Echinococcosis: diagnosis and diagnostic interpretation in population studies

Investigation and genetic polymorphism analysis of rodents infected with Echinococcus in Ili Prefecture, Xinjiang Uygur Autonomous Region, China

Introduction

Alveolar echinococcosis (AE) is a life-threatening disease in humans caused by the larval stage of Echinococcus multilocularis. Domestic animals, dogs, foxes, and small mammals constitute the circular chain of AE. To evaluate the infection, distribution, and genetic polymorphism of AE in the Ili Prefecture (Nilka, Xinyuan and Zhaosu), we conducted this survey.

Methods

In June and July 2018, 267 small mammals were captured using water-infusion and mousetrap methods. Combined pathogenic and molecular biological methods were used to observe the histopathology of Echinococcus carried by rodents, amplify the mitochondrial nad1 gene of the pathogen, and investigate the genotype and haplotype diversity of Echinococcus in rodents in Ili Prefecture.

Results

Morphological identification revealed that these captured small mammals belonged to three species, with Microtus gregalis being the dominant species (183/267). Pathological and molecular biological results confirmed that E. multilocularis was the pathogen of echinococcosis in small mammals, with an infection rate of 15.73% (42/267). Among the three areas sampled, the highest infection rate of rodents was 25.45% (14/55) in Nilka County. However, there was no significant difference in the infection rates between regions (χ2 = 5.119, p > 0.05). Of the three captured rodent species, M. gregalis had the highest infection rate of 17.49% (32/183), but there was no significant difference in infection rates between the rodent species (χ2 = 1.364, p > 0.05). Phylogenetic analyses showed that the nad1 gene sequences obtained in this study clustered in the same clade as isolates from China. These isolates contained 21 haplotypes (Hap_1-21); Hap_2 was the most common haplotype (9/42). Furthermore, haplotype diversity (0.925 ± 0.027) and nucleotide diversity (0.01139 ± 0.00119) were higher in the Ili Prefecture than in other regions, indicating that population differentiation was high. Tajima's D and Fu's Fs tests were negative (p > 0.10), indicating that the population had expanded. The low fixation index (Fst) ranged from 0.00000 to 0.16945, indicating that the degree of genetic differentiation was different among different populations.

Discussion

In summary, Ili Prefecture is a high incidence area of AE, and Microtus spp. may play an important role in the transmission of AE in this area. The results of this study provide basic data for further study of the molecular epidemiology, genetic differences, and control of E. multilocularis in the Ili Prefecture, Xinjiang.

The Diagnostic Challenge of Cystic Echinococcosis in Humans: First Assessment of Underreporting Rates in Mongolia

Cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus, is significantly underreported in Mongolia due to geographical remoteness, a lack of early diagnostics, and poor clinical management. This study aimed to provide a more accurate estimate of CE in Mongolia by comparing data from surgical (reported) and diagnosed (unreported) cases and assessing the challenges faced by rural doctors in disease management and surveillance. We collected data on surgical cases hospitalized between 2006 and 2016 and newly diagnosed CE cases in 2016 from eight provinces. Using a quasi-Poisson regression model, we extrapolated the collected data to estimate the number of diagnosed cases for the entire country. Additionally, forty health professionals from all 21 provinces rated local clinical management for CE through a questionnaire. The results reveal that surgical cases (2.2 per year) represent only one-eighth of diagnosed cases (15.9 per year). The laboratory facilities, disease reporting, and cyst classification usage scored below 2. These results highlight the significant underreporting of CE in Mongolia and urge human and animal health experts, along with policymakers, to invest in combating CE, particularly in remote provincial areas. This study also emphasizes the need for standard clinical management involving cyst classification according to the WHO-IWGE and seamless integration of CE reporting and monitoring mechanisms, which can significantly contribute to the national and global burden estimation of CE.

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.

Efficacy and safety of video-assisted thoracoscopic surgery and thoracotomy in the treatment of pulmonary hydatid disease in the Tibetan Plateau: a retrospective study

Background

Although video-assisted thoracoscopic surgery (VATS) plays an increasingly significant part in treating thoracic disease, the role of thoracotomy is not replaced in cystic echinococcosis. The aim of this study was to demonstrate the application of VATS and traditional thoracotomy in the treatment of pulmonary hydatid disease in Shigatse of the Tibet Plateau and to compare the clinical safety and efficacy of these two surgical approaches.

Methods

A total of 53 patients with pulmonary hydatid who received thoracoscopic cystectomy with needle aspiration from January 2015 to December 2020 were enrolled in the study, and 126 patients who received thoracotomy during the same period were matched as the control group. The clinical characteristics, operative time, incidence of perioperative complications, length of stay, and hospitalization cost of the VATS and thoracotomy groups were analyzed to compare the safety and efficacy. Patients were followed up through telephone and outpatient service. In order to balance potential confounding baseline factors, propensity-score matching (PSM) was applied to establish a 1:1 VATS to thoracotomy group ratio.

Results

There were statistically significant differences between the VATS group and the thoracotomy group in operative time, blood loss, drainage volume, and postoperative hospital stay (P<0.05), with the VATS group being superior to the thoracotomy group. There were no significant differences in postoperative complications, adverse imaging outcomes, or recurrence rates between the 2 groups. In terms of complications, there was no significant difference in the incidence of postoperative air leakage, atelectasis, or other common complications between the 2 groups, while the frequency of postoperative fever and incision infection in the thoracotomy group was significantly higher than that in the VATS group (P<0.05). Moreover, the postoperative recurrence rate between the 2 groups showed no significant difference after a 3-year follow-up.

Conclusions

Compared to traditional thoracotomy, VATS had acceptable efficacy and safety and it could further accelerate postoperative recovery and reduce the cost in the treatment of pulmonary hydatid disease in the Tibetan Plateau. Thus, VATS should be promoted more widely to other Tibetan regions.

Findings of a community screening programme for human cystic echinococcosis in a non-endemic area

Cystic Echinococcosis (CE) is a zoonosis caused by infection with the larval stages of the taeniid cestodes of the species complex Echinococcus granulosus sensu lato. It is prevalent among transhumant communities in East Africa, including those residing in northern Kenya. The movement of livestock from these regions of high incidence to areas of low incidence creates an indirect risk of disease spill-over to humans. To assess possible establishment of the CE life cycle outside known endemic regions, we used a portable ultrasound scanner to screen for the presence of human CE in Bungoma County of western Kenya, an area which imports substantial numbers of cattle for slaughter from neighbouring pastoralist regions. Eight sentinel sites were purposively selected based on their proximity to slaughterhouses handling animals introduced from pastoralist regions, and necessary permissions to conduct the study were sought. Regression analyses were conducted to identify risk factors associated with the presence of abdominal and cystic lesions (CL). In total, 1002 participants were screened; of these, 654 (65.3%) were female and the median age was 43. Farming (n = 403; 43.4%) was the most frequent occupation, followed by professional (i.e. on regular salary) (n = 215; 23.1%), and business (n = 207; 22.3%) categories. Sixty-seven participants (6.7%) had abnormal ultrasound findings, of these, 7 (1.1%) had simple liver cysts/CL, as per WHO classification. As such, their outcome was inconclusive and they were not put on treatment but advised to attend follow-up investigations in a referral health facility. Other abnormal findings included splenomegaly (n = 14), ovarian cysts (n = 14), uterine fibroids (n = 10), polycystic kidneys (n = 6), and benign prostatic hyperplasia (n = 6). Age was unconditionally associated with the presence of presumptive CL. These results contribute to CE baseline data while providing insights on the implementation of ultrasound diagnosis in the field, as recommended by the WHO for targeted control of echinococcosis by 2030.

Multiple-bead assay for the differential serodiagnosis of neglected human cestodiases: Neurocysticercosis and cystic echinococcosis

BACKGROUND

Neurocysticercosis (NCC), and cystic echinococcosis (CE) are two neglected diseases caused by cestodes, co-endemic in many areas of the world. Imaging studies and serological tests are used in the diagnosis of both parasitic diseases, but cross-reactions may confound the results of the latter. The novel multiplex bead-based assay with recombinant antigens has been reported to increases the diagnostic accuracy of serological techniques.

