both diagnosis and management of this slowly progressive disease. The present study was a hospital-based retrospective study that examined the seropositivity rate for Echinococcus granulosus sensu lato antibody in patients suspected of CE at our tertiary health care center over 8 years from 2013 to 2020. Records of new visits to hospital/clinics and associated hospital discharge constituted the denominator of calculation. All samples were tested using commercially available indirect immunoglobulin G enzyme-linked immunosorbent assay kit. A total of 925 suspected patients with a clinical diagnosis of CE were screened. The age group that commonly tested positive for CE was 20 to 39 years, and liver was the predominant organ found to be affected. The seropositive rate was 41.2%. On further year-wise analysis, it was observed that the seropositivity rate had significantly declined from 61.4% in 2013 to 33.8% in 2020. This study clearly showed that there is a by 27.6% decline of CE seropositivity rate in 8 years. This declining rate may be attributed to improved socioeconomic status and better implementation of health programs.

Benign liver lesions 2022: Guideline for clinical practice of Associazione Italiana Studio del Fegato (AISF), Società Italiana di Radiologia Medica e Interventistica (SIRM), Società Italiana di Chirurgia (SIC), Società Italiana di Ultrasonologia in Medicina e Biologia (SIUMB), Associazione Italiana di Chirurgia Epatobilio-Pancreatica (AICEP), Società Italiana Trapianti d'Organo (SITO), Società Italiana di Anatomia Patologica e Citologia Diagnostica (SIAPEC-IAP) - Part I - Cystic lesions

Benign liver lesions are increasingly diagnosed in daily clinical practice due to the growing use of imaging techniques for the study of the abdomen in patients who have non-specific symptoms and do not have an increased risk of hepatic malignancy. They include simple or parasitic cysts and solid benign tumors which differ widely in terms of prevalence, clinical relevance, symptoms and natural history and often lead to significant clinical problems relating to diagnosis and clinical management. Following the need to have updated guidelines on the management of benign focal liver lesions, the Scientific Societies mainly involved in their management have promoted the drafting of a new dedicated document. This document was drawn up according to the present Italian rules and methodologies necessary to produce clinical, diagnostic, and therapeutic guidelines based on evidence. Here we present the first part of the guideline, concerning the characterization of focal hepatic lesions detected by ultrasound, and the diagnosis and clinical management of simple and parasitic hepatic cysts, and of polycystic liver disease.

Stretching Training Rehabilitation Has Potential to Alleviate Ankylosing Spondylitis in Mice by Inactivating the Wnt/β-Catenin Pathway

Ankylosing spondylitis (AS) is a chronic inflammatory disease characterized by invasion of the joints of the central axis that involves soft tissues and joints surrounding the spine. Stretching training rehabilitation (STR) has been widely applied for the treatment of AS. The Wnt/β-catenin signalling pathway is closely related to AS. In this study, we aimed to explore the potential molecular mechanisms underlying the protective effect of STR on AS both in vitro and in vivo. Male DBA/1 mice were employed to establish an AS animal model. Hematoxylin-eosin staining showed that STR reversed pathological damages in bone tissues and the total antioxidant capacity of AS mice and increased the antioxidant capacity by upregulating superoxide dismutase and malondialdehyde expression in DBA/1 mice. The MTT, RT-qPCR, and Western blotting results further indicated that STR improved the survival rate of cells by downregulating the expression of target genes in the Wnt/β-catenin pathway and by inhibiting cell inflammation and apoptosis. In conclusion, our findings indicated that STR treatment might be an effective therapeutical strategy for AS.

The current state of the issues of diagnosis and surgical treatment of liver echinococcosis (literature review)

The article presents a review of literature data in order to study current problems in the diagnosis and surgical treatment of liver echinococcosis. At the present stage of technological progress, it is possible to study the genetic, anatomical and pathophysiological aspects of echinococcosis. The article highlights the advantages and disadvantages of surgical operations performed in patients with echinococcal liver damage. Methods and results of surgical treatment in various clinics are considered. The main surgical directions in the treatment of parasitic liver damage have been determined. These are more radical anatomical and extensive liver resections and minimally invasive, including laparoscopic and robotic techniques. Each of the methods used has its own niche of application and its own limitations. An opinion is expressed about the prospects for the development of minimally invasive methods of surgical treatment. The authors note the actual absence of a unified standardized tactics of surgical treatment at the moment. It is noted that the literature contains only fragmentary data on the possibility of combining minimally invasive and classical methods of surgical treatment. Despite the introduction of new methods of treatment, the percentage of complications and mortality are still high. Thus, the lack of uniform diagnostic standards and principles for determining surgical tactics testifies to the urgency of the problem of treating parasitic liver damage and determines the search for new solutions in order to improve the results of surgical treatment of this pathology. 

