Ultrasound-Based Prevalence of Cystic Echinococcosis in the Samarkand Region of Uzbekistan: Results from a Field Survey

Cystic echinococcosis (CE) is a zoonosis caused by Echinococcus granulosus. Uzbekistan is endemic for CE, but estimates of disease burden are lacking. We present findings from a cross-sectional, ultrasound-based survey evaluating the prevalence of human CE in the Samarkand region, Uzbekistan. The survey was conducted between September and October 2019 in the Payariq district, Samarkand. Study villages were selected based on sheep breeding and reported human CE. Residents aged 5-90 years were invited to receive a free abdominal ultrasound examination. The WHO Informal Working Group on Echinococcosis classification was used for cyst staging. Information regarding CE diagnosis and treatment was collected. Of 2,057 screened subjects, 498 (24.2%) were male. Twelve (0.58%) had detectable abdominal CE cysts. In total, five active/transitional (N = 1 CE1, N = 1 CE2, N = 3 CE3b) and 10 inactive cysts (N = 8 CE4, N = 2 CE5) were identified. Two participants had cystic lesions with no pathognomonic features of CE and were given a 1-month course of albendazole for diagnostic purposes. Twenty-three additional individuals reported previous surgery for CE in the liver (65.2%), lungs (21.6%), spleen (4.4%), liver and lungs (4.4%), and brain (4.4%). Our findings confirm the presence of CE in the Samarkand region, Uzbekistan. Additional studies are needed to assess the burden of human CE in the country. All patients with a history of CE reported surgery, even though most cysts found during the current study were inactive. Therefore, it appears there is a lack of awareness by the local medical community of the currently accepted stage-specific management of CE.

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.

Bacterial and Fungal Occurrence in Hydatid Cysts from Livestock in Central Iran

Echinococcus granulosus sensu lato causes Cystic echinococcosis. This study investigated the bacterial and fungal species in the liver and lung hydatid cysts obtained from sheep, goats, cattle, and camels slaughtered in Yazd abattoir, Central Iran. In this study, 84 hydatid cysts were obtained from 20 sheep, 13 goats, 25 cattle, and 26 camels. The fertility and viability rates were assessed using light microscopy and eosin staining, respectively. The aspirated hydatid cysts were cultured to detect the presence of any bacteria and fungi. Bacterial isolates were identified by biochemical tests. DNA was also extracted from germinal layers, and then genotyping was carried out targeting the cox 1 gene. The statistical analysis was performed by SPSS version 16.0. This study showed that 22.62% (19/84) of hydatid cysts had bacterial occurrence, and none of the samples had fungal species. Among the fertile cysts, 52.6% had bacterial occurrence, of which 40% were viable. Most bacteria detected in hydatid cysts included Staphylococcus saprophyticus, Escherichia coli, and S. epidermidis. Hydatid cysts with bacterial occurrence were identified as G1-G3, G5, and G6/G7. The bacterial species occurrence in hydatid cysts had no significant relationship with fertility and viability (P > 0.05), without any significant relation with viability (P > 0.05), animal species (P > 0.05), involved organ in animals (P > 0.05), and hydatid cyst genotypes (P > 0.05). It should also be mentioned that this is the first study to assess the relationship between hydatid cyst genotyping and the occurrence of fungal and bacterial species.

Conservative Management of Liver Echinococcal Cysts in Pregnant Women: One Center's Experience in Pavia, Italy

Human cystic echinococcosis (CE) in pregnancy is rarely reported, with approximately one case of CE for every 20,000 to 30,000 pregnant women in endemic areas. Little information on its management is available. We report our experience with a watch-and-wait approach in this group of patients. We retrieved clinical data from pregnant patients with hepatic CE seen at our clinic from 1989 to 2021. All patients had at least one hepatic CE cyst and received no treatment during pregnancy. Ultrasound was used to monitor cyst evolution; outcome and complications of pregnancy and echinococcal infection were evaluated. Twelve patients with 15 pregnancies were included in this study. At the time of pregnancy, nine patients had a single cyst and two patients had multiple hepatic CE cysts. Cysts were in stage CE3a, CE3b, CE4, and CE5, according to the WHO Informal Working Group on Echinococcosis classification. All cysts except one remained stable in stage and size during and after pregnancy. In one patient with a history of multiple treatments with albendazole and with a CE4 cyst at the start of pregnancy, reactivation of the cyst during pregnancy was observed. All pregnancies except three had eutocic delivery. Cesarean sections were performed for reasons unrelated to CE. In our experience, "watch and wait" in pregnant women with uncomplicated transitional and inactive CE of the liver was a safe option in a small cohort of patients. Pooled data from other referral centers, including cases with CE1 and CE2 cysts, are needed to confirm the safety of this approach.