METHODOLOGY

We set-up an immunoassay based on the multiplex bead-based platform (MBA), using the rT24H (against Cysticercus cellulosae, causing cysticercosis) and r2B2t (against Echinococcus granulosus sensu lato, causing CE) recombinant antigens, for simultaneous and differential diagnosis of these infections. The antigens were tested on 356 sera from 151 patients with CE, 126 patients with NCC, and 79 individuals negative for both diseases. Specificity was calculated including sera from healthy donors, other neurological diseases and the respective NCC or CE sera counterpart. The diagnostic accuracy of this assay was compared with two commercial ELISA tests, Novalisa and Ridascreen, widely used in the routine diagnosis of cysticercosis and CE, respectively.

MAIN FINDINGS

For the diagnosis of NCC, sensitivity ranged from 57.94-63.49% for the rT24H-MBA, and 40.48-46.03% for Novalisa ELISA depending on exclusion or inclusion of sera having equivocal results on ELISA from the analysis; specificities ranged from 90.87-91.30% and 70.43-76.96%, respectively. AUC values of the ROC curve were 0.783 (rT24H) and 0.619 (Novalisa) (p-value < 0.001). For the diagnosis of CE, the sensitivity of the r2B2t-MBA ranged from 68.87-69.77% and of Ridascreen ELISA from 50.00-57.62%; specificities from 92.47-92.68% and from 74.15-80.98%, respectively. AUC values were 0.717 and 0.760, respectively.

CONCLUSIONS/SIGNIFICANCE

Overall, the recombinant antigens tested with the bead-based technology showed better diagnostic accuracy than the commercial assays, particularly for the diagnosis of NCC. The possibility of testing the same serum sample simultaneously for the presence of antibodies against both antigens is an added value particularly in seroprevalence studies for cysticercosis linked to control programs in endemic areas where these two parasites coexist.

Epidemiological, Morphometric, and Molecular Investigation of Cystic Echinococcosis in Camel and Cattle From Upper Egypt: Current Status and Zoonotic Implications

Cystic echinococcosis has been considered one of the major parasitic zoonoses which is associated with severe economic losses. The present study was undertaken to investigate the occurrence, organ distribution, cyst fertility, and viability of cystic echinococcosis in slaughtered camels and cattle from various abattoirs in Assiut Governorate, Egypt. The work also involved morphological, morphometric, and molecular identification of the parasite. The occurrence of hydatid cysts was investigated in total number of 100 lungs of camels and 574 liver and lungs of cattle admitted to three slaughterhouses at Assiut Governorate, Egypt. Moreover, several individual variable factors, including organ involvement, age, sex, and hydatid cyst characteristics, were studied to identify their possible association with the occurrence of the disease. Genomic DNA was extracted from the hydatid cysts, followed by molecular identification of the parasite through amplification of ribosomal DNA internal transcribed spacer (ITS) regions. Hydatid cysts were found in 6 camels (6%) out of 100 inspected camels, while 5 hydatid cysts (0.87%) were detected in a total number of 574 cattle examined. The parasite was detected exclusively in lungs of camels, while lungs were the main organ infected by the parasite in cattle and one hydatid cyst was found in the liver (0.17%). In camel, 66.7, 16.65, and 16.65%of detected cysts were fertile, sterile, and calcified, respectively, while in cattle, these percentages were 60, 20, and 20%, respectively. None of the studied variable factors were significantly associated with the occurrence of the disease in camels, with the exception that all cysts were found in the lung. Conversely, we found a significant association (P < 0.05) between the age and sex of the slaughtered cattle and the occurrence of hydatid cysts. In this respect, the rate of infection was higher in female cattle and those cattle more than 5 years (P < 0.05). The morphological, morphometric, and molecular studies confirmed the presence of the parasite. Taken together, our results concluded that camels and cattle play a potential role in maintaining the transmission cycle of this zoonotic parasite.

A One-Health evaluation of the burden of cystic echinococcosis and its prevention costs: Case study from a hypo-endemic area in Italy

An integrated model, based on a One Health approach, was implemented to estimate the epidemiological and economic outcomes of cystic echinococcosis (CE) in Veneto region, an hypo-endemic area of Northern Italy, and the costs for its prevention. Data and information needed to populate the model were retrieved from published literature, official statistics, expert opinions, or actively searched through data mining (i.e., Hospital and slaughterhouse data), when fundamental data were not available. Human-health and animal-health costs, both public and private, were considered. The overall impact of CE in the study area was estimated in an yearly cost of about 0.5 million €, due to an average of 19.5 human hospitalized cases and about 200 infected animals among cattle and sheep, per year. The human:animal costs ratio was about 8:1. Most of the infected animals were autochthonous, while the identification of an autochthonous source of the infection for the human cases was extremely difficult, and unlikely in most cases. No specific action resulted to be in place for human surveillance, while veterinary surveillance accounted for a yearly cost of about 22,000 €. Sheepherders were found to pay privately an overall amount of around 2000 € for the preventive treatment of their dogs every year, but the applied protocol proved to be sub-optimal. The source of most of the human cases was likely external to the study area, and their economic impact accounts for a cost that is far exceeding that of surveillance and preventive actions in place in the veterinary sector. Although autochthonous human cases appeared to be very rare, the strengthening of preventive actions and surveillance systems can reduce the risk of their increment.

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The study integrated epidemiology and economic aspects in a One Health perspective.

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The research estimates in detail the overall impact of CE in a hypo-endemic region in Italy.

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The study provided data for evidence-based actions to control CE in the study area.

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The investigated case study represents a reproducible model for zoonotic diseases evaluation.

Echinococcoses in Iran, Turkey, and Pakistan: Old Diseases in the New Millennium

Echinococcosis is considered a cosmopolitan zoonosis caused by different species of small taeniid tapeworms of the genus Echinococcus and is regarded as a neglected zoonosis. Cystic and alveolar echinococcoses are endemic diseases of Tibetan, Pamir, and Iranian plateaus. All of the countries within the Iranian plateau are affected by echinococcosis. Pakistan, Turkey, and Iran are the three most populous countries of the region, in which echinococcosis is highly endemic. The three neighboring countries share strong cultural and socioeconomic ties. The present study aimed to provide a broad review of the status of cystic and alveolar echinococcosis, summarizing the current knowledge about geographical distribution, molecular epidemiology, and transmission dynamics of Echinococcus granulosus sensu lato and Echinococcus multilocularis in this region. Additionally, we aimed to understand disease burden and risk factors as basic requirements for establishing a surveillance system and planning prevention and control programs. A considerable body of information is available on different aspects of echinococcosis in this region; however, several information and research gaps need to be filled before planning control programs. None of the countries in the region have an elaborate echinococcosis control program. Effective control programs require multi/intersectoral coordination within a One Health approach with a long-term political and administrative commitment and enhanced international collaboration among the three countries.

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.

Cystic Echinococcosis in Children: High Frequency of Multiple Organs Involved in the North of Iran

INTRODUCTION

Echinococcosis, as an important zoonotic infection, has a major worldwide distribution. Pediatric echinococcosis has still become health concerning issue in developing countries, particularly, in the Middle East and Iran. The aim of this study was to investigate the human echinococcosis in children in northern Iran.

METHODS

Patients admitted to the pediatric subspecialty hospital of Amir Kala, Babol, Iran, from 2011 to 2016 with a confirmed diagnosis of echinococcosis, were reviewed. Records of the patients, including demographic data, clinical manifestations of the disease, type of cysts, and other related factors, were collected.

RESULTS

Sixteen pediatric patients, twelve (75%) male, and four (25%) female were evaluated. All cases had cystic echinococcosis. The results showed that fever (75%) following vomiting, nausea, and coughing (44%) were the most common clinical manifestations. The most common localizations of cases were determined as liver (n=10, 62.5%) and lung (n=9, 56%). The frequency of the involvement of more than one organ was 31% (5 cases). The co-occurrence of liver and lung was seen in 2 (12.5%) cases, and in one case, the co-occurrence of the liver and spleen was reported. In one case, lung, liver and, the pelvis was involved, while in another case, liver, sub diaphragm and kidney involvement were observed.

