Parasiticidal effect of chemotherapy in alveolar hydatid disease: review of experience with mebendazole and albendazole in Alaskan Eskimos

Chemotherapy for the treatment of alveolar echinococcosis: Where are we?

Alveolar echinococcosis (AE) is a severe liver disease due to infection with the Echinococcus multilocularis larval stage, called the metacestode. Management of AE is based on benzimidazole chemotherapy (albendazole or mebendazole), associated with surgery when possible. Benzimidazoles are the only compounds recommended for the treatment of AE; however, these are parasitostatic, which means that the parasite can resume growth when treatment is interrupted. Also, benzimidazoles can cause liver dysfunction which may prevent their use. Numerous drugs have been reported to have in vitro activity against E. multilocularis, but few had satisfactory in vivo activity, and none were clearly more effective than benzimidazoles. These drugs belong to various therapeutic categories including anti-infective agents (e.g. amphotericin B, mefloquine, pentamidine derivatives), anti-neoplastic compounds (e.g. imatinib, nilotinib, bortezomib), plant-extracted compounds (e.g. thymol, crocin, carvacrol) and others (e.g. metformin, verapamil, thiaclopride). These treatments are generally of limited interest due to their toxicity, their unfavorable pharmacokinetics, or the scarcity of studies involving humans. Apart from benzimidazoles, only amphotericin B, mefloquine and nitazoxanide have been reported to be used for human AE treatment, with unsatisfactory results. Few studies have aimed at developing innovative strategies for AE drug therapy, such as vectorization of drugs using nanoparticles. Altogether, this review emphasizes the urgent need for new therapeutic strategies in AE management, for which there is currently no curative chemotherapy.

Annual assessment of Echinococcus multilocularis surveillance reports submitted in 2024 in the context of commission delegated regulation (EU) 2018/772

This report comprises the 14th assessment of the Echinococcus multilocularis surveillance scientific reports, provided by Finland, Ireland, United Kingdom (Northern Ireland) and Norway on their respective surveillance programmes. Every year since 2012, EFSA presents the assessment to the European Commission in which the sampling strategy, data collection and detection methods used by these countries are evaluated. More specifically, the surveillance programmes of these four countries are evaluated by checking the information submitted by each of them and verifying that the technical requirements are fulfilled as laid down in Commission Delegated Regulation (EU) 2018/772 of 21 November 2017 supplementing Regulation (EU) No 576/2013 of the European Parliament and of the Council with regard to preventive health measures for the control of Echinococcus multilocularis infection in dogs, and repealing Delegated Regulation (EU) No 1152/2011. The information is divided into four different categories for assessment: the type and sensitivity of the detection method, the selection of the target population, the sampling strategy and the methodology. For each category, the main aspects that need to be considered in order to accomplish the technical requirements of the legislation are checked against compliance of several criteria. The countries participating in this surveillance (Finland, Ireland, the United Kingdom (Northern Ireland) and Norway) succeeded in the fulfilment of the technical legal requirements foreseen in Commission Delegated Regulation (EU) 2018/772 concerning these four different categories. None of the four countries recorded positive samples in the 12-month reporting period.

Genetic diversity of Echinococcus multilocularis specimens isolated from Belgian patients with alveolar echinococcosis using EmsB microsatellites analysis

The genetic diversity of Echinococcus multilocularis (E. multilocularis) specimens isolated from patients with alveolar echinococcosis (AE), is a major field of investigation to correlate with sources of infection, clinical manifestations and prognosis of the disease. Molecular markers able to distinguish samples are commonly used worldwide, including the EmsB microsatellite. Here, we report the use of the EmsB microsatellite polymorphism data mining for the retrospective typing of Belgian specimens of E. multilocularis infecting humans. A total of 18 samples from 16 AE patients treated between 2006 and 2021 were analyzed through the EmsB polymorphism. Classification of specimens was performed through a dendrogram construction in order to compare the similarity among Belgian samples, some human referenced specimens on the EWET database (EmsB Website for the Echinococcus Typing) and previously published EmsB profiles from red foxes circulating in/near Belgium. According to a comparison with human European specimens previously genotyped in profiles, the 18 Belgian ones were classified into three EmsB profiles. Four specimens could not be assigned to an already known profile but some are near to EWET referenced samples. This study also highlights that some specimens share the same EmsB profile with profiles characterized in red foxes from north Belgium, the Netherlands, Luxembourg and French department near to the Belgian border. Furthermore, Belgian specimens present a genetic diversity and include one profile that don't share similarities with the ones referenced in the EWET database. However, at this geographical scale, there is no clear correlation between EmsB profiles and geographical location. Further studies including additional clinical samples and isolates from foxes and rodents of south Belgium are necessary to better understand the spatial and temporal circumstances of human infections but also a potential correlation between EmsB profiles and parasite virulence.

Annual assessment of Echinococcus multilocularis surveillance reports submitted in 2023 in the context of commission delegated regulation (EU) 2018/772

This report is part of the Echinococcus multilocularis surveillance scientific reports which are presented annually by EFSA to the European Commission and are intended to assess the sampling strategy, data collection and detection methods used by Finland, Ireland, United Kingdom (Northern Ireland) and Norway in their respective surveillance programmes. The surveillance programmes of these four countries were evaluated by checking the information submitted by each of them and verifying that the technical requirements were fulfilled as laid down in Commission Delegated Regulation (EU) 2018/772 of 21 November 2017 supplementing Regulation (EU) No 576/2013 of the European Parliament and of the Council with regard to preventive health measures for the control of Echinococcus multilocularis infection in dogs, and repealing Delegated Regulation (EU) No 1152/2011. The information was divided into four different categories for assessment: the type and sensitivity of the detection method, the selection of the target population, the sampling strategy and the methodology. For each category, the main aspects that need to be considered in order to accomplish the technical requirements of the legislation were checked against compliance of several criteria. The countries participating in this surveillance (Finland, Ireland, Norway and United Kingdom [Northern Ireland]) succeeded in the fulfilment of the technical legal requirements foreseen in Commission Delegated Regulation (EU) 2018/772 concerning these four different categories None of the four countries recorded positive samples in the 12-month reporting period.

Annual assessment of Echinococcus multilocularis surveillance reports submitted in 2022 in the context of Commission Delegated Regulation (EU) 2018/772

This report is part of the Echinococcus multilocularis surveillance scientific reports which are presented annually by EFSA to the European Commission and are intended to assess the sampling strategy, data collection and detection methods used by Finland, Ireland, United Kingdom (Northern Ireland) and Norway in their respective surveillance programmes. The surveillance programmes of these four countries were evaluated by checking the information submitted by each of them and verifying that the technical requirements were fulfilled as laid down in Commission Delegated Regulation (EU) 2018/772 of 21 November 2017 supplementing Regulation (EU) No 576/2013 of the European Parliament and of the Council with regard to preventive health measures for the control of Echinococcus multilocularis infection in dogs, and repealing Delegated Regulation (EU) No 1152/2011. The information was divided into four different categories for assessment: the type and sensitivity of the detection method, the selection of the target population, the sampling strategy and the methodology. For each category, the main aspects that need to be considered in order to accomplish the technical requirements of the legislation were checked against compliance of several criteria. Three of the countries participating in this surveillance (Finland, Ireland and Norway (mainland)) succeeded in the fulfilment of the technical legal requirements foreseen in Commission Delegated Regulation (EU) 2018/772 concerning these four different categories. United Kingdom (Northern Ireland) fulfils those requirements, only assuming a diagnostic test sensitivity value of 0.99 (value provided by the national reference laboratory, higher than the conservative sensitivity value suggested by EFSA, i.e. 0.78). None of the four countries recorded positive samples in the 12-month reporting period.