Trends in the Surgical Incidence of Cystic Echinococcosis in Uzbekistan from 2011 to 2018

Cystic echinococcosis (CE) is a zoonosis with a cosmopolitan distribution caused by Echinococcus granulosus sensu lato tapeworms. Although Uzbekistan and other countries in Central Asia are considered endemic, estimates of disease burden are lacking. We present data regarding surgically managed cases of CE obtained from Uzbekistan's national disease surveillance registry. These data are from medical centers in Uzbekistan authorized to treat the disease and reported to the Uzbek Center for Sanitation and Epidemiology from the period 2011 to 2018. Information included patient age class (children 14 years or younger versus adults 15 years and older), but no data regarding cyst location. Incidence rates were calculated using data from the national population registry, and the Cuzick nonparametric test for trends was used to test for differences in the incidence over time at the country and regional levels. A total of 7,309 CE cases were reported. Of these, 857 (11.73%) involved pediatric patients. The mean incidence rates were 4.4 per 100,000 population in 2011 and 2.3 per 100,000 population in 2018 (P = 0.016). One region (Republic of Karalpakistan) showed a nonstatistically significant increase (P = 0.824). All other regions except three showed a statistically significant decrease. We present data showing a decrease in the overall incidence of surgically treated CE in Uzbekistan from 2011 to 2018. However, the presence of cases involving children suggests ongoing parasite transmission. The absence of clinical information (starting with cyst stage and localization) needs to be addressed to improve the national surveillance system. Field studies are also needed to further explore the epidemiology of CE in the country.

Detection of Anti-Echinococcus granulosus Antibodies in Humans: An Update from Pakistan

Human cystic echinococcosis (CE) is a zoonotic disease caused by the larval stage of Echinococcus granulosus sensu lato that causes economic losses by affecting livestock and also poses a public health threat worldwide. The present study is the first retrospective report on the seroprevalence of anti-E. granulosus antibodies in humans in Pakistan. The study used data from 93 blood analysis reports of patients suspected of having CE from different medical centers in Lahore, Pakistan. Out of 93 sera samples, 20 (21.5%) were seropositive, and higher seropositivity (17.2%) was recorded with the indirect hemagglutination test (IHA) than with enzyme-linked immunosorbent assay (ELISA). The findings indicated that age, gender, and year had no significant relationship with the seropositivity of CE. The current study provides directions towards the management of the disease in the near future in Pakistan.

Ultrasound-based evaluation of the prevalence of abdominal cystic echinococcosis in the Turkestan region of Kazakhstan

BACKGROUND

Human cystic echinococcosis (CE) is a zoonotic disease caused by Echinococcus granulosus sensu lato. CE is known to be endemic in some parts of Central Asia. We present findings from an ultrasound-based survey to estimate the prevalence of CE in the Turkestan oblast of Kazakhstan.

METHODS

In October 2019, six villages were chosen based on records from a national surveillance dataset. Inhabitants aged 5-90 y were invited to undergo a free abdominal ultrasound to screen for CE cysts. All identified cysts were staged according to the WHO-endorsed classification for CE cysts.

RESULTS

A total of 2252 individuals underwent ultrasound screening. Twenty-two (0.98%) individuals had CE, with a combined total of 33 cysts: 25 (75.7%) inactive (14 CE4, 11 CE5) and 8 (24.3%) active/transitional (2 CE1, 1 CE2, 3 CE3a, 2 CE3b). One patient had a postsurgical cavity. Sixty-eight patients (3.0%) reported CE prior to surgical treatment. In 25 (36.8%) previously diagnosed patients, albendazole prophylaxis was not used.