CONCLUSION

Cystic echinococcosis should be kept in mind when a cystic lesion is encountered anywhere in the body, particularly, in patients lining in the endemic regions. Since cystic echinococcosis has a considerable economic impact in Iran, the implementation of a control program and the surveillance system are highly recommended to reduce the economic burden of this disease.

Meta-analysis of the prevalence of Echinococcus in dogs in China from 2010 to 2019

BACKGROUND

Echinococcosis (canine Echinococcus disease) is a neglected tropical disease that causes serious public harm. Dogs, as a terminal host of Echinococcus spp., are a key part of the Echinococcus epidemic. Echinococcosis spreads easily in humans and animals in some areas of China and it is therefore necessary to fully understand the prevalence of Echinococcus spp. in dogs.

METHODOLOGY/PRINCIPAL FINDINGS

PubMed, ScienceDirect, Chongqing VIP, China National Knowledge Infrastructure (CNKI), and WanFang databases were searched for relevant articles published in the past 10 years. A final total of 108 studies were included. The overall prevalence of Echinococcus spp. in dogs in China was 7.3%, with the highest point estimate found in sampling year 2015 (8.2%) and publication year 2015 (16.5%). Northwestern China (7.9%) had the highest infection rate in China. Qinghai Province (13.5%) showed the highest prevalence among the 11 provinces we included. We also found that geographical and climatic factors are related to the incidence of canine echinococcosis. We further investigated the source of heterogeneity by analysis of subgroups (sampling district, detection method, dog type, season, parasite species, medication, and study quality level).

CONCLUSIONS/SIGNIFICANCE

Our research indicated that Echinococcus spp. were still prevalent in some areas in China. More localized prevention and control policies should be formulated, including improving drinking water hygiene and strengthening hygiene promotion. We recommend the rational use of anti-Echinococcus drugs. In addition, treatment of livestock offal and feces and improving the welfare of stray dogs may play an important role in reducing canine Echinococcus infections.

Combining derivative Raman with autofluorescence to improve the diagnosis performance of echinococcosis

Echinococcosis is a zoonotic parasitic disease transmitted by animals and distributed all over the world. There is no standardized and widely accepted treatment method, and early and accurate diagnosis is crucial for the prevention and cure of echinococcosis. Here, we explored the feasibility of using derivative Raman in combination with autofluorescence (AF) to improve the diagnosis performance of echinococcosis. The spectra of serum samples from patients with echinococcosis, as well as healthy volunteers, were recorded at 633 nm excitation. The normalized mean Raman spectra showed that there is a decrease in the relative amounts of β carotene and phenylalanine and an increase in the percentage of tryptophan, tyrosine, and glutamic acid contents in the serum of echinococcosis patients as compared to that of healthy subjects. Then, principal components analysis (PCA), combined with linear discriminant analysis (LDA), were adopted to distinguish echinococcosis patients from healthy volunteers. Based on the area under the ROC curve (AUC) value, the derivative Raman + AF spectral data set achieved the optimal results. The AUC value was improved by 0.08 for derivative Raman + AF (AUC = 0.98), compared to Raman alone. The results demonstrated that the fusion of derivative Raman and AF could effectively improve the performance of the diagnostic model, and this technique has great application potential in the clinical screening of echinococcosis.

Immunological detection of human and camel cystic echinococcosis using different antigens of hydatid cyst fluid, protoscoleces, and germinal layers

BACKGROUND AND AIM

Cystic echinococcosis (CE)/hydatidosis is one of the most prevalent neglected zoonotic diseases. It is initially asymptomatic and does not produce any clinical signs until the cyst becomes enlarged, causing localized pressure on internal organs and tissues. Therefore, the detection of Echinococcus granulosus antibodies is highly essential. This study evaluated the antigens of hydatid cyst fluid, protoscoleces, and germinal layers for efficient immunological diagnosis of CE in humans and camels.

MATERIALS AND METHODS

Hydatid cyst fluid (FLc), protoscoleces (Psc), and the germinal layer (GLc) antigens were prepared from camel-lung hydatid cysts. In the same way, hydatid cyst fluid (FLh) and protoscoleces (Psh) antigens from human-liver cyst aspirate were produced. The comparative immunodiagnostic efficacy of the prepared antigens was verified using indirect enzyme-linked immunosorbent assay (ELISA), SDS-PAGE, and immunoblotting.

RESULTS

ELISA proves that FLc and GLc antigens were higher than FLh and Psh antigens. This shows that binding reactivity in naturally infected human sera, camel sera, and Psc is the most potent, exhibiting 100% sensitivity with 78.26% and 76.47% specificity in camel and human sera, respectively. The CE prevalence using diagnostic Psc was 54.79% and 61.32% in tested human and camel sera, respectively. The electrophoretic profiles of all shared antigens showed similarities at 52, 41, and 22 kDa. Immunoblotting demonstrated common immune-reactive bands in all antigen types at 52 and 41 kDa against positive human and camel sera.

CONCLUSION

This immunological study introduces camel hydatid cyst Psc as a potent diagnostic antigen and new immune-reactive fractions of 52 and 41 kDa for diagnosing hydatidosis in humans and camels.

Label-free detection of echinococcosis and liver cirrhosis based on serum Raman spectroscopy combined with multivariate analysis

In this paper, we investigated the feasibility of using serum Raman spectroscopy and multivariate analysis method to discriminate echinococcosis and liver cirrhosis from healthy volunteers. Raman spectra of serum samples from echinococcosis, liver cirrhosis, and healthy volunteers were recorded under 532 nm excitation. The normalized mean Raman spectra revealed specific biomolecular differences associated with the disease, mainly manifested as the contents of β carotene in the serum of patients with echinococcosis and liver cirrhosis were lower than those of healthy people. Furthermore, principal components analysis (PCA), combined with linear discriminant analysis (LDA), was adopted to distinguish patients with echinococcosis, liver cirrhosis, and healthy volunteers. The overall diagnostic accuracy based on the PCA-LDA algorithm was 87.7 %. The diagnostic sensitivities to healthy volunteers, patients with echinococcosis, and liver cirrhosis were 92.5 %, 81.5 %, and 89.1 %, and the specificities were 93.2 %, 96.1 %, and 92.4 %, respectively. This exploratory work demonstrated that serum Raman spectroscopy technology combined with PCA-LDA diagnostic algorithm has great potential for the non-invasive identification of echinococcosis and liver cirrhosis.

Pulmonary Echinococcosis or Lung Hydatidosis: A Narrative Review

Background: Lung hydatidosis is a zoonosis related to infection by the Echinococcus tapeworm species. Lung involvement in this condition is second only to the liver echinococcosis. Diagnosis ordinarily results from an accidental finding in a direct chest radiograph evaluation because of the delayed growth of the cysts. Moreover, a consistent treatment regimen or approach may not be feasible because of the variability of pulmonary echinococcosis. In this review, we expect to sum up the main features of lung hydatidosis with a perspective on medical and surgical treatment. Methods: Cochrane Library and PubMed were the databases used to perform a narrative literature review. Search terms included "pulmonary echinococcosis" and "lung hydatidosis." The MeSH terms were "lung" [All Fields] AND {"echinococcosis" [MeSH Terms] OR ("hydatidosis" [All Fields] OR "pulmonary" [All Fields] AND "echinococcosis" [All Fields] OR "hydatidosis." A search period from September 1980 to May 2020 was chosen to compare studies from different decades, given the changes in pulmonary echinococcosis management. Results: A uniform treatment regimen or approach may not be feasible because of the variability of pulmonary echinococcosis. No clinical trials have analyzed and compared all the diverse treatment approaches. Cyst size, characteristics, position in the lung and clinical presentation, and the availability of medical/surgical expertise and equipment are the mainstays of echinococcosis management. When feasible, surgery is as yet the principal therapeutic choice to eliminate the cysts; anti-parasitic drugs may minimize complications during high-risk surgery or be used as definitive therapy in some instances with contraindications to surgery. Conclusions: Lung hydatidosis management must become less heterogeneous. We support treatment directed to the subject established on the clinical scenario, host factors, and surgical risk. Strict cooperation in this process between infectious disease specialists and surgeons may optimize best practices to help create shared practical guidelines to simplify clinicians' decision-making. Furthermore, we need a consensus for lung hydatidosis treatment and inserting this disease to global surgery agenda will have a positive impact on acquiring high-quality data that enables us to create an evidence-based guideline for this disease.