Prediction of benzimidazole therapy duration with PET/CT in inoperable patients with alveolar echinococcosis

Alveolar echinococcosis is a rare parasitic disease, most frequently affecting the liver, as a slow-growing tumor-like lesion. If inoperable, long-term benzimidazole therapy is required, which is associated with high healthcare costs and occasionally with increased morbidity. The aim of our study was to determine the role ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in staging of patients with alveolar echinococcosis and to identify quantitative imaging parameters related to patient outcome and/or duration of benzimidazole therapy. In this single-center retrospective cohort study, 47 PET/CT performed for staging in patients with confirmed alveolar echinococcosis were analysed. In 43 patients (91%) benzimidazole therapy was initiated and was successfully stopped after a median of 870 days (766–2517) in 14/43 patients (33%). In inoperable patients, tests for trend of survivor functions displayed clear trends for longer benzimidazole therapy duration (p = 0.05; n = 25), and for longer time intervals to reach non-detectable serum concentration of Em-18 antibodies (p = 0.01, n = 15) across tertiles of SUVratio (maximum standardized uptake value in the echinococcus manifestation compared to normal liver tissue). Hence, in inoperable patients with alveolar echinococcosis, PET/CT performed for staging may predict the duration of benzimidazole therapy.

Follow-up PET/CT of alveolar echinococcosis: Comparison of metabolic activity and immunodiagnostic testing

Purpose

To investigate the potential role of follow-up ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in therapy control of inoperable patients with alveolar echinococcosis.

Materials and methods

In this single-center retrospective cohort study, 48 PET/CT of 16 patients with confirmed alveolar echinococcosis were analysed. FDG-uptake of the most active echinococcosis manifestation was measured (i.e., maximum standardized uptake value (SUVmax) and in relation to background activity in normal liver tissue (SUVratio)) and compared to immunodiagnostic testing. For clinical patient follow-up, patient demographics, laboratory data, including E. granulosus hydatid fluid (EgHF) antibody units (AU) as well as clinical and treatment information were assessed for all patients at the time of PET/CT, and at the last recorded clinical visit.

Results

Metabolic activity of PET/CT measured in the echinococcosis manifestation was significantly correlated with EgHF AU (p < 0.001). The differences in metabolic activity of echinococcosis manifestations between two consecutive PET/CT examinations of the same patient and differences in EgHF AU in the respective time intervals displayed a significant positive correlation (p = 0.01). A trend for a more rapid decline in SUVratio liver over time was found in patients who stopped benzimidazole therapy versus patients who did not stop therapy (p = 0.059).

Conclusion

In inoperable patients with alveolar echinococcosis, the course of metabolic activity in follow-up PET/CT is associated to the course EgHF antibody levels. Both parameters may potentially be used to evaluate the course of the disease and potentially predict the duration of benzimidazole therapy.

Evaluation of a structured treatment discontinuation in patients with inoperable alveolar echinococcosis on long-term benzimidazole therapy: A retrospective cohort study

Objectives

Alveolar echinococcosis (AE) is an orphan zoonosis of increasing concern in endemic areas, including Europe. It frequently presents in an advanced, inoperable stage, that requires life-long parasitostatic benzimidazole therapy. In some patients, long-term therapy leads to negative anti-Em18 antibody ELISA and PET. It is disputed, whether these patients are truly cured and treatment can be safely discontinued. Our aim was to retrospectively assess long-term outcome of 34 patients with inoperable AE who participated in a previous study to determine feasibility of benzimidazole treatment cessation.

Methods

Retrospective analysis of medical charts was undertaken in all 34 AE patients who participated in our previous study. Of particular interest were AE recurrence or other reasons for re-treatment in patients who stopped benzimidazole therapy and whether baseline clinical and laboratory parameters help identify of patients that might qualifiy for treatment cessation. Additionally, volumetric measurement of AE lesions on contrast-enhanced cross-sectional imaging was performed at baseline and last follow-up in order to quantify treatment response.

Results

12 of 34 patients stopped benzimidazole therapy for a median of 131 months. 11 of these patients showed stable or regressive AE lesions as determined by volumetric measurement. One patient developed progressive lesions with persistently negative anti-Em18 antibody ELISA but slight FDG-uptake in repeated PET imaging. At baseline, patients who met criteria for treatment cessation demonstrated higher lymphocyte count and lower total IgE.

Conclusion

Treatment cessation is feasible in inoperable AE patients, who demonstrate negative anti-Em18 antibody ELISA and PET on follow-up. Close monitoring including sectional imaging is strongly advised.

Alveolar Echinococcosis-A Challenging Task for the Hepatobiliary Surgeon

(1) Background: Alveolar echinococcosis (AE) is an ultimately fatal disease, whose only curative treatment is surgery. Due to its late presentation extended liver resections are often necessary. The true benefit of extensive surgery has yet to be established; (2) Methods: We present a single center experience of 33 cases of Echinococcus multilocularis that have been treated at a high-volume hepatobiliary surgery center between 2004 and 2021. (3) Results: Of the 33 patients 24 patients underwent major liver resection (73%). In addition to the liver resection patients frequently underwent complex extrahepatic procedures such as lymphadenectomy (n = 21, 61%), vascular resections and reconstructions (n = 9, 27%) or resections and reconstruction of the extrahepatic bile duct (n = 11, 33%). Seven patients suffered from ≥ grade III complications (21%). Complete resection was achieved in 17 patients. Fourteen patients had R1 resections and two had macroscopic parasitic remnant (R2). Progressive disease was reported in three patients (The two R2 patients and one R1 resected patient). At a median follow-up of 54 months no mortality has occurred in our cohort; (4) Conclusions: Liver resection remains the gold standard for AE. Even in extensive disease the combination of complex resection and perioperative benzimidazoles can achieve favorable long-term outcomes.

