Echinococcosis: Advances in the 21st Century

Echinococcosis is a zoonosis caused by cestodes of the genus Echinococcus (family Taeniidae). This serious and near-cosmopolitan disease continues to be a significant public health issue, with western China being the area of highest endemicity for both the cystic (CE) and alveolar (AE) forms of echinococcosis. Considerable advances have been made in the 21st century on the genetics, genomics, and molecular epidemiology of the causative parasites, on diagnostic tools, and on treatment techniques and control strategies, including the development and deployment of vaccines. In terms of surgery, new procedures have superseded traditional techniques, and total cystectomy in CE, ex vivo resection with autotransplantation in AE, and percutaneous and perendoscopic procedures in both diseases have improved treatment efficacy and the quality of life of patients. In this review, we summarize recent progress on the biology, epidemiology, diagnosis, management, control, and prevention of CE and AE. Currently there is no alternative drug to albendazole to treat echinococcosis, and new compounds are required urgently. Recently acquired genomic and proteomic information can provide a platform for improving diagnosis and for finding new drug and vaccine targets, with direct impact in the future on the control of echinococcosis, which continues to be a global challenge.

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.

Populations at risk for alveolar echinococcosis, France

During 1982–2007, alveolar echinococcosis (AE) was diagnosed in 407 patients in France, a country previously known to register half of all European patients. To better define high-risk groups in France, we conducted a national registry-based study to identify areas where persons were at risk and spatial clusters of cases. We interviewed 180 AE patients about their way of life and compared responses to those of 517 controls. We found that almost all AE patients lived in 22 départements in eastern and central France (relative risk 78.63, 95% CI 52.84–117.02). Classification and regression tree analysis showed that the main risk factor was living in AE-endemic areas. There, most at-risk populations lived in rural settings (odds ratio [OR] 66.67, 95% CI 6.21–464.51 for farmers and OR 6.98, 95% CI 2.88–18.25 for other persons) or gardened in nonrural settings (OR 4.30, 95% CI 1.82–10.91). These findings can help sensitization campaigns focus on specific groups.

Echinococcus multilocularis: an emerging pathogen in Hungary and Central Eastern Europe?

Echinococcus multilocularis, the causative agent of human alveolar echinococcosis, is reported for the first time in Red Foxes (Vulpes vulpes) in Hungary. This parasite may be spreading eastward because the population of foxes has increased as a consequence of human interventions, and this spread may result in the emergence of alveolar echinococcosis in Central Eastern Europe.

Resistance/susceptibility to Echinococcus multilocularis infection and cytokine profile in humans. II. Influence of the HLA B8, DR3, DQ2 haplotype

Differences have been shown between HLA characteristics of patients with different courses of alveolar echinococcosis (AE). Notably the HLA B8, DR3, DQ2 haplotype was associated with more severe forms of this granulomatous parasitic disease. We compared IL-10, IL-5, interferon-gamma (IFN-gamma) and tumour necrosis factor (TNF) secretion by peripheral blood mononuclear cells (PBMC) isolated from eight HLA-DR3+, DQ2+, B8+ AE patients and from 10 HLA-DR3-, DQ2-, B8- patients after non-specific mitogenic and specific Echinococcus multilocularis antigenic in vitro stimulation. PBMC from seven HLA-DR3+, DQ2+, B8+ healthy subjects and nine HLA-DR3-, DQ2-, B8- subjects were also studied as controls. PBMC from AE patients with HLA DR3+, DQ2+ haplotype secreted higher levels of IL-10 without any stimulation and after specific antigenic stimulation than did patients without this haplotype. Higher levels of IL-5 and IFN-gamma were also produced by these patients' PBMC after stimulation with non-purified parasitic antigenic preparations; however, the specific alkaline phosphatase antigen extracted from E. multilocularis induced only Th2-type cytokine secretion. A spontaneous secretion of TNF by HLA DR3+, DQ2+ B8+ AE patients was also found. These results suggest that HLA characteristics of the host can influence immune-mediated mechanisms, and thus the course of AE in humans; specific antigenic components of E. multilocularis could contribute to the preferential Th2-type cytokine production favoured by the genetic background of the host.

Echinococcus multilocularis Infection, Southern Ontario, Canada

Alveolar echinococcosis, the disease caused by infection with the intermediate stage of the Echinococcus multilocularis tapeworm, is typically fatal in humans and dogs when left untreated. Since 2012, alveolar echinococcosis has been diagnosed in 5 dogs, 3 lemurs, and 1 chipmunk in southern Ontario, Canada, a region previously considered free of these tapeworms. Because of human and animal health concerns, we estimated prevalence of infection in wild canids across southern Ontario. During 2015–2017, we collected fecal samples from 460 wild canids (416 coyotes, 44 foxes) during postmortem examination and analyzed them by using a semiautomated magnetic capture probe DNA extraction and real-time PCR method for E. multilocularis DNA. Surprisingly, 23% (95% CI 20%–27%) of samples tested positive. By using a spatial scan test, we identified an infection cluster (relative risk 2.26; p = 0.002) in the western-central region of the province. The cluster encompasses areas of dense human population, suggesting zoonotic transmission.