Different manifestation of Echinococcus granulosus immunogenic antigens in the liver and lungs of intermediate host

Hydatidosis is one of the most important zoonotic diseases with a worldwide distribution and it seems that the survival of Echinococcus granulosus in nature for many years, is due to having different mechanisms to escape from the host immune systems. One of these efficient mechanisms is the production of various antigens and proteins by the larva of the parasite and the main purpose of this study is evaluation of manifestation of various antigens in different parts of intermediate host. The hepatic and pulmonary hydatid cysts were gathered from sheep and the antigens of different parts of the cysts (laminated layer, protoscolices and cyst fluid) were separated and analyzed by SDS-PAGE and then transferred to nitrocellulose paper and finally, Western blot analysis was evaluated the immunogenicity of proteins. The antigens of laminated layer, protoscolices and hydatid cyst fluid, in different tissues of the liver and lungs, manifest various proteins and also these antigens are immunogenically different. Also, it is found more immunogenic proteins in the laminated layer than the other parts of the cysts. The various proteins are generated by Echinococcus granulosus larva depending on the type of tissues attacked by the parasite. Increasing the chance of survival may be the main cause of manifestation various antigens in different parts of cysts and host tissues. These antigenic variations might have made diagnostic serologic test unreliable.

Epidemiological distribution of Echinococcus granulosus s.l. infection in human and domestic animal hosts in European Mediterranean and Balkan countries: A systematic review

Cystic echinococcosis (CE) is a neglected zoonosis caused by infection with the cestode Echinococcus granulosus sensu lato. We carried out a systematic literature review on E. granulosus s.l. human and animal (cattle, sheep, dog) infection in European Mediterranean and Balkan countries in 2000–2019, to provide a picture of its recent epidemiology in this endemic area. MEDLINE, EMBASE, Scopus, Google Scholar and Open Grey databases were searched. Included cases were: i) for humans, data from hospital records and imaging studies; ii) for dogs, data from necropsy and coprological studies; iii) for ruminants, cases based on slaughter inspection. The NUTS (Nomenclature of Territorial Units for Statistics) classification was used to categorize extracted data in epidemiological units, defined as data referred to one NUTS2 (basic region) in one year time. Data were then aggregated to NUTS1 level (major regions), calculating the average incidence value of included epidemiological units. For prevalence studies covering different epidemiological units, the pooled prevalence was estimated. Data were extracted from 79 publications, 25 on human infection (covering 437 epidemiological units), and 54 on animal infection (52 epidemiological units for cattle, 35 for sheep and 25 for dogs). At NUTS1 level, average annual incidence rates of human CE ranged from 0.10–7.74/100,000; pooled prevalence values ranged from 0.003–64.09% in cattle, 0.004–68.73% in sheep, and 0–31.86% in dogs. Southern and insular Italy, central Spain, Romania and Bulgaria reported the highest values. Bovine data showed a more similar pattern to human data compared to sheep and dogs. Limitation of evidence included the paucity of human prevalence studies, data heterogeneity, and the patchy geographical coverage, with lack of data especially for the Balkans. Our results confirm Italy, Spain, and Eastern Europe being the most affected areas, but data are extremely heterogeneous, geographical coverage very patchy, and human prevalence studies extremely scant. Results also highlight the notorious problem of underreporting of E. granulosus s.l. infection in both humans and animals.

Cystic echinococcosis (CE) is a neglected zoonosis caused by infection with the parasite Echinococcus granulosus sensu lato, naturally transmitted between canids and livestock; CE in humans can be a serious condition. In endemic areas, CE is responsible for significant health and economic losses, but its real burden is difficult to estimate. E. granulosus s.l. is especially present in areas where livestock breeding is practiced, including European Mediterranean and Balkan countries. We carried out a systematic literature review on the epidemiology of E. granulosus s.l. human and animal infection in this area in 2000–2019. Data were extracted from 79 publications, and referred to Nomenclature of Territorial Units for Statistics (NUTS) levels per year. Average annual incidence rates of human CE ranged from 0.10–7.74/100,000; pooled prevalences ranged from 0.003–64.09% in cattle, 0.004–68.73% in sheep, and 0–31.86% in dogs. Bovine data showed a more similar pattern to human data compared to sheep and dogs. Our results confirm that Italy, Spain, and Eastern Europe are the most affected areas, but data are extremely heterogeneous, geographical coverage very patchy, and human prevalence studies extremely scant. Results also highlight the well-known problem of underreporting of E. granulosus s.l. infection in both humans and animals.

Source attribution of human echinococcosis: A systematic review and meta-analysis

BACKGROUND

A substantial proportion of echinococcosis transmission to humans via contamination of food has been assumed. However, the relative importance of food as a transmission vehicle has previously been estimated through expert opinion rather than empirical data.

OBJECTIVE

To find and evaluate empirical data that could be used to estimate the source attribution of echinococcosis, in particular the proportion that is transmitted through contaminated food.

METHODS

A systematic review was undertaken to identify reports on the risk factors for human cystic (CE) and alveolar (AE) echinococcosis. Data bases searched included PubMed, Scopus, Web of Knowledge, Cab Direct, Science Direct, Google Scholar, eLIBRARY.RU, CyberLeninka, CNKI and VIP. Search terms included Echinococc*, hydatid, epidemiology, logistic regression, risk factors, odds ratio, relative risk, risk factors. Reports, including grey literature where available, that had suitable data were selected and data were extracted. The main pathways of transmission were hypothesised to be contact with the definitive host, contaminated water, contaminated food and contaminated environment (other than food). For each study the attributable fraction for these potential sources of infection was calculated from the data presented. A meta-analysis was then undertaken to obtain pooled estimates for the relative contribution of these transmission pathways.

RESULTS

Data from 28 cross-sectional studies and 14 case-control studies were extracted. There was strong evidence for transmission by direct contact with dogs for both CE and AE. The estimated attributable fractions were 26.1% (CI 13.8%-39.6%) and 34.4% (CI 20.7% -48.2%) respectively. Transmission through contaminated water was estimated to be responsible for approximately 29.4% (CI 12.1%-51.7%) for CE and 24.8% (CI 10.6% to 42.6%) for AE. Contaminated food may be responsible for approximately 23.4% of CE cases (CI 2.1%-47.3%). Globally, there was insufficient evidence to conclude AE can be transmitted by food, although case control studies from low human incidence areas suggested that possibly 32.5% (CI 10.0%-53.2%) could be transmitted by food. There was also insufficient evidence that direct contact with foxes was a significant source of human disease. There were no suitable studies with a risk of environmental contact reported, but the residual attributable fraction thatwould likely include this pathway was approximately 21.1% for CE and 11.1% for AE.

CONCLUSIONS

The results support the hypothesis that dog contact and drinking contaminated water are major pathways of transmission of both CE and AE. For contaminated food, the results are less consistent, but suggest that it is an important transmission pathway and provide better evidence than expert elicitations as previously used.

Sero-epidemiology of Hydatidosis Among General Population of Jolfa County, Northwestern Iran Using IHA, ELISA and Western Blot (2017-2018)

BACKGROUND

Human hydatidosis is mostly a latent and neglected disease with known endemicity in Iran.

AIMS

Due to the importance of this infection in the country and its latent nature, we aimed to evaluate the serological status of hydatid cyst in northwestern Iran.

OBJECTIVES

Herein, we evaluated the serological status of hydatid cyst in urban and rural inhabitants of Jolfa county, northwestern Iran during 2017-2018.