Annual assessment of Echinococcus multilocularis surveillance reports submitted in 2021 in the context of Commission Delegated Regulation (EU) 2018/772

This report is part of the Echinococcus multilocularis surveillance scientific reports which are presented annually by EFSA to the European Commission and are intended to assess the sampling strategy, data collection and detection methods used by Finland, Ireland, United Kingdom (Northern Ireland) and Norway in their respective surveillance programmes. The surveillance programmes of these four countries were evaluated by checking the information submitted by each of them and verifying that the technical requirements were fulfilled as laid down in Commission Delegated Regulation (EU) 2018/772 of 21 November 2017 supplementing Regulation (EU) No 576/2013 of the European Parliament and of the Council with regard to preventive health measures for the control of Echinococcus multilocularis infection in dogs, and repealing Delegated Regulation (EU) No 1152/2011. The information was divided in four different categories for assessment: the type and sensitivity of the detection method, the selection of the target population, the sampling strategy and the methodology. For each category, the main aspects that need to be considered in order to accomplish the technical requirements of the legislation were checked against compliance of several criteria. Three of the countries participating in this surveillance (Finland, Ireland and Norway (mainland)) succeeded in the fulfilment of the technical legal requirements foreseen in Commission Delegated Regulation (EU) 2018/772 concerning these four different categories. Northern Ireland did not fulfil those requirements, not even assuming a diagnostic test sensitivity value of 0.99 (value provided by the national reference laboratory, higher than the conservative sensitivity value suggested by EFSA, i.e. 0.78). None of the four countries recorded positive samples in the 12-month reporting period.

Dramatic response to albendazole in transplantation candidates with unresectable hepatic alveolar hydatid disease

Long-term albendazole treatment should be given to all patients with unresectable hepatic alveolar echinococcosis as dramatic regression is possible in 15%-20%. It may be prudent to prepare a living donor for possible salvage transplant in case of a severe complication. Preemptive transplantation in mildly symptomatic patients should be discouraged.

Unravelling the genetic diversity and relatedness of Echinococcus multilocularis isolates in Eurasia using the EmsB microsatellite nuclear marker

The cestode Echinococcus multilocularis is the causative agent of alveolar echinococcosis, a severe helminthic zoonotic disease distributed in the Northern Hemisphere. The lifecycle of the parasite is mainly sylvatic, involving canid and rodent hosts. The absence of genetic data from most eastern European countries is a major knowledge gap, affecting the study of associations with parasite populations in Western Europe. In this study, EmsB microsatellite genotyping of E. multilocularis was performed to describe the genetic diversity and relatedness of 785 E. multilocularis isolates from four western and nine eastern European countries, as well as from Armenia and the Asian parts of Russia and Turkey. The presence of the same E. multilocularis populations in the Benelux resulting from expansion from the historical Alpine focus can be deduced from the main profiles shared between these countries. All 33 EmsB profiles obtained from 528 samples from the nine eastern European countries belonged to the European clade, except one Asian profile form Ryazan Oblast, Russia. The expansion of E. multilocularis seems to have progressed from the historical Alpine focus through Hungary, Slovakia, the Czech Republic and southern Poland towards Latvia and Estonia. Most of the samples from Asia belong to the Asian clade, with one EmsB profile shared between Armenia and Turkey, and two between Turkey and Russia. However, two European profiles were described from two foxes in Turkey, including one harboring worms from both European and Asian clades. Three EmsB profiles from three Russian samples were associated with the Arctic clade. Two E. multilocularis profiles from rodents from Lake Baikal belonged to the Mongolian clade, described for the first time here using EmsB. Further worldwide studies on the genetic diversity of E. multilocularis using both mitochondrial sequencing and EmsB genotyping are needed to understand the distribution and expansion of the various clades.

PET/CT helps to determine treatment duration in patients with resected as well as inoperable alveolar echinococcosis

PURPOSE

The aim of the study was to determine the role of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) at the end of benzimidazole therapy in alveolar echinococcosis.

METHODS

A total of 22 patients undergoing PET/CT at the end of benzimidazole therapy were retrospectively registered. Maximum standardized uptake values (SUV_max) were measured in remaining echinococcus manifestations and compared to normal liver tissue. Long-term clinical follow-up was performed, and recorded data included laboratory parameters, clinical information and imaging.

RESULTS

All patients had no detectable levels of Em-18 antibodies and all echinococcus manifestations were negative on PET/CT, i.e. without focally increased FDG uptake or uptake higher than normal/non-infected liver tissue. All manifestations displayed significantly less FDG-uptake than normal liver tissue, i.e. SUVmax 1.8 (interquartile range (IQR) 1.5-3.5) vs. 3.0 (IQR 2.6-5.7), (p < 0.001). Patients were clinically followed for a median of 9.5 years (IQR 6.5-32.0 years) after their initial diagnosis and for 4.5 years (IQR 3.0-14.0 years) after discontinuation of benzimidazole therapy. No patient showed signs of recurrent infection at the last clinical visit. The 10-year and 20-year freedom from all-cause mortality was 95.0% (95% confidence interval 69.5% - 99.3%), for both. Two events occurred in 292 patient years of follow-up; i.e. two patients (9%) died, one because of pancreatic cancer, the other one because of unknown reasons with no detectable antibody levels.

CONCLUSIONS

Negative FDG-PET/CT results combined with no detectable levels of Em-18 antibodies may allow for the safe discontinuation of benzimidazole therapy in patients with alveolar echinococcosis.

Emerging human alveolar echinococcosis in Hungary (2003-2018): a retrospective case series analysis from a multi-centre study

Background

Human alveolar echinococcosis (AE) caused by Echinococcus multilocularis is an underreported, often misdiagnosed and mistreated parasitic disease mainly due to its low incidence. The aim of this study was to describe the epidemiological and clinical characteristics of human AE patients in Hungary for the first time.

Method

Between 2003 and 2018, epidemiological and clinical data of suspected AE patients were collected retrospectively from health database management systems.

Results

This case series included a total of 16 AE patients. The mean age of patients was 53 years (range: 24–78 years). The sex ratio was 1:1. Four patients (25%) revealed no recurrence after radical surgery and adjuvant albendazole (ABZ) therapy. For five patients (31.3%) with unresectable lesions, a stabilization of lesions with ABZ treatment was achieved. In seven patients (43.8%), progression of AE was documented. The mean diagnostic delay was 33 months (range: 1–122 months). Three AE related deaths (fatality rate 18.8%) were recorded.

Conclusions

AE is an emerging infectious disease in Hungary with a high fatality rate since based on our results, almost every fifth AE patient died in the study period. Differential diagnosis and appropriate surgical and medical therapy for AE is an urging challenge for clinicians in Hungary, as well as in some other European countries where E. multilocularis is prevalent.