CONCLUSIONS

CE is endemic in the study region, with ongoing transmission. The number of surgically treated CE patients suggests an underestimation of the disease burden by the current surveillance system. Further studies on local CE epidemiology and the implementation of expert treatment recommendations are needed.

Prospective collection of clinical data on cystic echinococcosis: experience with the European Registry of Cystic Echinococcosis in Pavia, Italy

BACKGROUND

Cystic echinococcosis (CE) is a chronic, complex and neglected infection that may cause serious disease in humans. Given its peculiar epidemiologic and clinical features, collection of clinical data is challenging. Notification systems, when available, fail to record important clinical features, available data are mostly retrospectively collected and no prospectively enrolled uniform surveillance systems exist. The European Register of Cystic Echinococcosis database (ERCE) is the first systematic attempt to address these issues.

METHODS

Here, we describe the demographics and clinical characteristics of 436 patients who accessed the CE clinic at the University of Pavia-San Matteo Hospital Foundation, in Pavia, Italy, from March 2012 to February 2020.

RESULTS

Overall, 436 patients, consisting of 204 (46.8%) males and 232 (53.2%) females were enrolled; the mean age at enrollment was 50 (range 4-88) y. Of the 436 patients, 248 (56.9%) were born in Italy while 188 (43.1%) were foreign-born. In total, 638 CE cysts were counted, most of them in the CE4 (230; 36.1%) and CE3b (131; 20.5%) stages.

CONCLUSIONS

This is the largest cohort of CE patients with detailed clinical and demographic data published to date. We strongly encourage colleagues caring for CE patients in the European Union to join the ERCE.

Field Performance of a Rapid Diagnostic Test for the Serodiagnosis of Abdominal Cystic Echinococcosis in the Peruvian Highlands

We evaluated the performance of a commercial rapid diagnostic test (RDT) in a field setting for the diagnosis of abdominal cystic echinococcosis (CE) using sera collected during an ultrasound population screening in a highly endemic region of the Peruvian Andes. Abdominal CE was investigated by ultrasonography. Sera collected from individuals with abdominal CE (cases) and age- and gender-matched volunteers with no abdominal CE (controls) were tested independently in two laboratories (Peru and Italy) using the VIRapid® HYDATIDOSIS RDT and RIDASCREEN® Echinococcus IgG enzyme-linked immunosorbent assay. Performance indexes of single and serially combined tests were calculated and applied to hypothetical screening and clinical scenarios. Test concordance was also evaluated. Prevalence of abdominal CE was 6.00% (33 of 546) by ultrasound. Serum was obtained from 33 cases and 81 controls. The VIRapid test showed similar sensitivity (76% versus 74%) and lower specificity (79% versus 96%) than results obtained in a hospital setting. RDTs showed better performance when excluding subjects reporting surgery for CE and if weak bands were considered negative. Concordance between tests was moderate to very good. In hypothetical screening scenarios, ultrasound alone or confirmed by RDTs provided more reliable prevalence figures than serology alone, which overestimated it by 5 to 20 times. In a simulation of case diagnosis with pre-test probability of CE of 50%, positive and negative post-test probabilities of the VIRapid test were 78% and 22%, respectively. The application of the VIRapid test alone would not be reliable for the assessment of population prevalence of CE, but could help clinical decision making in resource-limited settings.

Serology for the diagnosis of human hepatic cystic echinococcosis and its relation with cyst staging: A systematic review of the literature with meta-analysis

Background

The diagnosis of cystic echinococcosis (CE) is primarily based on imaging, while serology should be applied when imaging is inconclusive. CE cyst stage has been reported among the most important factors influencing the outcome of serodiagnosis. We performed a systematic review and meta-analysis of the relation between cyst stage of hepatic CE and diagnostic sensitivity of serological tests, to evaluate whether their relation is a consistent finding and provide guidance for the interpretation of results of serological tests.

Methodology/Principal findings

MEDLINE, EMBASE, CENTRAL, and Lilacs databases were searched on December 1^st 2019. Original studies published after 2003 (year of publication of the CE cyst classification), reporting sensitivity of serological tests applied to the diagnosis of human hepatic CE, as diagnosed and staged by imaging, were included. The quality of studies was assessed using the Newcastle-Ottawa Scale. Data from 14 studies were included in the meta-analysis. Summary estimates of sensitivities and 95% confidence intervals were obtained using random effects meta-analysis. Overall, test sensitivity was highest in the presence of CE2 and CE3 (CE3a and/or CE3b), and lowest in the presence of CE5 and CE4 cysts. ELISA, ICT and WB showed the highest sensitivities, while IHA performed worst.