METHODS

In total, 1296 blood samples were obtained from human individuals and the presence of anti-E. granulosus antibodies was investigated using IHA, ELISA and WB.

RESULTS

Based on results, 25 IHA positive person were detected in the examined population, however ELISA test showed 14 of 25 IHA positive patients as negative. Also, 269 IHA negative fellows were shown as negative by ELISA. WB analysis of sera from 25 IHA positive subjects revealed consistent results with the ELISA test, and the most reactive SHCF Ag was a 37 KDa protein. The age-standardized seroprevalence of hydatidosis among Jolfa's general population was 1.12% with 95%CI: 1.02-1.20. Moreover, there existed a significant association between keeping/- contact with dogs (P = 0.022) as well as vegetable consumption (P < 0.001) with ELISA positive test results.

CONCLUSION

Along with such serological evidence in this region, we highly suggest physical examination and applying imaging techniques for suspected cases in the area for a better understanding of CE.

Identification of potential 'hot spots' of cystic echinococcosis transmission in the province of Río Negro, Argentina

Cystic echinococcosis (CE) is a parasitic zoonosis caused by Echinococcus granulosus. The control program of CE of Rio Negro province, Argentina, involves annual surveillance using ultrasound (US) screening in school children, and five-year cross-sectional surveys to detect livestock farms with parasitized dogs by coproELISA with confirmation tests (Western Blot or PCR). Control program is based on deworming of dogs with praziquantel and the aim is to identify areas at risk of Cystic echinococcosis transmission to humans, using all available data sources. The information was spatially distributed in 13 program areas and, at a smaller geographical scale, in 80 Primary Health Care Centers. CoproELISA surveys involved three randomized sampling periods (2003-05, 2009-10, 2017-18), with 1790 canine fecal samples. The US surveys were conducted in 2003-08, 2009-16 and 2017-18 in 34,515 children. Heat maps were created at the smallest geographic scale with QGIS 3.4.6. For the consecutive sampling periods, prevalence of positive canine fecal samples from livestock farms were 14.7, 12.1 and 7.8%, respectively, and children prevalence was 0.4, 0.2 and 0.1%, respectively. The study has been developed on a scale according to which the temporal-spatial distribution of CE allows to adjust control strategies in those areas of potential transmission of the zoonosis to humans.

Species specificity preliminary evaluation of an IL-4-based test for the differential diagnosis of human echinococcosis

The diagnosis of cystic echinococcosis (CE) is based on imaging, while serology is a complementary test of particular use when imaging is inconclusive. Serology has several limitations. Among them, false‐positive results are often obtained in subjects with alveolar echinococcosis (AE), rendering difficult the differential diagnosis. We set up an immune assay based on IL‐4‐specific production after stimulating whole blood with an antigen B (AgB)‐enriched fraction from E granulosus that associates with CE and CE cysts in active stage. We aimed to evaluate potential cross‐reactivity of this test using samples from patients with AE. Twelve patients with AE were recruited; IL‐4 levels ranged from 0 to 0.07 pg/mL. Based on the previously identified cut‐off of 0.39 pg/mL using samples from patients with CE, none of samples from AE patients scored positive. In contrast, almost 80% of samples from AE patients scored positive in serology tests based on different E granulosus‐derived antigenic preparations. Our preliminary data show that this experimental whole‐blood assay has no cross‐reactivity in our cohort of patients with AE, in turn indicating a high specificity of the assay for CE diagnosis. This result supports further work towards the development of improved diagnostic tests for CE.

Validation of PCR-based protocols for the detection of Echinococcus multilocularis DNA in the final host using the Intestinal Scraping Technique as a reference

Oral uptake of infectious Echinococcus multilocularis eggs shed by canids with their faeces may lead to development of alveolar echinococcosis in humans, which is clinically similar to a malignant infiltrative tumor and may be fatal if left untreated. E. multilocularis is therefore regarded as one of the most important and neglected metazoan parasites in the Northern hemisphere. The diagnosis of this tapeworm in the final host plays a key role in the epidemiology of E. multilocularis.

The diagnostic performance of a magnetic-capture (MC) DNA extraction protocol in combination with a minor groove-binder real time PCR (MC-MGBqPCR) for the detection of E. multilocularis eggs was determined relative to a highly sensitive variant of the Intestinal Scraping Technique (IST) using faecal samples of foxes. In addition, we compared results obtained by MC-MGBqPCR with those of a previously validated protocol (QIAamp Fast DNA Stool Mini Kit (QT) combined with a TaqMan qPCR). Furthermore, a workflow using the NucleoMagVet DNA extraction kit (NM) in combination with MGBqPCR and TaqMan-qPCR was also included in the comparisons.

To estimate the analytical sensitivity, phosphate-buffered saline and fox faecal samples were spiked with different numbers of eggs and tested in defined combinations of DNA extraction and PCR protocols. To assess the diagnostic sensitivity of the different workflows, samples were used that had been collected from the ampulla recti or the rectum of 120 foxes hunted in Brandenburg, Germany. The samples represented five IST categories formed according to the E. multilocularis worm burden of the foxes. For DNA extraction by MC or using two other commercial extraction kits, the supernatants obtained from 3 g of bead-beaten faecal samples were used. The extracted DNAs were then processed in the respective PCR protocols.

The MC-MGBqPCR showed the highest diagnostic sensitivity (93%; 95% Confidence Interval (CI): 86–97%) relative to IST. The QT extraction protocol in combination with TaqMan-qPCR had the second highest sensitivity (89%; 95% CI: 80–94%), followed by NM with MGBqPCR (86%; 95% CI: 77–93%) in comparison to IST. The lowest diagnostic sensitivity was found for the NM combined with the TaqMan-qPCR protocol (72%; 95% CI: 62–82%).

In conclusion, the MC-MGBqPCR seems to represent a suitable alternative to IST. However, applied to 3 g faecal samples, the less costly QT-TaqMan-qPCR workflow yielded a similar diagnostic sensitivity relative to IST. However, differences between these two workflows were not statistically significant.

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PCR based protocols can be used for the detection of E. multilocularis in faeces of final hosts after careful validation

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A DNA capture method seems to represent a suitable alternative to the Intestinal Scraping Technique

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The QT-TaqMan-qPCR workflow yielded also a similar diagnostic sensitivity relative to the Intestinal Scraping Technique

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None of the DNA extraction kits was able to remove faecal PCR inhibitors completely

Lateral flow dipstick antigen assay for human cystic echinococcosis

Cystic echinococcosis (CE) is a neglected zoonotic disease with a worldwide distribution and is a major public health problem in some areas. Diagnosis of CE is mainly based on clinical symptoms, imaging and serological testing, however, improvement in serodiagnosis is still needed. This study was aimed at detecting circulating Echinococcus antigen in CE patients using a lateral flow dipstick (LFD) assay. Three types of hydatid antigens i.e. hydatid cyst fluid (HCF), native antigen B (nAgB) and recombinant antigen B (rAgB) were prepared and polyclonal rabbit antiserum was raised against each antigen. Purified IgG fractions were prepared and a portion was conjugated to gold nanoparticles. After a series of optimizations, a final antigen detection LFD assay was developed using a combination of anti-nAgB-IgG and gold-conjugated anti-HCF-IgG. Evaluation of the assay showed that 27 out of 35 (77%) serum samples from CE patients gave positive results. Meanwhile, the test showed a diagnostic specificity of 82% when tested with sera from 38 healthy individuals and 13 patients with other parasitic diseases. In conclusion, the antigen detection LFD assay seemed to be useful for diagnosis of CE and possibly for post-treatment follow-up, and merit further evaluation studies. We foresee that it may improve serodiagnosis of CE when used in tandem with an antibody detection test.

Demographic aspects of human hydatidosis in Iranian general population based on serology: A systematic review and meta-analysis

AIM

Human cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus cestodes, is a globally distributed chronic disease that is an important socioeconomic and public health problem in humans and livestock in developing countries, including Iran. The aim of this study was to determine the overall seroprevalence of hydatid infection in the general population of Iran.