Contamination of wastewater with Echinococcus multilocularis - possible implications for drinking water resources in the QTP China

Echinococcus multilocularis is a parasite that causes a dangerous zoonosis, alveolar echinococcosis (AE). Its presence in water sources, however, has scarcely been studied heretofore. Accordingly, 222 samples of different origin including wastewater from wastewater treatment plants (WWTPs) (n = 137), slaughterhouse (n = 49) as well as water from rivers (n = 26) and a cattle farm (n = 10) were collected from Xining City and a rural area in Qinghai-Tibet Plateau (QTP), an endemic area. Material obtained after processing of 10 L volume samples was subsequently analysed using three molecular detection methods: nested PCR, real-time PCR and LAMP. E. multilocularis DNA was found in 13 (5.85%) water samples; including 8 (5.8%), 3 (6%), 2 (20%) and 0 positive samples found in WWTPs, a slaughterhouse, a cattle farm and rivers, respectively. All three (LAMP, PCR, RT-PCR) molecular tools displayed high agreement and effectiveness in their ability of detecting the parasite's DNA in environmental material. This is the first investigation describing E. multilocularis detection in wastewater samples, using three sensitive molecular diagnostic tools. Results indicate the role of wastewater in dissemination of E. multilocularis and the risk of contamination of water sources.

First detection of Echinococcus multilocularis in environmental water sources in endemic areas using capsule filtration and molecular detection methods

Water is one of the possible transmission routes for water- and foodborne parasites to humans. Echinococcus multilocularis is a parasite, which causes alveolar echinococcosis (AE). Nevertheless, no environmental studies have been performed as yet to confirm the occurrence of E. multilocularis in water supplies. Accordingly, 105 water samples of 50 L volume were collected from surface waters (lakes, rivers, canals) and wells in the Warmia-Masuria Province (Echinococcus endemic area) and Pomerania Province (Echinococcus non-endemic area), Poland. The water was filtered and subsequently analysed with nested PCR and real-time PCR. E. multilocularis DNA was found in two (1.9%) samples, which originated from two lakes localised in the Warmia-Masuria Province. Sequencing of the positive samples confirmed that the PCR products were fragments of the E. multilocularis mitochondrial 12S rRNA gene. This is the first investigation describing E. multilocularis detection in environmental water samples, using molecular diagnostic tools. The results indicate that water could be considered as a potential source of E. multilocularis infections in humans and animals, in endemic areas.

Case Report: Role of Interventional Radiology in the Management of Patients with Alveolar Echinococcus: Successful Management of Three Cases

Alveolar echinococcus (AE) is an infestation by Echinococcus multilocularis. Partial hepatectomy or liver transplantation is the first choice of treatment. However, the disease is usually diagnosed at an unresectable stage. In those cases, invasion of the bile ducts and vessels, and necrosis in the center of the lesion lead to severe complications, such as cholangitis and liver abscesses. Palliative surgery has been reported to not offer advantages in management, and percutaneous and endoscopic interventions have become more prominent in management. In this case series, outcomes in three cases with unresectable AE were reported. In one of the cases, interventional procedures were used to manage the complications after surgery. In the second case, the cystic component was aspirated to decrease the size before the surgery and in the third case, it was used to drain biliary tree and no surgery was done.

The Echinococcoses: Diagnosis, Clinical Management and Burden of Disease

The echinococcoses are chronic, parasitic diseases that are acquired after ingestion of infective taeniid tapeworm eggs from certain species of the genus Echinococcus. Cystic echinococcosis (CE) occurs worldwide, whereas, alveolar echinococcosis (AE) is restricted to the northern hemisphere, and neotropical echinococcosis (NE) has only been identified in Central and South America. Clinical manifestations and disease courses vary profoundly for the different species of Echinococcus. CE presents as small to large cysts, and has commonly been referred to as 'hydatid disease', or 'hydatidosis'. A structured stage-specific approach to CE management, based on the World Health Organization (WHO) ultrasound classification of liver cysts, is now recommended. Management options include percutaneous sterilization techniques, surgery, drug treatment, a 'watch-and-wait' approach or combinations thereof. In contrast, clinical manifestations associated with AE resemble those of a 'malignant', silently-progressing liver disease, with local tissue infiltration and metastases. Structured care is important for AE management and includes WHO staging, drug therapy and long-term follow-up for at least a decade. NE presents as polycystic or unicystic disease. Clinical characteristics resemble those of AE, and management needs to be structured accordingly. However, to date, only a few hundreds of cases have been reported in the literature. The echinococcoses are often expensive and complicated to treat, and prospective clinical studies are needed to better inform case management decisions.

Current status of diagnosis and treatment of hepatic echinococcosis

Echinococcus granulosus (E. granulosus) and Echinococcus multilocularis (E. multilocularis) infections are the most common parasitic diseases that affect the liver. The disease course is typically slow and the patients tend to remain asymptomatic for many years. Often the diagnosis is incidental. Right upper quadrant abdominal pain, hepatitis, cholangitis, and anaphylaxis due to dissemination of the cyst are the main presenting symptoms. Ultrasonography is important in diagnosis. The World Health Organization classification, based on ultrasonographic findings, is used for staging of the disease and treatment selection. In addition to the imaging methods, immunological investigations are used to support the diagnosis. The available treatment options for E. granulosus infection include open surgery, percutaneous interventions, and pharmacotherapy. Aggressive surgery is the first-choice treatment for E. multilocularis infection, while pharmacotherapy is used as an adjunct to surgery. Due to a paucity of clinical studies, empirical evidence on the treatment of E. granulosus and E. multilocularis infections is largely lacking; there are no prominent and widely accepted clinical algorithms yet. In this article, we review the diagnosis and treatment of E. granulosus and E. multilocularis infections in the light of recent evidence.

Alveolar echinococcosis: correlation between hepatic MRI findings and FDG-PET/CT metabolic activity

OBJECTIVE

To correlate the appearance of alveolar echinococcosis (AE) hepatic lesions in magnetic resonance imaging (MRI) as defined by Kodama, to the metabolic activity visualized in 18-fluoro-deoxyglucose positron emission tomography combined with computed tomography (PET/CT).

MATERIALS AND METHODS

Forty-two patients diagnosed with AE and who underwent both MRI and PET/CT were included. The forty-two hepatic lesions were divided into five types according to Kodama's classification by three independent readers blinded with regard to the PET/CT information. Concerning PET/CT, two independent readers, unaware of the MRI information, considered the results as positive when an increased FDG-uptake was observed at 1 or 3 h after FDG-injection, and as negative when no increased uptake was noted. Inter-observer agreement was assessed by using κ statistics.

RESULTS

Forty-two lesions were counted and the mean diameter of overall evaluated lesions was 6.3 cm. One lesion (2.4%) was categorized as type 1, 11 (26.2%) as type 2, 24 (57.1%) as type 3, 3 (7.1%) as type 4, and 3 (7.1%) as type 5. The inter-observer analysis found a κ coefficient of 0.96. All type-1, 90.9% of type-2 and 87.5% of type-3 lesions showed an increased FDG-uptake on PET/CT images. All non-microcystic AE liver lesions (types 4 and 5) showed no abnormal increased FDG-uptake on PET/CT images. The inter-observer analysis at 1 and 3 h found a κ coefficient of 0.95 and 0.92, respectively.

CONCLUSIONS

In patients with AE liver lesions, the absence of microcysts on MRI is strongly correlated to a metabolically inactive disease.