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.

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.

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.

Extracellular non-coding RNA signatures of the metacestode stage of Echinococcus multilocularis

Extracellular RNAs (ex-RNAs) are secreted by cells through different means that may involve association with proteins, lipoproteins or extracellular vesicles (EV). In the context of parasitism, ex-RNAs represent new and exciting communication intermediaries with promising potential as novel biomarkers. In the last years, it was shown that helminth parasites secrete ex-RNAs, however, most work mainly focused on RNA secretion mediated by EV. Ex-RNA study is of special interest in those helminth infections that still lack biomarkers for early and/or follow-up diagnosis, such as echinococcosis, a neglected zoonotic disease caused by cestodes of the genus Echinococcus. In this work, we have characterised the ex-RNA profile secreted by in vitro grown metacestodes of Echinococcus multilocularis, the casuative agent of alveolar echinococcosis.

We have used high throughput RNA-sequencing together with RT-qPCR to characterise the ex-RNA profile secreted towards the extra- and intra-parasite milieus in EV-enriched and EV-depleted fractions. We show that a polarized secretion of small RNAs takes place, with microRNAs mainly secreted to the extra-parasite milieu and rRNA- and tRNA-derived sequences mostly secreted to the intra-parasite milieu. In addition, we show by nanoparticle tracking analyses that viable metacestodes secrete EV mainly into the metacestode inner vesicular fluid (MVF); however, the number of nanoparticles in culture medium and MVF increases > 10-fold when metacestodes show signs of tegument impairment. Interestingly, we confirm the presence of host miRNAs in the intra-parasite milieu, implying their internalization and transport through the tegument towards the MVF. Finally, our assessment of the detection of Echinococcus miRNAs in patient samples by RT-qPCR yielded negative results suggesting the tested miRNAs may not be good biomarkers for this disease.

A comprehensive study of the secretion mechanisms throughout the life cycle of these parasites will help to understand parasite interaction with the host and also, improve current diagnostic tools.

Extracellular RNAs (ex-RNAs) are secreted by cells through association with proteins or extracellular vesicles (EV). In the context of parasitism, ex-RNAs represent novel communication intermediaries with promising potential as biomarkers. In order to better understand the role ex-RNAs may play in the context of the zoonotic disease echinococcosis, we have characterised the RNA profile secreted by the larval stage (metacestode) of Echinococcus multilocularis.

By analysing the products secreted towards the extra- and intra-parasite milieus, we demonstrate that the metacestode displays a polarized secretion of different classes of small non-coding RNAs (sRNAs). In addition, we show that EV secretion occurs mainly towards the inner fluid of the metacestodes. Interestingly, we confirm the presence of host sRNAs in the intra-parasite milieu, implying their internalization and transport through the tegument. Finally, the detection of Echinococcus miRNAs in patient samples yielded negative results suggesting the tested miRNAs may not be good biomarkers for this disease.

In summary, our results provide a detailed description of the ex-RNA landscape of the E. multilocularis metacestode together with information on the distribution of the detected RNA classes in different extracellular compartments. This information is of importance to better understand host-parasite interaction and also, to improve current diagnostic tools.

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.

Incidence Rates of Surgically Managed Cystic Echinococcosis in Kazakhstan, 2007-2016

Cystic echinococcosis (CE) is a zoonotic disease caused by the larval stage of the cestode Echinococcus granulosus. The parasite typically infects dogs and ungulates, with humans acting as dead-end hosts. Information on the epidemiology of CE is lacking from Central Asia, including from Kazakhstan where CE cases are reported centrally. This study presents data from the Kazakhstan Scientific and Practical Center for Sanitary and Epidemiological Evaluation and Monitoring on CE patients treated surgically, with a diagnosis confirmed by pathology. Evaluation of data from 2007 to 2016 indicated that the CE incidence rate decreased during this time period in most areas of Kazakhstan (country-level incidence rate of 5.6 versus 4.7 cases/100,000 population in 2007 and 2016, respectively). Cystic echinococcosis had a higher incidence in southern Kazakhstan, with an incidence rate between 7.0 and 10.5 cases per 100,000 population, whereas northern regions had rates less than 4.0 cases per 100,000 population. Moreover, despite the overall decrease, CE incidence continues to increase in the south. Cystic echinococcosis surveillance is needed, particularly in the south, to help inform policymakers and orient disease control efforts.