MATERIALS AND METHODS

This systematic review began by searching electronic databases in English (PubMed, Science Direct, Scopus, and Google Scholar) and Persian (Magiran, Scientific Information Database, Iran Medex, and Iran Doc).

RESULTS

Our search resulted in a total of 40 reports published from 1995 to 2015. Of 49,460 individuals surveyed, 3090 cases of hydatidosis were reported. Community-based studies showed that the seroprevalence of CE in the Iranian general population was 6.0% (95% confidence interval: 5.0-7.0%). The age group with the highest CE seroprevalence was 20-40 years, and the lowest one was in the under 20 year's group. The seroprevalence of hydatidosis in males was significantly higher than that in females. In addition, the intended rate was significantly higher in rural regions than in urban areas.

CONCLUSION

Management program for developing more efficient diagnostic tests should be established. Further, cost-effective preventive approaches, including relevant research, should be considered. Finally, hydatid cyst control programs that are important for interrupting the transmission of human CE should be improved.

Ultrasound and Cystic Echinococcosis

The introduction of imaging techniques in clinical practice 40 years ago changed the clinical management of many diseases, including cystic echinococcosis (CE). For the first time cysts were clearly seen before surgery. Among the available imaging techniques, ultrasound (US) has unique properties that can be used to study and manage cystic echinococcosis. It is harmless, can image almost all organs and systems, can be repeated as often as required, is portable, requires no patient preparation, is relatively inexpensive and guides diagnosis, treatment and follow-up without radiation exposure and harm to the patient. US is the only imaging technique which can be used in field settings to assess CE prevalence because it can be run even on solar power or a small generator in remote field locations. Thanks to US classifications, the concept of stage-specific treatments was introduced and because US is repeatable, the scientific community has gained a clearer understanding of the natural history of the disease. This paper reviews the scope of US in CE, describes its strengths and weaknesses compared to other imaging techniques and its relationship with serodiagnosis and discusses sonographic features that may be helpful in differential diagnosis.

Performance of the commercially available SERION ELISA classic Echinococcus IgG test for the detection of cystic echinococcosis in clinical practice

Diagnosis of cystic echinococcosis (CE) is at present mainly based on imaging techniques. Serology has a complementary role, partly due to the small number of standardized and commercially available assays. Therefore we examined the clinical performance of the SERION ELISA classic Echinococcus IgG test. Using 10 U/ml as a cut-off point, and serum samples from 50 CE patients and 105 healthy controls, the sensitivity and specificity were 98.0% and 96.2%, respectively. If patients with other infectious diseases were used as negative controls, the specificity decreased to 76.9%, which causes poor positive predictive values. However, if results between 10 and 15 U/ml are classified as indecisive, the specificity of positive results (≥15 U/ml) increased to 92.5% without greatly affecting the sensitivity (92.0%). Using this approach in combination with imaging studies, the SERION ELISA classic Echinococcosis IgG test can be a useful aid in the diagnosis of CE.

A Community-Based Study to Estimate the Seroprevalence of Trichinellosis and Echinococcosis in the Roma and Non-Roma Population of Slovakia

Trichinellosis and cystic and alveolar echinococcosis are serious parasitic diseases transmissible between animals and humans. Moreover, alveolar echinococcosis is considered one of the most dangerous of human helminthoses. Roma communities are particularly numerous in Central and Eastern Europe. They are often concentrated in economically undeveloped regions and live in segregated localities with unsatisfactory housing and sanitary conditions. The study aimed to find out the seroprevalence of Trichinella and Echinococcus infections in the Roma population of segregated settlements and to compare it with the seropositivity of the non-Roma population of eastern Slovakia. Out of 823 samples, three sera showed seropositivity to Trichinella in the ELISA (Enzyme-linked immunosorbent assay) test. Subsequent Western blot reaction (WB) confirmed seropositivity in two Roma women. ELISA seropositivity to E. multilocularis was recorded in six persons (0.73%), and five (0.61%) respondents were seropositive to E. granulosus, but WB confirmed the presence of antibodies to Echinococcus spp. in one Roma participant. Positive persons suffered from unspecific clinical symptoms; Trichinella-positive persons reported headache, cough, fatigue, and muscle pain. The Echinococcus-positive participant suffered from headache and back pain. The study showed that the worse living conditions of the Roma community did not significantly influence the occurrence of Trichinella and Echinococcus infections in this minority.

Latent class models for Echinococcus multilocularis diagnosis in foxes in Switzerland in the absence of a gold standard

Background

In Europe the principal definitive host for Echinococcus multilocularis, causing alveolar echinococcosis in humans, is the red fox (Vulpes vulpes). Obtaining reliable estimates of the prevalence of E. multilocularis and relevant risk factors for infection in foxes can be difficult if diagnostic tests with unknown test accuracies are used. Latent-class analysis can be used to obtain estimates of diagnostic test sensitivities and specificities in the absence of a perfect gold standard. Samples from 300 foxes in Switzerland were assessed by four different diagnostic tests including necropsy followed by sedimentation and counting technique (SCT), an egg-PCR, a monoclonal and a polyclonal copro-antigen ELISA. Information on sex, age and presence of other cestode species was assessed as potential covariates in the Bayesian latent class models. Different Bayesian latent-class models were run, considering dichotomized test results and, additionally, continuous readings resulting in empirical ROC curves.

Results

The model without covariates estimated a true parasite prevalence of 59.5% (95% CI: 43.1–66.4%). SCT, assuming a specificity of 100%, performed best among the four tests with a sensitivity of 88.5% (95% CI: 82.7–93.4%). The egg-PCR showed a specificity of 93.4% (95% CI: 87.3–99.1%), although its sensitivity of 54.8% was found moderately low (95% CI: 48.5–61.0%). Relatively higher sensitivity (63.2%, 95% CI: 55.3–70.8%) and specificity (70.0%, 95% CI: 60.1–79.4%) were estimated for the monoclonal ELISA compared to the polyclonal ELISA with a sensitivity and specificity of 56.0% (95% CI: 48.0–63.9%) and 65.9% (95% CI: 55.8–75.6%), respectively. In the Bayesian models, adult foxes were found to be less likely infected than juveniles. Foxes with a concomitant cestode infection had double the odds of an E. multilocularis infection. ROC curves following a Bayesian approach enabled the empirical determination of the best cut-off point. While varying the cut-offs of both ELISAs, sensitivity and specificity of the egg-PCR and SCT remained constant in the Bayesian latent class models.

Conclusions

Adoption of a Bayesian latent class approach helps to overcome the absence of a perfectly accurate diagnostic test and gives a more reliable indication of the test performance and the impact of covariates on the prevalence adjusted for diagnostic uncertainty.

Electronic supplementary material

The online version of this article (10.1186/s13071-017-2562-1) contains supplementary material, which is available to authorized users.

First detection of Echinococcus multilocularis in rodent intermediate hosts in Turkey

Echinococcus multilocularis is the causative agent of alveolar echinococcosis (AE), a potentially fatal zoonotic disease. Large parts of Turkey are considered as endemic for E. multilocularis. The aim of this study was to determine the occurrence of metacestode of E. multilocularis in wild rodents in Erzurum, an endemic region for human AE in Turkey. During the sampling period, a total of 498 rodents were trapped in twenty counties of Erzurum Province. Suspected lesions were observed on the livers of 48 rodents, and then partial fragment of mitochondrial 12S rRNA gene was PCR-amplified. Five liver samples exhibited E. multilocularis infection. The prevalence of E. multilocularis for Microtus spp. was 1·3%. All of the infected rodents had fertile metacestodes. Infected rodents were morphologically and molecularly analysed and were confirmed to be Microtus irani by the mitochondrial cytochrome b gene sequence analysis. This is the first report of the presence of E. multilocularis in rodent intermediate hosts in Turkey. Our findings of infected M. irani with protoscoleces show that this rodent can act as suitable intermediate host for E. multilocularis’ life cycle in Turkey. However, there was a complete lack of data on the infection of carnivores from the country. An extensive survey is recommended to determine the prevalence of E. multilocularis in definitive hosts in this endemic region.