Outcome after Discontinuing Long-Term Benzimidazole Treatment in 11 Patients with Non-resectable Alveolar Echinococcosis with Negative FDG-PET/CT and Anti-EmII/3-10 Serology

Background/Aims

Benzimidazoles are efficacious for treating non-resectable alveolar echinococcosis (AE), but their long-term parasitocidal (curative) effect is disputed. In this study, we prospectively analyzed the potential parasitocidal effect of benzimidazoles and whether normalization of FDG-PET/CT scans and anti-Emll/3-10-antibody levels could act as reliable "in vivo" parameters of AE-inactivation permitting to abrogate chemotherapy with a low risk for AE-recurrence.

Method

This prospective study included 34 patients with non-resectable AE subdivided into group A (n = 11), followed-up after diagnosis and begin of chemotherapy at months 6, 12 and 24, and group B (n = 23) with a medium duration of chemotherapy of 10 (range 2–25) years. All patients were assessed by FDG-PET/CT examinations and anti-EmII/3-10 serology. Chemotherapy was abrogated in patients with normalization of FDG-PET/CT and serum anti-EmII/3-10 levels. These patients were closely followed-up for AE recurrence. Endpoint (parasitocidal efficacy) was defined by the absence of AE-recurrence >24 months after stopping treatment.

Results

Normalization of FDG-PET/CT scan and anti-EmII/3-10 levels occurred in 11 of 34 patients (32%). After abrogation of chemotherapy in these 11 patients, there was no evidence of AE-recurrence within a median of 70.5 (range 16–82) months. However, the patients’ immunocompetence appears pivotal for the described long-term parasitocidal effect of benzimidazoles.

Conclusions

The combination of negative FDG-PET/CT-scans and anti-EmII/3-10 antibody levels seem to be reliable parameters for assessing in vivo AE-larval inactivity after long-term benzimidazole chemotherapy.

Trial Registration

clinicaltrials.gov: NCT00658294

Alveolar echinococcosis is one of the mostly deadly human parasitic diseases if left untreated. The treatment of choice is surgical resection, followed by two years of benzimidazole treatment. Unfortunately, only about 30–40% of patients have a resectable disease, while the others require medical treatment with benzimidazoles. As this therapy is only considered to be parasitostatic and as there are not yet reliable tools to assess parasite viability, the treatment usually is life-long. In this study, we evaluated FDG-PET/CT and antibody levels against the recombinant Emll/3-10 antigen as markers for parasite viability, allowing to select patients in whom chemotherapy could be stopped with low risk of AE-recurrence. Eleven 11 patients were identified with negative FDG-PET/CT-scans and anti-EmII/3-10 antibody levels in whom benzimidazole treatment was stopped with no evidence of AE-recurrence within a median follow-up of 70.5 (range 16–82) months. Therefore, this study provides evidence that benzimidazole treatment is parasitocidal in a subset of patients.

Zoonotic infections in Alaska: disease prevalence, potential impact of climate change and recommended actions for earlier disease detection, research, prevention and control

Over the last 60 years, Alaska's mean annual temperature has increased by 1.6°C, more than twice the rate of the rest of the United States. As a result, climate change impacts are more pronounced here than in other regions of the United States. Warmer temperatures may allow some infected host animals to survive winters in larger numbers, increase their population and expand their range of habitation thus increasing the opportunity for transmission of infection to humans. Subsistence hunting and gathering activities may place rural residents of Alaska at a greater risk of acquiring zoonotic infections than urban residents. Known zoonotic diseases that occur in Alaska include brucellosis, toxoplasmosis, trichinellosis, giardiasis/cryptosporidiosis, echinococcosis, rabies and tularemia. Actions for early disease detection, research and prevention and control include: (1) determining baseline levels of infection and disease in both humans and host animals; (2) conducting more research to understand the ecology of infection in the Arctic environment; (3) improving active and passive surveillance systems for infection and disease in humans and animals; (4) improving outreach, education and communication on climate-sensitive infectious diseases at the community, health and animal care provider levels; and (5) improving coordination between public health and animal health agencies, universities and tribal health organisations.

Hepatic Encephalopathy in Connection With Budd-Chiari Syndrome due to Infection With Echinococcus Multilocularis: A Case Report

Budd-Chiari syndrome (BCS) is a hepatic venous outflow block generally resulting from disorders affecting hepatic venous system. Elevated hepatic venous pressure results in portal hypertension. BCS may also cause hepatic encephalopathy. Echinococcus multilocularis is a tapeworm parasite and the natural course of the disease may affect liver parenchyma as well as hepatic venous tree. It is the most terrible parasitic disease of the liver and is easily confused with hepatic malignancies. Albendazole therapy may suppress disease progression. Alveolar echinococcosis of the liver rarely causes Budd-Chiari syndrome-related hepatic encephalopathy (HE). We report a rare case of alveolar echinococcosis-related BCS with HE, who was successfully managed by rifaximin and albendazole.

Long-term results of hepatectomy for patients with alveolar echinococcosis: a single-center experience

BACKGROUND

Hepatectomy is the first-line treatment for alveolar echinococcosis (AE) if complete resection is feasible. However, a strategy for the treatment of patients with AE in whom the tumor cannot be resected completely remains to be defined.

STUDY DESIGN

Data were retrospectively collected from 188 consecutive patients between 1984 and 2009. Overall survival (OS), progression-free survival (PFS), and risk factors were analyzed in patients classified into 3 groups (group A: complete resection, group B: reduction surgery, and group C: drainage or exploratory laparotomy).

RESULTS

In group A (n = 119), the 10-, 15-, and 20-year OS was 98.9%. In group B (n = 63), the 10-, 15-, and 20-year OS was 97.1%, 92.8%, and 61.9%. In group C (n = 6), the 10- and 15-year OS was 50.0% and 33.3%. Patients in groups A and B had better prognoses than those in group C (p < 0.001). In group A, the 10-, 15-, and 20-year PFS was 96.5%, 94.4%, and 94.4%. In group B, the 10-, 15-, and 20-year PFS was 87.1%, 71.6%, and 61.4%. In group C, the 10- and 15-year PFS was 50.0% and 33.3%. Patients in group A had better PFS than those in groups B and C (p < 0.001). Curability was the only independent factor for both OS and PFS by multivariate analysis.

CONCLUSIONS

Although the most effective therapy for AE is complete resection, a better prognosis can be achieved by reduction surgery and/or adjuvant albendazole therapy for patients with AE that cannot be completely resected.

Inferior vena cava syndrome due to Echinococcus multilocularis

Alveolar echinococcosis is an invasive, tumor-like zoonosis, accidentally transmitted to humans. We present a case of recurrent inferior vena cava (IVC) syndrome due to alveolar echinococcosis and strongly suspected on transthoracic echocardiographic examination.