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

The diagnosis of cystic echinococcosis (CE) is based on imaging. Serology supports imaging in suspected cases, but no consensus exists on the algorithm to apply when imaging is inconclusive. We performed a retrospective analysis of serology results of patients with untreated hepatic CE and non-CE lesions, seen from 2005 to 2017, to evaluate their accuracy in the differential diagnosis of hepatic CE. Serology results of three seroassays for echinococcosis (ELISA RIDASCREEN, indirect hemagglutination (IHA) Cellognost, and Western blot LDBIO) and clinical characteristics of eligible patients were retrieved. Patients were grouped as having active or inactive CE and liquid or solid non-CE lesions. Sensitivity, specificity, and diagnostic accuracy were compared between scenarios encompassing different test combinations. Eligible patients included 104 patients with CE and 257 with non-CE lesions. Sensitivity and diagnostic accuracy of Western blot (WB) were significantly higher than those of the following: 1) IHA or ELISA alone, 2) IHA+ELISA interpreted as positive if both or either tests positive, and 3) IHA+ELISA confirmed by WB if discordant. The best performances were obtained when WB was applied on discordant or concordant negative IHA+ELISA. Analyses performed within "active CE (n = 52) versus liquid non-CE (n = 245)" and "inactive CE (n = 52) versus solid non-CE (n = 12)" groups showed similar results. Specificity was high for all tests (0.99-1.00) and did not differ between test combination scenarios. WB may be the best test to apply in a one-test approach. Two first-level tests confirmed by WB seem to provide the best diagnostic accuracy. Further studies should be performed in different settings, especially where lower test specificity is likely.

Shortage of Albendazole and Its Consequences for Patients with Cystic Echinococcosis Treated at a Referral Center in Italy

Albendazole (ABZ) is the best drug available to treat cystic echinococcosis (CE), a neglected tropical disease. Cystic echinococcosis patients often receive a continuous course of the drug for 6-12 months. In Italy, ABZ shortages occur almost on a yearly basis. We searched clinical records at the World Health Organization Collaborating Center for the Clinical Management of CE in Pavia, Italy, to estimate the amount of ABZ prescribed to patients between January 2012 and February 2017. The cost of ABZ was estimated at €2.25 per tablet based on the current market price in Italy. Patients to whom ABZ had been prescribed were contacted to determine if they had experienced difficulties in purchasing the drug and to assess how such problems affected their treatment. Of 348 identified CE patients, 127 (36.5%) were treated with ABZ for a total of 20,576 days. This led to an estimated cost of €92,592. Seventy-five patients were available for follow-up, 42 (56%) reported difficulties in obtaining ABZ. Of these patients, four (9.5%) had to search out of their region and 10 (23.8%) had to go out of the country. A total of 27 patients (64%) had to visit more than five pharmacies to locate the drug and 10 patients (23.8%) interrupted treatment because of ABZ nonavailability. Shortages in ABZ distribution can disrupt CE treatment schedules and jeopardize patient health.

Inefficient and abortive classical complement pathway activation by the calcium inositol hexakisphosphate component of the Echinococcus granulosus laminated layer

Persistent extracellular tissue-dwelling pathogens face the challenge of antibody-dependent activation of the classical complement pathway (CCP). A prime example of this situation is the larva of the cestode Echinococcus granulosus sensu lato, causing cystic echinococcosis. This tissue-dwelling, bladder-like larva is bounded by a cellular layer protected by the outermost acellular "laminated layer" (LL), to which host antibodies bind. The LL is made up of a mucin meshwork and interspersed nano-deposits of calcium inositol hexakisphosphate (calcium InsP₆). We previously reported that calcium InsP₆ bound C1q, apparently initiating CCP activation. The present work dissects CCP activation on the LL. Most of the C1 binding activity in the LL corresponded to calcium InsP₆, and this binding was enhanced by partial proteolysis of the mucin meshwork. The remaining C1 binding activity was attributable to host antibodies, which included CCP-activating IgG isotypes. Calcium InsP₆ made only a weak contribution to early CCP activation on the LL, suggesting inefficient C1 complex activation as reported for other polyanions. CCP activation on calcium InsP₆ gave rise to a dominant population of C3b deposited onto calcium InsP₆ itself that appeared to be quickly inactivated. Apparently as a result of inefficient initiation plus C3b inactivation, calcium InsP₆ made no net contribution to C5 activation. We propose that the LL protects the underlying parasite cells from CCP activation through the combined effects of inefficient permeation of C1 through the mucins and C1 retention on calcium InsP₆. This mechanism does not result in C5 activation, which is known to drive parasite-damaging inflammation.