Large-scale evaluation of a rapid diagnostic test for human cystic echinococcosis

Cystic echinococcosis (CE) is a neglected zoonotic disease, diagnosed through clinical findings, imaging techniques, and serology, for which many serological tests are available. Here we report a rapid unit assay, the immunochromatographic VIRapid® HYDATIDOSIS test (Vircell, Granada, Spain), potentially suitable for laboratories in low-prevalence or poorly equipped areas. This test was evaluated with a large retrospective cohort (224 sera), including patients suffering from CE or from other parasitic or liver diseases. The test was also assessed in routine conditions with a prospective cohort (115 sera) in areas where both cystic and alveolar echinococcoses have been diagnosed. Its performance (in terms of sensitivity, specificity, and both positive and negative likelihood ratios) was similar to an ELISA based on a crude antigen. Our study shows that this test performs adequately in the diagnostic process, when used with caution, especially regarding cross-reactivity with other parasitic diseases.

Echinococcus granulosus ss in dog - A report in center-northern Portugal

Routine parasitic control and health care of the dog is lacking in many Portuguese rural communities. Freely roaming and stray dogs are responsible for the maintenance of a permanent parasitic infection pressure, namely of zoonotic importance. Therefore, a good understanding of the epidemiology of Echinococcus granulosus including the transmission to man is of great significance to further the awareness within the rural populations and the local health authorities of this zoonotic parasite. This report aims at a better understanding of the epidemiology of Echinococcus granulosus in the Cantanhede region, located in the Central region of Portugal, through the necropsy of stray dogs. At the Official Veterinary Kennel of this Municipality, 105 stray dogs were studied for the presence of Echinococcus granulosus following the adult cestode recovery with necropsy procedure of the first third part of the small intestine. One dog revealed to be positive (1.05%) and the sampled Echinococcus were genotyped and identified as E. granulosus ss. As this genotype is widely spread and has been reported in different parts of the world, further work is necessary to be conducted in this and other regions of Portugal for a better understanding of E. granulosus epidemiology within the typical small rural farms where pig rearing plays an important economic role.

Serological evidence of human cystic echinococcosis and associated risk factors among general population in Mazandaran Province, northern Iran

The aim of the present study was to determine the seroprevalence of CE among human referring to Health Centers in Mazandaran Province, northern Iran and to identify the risk factors involved in spreading the disease. Between 2013 and 2014, the serum samples were taken randomly from 600 subjects referring to health centers in Mazandaran Province. After obtaining informed consent for each participant, a questionnaire including demographic characteristics and associated risk factors was filled for each individual. Anti-CE antibody was tested by enzyme-linked immunosorbent assay (ELISA), using native antigen B. Our results showed 31.6% (n = 190) seropositivity. There were significant difference between seropositivity and sex and residence. Males were significantly more seropositive than females (24.6% versus 7%, P = 0.0001). Regression analysis showed that the subjects who are living in rural areas were 4.4 times more likely to be at risk to CE than urban areas (OR = 4.4; 95% CI = 2.91, 6.64). Contact with dogs, soil and consumed raw vegetables was appeared as main risk factors for CE among community in Mazandaran and it may increase the probability of infection. The high prevalence of CE among individuals indicated that hydatidosis is still a major health problem among community in the investigated areas.

Association between Echinococcus granulosus infection and cancer risk - a pilot study in Cyprus

BACKGROUND

Infections from microorganisms and parasites have been connected with either increased or decreased cancer risk. The objective of this study was to investigate whether infection by Echinococcus granulosus is associated with cancer risk.

METHODS

We assembled a pilot retrospective cohort of patients who were diagnosed as being infected by E. granulosus in Cyprus between 1930 and 2011. Age/gender-matched non-infected family members and neighbors were selected as references. Medical history was ascertained from each study subject through in-person interview. Cox proportional hazards regression analysis was performed to assess the association of being infected by E. granulosus with cancer risk.

RESULTS

Individuals with prior infection by E. granulosus (n=249) were more likely to have cancer compared to those without infection (n=753), 11.65% vs. 8.37% (p=0.0492). Survival analysis also showed that subjects with prior infection had a higher risk for developing cancer. The hazards ratio (HR) was 1.595, [95% confidence interval (CI) between 1.008 and 2.525]. The risk ratio did not change significantly (HR=1.536; 95% CI: 0.965-2.445) after adjusting for gender, year of birth, smoking status, alcohol consumption, and family history of cancer.

CONCLUSIONS

Our study suggests that infection by E. granulosus may increase cancer risk. If this observation can be confirmed independently, further investigation of the mechanisms underlying the association is warranted.

Musculoskeletal Hydatid Cysts Resembling Tumors: A Report of Five Cases

Although challenges in treatment of musculoskeletal hydatid cysts (HC) lesions have been documented, data regarding the musculoskeletal HC lesions resembling tumor is scarce. This paper presented 5 patients (3 males, 2 females) with a mean age of 41.6 years with tumor-like lesions of HC. Three of them had left ilium and acetabulum involvement, one involved left femur, and one involved left thigh muscle compartments. Pain was the main symptom and was seen in all patients. Clinical examination, radiologic evaluation, and histologic analysis were performed for diagnosis. Patients were treated through different surgical options, including simple debridement, bone cement filling with or without internal fixation, hip arthrodesis, reconstruction using hemipelvic replantation with femoral prosthesis and distal femur endoprosthetic replacement. After surgery, the operation region was washed by 20% hypertonic saline, and debridement was performed carefully without contamination. All patients received albendazole treatment. Cases were followed up 1 to 9 years for the recurrence. Walking difficulty and pain were the main symptoms during the follow-up. One patient was symptom-free. A reoccurrence in the perioperative soft tissue was detected in only one patient and control visits with antihelmintic treatment were recommended. We would like to emphasize that HC should be kept in mind for the differential diagnosis of the cystic or tumoral lesions of the musculoskeletal system, particularly in the endemic regions. Prompt diagnosis is of paramount importance for preventing destruction and complications.

Antibody response to glycan antigens of hydatid cyst fluid, laminated layer and protoscolex of Echinococcus granulosus

Background: Hydatid disease is characterized by long-term growth of hydatid cysts in the human. The glycan antigens have an important role in the immunology of hydatid cyst. In this study immunological reaction of host sera to different glycan antigens of the cyst, has been investigated.

Methods: The antibody responses were tested to glycoprotein and glycolipid of the laminated layer (LL), cyst fluid (CF) and protoscolex (PS) antigens of E. Granulosus using ELISA and western immunoblotting tests. Thin-layer chromatography and ß-elimination were used for glycan purification.

Results: Both hydatid cyst and normal human sera reacted with hydatid cyst fluid, protoscolices, laminated layer, glycoprotein and glycolipid antigens. The most antigen-antibody reaction was related to CF and PS antigens, and LL antigens had the minimal reaction with the sera. Thin layer chromatography (TLC) of the antigens showed presence of many glycan bands in the laminated layer.

Conclusion: The parasite may elaborate different glycan antigens in LL to evade host immune response.

Cystic echinococcosis: Future perspectives of molecular epidemiology

Human cystic echinococcosis (CE) has been considered to be caused predominantly by Echinococcus granulosus sensu stricto (the dog-sheep strain). Molecular approaches on CE, however, have revealed that human cases are also commonly caused by another species, Echinococcus canadensis. All indices for classification and standardization of CE pathology including available images, epidemiology, diagnostics and treatment are currently based largely on a mixture of infections which include at least E. granulosus s.s. and E. canadensis. Involvement of other species of Echinococcus in CE including E. ortleppi or otherwise cryptic diversity demonstrated recently in Africa requires further elucidation. Molecular identification of the causative species in CE cases is essential for better understanding of pathogenesis and disease. This article stresses the importance of molecular species identification of human CE as a foundation for re-evaluation of evidence-based epidemiology.