Conclusions/Significance

The results of our study confirm the presence of a clear and consistent relation between cyst stage and serological tests results. Limitations of evidence included the heterogeneity of the antigenic preparations used, which prevented to determine whether the relation between cyst stage and sensitivity was influenced by the type of antigenic preparation, the paucity of studies testing the same panel of sera with different assays, and the lack of studies assessing the performance of the same assay in both field and hospital-based settings. Our results indicate the absolute need to consider cyst staging when evaluating serological results of patients with hepatic CE.

Cystic echinococcosis is a neglected zoonosis induced by the development of parasitic cysts in intermediate hosts, including humans, mostly in the liver. The diagnosis of CE is based on imaging. As CE cysts may assume different aspects (stages), the range of differential diagnoses is broad, from harmless simple cysts to neoplasms. Serological assays for the detection of serum antibodies are applied when imaging is inconclusive, but their performance depend on a number of factors, among which cyst stage has been reported as important. If this was a robust finding, it would be absolutely required to interpret serological findings in the light of CE cyst staging. The results of our systematic review and meta-analysis of the relation between cyst stage of hepatic CE and diagnostic sensitivity of serological tests confirmed that such relation is clear and consistent, and indicate the absolute need to consider cyst staging when evaluating serology results of patients with hepatic CE.

Evaluation of Nine Commercial Serological Tests for the Diagnosis of Human Hepatic Cyst Echinococcosis and the Differential Diagnosis with Other Focal Liver Lesions: A Diagnostic Accuracy Study

The differential diagnosis of hepatic cystic echinococcosis (CE) may be challenging. When imaging is insufficient, serology can be applied, but no consensus diagnostic algorithm exists. We evaluated the performances of nine serological tests commercialized in Europe for the diagnosis of “echinococcosis”. We performed a diagnostic accuracy study using a panel of sera from patients with hepatic CE (n = 45 “liquid” content stages, n = 25 “solid” content stages) and non-CE focal liver lesions (n = 54 with “liquid” content, n = 11 with “solid” content). The diagnosis and staging of CE were based on ultrasound (gold standard). Nine commercial seroassays (5 ELISA, 2 WB, 1 Chemiluminescence Immunoassay [CLIA] and 1 Immunochromatographic test [ICT]) were the index tests. Sensitivity (Se) ranged from 43 to 94% and from 31 to 87%, and specificity (Sp) from 68 to 100% and from 94 to 100%, when borderline results were considered positive or negative, respectively. Three seroassays (2 ELISA, 1 WB) were excluded from further analyses due to poor performances. When tests were combined, Sp was 98–100%. The best results were obtained using the WB-LDBIO alone (Se 83%) or as a third test after two non-WB tests (Se 67–86%). A validated WB or two non-WB tests, read with stringent criteria (borderline = negative and considered positive only if concordant positive), possibly confirmed by the WB, appear sensible approaches.

Cystic Echinococcosis in Pakistan: A Review of Reported Cases, Diagnosis, and Management

Cystic echinococcosis (CE) is a zoonotic disease that occurs in humans and ungulates due to infection with the larval stage of the taeniid cestode Echinococcus granulosus sensu lato. It has been estimated that approximately one million people are infected annually, resulting in US$3 billion in human and livestock-associated direct and indirect losses per year. CE is a serious public health concern in many parts of the world, including Pakistan. This review discusses the causative agent as well as the epidemiology, diagnosis, and treatment of CE in Pakistan.