Correction to: Role of microRNAs in host defense against Echinococcus granulosus infection: a preliminary assessment

The published article unfortunately contained mistake. After replacing the image from colored version to black and white, the Fig. 1 caption, unfortunately, was left unupdated.

Evaluation of the recombinant antigens B2t and 2B2t, compared with hydatid fluid, in IgG-ELISA and immunostrips for the diagnosis and follow up of CE patients

Cystic echinococcosis (CE) is one of the most widespread helminthic zoonoses and is caused by the tapeworm Echinococcus granulosus complex. CE diagnosis and monitoring primarily rely on imaging techniques, complemented by serology. This is usually approached by the detection of IgG antibodies against hydatid fluid (HF), but the use of this heterogeneous antigenic mixture results in a variable percentage of false positive and negative results, and has shown to be useless for follow-up due to the long persistence of anti-HF antibodies in cured patients. To improve test performances and standardization, a number of recombinant antigens mainly derived from HF have been described, among them the B2t and 2B2t antigens. The performance of these antigens in the diagnosis and follow up of patients with CE has been so far evaluated on a limited number of samples. Here, we evaluated the performances of tests based on B2t and 2B2t recombinant antigens compared to HF in IgG-ELISA and immunochromatography (IC) for the diagnosis and follow-up of patients with CE in a retrospective cohort study. A total of 721 serum samples were collected: 587 from 253 patients with CE diagnosed by ultrasonography (US), 42 from patients with alveolar echinococcosis and 92 from healthy donors from Salamanca (Spain). The highest overall sensitivity was obtained with HF in ELISA (85.5%), followed by IC containing HF and 2B2t-HF (83.0% and 78.2%, respectively). The lowest sensitivity was obtained with B2t and 2B2t in ELISA (51.8%). The highest specificity was obtained with IC containing 2B2t-HF (100%), and the lowest with HF-ELISA (78.0%). The lowest cross-reactivity with sera from patients with alveolar echinococcosis was detected with the recombinant antigens in ELISA (9.5% - 16.7%) and the highest with the HF-IC (64.3%). The results of B2t and 2B2t-ELISA were influenced by cyst stage, as classified by US according to the WHO-Informal Working Group on Echinococcosis (WHO-IWGE), with low sensitivity for inactive (CE4 and CE5) cysts, and by the drug treatment, with higher sensitivity in patients after drug treatment compared with patients not subjected to drug treatment. The two recombinant antigens in ELISA provided promising results for monitoring patients in follow-up, although their use is limited to patients with positive serology against them at the beginning of the follow-up. Potential biological reasons behind the low sensitivity of the recombinant antigens and possible strategies to enhance the performance of CE serology are discussed.

Cystic echinococcosis (CE) is a helminthic zoonosis caused by Echinococcus granulosus sensu lato. CE diagnosis and monitoring is of paramount importance for the clinical management of patients and primarily rely on imaging techniques, complemented by serology. CE serology is usually based on the detection of antibodies against hydatid fluid (HF), but the use of this heterogeneous antigenic mixture shows several drawbacks, including false positive and negative results, unsatisfied predictive values, and long persistence of detectable antibody levels in cured patients. As an alternative, to improve test performances and standardization, several recombinant antigens have been described, but these have been so far evaluated only on a limited number of samples. Here, two recombinant antigens derived from one of the immunodominant HF antigens (antigen B2) have been tested in enzyme-linked immunosorbent assay (ELISA) and in immunochromatographic strips (IC) against 721 serum samples. Although more specific than the HF, the recombinant antigens in ELISA showed low sensitivity for patients with inactive (CE4 and CE5) cysts and for patients not subjected to drug treatment. This limited their use for follow-up, although promising, to those patients with positive serology at the beginning of the follow-up period. These results will aid in the future development of a serological test with enhanced performance in the diagnosis and follow-up of patients with CE.