Emerging food-borne parasites

Parasitic food-borne diseases are generally underrecognised, however they are becoming more common. Globalization of the food supply, increased international travel, increase of the population of highly susceptible persons, change in culinary habits, but also improved diagnostic tools and communication are some factors associated with the increased diagnosis of food-borne parasitic diseases worldwide. This paper reviews the most important emerging food-borne parasites, with emphasis on transmission routes. In a first part, waterborne parasites transmitted by contaminated food such as Cyclospora cayetanensis, Cryptosporidium and Giardia are discussed. Also human fasciolosis, of which the importance has only been recognised in the last decades, with total numbers of reported cases increasing from less than 3000 to 17 million, is looked at. Furthermore, fasciolopsiosis, an intestinal trematode of humans and pigs belongs to the waterborne parasites as well. A few parasites that may be transmitted through faecal contamination of foods and that have received renewed attention, such as Toxoplasma gondii, or that are (re-)emerging, such as Trypanosoma cruzi and Echinococcus spp., are briefly reviewed. In a second part, meat-borne parasite infections are reviewed. Humans get infected by eating raw or undercooked meat infected with cyst stages of these parasites. Meat inspection is the principal method applied in the control of Taenia spp. and Trichinella spp. However, it is often not very sensitive, frequently not practised, and not done for T. gondii and Sarcocystis spp. Meat of reptiles, amphibians and fish can be infected with a variety of parasites, including trematodes (Opisthorchis spp., Clonorchis sinensis, minute intestinal flukes), cestodes (Diphyllobothrium spp., Spirometra), nematodes (Gnathostoma, spp., anisakine parasites), and pentastomids that can cause zoonotic infections in humans when consumed raw or not properly cooked. Another important zoonotic food-borne trematode is the lungfluke (Paragonimus spp.). Traditionally, these parasitic zoonoses are most common in Asia because of the particular food practices and the importance of aquaculture. However, some of these parasites may emerge in other continents through aquaculture and improved transportation and distribution systems. Because of inadequate systems for routine diagnosis and monitoring or reporting for many of the zoonotic parasites, the incidence of human disease and parasite occurrence in food is underestimated. Of particular concern in industrialised countries are the highly resistant waterborne protozoal infections as well as the increased travel and immigration, which increase the exposure to exotic diseases. The increased demand for animal proteins in developing countries will lead to an intensification of the production systems in which the risk of zoonotic infections needs to be assessed. Overall, there is an urgent need for better monitoring and control of food-borne parasites using new technologies.

Long-term experience on surgical treatment of alveolar echinococcosis

INTRODUCTION

Alveolar echinococcosis (AE) is life-threatening and reports on surgical procedures and results are rare, but essential.

MATERIALS AND METHODS

Longitudinal surveillance and long-term follow-up of patients surgically treated for AE during the periods 1982-1999 (group A) and 2000-2006 (group B).

SETTING

University hospital within an endemic area.

RESULTS

The median (min-max) follow-up period was 141 (5-417) months. Forty-eight surgical procedures were performed in 36 patients with AE: 63% were partial resections of the liver (additional extrahepatic resection in ten of them), 17% just extrahepatic resections, 10% biliodigestive anastomosis, and 10% exploratory laparotomies. Seventy-five percent of the operations were first-time procedures, 25% done due to a relapse. Forty-two percent of the operations were estimated to be curative (R0), whereas 58% were palliative (R1, R2). All patients had additional medical treatment and periodical follow-up. Two out of 18 (11%) patients, estimated to have had curative surgery, developed a relapse 42 and 54 months later. R0-resection rates depended on the primary, neighboring, metastasis stage of AE (S1, 100%; S2, 100%; S3a, 33%; S3b, 27%; S4, 11%). During the period 2000-2006 elective radical surgery for AE was done only if a safe distance of at least 2 cm was attainable. This concept was associated with an increased R0-resection rate of 87% for group B compared to 24% for group A. Operative procedures done to control complicated courses of AE (jaundice, cholangitis, vascular compression, bacterial superinfection) have not been curative (R2) in 82% because the disease had spread into irresectable structures. Morbidity was 19%. All patients with curative resections are alive. Fifty-six percent of the patients with palliative treatment are alive as long as 14-237 months, 28% died from AE 164-338 months after diagnosis (late lethality), and 17% died due to others diseases 96-417 months after diagnosis of AE. One out of seven (14%) patients suffering from suppurative parasitic necrosis died because it was impossible to control systemic sepsis (3% hospital lethality).

CONCLUSION

Curative surgery for AE is feasible if the parasitic mass is removable entirely. The earlier the stage, the more frequent is R0 resectability. The observance of a minimal safe distance increases the rate of R0 resections. The benefit of palliative surgery is uncertain due to favorable long-term results of medical treatment alone. However, necrotic tissue is at risk of bacterial superinfection, which can cause life-threatening sepsis. Palliative surgery is an option to treat complications, which could not be managed otherwise.

The first case of human alveolar echinococcosis in Hungary

Infection caused by Echinococcus multilocularis is a rare helminthiasis, human cases have not been diagnosed in Hungary until now. The endemic region is Central Europe; the occurrence of this infection has been reported from most of the neighbouring countries; however, E. multilocularis has been found in the red fox population in Hungary. Summarizing the recent knowledge concerning epidemiological, clinical patterns and therapeutic options, the authors describe the first Hungarian case of alveolar echinococcosis. In the presence of appropriate clinical findings, the possibility of this rare infection has to be considered in the differencial diagnosis of infiltrative hepatic lesions.

Imaging of Parasitic Diseases of the Thorax

A broad spectrum of parasitic infections frequently affects the lungs, mediastinum, and thoracic wall, manifesting with abnormal imaging findings that often make diagnosis challenging. Although most of these infections result in nonspecific abnormalities, familiarity with their imaging features and the diagnostic pathways help the radiologist to formulate an adequate differential diagnosis and to guide diagnosticians in reaching a definitive diagnosis.

Assessment of disease activity in alveolar echinococcosis: a comparison of contrast enhanced ultrasound, three-phase helical CT and [(18)F] fluorodeoxyglucose positron emission tomography

BACKGROUND

Objective of the present study was to assess activity or vascularization of focal liver lesions in alveolar echinococcosis (AE) using [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) in comparison with contrast enhanced ultrasound (CEUS) and three-phase helical computed tomography (CT).

METHODS

In this prospective study, 17 patients with confirmed AE of the liver were included (6 males, 11 females; average age: 59 +/- 16 years; average duration of disease: 10.5 years) and were then examined using FDG-PET, precontrast ultrasound (US), CEUS, and three-phase helical CT. We assessed metabolic activity (FDG-PET) and vascularization (CEUS and CT) of Echinococcus multilocularis specific hepatic lesions.

RESULTS

FDG-PET identified increased metabolic activity in the corresponding lesions in seven patients (41.2%). A vascularization pattern of echinococcal lesions was visualized in 9 patients (52.9%) by CEUS and in 4 patients (23.5%) by CT. All positive FDG-PET findings were also positive at CEUS.

CONCLUSIONS

There was association between findings of metabolic activity in AE at FDG-PET and vascularized lesions of the liver returned by CEUS. This suggests that CEUS may represent a cost-effective tool in the decision making to perform FDG-PET examination.