Evaluation of the sensitivity and specificity of GST-tagged recombinant antigens 2B2t, Ag5t and DIPOL in ELISA for the diagnosis and follow up of patients with cystic echinococcosis

Cystic echinococcosis (CE) is a neglected zoonotic disease caused by Echinococcus granulosus sensu lato. Diagnosis and monitoring of CE rely primarily on imaging while serology is used as a confirmatory test. However, imaging is not always conclusive and currently available serological assays have suboptimal sensitivity and specificity, lack standardization, and are not useful for patients´ follow-up. Seroassays for CE are usually based on hydatid fluid (HF), a complex, variable antigenic mixture, and cross-reactivity exists especially with alveolar echinococcosis. Recombinant proteins based on immunogenic antigens most abundant in HF, such as AgB1, AgB2 and Ag5, have been used to overcome these limitations. None of them so far showed potential to replace HF; however, their performance have been largely tested on a limited number of samples, and comparison of different antigens using the same cohort has been rarely performed. The combination of several immunogenic epitopes in a single recombinant protein could enhance test sensitivity. For the diagnosis and follow-up of patients with CE, we compared the performance of the crude HF, previously described recombinant 2B2t antigen, and GST-tagged version of 2B2t, and novel designed recombinants (GST-Ag5t and the GST-DIPOL chimera containing AgB1, AgBB2 and Ag5 epitopes) by IgG-ELISA format. Samples belong to a retrospective cohort of 253 well-characterized patients with CE, previously described for the evaluation of the 2B2t antigen, 92 patients with alveolar echinococcosis, and 82 healthy donors. The reference standard for CE diagnosis was the presence of a CE lesion as diagnosed by ultrasonography. The highest sensitivity was obtained with HF [86.7%, 95% confidence interval (CI): 81.2–91.0], followed by GST-2B2t (70.0%, 95% CI: 63.1–76.2), 2B2t (65.5%, 95% CI: 58.5–72.0), GST-Ag5t (64.5%, 95% CI: 57.5–71.1) and GST-DIPOL (63.1%, 95% CI: 56.0–69.7). The GST-2B2t had the best specificity (95.8%, 95% CI: 88.3–99.1) and the lowest cross-reactivity (38.7%, 95% CI: 27.6–50.6). Good response to treatment also correlated to negative test results in the GST-2B2t ELISA. While none of the tested recombinant antigen appears suitable to replace HF for the diagnosis of CE, GST-2B2t should be further explored as a confirmation test, based on its high specificity and low cross-reactivity, and for the follow-up after treatment in those patients with positive serology for this antigen.

Cystic echinococcosis (CE) is a neglected parasitic zoonosis. Its diagnosis and follow-up require evaluation with imaging. Currently available serological tests are applied to confirm the diagnosis in doubtful cases, although having limitations in diagnostic accuracy, and they are not useful for patients’ follow-up. Seroassays for CE are usually based on hydatid fluid (HF) obtained from infected animals, with consequent problems of heterogeneity and low specificity. The use of semi-purified HF derivatives or recombinant antigens has been attempted to improve these aspects, but with an unacceptable loss in sensitivity. Most newly developed antigens have been tested on a limited number of samples, not always well characterized, and have been rarely compared using the same samples cohort. Here, we tested and compared three recombinant antigens (2B2t, GST-2B2t and GST-Ag5t), and a recombinant chimeric antigen (DIPOL) based on three highly immunogenic components of HF (B1, B2 and Ag5), in an attempt to increase the sensitivity of recombinant antigen-based seroassays for the diagnosis and follow-up of patients with CE. We found that GST-2B2t had higher sensitivity than the other antigenic preparations, but still not as high as HF, and that GST-2B2t and GST-DIPOL had statistically higher specificity than any of the other tested antigens. GST-2B2t also showed potential for the follow-up of patients with CE after drug treatment.

Evidence of Low Prevalence of Cystic Echinococcosis in the Catanzaro Province, Calabria Region, Italy

Cystic echinococcosis (CE) is one of the neglected tropical diseases recognized by the WHO. Echinococcus granulosus sensu lato affects more than 1 million people worldwide and is responsible for high costs in the healthcare system. A clear knowledge of the prevalence of CE and its clinical characteristics could have an important impact on the approach to its diagnosis and to the public health planning of treatment and control interventions. We performed a prevalence study in four municipalities of Catanzaro Province, South Italy. This area is considered to be at high risk of CE because of ovine breeding. We screened by abdominal ultrasound 2,426 volunteers, four of whom had abdominal CE. Given the need for prevention and control programs for CE in endemic areas of Italy, a detailed mapping of prevalence of CE, to complement data obtained through hospital discharge records, appears imperative.