Watch and Wait Approach for Inactive Echinococcal Cyst of the Liver: An Update

Human cystic echinococcosis (CE) is a chronic, complex and neglected infection causing severe disease in humans. Hepatic CE cysts are detected and classified mainly by using ultrasound. Expert opinion and published data suggest that uncomplicated inactive liver cysts do not require treatment and only need to be monitored over time ("Watch and Wait"). Here we update our findings as published in 2014 on the "Watch and Wait" approach applied to inactive, asymptomatic cysts of the liver to keep the medical community informed. Clinical data of patients who accessed the World Health Organization Collaborating Center for CE at the University of Pavia-San Matteo Hospital Foundation from January 1991 to October 2017 were analyzed. Inclusion criteria were presence of one or more inactive uncomplicated cysts in the liver (CE4 or CE5), without any history of previous treatment, and an ultrasound-based follow-up of at least 24 months. Fifty-three patients with 66 inactive cysts fulfilled the inclusion criteria. Of these, 11 patients are newly described here; 37 were part of our previously described cohort and the follow-up for 17 of them was further extended; and five were excluded from the previously published analysis as their follow-up was too short, but could be included now. Without the need for treatment and without development of complications, 98.5% of cysts remained inactive over time. In only one patient (1.9% of patients), a reactivation of one cyst (1.5% of cysts) was observed.

Preliminary assessment of the diagnostic performances of a new rapid diagnostic test for the serodiagnosis of human cystic echinococcosis

Rapid diagnostic tests for cystic echinococcosis (CE) are convenient to support ultrasound diagnosis in uncertain cases, especially in resource-limited settings. We found comparable diagnostic performances of the experimental Hyd Rapid Test and the commercial VIRapid HYDATIDOSIS Test, used in our diagnostic laboratory, using samples from well-characterized hepatic CE cases.

Is there echinococcosis in West Africa? A refugee from Niger with a liver cyst

BACKGROUND

Italy is presently facing an increase in immigration from sub-Saharan Africa through the Mediterranean Sea. Case reports of human cystic echinococcosis (CE) have been reported from most sub-Saharan countries. Therefore, an increase in the number of patients with CE coming from these areas in the Italian and European centers for infectious diseases is expected. Unfortunately, the epidemiology of CE in sub-Saharan countries is poorly known, which makes clinical suspicion and diagnosis of such infection difficult in patients coming from these areas.

RESULTS

Here we report a case of hepatic CE in a patient from Niger who arrived in Italy through Libya and visited in a Tropical Medicine referral center in Northern Italy. The parasite was identified molecularly as the G6 "camel" strain of Echinococcus granulosus (E. canadensis). The diagnosis and management of a chronic and clinically complex infection like CE in such situation is difficult. Only 40 cases of CE from Niger have been reported; of these, 75% had extra-hepatic localization. To our knowledge, no strain characterization of human isolates from Niger has been reported so far. The CE cyst of the patient was in CE3a stage, indicating active transmission from the area in which the patient came. However, prevalence data from Niger, and from any other country in West Africa, are almost inexistent.

CONCLUSIONS

We argue that population epidemiology surveys with ultrasound are warranted in Sahelian countries, including Niger. These studies could improve the knowledge of CE epidemiology, provide health authorities with important information for public health interventions targeting this zoonosis, and shed light on any difference between tissue tropism and clinical manifestations caused by the different E. granulosus strains.

Correlation of serum sHLA-G levels with cyst stage in patients with cystic echinococcosis: is it an immune evasion strategy?

Patients with cystic echinococcosis (CE) can harbour cysts for years or even decades, apparently without effect of the immune system on the metacestode. Although several immune evasion mechanisms by echinococcal cysts have been described, it is unclear whether the human leucocyte antigen (HLA) system plays a role in the susceptibility or resistance to CE in humans. HLA-G molecules are known to exert a suppressive action on dendritic cells maturation and on natural killer (NK) cells functions, therefore hampering T-cell responses and NK cytolysis. HLA-G plays an important role in immune tolerance, is involved in foetus and in allotransplant tolerance, and may be involved in tumoral and viral immune evasion. In this study, we assessed the presence and levels of soluble HLA-G (sHLA-G) in patients with CE using a commercial ELISA kit to determine whether host's HLA-G may have a role in the course of human CE.