In vitro activities of itraconazole, methiazole, and nitazoxanide versus Echinococcus multilocularis larvae

Albendazole (ABZ) and mebendazole are the only drugs licensed for treatment of human alveolar echinococcosis. In order to augment the armamentarium against this deadly disease, we tested a series of drugs for their efficacy against Echinococcus multilocularis larvae. E. multilocularis larvae grown intraperitoneally in Mongolian gerbils were transferred into tissue culture. Vesicles budded from the tissue blocks and after 6 weeks, drugs were added, and the effect on the vesicles was observed. We tested the following drugs at various concentrations: ABZ, artemether, caspofungin, itraconazole (ITZ), ivermectin, methiazole (MTZ), miltefosine, nitazoxanide (NTZ), rifampin, and trimethoprim-sulfamethoxazole. ABZ, ITZ, MTZ, and NTZ effectively destroyed parasite vesicles in this in vitro culture system. At high NTZ doses of 10 microg/ml, disintegration of all vesicles was observed after 7 days and was significantly more rapid than with ABZ at equal concentrations (21 days). After drug discontinuation, regrowth of vesicles occurred between 7 and 14 days for all four drugs, indicating a parasitostatic effect. Combination treatment with NTZ-ABZ at concentrations between 1 and 10 microg/ml for either 3 weeks, 3 months, or 6 months yielded no vesicle regrowth during 8 months after drug discontinuation. The treated larval tissue was injected intraperitoneally into gerbils, and no regrowth of larval tissue was observed, suggesting a parasitocidal effect after combined treatment. ITZ, MTZ, and NTZ are potent inhibitors of larval growth, although they proved to be parasitostatic only. The combination of NTZ plus ABZ was parasitocidal in vitro. Animal experiments are warranted for studies of dose, toxicity, and drug interactions.

14-3-3- and II/3-10-gene expression as molecular markers to address viability and growth activity of Echinococcus multilocularis metacestodes

The present study aimed to search for and characterize parasite molecules, whose expression levels correlate with the viability and growth activity of Echinococcus multilocularis metacestodes. We focused on the expression profiles of 2 parasite-derived genes, 14-3-3 and II/3-10, as putative molecular markers for viability and growth activity of the larval parasite. In experiments in vivo, gene expression levels of 14-3-3 and II/3-10 were relatively quantified by real-time reverse transcription-PCR using a housekeeping gene, beta-actin, as a reference reaction. All three reactions were compared with growth activity of the parasite developing in permissive nu/nu and in non-permissive wild type BALB/c mice. At 2 months p.i., the transcription level of 14-3-3 was significantly higher in parasites actively proliferating in nu/nu mice compared to parasites moderately growing in wild type mice. Immunoblotting experiments confirmed at the protein level that 14-3-3 was over-expressed in parasites derived from nu/nu mice at 2 months p.i. In vitro treatment of E. multilocularis with an anti-echinococcal drug nitazoxanide resulted in a significant decrease of both 14-3-3 and II/3-10 transcription levels found after 8 days of treatment, which correlated with the kinetics of a housekeeping gene, beta-actin. The conclusion is that 14-3-3, combined with II/3-10, exhibits good potential as a molecular marker to assess viability and growth activity of the parasite.

Repeated treatment of cystic echinococcosis in patients with a long-term immunological response after successful surgical cyst removal

Six cystic echinococcosis patients underwent surgery for the removal of echinococcal cysts. All were treated with albendazole prior to and following treatment. After surgery, no cysts were detected in five of the six patients examined. Both ELISA and immunoblot analysis have been used to determine specific IgG, IgG4 and IgE activities. Total elimination of IgG and IgG4 was not achieved in any of the patients studied. Prior to the first surgery/treatment, specific IgG, IgG4 and IgE antibodies were demonstrated in all patients, except one who did not show any IgE activity. The first treatment was followed by highly elevated IgE in two patients; in one of them it was further combined with an apparent decrease in IgG activity. Repeated treatment with albendazole given 0.8-8.5 years after the first treatment/surgery was followed by either moderate or highly reduced IgE activity in two patients, respectively, and a slight increase in IgG4 in another patient. A third course of treatment, given 2-2.5 years after the second treatment, barely affected the antibody activities. The present study suggests that anti-echinoccocal antibody activity may remain high many years after successful cyst removal. Determination of IgG, IgG4 and IgE responses is preferable for the assessment of treatment results. The presence of anti-echinococcal antibodies after surgery with no cyst detection does not necessarily indicate an active echinococcal infection.

Comparison of contrast-enhanced power Doppler ultrasound (Levovist) and computed tomography in alveolar echinococcosis

BACKGROUND

To date, no study has compared unenhanced and contrast-enhanced (Levovist) power Doppler ultrasound with three-phase helical computed tomography (CT) for the analysis of the vascularization of hepatic lesions in patients who have alveolar echinococcosis.

METHODS

Fifteen patients (11 female and four male; average age, 45.8 years) with confirmed Echinococcus multilocularis infection underwent unenhanced and contrast-enhanced (Levovist) power Doppler ultrasound (2- to 5-MHz transducer head) and three-phase helical CT. The largest identified lesion in each patient was studied.

RESULTS

CT visualized vascularization peripheral or central to the largest echinococcal lesions in 11 of 15 patients. Vascularization in the area of the echinococcal lesions was not visualized by unenhanced or contrast-enhanced power Doppler ultrasound in any of the 15 patients studied.

CONCLUSION

Three-phase helical CT visualizes the vascularization associated with Echinococcus multilocularis lesions in the liver. Neither unenhanced nor contrast-enhanced ultrasound in power mode is suitable for this application.

Immunosurveillance of alveolar echinococcosis by specific humoral and cellular immune tests: long-term analysis of the Swiss chemotherapy trial (1976-2001)

BACKGROUND/AIMS

Long-term chemotherapy with benzimidazoles is beneficial in non-resectable alveolar echinococcosis (AE). Criteria to track early therapeutic efficacy are lacking and the clinical impact of immunosurveillance is unsettled. We aimed to analyze this issue particularly for assessing the putative parasitocidal efficacy of chemotherapy.

METHODS

The present study is part of our prospective Swiss trial outlined previously and comprises 57 patients with a median follow-up of 18.5 (3-30) years and with repeated tests of humoral and cell-mediated immunity. The series was subdivided into group A (n=23; curative surgery) and group B (n=34: non-resectable AE).

RESULTS

Long-term survival was 87% (group A) and 76% (group B). The profiles of specific antibodies against EmII/3-10 antigen normalized within 3 years in most group A-patients, but remained above the cut-off value in 40% of group B-patients. This lack of normalization was associated with lower bioavailability of mebendazole. AE-recurrence after 'radical' surgery (up to 13 years) was associated with high anti-EmII/3-10 concentrations in 7 of 8 cases. Following abrogation of longterm chemotherapy in group B, no AE-recurrence occurred in 9/18 patients, suggestive of parasitocidal efficacy and documented by a normal EmII/3-10 profile.