The Seroprevalence of Human Cystic Echinococcosis in Iran: A Systematic Review and Meta-Analysis Study

Human cystic echinococcosis (HCE), a zoonotic infection of the larval stage of Echinococcus granulosus, has high effect on public health in human population all around the world. Iran is one of the most important endemic areas in the Middle East. This systematic review and meta-analysis was performed to evaluate the seroprevalence of HCE in Iranian population. An electronic search for articles from 1985 until April 2015 was performed using data bases PubMed, Scopus, Google Scholar, Magiran, IranMedex, Iran Doc, and Scientific Information Database (SID) both in English and in Persian. A random-effects meta-analysis was used to combine results from individual studies. The information was analyzed by STATA version 11.1. A total of 33 articles met our eligibility criteria and were included in a meta-analysis. The pooled estimate of the prevalence of HCE based on random-effects model was estimated 6.0% (95% CI: 4.0%, 7.0%). The prevalence of the disease significantly increased with age and prevalence rate in males was significantly lower than females (p < 0.001). The using of CIE or CCIEP method was also significantly greater than the other methods (p < 0.001). There was a publication bias in prevalence of studies. HCE is highly prevalent in Iran. Public education for preventive strategies and finally reducing transmission of the parasite and infection in population is needed.

Investigation of the use of serology and ultrasonography to detect hepatic cystic echinococcosis in Heilongjiang, China, using a Bayesian framework

BACKGROUND

Cystic echinococcosis (CE) is a public health problem in China. However, the prevalence and incidence of CE in Heilongjiang province is still poorly understood. Because there is no perfect gold standard, evaluation of ultrasound (US) and serological methods have been limited. This study evaluated the use of these two diagnostic methods for the diagnosis of CE in suspected cases.

METHODS

A total of 522 suspected hepatic CE patients, as well as their demographic and clinical features were collected and detected by immunoglobulin (IgG)-ELISA and US. The marginal posterior densities of sensitivity and specificity for both tests, and the prevalence of hepatic CE amongst participants, were estimated from the product of the likelihood function of observed and latent data by a Bayesian framework.

RESULTS

Most of the patients were from rural areas. The most common symptom was upper abdominal pain. The antibody-positive proportion determined by IgG-ELISA was 24.33% (127/522), significantly higher than with US examination (17.24%, 90/522). Bayesian analysis indicated that the estimated prevalence of CE amongst suspected cases was 17.70% (95% credible interval: 14.23-21.54%). The sensitivity and specificity of the ELISA test were 92.63% and 90.37%, and that of US were 93.05% and 98.44%, respectively. Among US-confirmed hepatic CE cases, the male to female ratio was 0.46 and the peak age group was 40-49 years.

CONCLUSIONS

The results of the current study demonstrate that CE is present in Heilongjiang province. They also suggest that, whilst ultrasonography appears to be the detection modality of choice, serology may have a use for detection of infection in individuals suspected to be infected. This may have applications for surveillance within the province.

A Study of Cross-Reactivity Between Recombinant EPC1 Antigen of Echinococcus granulosus in Serum from Patients with Confirmed Cystic Echinococcosis Infection and Other Parasitic Infections

A standardized test for the serodiagnosis of cystic echinococcosis (CE) remains an important challenge because of the problems in specificity and sensitivity of the available commercial kits and lack of proper evaluation of antigen. Using appropriate sources of antigenic material is crucial in improvement of the serological methods such as enzyme-linked immunosorbent assay (ELISA). This study was conducted to evaluate the performance of protein named Echinococcus protoscolex calcium binding protein EPC1 for the detection of antibodies in sera from patients with CE. Expressed and purified recombinant protein EPC1 (rEPC1) was used as antigen in ELISA method. Characterization of the rEPC1 antigen was evaluated using the serum of 25 patients with both surgical and imaging confirmed CE and 25 healthy donors as negative controls. Also, a panel of sera including chronic toxoplasmosis (IgG positive), strongyloidosis, fascioliasis, toxocariasis, and kala azar were used and patients with related parasites were confirmed by medical laboratories or clinically by research centers using microscopy or specific ELISA. rEPC1 showed relatively promising performance in total IgG ELISA for the detection of antibodies in sera from the negative controls, and the cut off value 0.4 units of optical density at 490 nm was calculated for ELISA. In this study, sensitivity of 100%, specificity of 93.7, positive predictive value of 92.6%, and negative predictive value of 100% were calculated for rEPC1. On the other hand, commercial ELISA kit based on the native antigen B of Echinococcus granulosus had sensitivity of 96.2% and specificity of 96.8%. No significant difference was found for sensitivity or specificity between the rEPC1 and commercial kit. However, rEPC1 may be a valuable antigen for diagnosis of human CE.

Comparison of the Diagnostic Accuracy of Three Rapid Tests for the Serodiagnosis of Hepatic Cystic Echinococcosis in Humans

BACKGROUND

The diagnosis of cystic echinococcosis (CE) is based primarily on imaging, in particular with ultrasound for abdominal CE, complemented by serology when imaging results are unclear. In rural endemic areas, where expertise in ultrasound may be scant and conventional serology techniques are unavailable due to lack of laboratory equipment, Rapid Diagnostic Tests (RDTs) are appealing.

METHODOLOGY/PRINCIPAL FINDINGS

We evaluated the diagnostic accuracy of 3 commercial RDTs for the diagnosis of hepatic CE. Sera from 59 patients with single hepatic CE cysts in well-defined ultrasound stages (gold standard) and 25 patients with non-parasitic cysts were analyzed by RDTs VIRapid HYDATIDOSIS (Vircell, Spain), Echinococcus DIGFA (Unibiotest, China), ADAMU-CE (ICST, Japan), and by RIDASCREEN Echinococcus IgG ELISA (R-Biopharm, Germany). Sensitivity, specificity and ROC curves were compared with McNemar and t-test. For VIRapid and DIGFA, correlation between semiquantitative results and ELISA OD values were evaluated by Spearman's coefficient. Reproducibility was assessed on 16 randomly selected sera with Cohen's Kappa coefficient. Sensitivity and Specificity of VIRapid (74%, 96%) and ADAMU-CE (57%, 100%) did not differ from ELISA (69%, 96%) while DIGFA (72%, 72%) did (p = 0.045). ADAMU-CE was significantly less sensitive in the diagnosis of active cysts (p = 0.019) while DIGFA was significantly less specific (p = 0.014) compared to ELISA. All tests were poorly sensitive in diagnosing inactive cysts (33.3% ELISA and ADAMU-CE, 42.8% DIGFA, 47.6% VIRapid). The reproducibility of all RDTs was good-very good. Band intensity of VIRapid and DIGFA correlated with ELISA OD values (r = 0.76 and r = 0.79 respectively, p<0.001).

CONCLUSIONS/SIGNIFICANCE

RDTs may be useful in resource-poor settings to complement ultrasound diagnosis of CE in uncertain cases. VIRapid test appears to perform best among the examined kits, but all tests are poorly sensitive in the presence of inactive cysts, which may pose problems with accurate diagnosis.

Echinococcus granulosus: Epidemiology and state-of-the-art of diagnostics in animals

Diagnosis and detection of Echinococcus granulosus (sensu lato) infection in animals is a prerequisite for epidemiological studies and surveillance of echinococcosis in endemic, re-emergent or emergent transmission zones. Advances in diagnostic approaches for definitive hosts and livestock, however, have not progressed equally over the last 20 years. Development of laboratory based diagnostics for canids using coproantigen ELISA and also coproPCR, have had a huge impact on epidemiological studies and more recently on surveillance during hydatid control programmes. In contrast, diagnosis of cystic echinococcosis (CE) in livestock still relies largely on conventional post-mortem inspection, despite a relatively low diagnostic sensitivity especially in early infections, as current serodiagnostics do not provide a sufficiently specific and sensitive practical pre-mortem alternative. As a result, testing of dog faecal samples by coproantigen ELISA, often combined with mass ultrasound screening programmes for human CE, has been the preferred approach for monitoring and surveillance in resource-poor endemic areas and during control schemes. In this article we review the current options and approaches for diagnosis of E. granulosus infection in definitive and animal intermediate hosts (including applications in non-domesticated species) and make conclusions and recommendations for further improvements in diagnosis for use in epidemiological studies and surveillance schemes.