Costs Associated with Surgically Treated Cases of Abdominal Cystic Echinococcosis: A Single Center's Experience from 2008 to 2014, Pavia, Italy

Cystic echinococcosis (CE) is a globally distributed zoonosis caused by the Echinococcus granulosus sensu lato species complex. Four approaches are available for treatment of abdominal CE: surgery, percutaneous aspiration, chemotherapy with albendazole, and watch-and-wait. Allocation of patients to these different treatment options mainly depends on the stage of the cystic lesion. However, as available guidelines are not widely followed, surgery is often applied even without the correct indication outside referral centers. This is not only a disadvantage for the patient, but also a waste of money. In this study, we evaluated the cost of the surgical approach for abdominal CE by analyzing hospitalization costs for 14 patients admitted to the General Surgery Ward at the "San Matteo" Hospital Foundation in Pavia, Italy, from 2008 through 2014. We found that the total cost of a single hospitalization, including hospital stay, surgical intervention, personnel, drugs, and administrative costs ranged from €5,874 to 23,077 (median €11,033) per patient. Our findings confirm that surgery can be an expensive option. Therefore, surgical intervention should be limited to cyst types that do not benefit from nonsurgical therapies and appropriate case management can best be accomplished by using a cyst stage-specific approach.

Diagnostic Accuracy of Antigen 5-Based ELISAs for Human Cystic Echinococcosis

BACKGROUND

Clinical diagnosis and follow up of cystic echinococcosis (CE) are based on imaging complemented by serology. Several immunodiagnostic tests are commercially available, but the development of new tools is still needed to overcome the lack of standardization of the target antigen, generally consisting of a crude extract of Echinococcus granulosus hydatid cyst fluid. In a previous work, we described a chromatographic method for the preparation of a highly enriched Antigen 5 fraction from hydatid cyst fluid. The high reactivity of patient sera against this preparation prompted us to evaluate further this antigen for the serodiagnosis of CE on a larger cohort of samples.

METHODOLOGY/PRINCIPAL FINDINGS

A total of 327 sera from CE patients with heterogeneous conditions for cyst stage, cyst number, organ localization, drug therapy, and surgical intervention, together with 253 sera from healthy controls, were first analyzed by an ELISA based on the Ag5 preparation in two different experimental setups and, in parallel, by a commercial ELISA routinely used in clinical laboratories for CE serodiagnosis. The Ag5 ELISAs revealed different sensitivity (88.3% vs 95.3%) without significant differences in specificity (94.1% vs 92.5%), for the two setups, respectively. Moreover, possible relationships between the Ag5 ELISA absorbance results and clinical variables were investigated. Chi squared test, bivariate logistic regression and multiple regression analyses highlighted differences in the serology reactivity according to pharmacological treatment, cyst activity, and cyst number.

CONCLUSIONS/SIGNIFICANCE

The two Ag5 ELISAs revealed different performances depending on the setup. The good diagnostic sensitivity and the high reliability of the Ag5 preparation method make this antigen a promising candidate for the serodiagnosis of CE. Further studies will be needed to evaluate the ability of our test to provide useful information on specific CE clinical traits.

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.

Factors Influencing the Serological Response in Hepatic Echinococcus granulosus Infection

Knowledge of variables influencing serology is crucial to evaluate serology results for the diagnosis and clinical management of cystic echinococcosis (CE). We analyzed retrospectively a cohort of patients with hepatic CE followed in our clinic in 2000-2012 to evaluate the influence of several variables on the results of commercial enzyme-linked immunosorbent assay (ELISA) and indirect hemagglutination (IHA) tests. Sera from 171 patients with ≥ 1 hepatic CE cyst, and 90 patients with nonparasitic cysts were analyzed. CE cysts were staged according to the WHO-IWGE classification and grouped by activity. A significant difference in ELISA optical density (OD) values and percentage of positivity was found among CE activity groups and with controls (P < 0.001). The serological response was also influenced by age (P < 0.001) and cyst number (P = 0.003). OD values and cyst size were positively correlated in active cysts (P = 0.001). IHA test showed comparable results. When we analyzed the results of 151 patients followed over time, we found that serology results were significantly influenced by cyst activity, size, number, and treatment ≤ 12 months before serum collection. In conclusion, serological responses as assessed by commercial tests depend on CE cyst activity, size and number, and time from treatment. Clinical studies and clinicians in their practice should take this into account.