CONCLUSIONS

The EmII/3-10 profile is of value in monitoring AE after surgery and/or chemotherapy.

Structured treatment interruption in patients with alveolar echinococcosis

In human alveolar echinococcosis (AE), benzimidazoles are given throughout life because they are only parasitostatic. It has been a longstanding goal to limit treatment, and recent reports suggest that, in selected cases, benzimidazoles may be parasitocidal. Previously, we showed that positron -emission tomography (PET) using [(18)F]fluoro-deoxyglucose discriminates active from inactive lesions in AE. We have now performed a 3-year prospective study in 23 patients and conducted a structured treatment interruption in those without signs of PET activity. Disease progression was further assessed by ultrasound, computerized tomography, laboratory parameters, and clinical examination. We found PET-negative lesions in 15 of 23 patients and benzimidazoles were discontinued in these patients. After 18 months, patients were reevaluated, and, of the 15 initially PET-negative patients, 8 showed either new activity on PET (n = 6) or signs of clinical progression (n = 2). Reinitiation of benzimidazoles halted parasite growth again. No further progression was detected after 36 months. PET had a sensitivity of 91% for the detection of active lesions. In conclusion, despite successful suppression of metabolic activity, in most cases benzimidazoles do not kill the parasite. PET is a reliable tool for assessing metabolic activity and for timely detection of relapses. Neither duration of treatment, kind of treatment, lesion size, calcifications, or regressive changes reliably indicate parasite death. We discourage the discontinuation of benzimidazoles in inoperable AE even after many years of treatment. However, patients with a poor compliance of benzimidazole intake or patients suffering from side effects to benzimidazoles might be assessed for PET negativity. If permanent discontinuation of benzimidazoles is attempted, the course of disease should be followed by PET.

Echinococcosis

Echinococcosis is a near-cosmopolitan zoonosis caused by adult or larval stages of cestodes belonging to the genus Echinococcus (family Taeniidae). The two major species of medical and public health importance are Echinococcus granulosus and Echinococcus multilocularis, which cause cystic echinococcosis and alveolar echinococcosis, respectively. Both are serious and severe diseases, the latter especially so, with high fatality rates and poor prognosis if managed incorrectly. Several reports have shown that both diseases are of increasing public health concern and that both can be regarded as emerging or re-emerging diseases. In this review we discuss aspects of the biology, life cycle, aetiology, distribution, and transmission of the Echinococcus organisms, and the epidemiology, clinical features, treatment, and diagnosis of the diseases they cause. We also discuss the countermeasures available for the control and prevention of these diseases. E granulosus still has a wide geographical distribution, although effective control against cystic echinococcosis has been achieved in some regions. E multilocularis and alveolar echinococcosis are more problematic, since the primary transmission cycle is almost always sylvatic so that efficient and cost-effective methods for control are unavailable.

Echinococcus granulosus infection: the challenge of surgical treatment

BACKGROUND

Cystic echinococcosis (CE) is a worldwide zoonosis caused by larval stages of the cestode Echinococcus granulosus. Surgery, chemotherapy, and interventional procedures are the therapeutic options. Surgery can cure the patient if the parasite is removed entirely. However, the technical procedures are inconsistent and comprise partial liver resection or opening of the parasitic cyst and removal of the parasite. Laparotomy is the most common approach. In selected cases laparoscopic methods are successful. Retrospective studies outweigh prospective ones by far. However, proper management gives favorable results.

METHODS

We critically review the literature and present a brief summary of current surgical strategy and focus on issues relevant for surgeons: diagnosis, indication for medical treatment, indication for surgical treatment, surgical procedures, scolicidal agents, morbidity, mortality, recurrence, perioperative medication, standards.

RESULTS

All surgical procedures aim at the complete removal of the parasite. Liver resection and pericystectomy are procedures that resect the closed cysts with a fairly wide safety margin. A meta-analysis shows the best results regarding lethality (1.2%), morbidity (11.7%), and recurrence rates (2%) for resective operations. However, most surgeons consider these methods as too radical for a benign disease. Procedures that remove the parasite and keep the pericyst (=cystectomy) are easier to carry out than resective ones. The meta-analysis presented revealed a lethality of 2%, morbidity of 23%, and recurrence rate of 10.4% for these operations. Omentoplasty is the option of choice for the management of the remaining cyst cavity. Despite alternative procedures surgery is the treatment of choice. Supportive measures comprise the use of scolicidal agents and postoperative benzimidazole administration. However, a critical review of the literature disclosed a lack of scientific confirmation of established treatment modalities and procedures. The results of ultrasound imaging were classified and correlated to the developmental phases of CE.

CONCLUSIONS

Cystectomy and omentoplasty for CE should be the standard surgical procedure because it is safe, simple, and effective and meets all criteria of surgical treatment for hydatid disease: entire elimination of the parasite, no intraoperative spillage especially by using a cone, and saving healthy tissue. Pericystectomy should be used for peripherally located liver cysts that are surrounded by parenchyma only partially. Ultrasonic classification of the parasitic lesion should be used as a guideline for therapeutic measures.

European echinococcosis registry: human alveolar echinococcosis, Europe, 1982-2000

Surveillance for alveolar echinococcosis in central Europe was initiated in 1998. On a voluntary basis, 559 patients were reported to the registry. Most cases originated from rural communities in regions from eastern France to western Austria; single cases were reported far away from the disease-"endemic" zone throughout central Europe. Of 210 patients, 61.4% were involved in vocational or part-time farming, gardening, forestry, or hunting. Patients were diagnosed at a mean age of 52.5 years; 78% had symptoms. Alveolar echinococcosis primarily manifested as a liver disease. Of the 559 patients, 190 (34%) were already affected by spread of the parasitic larval tissue. Of 408 (73%) patients alive in 2000, 4.9% were cured. The increasing prevalence of Echinococcus multilocularis in foxes in rural and urban areas of central Europe and the occurrence of cases outside the alveolar echinococcosis-endemic regions suggest that this disease deserves increased attention.

European echinococcosis registry: human alveolar echinococcosis, Europe, 1982-2000

Surveillance for alveolar echinococcosis in central Europe was initiated in 1998. On a voluntary basis, 559 patients were reported to the registry. Most cases originated from rural communities in regions from eastern France to western Austria; single cases were reported far away from the disease-"endemic" zone throughout central Europe. Of 210 patients, 61.4% were involved in vocational or part-time farming, gardening, forestry, or hunting. Patients were diagnosed at a mean age of 52.5 years; 78% had symptoms. Alveolar echinococcosis primarily manifested as a liver disease. Of the 559 patients, 190 (34%) were already affected by spread of the parasitic larval tissue. Of 408 (73%) patients alive in 2000, 4.9% were cured. The increasing prevalence of Echinococcus multilocularis in foxes in rural and urban areas of central Europe and the occurrence of cases outside the alveolar echinococcosis-endemic regions suggest that this disease deserves increased attention.