The Italian registry of cystic echinococcosis (RIEC): the first prospective registry with a European future

Cystic echinococcosis (CE), a worldwide zoonosis, is highly endemic in southern and eastern Europe. Its actual prevalence is unknown due to the lack of efficient reporting systems designed to take into account the particular features of the disease. Neglect of CE makes diagnosis and clinical management difficult outside referral centres, with inconsistencies in clinical practice and often unnecessary procedures carried out that have associated risks and costs. The Italian registry of CE (RIEC) is a prospective multicentre registry of CE patients seen from January 2012 in Italian health centres; data are voluntarily submitted to the registry. Its aims are to show the prevalence of CE in Italy, bring the importance of this infection to the attention of health authorities, encourage public health policies towards its control, and stimulate biological, epidemiological and clinical research on CE. From January 2012 to February 2014, a total 346 patients were enrolled in 11 centres, outnumbering national reports of many CE-endemic European countries. We discuss preliminary data and challenges of the RIEC, template for the European registry of CE, which has been implemented within the Seventh Framework Programme project HERACLES (Human cystic Echinococcosis ReseArch in CentraL and Eastern Societies) since September 2014.

Liver fibrosis, microbial translocation and immune activation markers in HIV and HCV infections and in HIV/HCV co-infection

BACKGROUND

Liver fibrosis is accelerated in patients co-infected with human immunodeficiency virus and hepatitis C viruses.

AIMS

We investigated the correlation between liver fibrosis, immune activation and microbial translocation.

METHODS

This cross-sectional study included patients with hepatitis C virus (HCV) and human immunodeficiency virus (HIV) mono-infections, HIV/HCV co-infection, and healthy controls (20 subjects/group). Peripheral blood was analysed to determine the levels of Forkhead box 3 (Foxp3) T cells, TGF-β1, CD14 (soluble and surface isoforms), IL-17 and bacterial translocation products. These measurements were correlated to the severity of liver fibrosis, measured with the FIB-4 score and transient elastography.

RESULTS

Foxp3T cell levels were significantly elevated in HIV mono-infected and co-infected groups (p<0.0005). FIB-4 and liver stiffness values inversely correlated with TGF-β1 (p=0.0155 and p=0.0498). Bacterial DNA differed significantly in the HIV-positive compared to the other groups: HIV/HCV co-infected subjects had significantly higher serum levels of bacterial translocation products, CD14, and IL-17 levels (p<0.001).

CONCLUSIONS

Fibrosis stage in HIV/HCV co-infection may be influenced by immune activation due either by viral infections or to bacterial translocation.

Long-term sonographic and serological follow-up of inactive echinococcal cysts of the liver: hints for a "watch-and-wait" approach

Human cystic echinococcosis is a chronic, complex and neglected infection. Its clinical management has evolved over decades without adequate evaluation of efficacy. Recent expert opinion recommends that uncomplicated inactive cysts of the liver should be left untreated and solely monitored over time ("watch-and-wait" approach). However, clinical data supporting this approach are still scant and published mostly as conference proceedings. In this study, we report our experience with long-term sonographic and serological follow-up of inactive cysts of the liver. From March 1994 to October 2013, 38 patients with 47 liver cysts, diagnosed as inactive without any previous treatment history, were followed with ultrasound and serology at 6-12 months intervals for a period of at least 24 months (median follow-up 51.95 months) in our outpatient clinic. In 97.4% of patients, the cysts remained inactive over time and in only one case was reactivation of the cyst detected. No complications occurred during the time of monitoring. During follow-up, serology tests for CE were negative at diagnosis or became negative in 74.1% and were positive or became positive in 25.9% of cases. Patients with inactive cysts on ultrasound but positive serological tests were also investigated by CT scan (chest and abdomen) to rule out extra-hepatic cyst localization. This study confirms the importance of a stage-specific approach to the management of cystic echinococcosis and supports the use of a monitoring-only approach to inactive, uncomplicated cysts of the liver. It also confirms that serology plays only an ancillary role in the clinical management of these patients, compared to ultrasound and other imaging techniques. The implications of these findings for clinical management and natural history of cystic echinococcosis are discussed.

Molecular and serological evidence for the circulation of the tick symbiont Midichloria (Rickettsiales: Midichloriaceae) in different mammalian species

Background

The Midichloriaceae is a novel family of the order Rickettsiales, that encompasses intracellular bacteria associated with hard ticks (Ixodidae) and other arthropods. The most intensively investigated member of this family is Midichloria mitochondrii, a symbiotic bacterium of the sheep tick Ixodes ricinus, characterized by the capacity of multiplying inside the mitochondria. A recent study suggested that these bacteria might be inoculated into the human host during the tick bite. The purpose of this study was to determine the potential infectivity of Midichloria bacteria for non-human animals exposed to the risk of tick bite.

Methods

Blood from horses, cattle, sheep and dogs exposed to the risk of tick bite was included in this study. DNAs were extracted, and amplified using 16S ribosomal RNA primers conserved in the Midichloria genus. Furthermore, sera from dogs exposed to the risk of tick bite were analyzed in order to evaluate the presence of antibodies against the recombinant flagellar protein (rFliD) from M. mitochondrii using an ELISA test.

Results

Here we present two lines of evidence that support the possibility that bacteria from the genus Midichloria are inoculated into vertebrate hosts during a tick bite: (i) a direct evidence, i.e. the detection of circulating DNA from bacteria related with M. mitochondrii, in the blood of vertebrates exposed to tick parasitism; (ii) a further indirect evidence, i.e. the presence of antibodies against an antigen from M. mitochondrii in dogs exposed to the risk of tick bite. It is interesting to note that variability was detected in the Midichloria gene sequences recovered from positive animals, and that some of these sequences were identical to those generated from tick-associated Midichloria.

Conclusions

Based on the results, and on the overall information so far published on the genus Midichloria, we suggest that these bacteria are likely to represent a novel group of vector-borne agents, with the potential of infecting mammalian hosts. Whether inoculation of Midichloria bacteria could cause a true infection and pathological alteration in mammalian hosts is still to be determined. Surely, results emphasize the relevance of Midichloria bacteria in investigations on tick immunology and tick-bite markers.

Immunoblotting with human native antigen shows stage-related sensitivity in the serodiagnosis of hepatic cystic echinococcosis

The diagnosis of hepatic cystic echinococcosis is based on ultrasonography and confirmed by serology. However, no biological marker of cyst viability is currently available implying years-long patient follow-up, which is not always feasible in endemic areas. We characterized the performance of an immunoblotting test based on human hydatid cyst fluid with particular regard to its ability to distinguish between cyst stages. Sera from patients with cysts in different stages showed distinctive band pattern recognition. Most importantly, the test discriminated in 80% of cases CE3a from CE3b transitional cysts, known to have different viability profiles. Interestingly, we observed a rapid change in band pattern recognition of sera from one patient at time points when his cyst passed from active to transitional to inactive stages. Further identification of different antigens expressed by different cyst stages will support the development of diagnostic tools that could early define cyst viability, to guide clinical decision making, and shorten patient follow-up.

Humans parasitized by the hard tick Ixodes ricinus are seropositive to Midichloria mitochondrii: is Midichloria a novel pathogen, or just a marker of tick bite?

Midichloria mitochondrii is an intracellular bacterium found in the hard tick Ixodes ricinus. In this arthropod, M. mitochondrii is observed in the oocytes and in other cells of the ovary, where the symbiont is present in the cell cytoplasm and inside the mitochondria. No studies have so far investigated whether M. mitochondrii is present in the salivary glands of the tick and whether it is transmitted to vertebrates during the tick blood meal. To address the above issues, we developed a recombinant antigen of M. mitochondrii (to screen human sera) and antibodies against this antigen (for the staining of the symbiont). Using these reagents we show that (i) M. mitochondrii is present in the salivary glands of I. ricinus and that (ii) seropositivity against M. mitochondrii is highly prevalent in humans parasitized by I. ricinus (58%), while it is very low in healthy individuals (1·2%). These results provide evidence that M. mitochondrii is released with the tick saliva and raise the possibility that M. mitochondrii is infectious to vertebrates. Besides this, our study indicates that M. mitochondrii should be regarded as a package of antigens inoculated into the human host during the tick bite. This implies that the immunology of the response toward the saliva of I. ricinus is to be reconsidered on the basis of potential effects of M. mitochondrii and poses the basis for the development of novel markers for investigating the exposure of humans and animals to this tick species.