Immunoregulation in larval Echinococcus multilocularis infection

Alveolar echinococcosis (AE) is a clinically very severe zoonotic helminthic disease, characterized by a chronic progressive hepatic damage caused by the continuous proliferation of the larval stage (metacestode) of Echinococcus multilocularis. The proliferative potential of the parasite metacestode tissue is dependent on the nature/function of the periparasitic immune-mediated processes of the host. Immune tolerance and/or down-regulation of immunity are a marked characteristic increasingly observed when disease develops towards its chronic (late) stage of infection. In this context, explorative studies have clearly shown that T regulatory (Treg) cells play an important role in modulating and orchestrating inflammatory/immune reactions in AE, yielding a largely Th2-biased response, and finally allowing thus long-term parasite survival, proliferation and maturation. AE is fatal if not treated appropriately, but the current benzimidazole chemotherapy is far from optimal, and novel options for control are needed. Future research should focus on the elucidation of the crucial immunological events that lead to anergy in AE, and focus on providing a scientific basis for the development of novel and more effective immunotherapeutical options to support cure AE by abrogating anergy, anticipating also that a combination of immuno- and chemotherapy could provide a synergistic therapeutical effect.

Species identification of human echinococcosis using histopathology and genotyping in northwestern China

Human cystic echinococcosis, caused by infection with the larval stage of Echinococcus granulosus, and alveolar echinococcosis, caused by the larval form of E. multilocularis, are known to be important public health problems in western China. Echinococcus shiquicus is a new species of Echinococcus recently described in wildlife hosts from the eastern Tibetan plateau and its infectivity and/or pathogenicity in humans remain unknown. In the current study, parasite tissues from various organs were collected post-operatively from 68 echinococcosis patients from Sichuan and Qinghai provinces in eastern China. The tissues were examined by histopathology and genotyped using DNA sequencing and PCR-RFLP. Histopathologically, 38 human isolates were confirmed as E. granulosus and 30 as E. multilocularis. Mitochondrial cob gene sequencing and PCR-RFLP with rrnL as the target gene confirmed 33 of 53 of the isolates to have the G1 genotype of sheep/dog strain of E. granulosus as the only source of infection, while the remaining 20 isolates were identified as E. multilocularis. No infections were found to be caused by E. shiquicus. Additionally, 5 of 20 alveolar echinococcosis patients were confirmed to have intracranial metastases from primary hepatic alveolar echinococcosis lesions. All these cases originated from four provinces or autonomous regions but most were distributed in Sichuan and Qinghai provinces, where high prevalence rates of human alveolar echinococcosis and cystic echinococcosis were previously documented.

Parasites of the liver - epidemiology, diagnosis and clinical management in the European context

Parasites in the liver cause significant global morbidity and mortality, as they can lead to recurrent cholangitis, cirrhosis, liver failure and cancer. Due to climate change and globalisation, their incidence is increasing, especially in Europe. The correct diagnosis of a hepatic parasite is often delayed because clinicians are unfamiliar with respective entities. Therefore, in this review, we aim to provide clinicians with a comprehensive clinical picture of hepatic parasites and to bring these neglected parasitic liver diseases to the wider attention of hepatology stakeholders in Europe and around the world.

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

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

Cystic and alveolar echinococcosis

Echinococcosis of the CNS is very rare. Cystic (CE) and alveolar echininococcosis (AE) vary in their clinical manifestations, course of disease, and prognosis, to the extent that clinicians should look at these two parasitic infections as distinctly different entities. CE causes displacement and pressure atrophy, while AE expands by infiltrative growth. Due to the embolic nature of CE and AE, CNS lesions are most commonly localized supratentorially in the middle cerebral artery. Symptoms and clinical signs are those of space-occupying lesions. Diagnosis is primarily based on imaging (MRI, CT); serology can help to confirm the diagnosis, but is unreliable. In vivo MRS techniques for immobile intracranial CE lesions have become feasible and will assist in diagnosing such lesions in the future. Patients with cerebral CE and AE need an individual therapeutic approach and should generally be managed by a multidisciplinary team of clinicians experienced in the management of CE and neurosurgeons. A minimum follow-up of 5 years, but ideally 10 years, is necessary. Treatment is difficult in advanced disease, in particular in AE, when curative surgery is not possible. AE and CE are among the most neglected infectious diseases and urgently need more attention to improve early detection in exposed populations, diagnosis, and treatment.

Foxp3+ T Regulatory Cells as a Potential Target for Immunotherapy against Primary Infection with Echinococcus multilocularis Eggs

Alveolar echinococcosis (AE) is a lethal disease caused by infection with the metacestode stage of the helminth Echinococcus multilocularis, which develops into a tumorlike mass in susceptible intermediate hosts. The growth potential of this parasite stage is directly linked to the nature of the surrounding periparasitic immune-mediated processes. In a first step (experiment 1), mice were orally infected with E. multilocularis eggs, to be used for assessing the hepatic expression profiles of 15 selected cytokine and chemokine genes related to acquired immunity from 21 to 120 days postinfection. The early stage of infection in immunocompetent animals was marked by a mixed Th1/Th2 immune response, as characterized by the concomitant presence of gamma interferon (IFN-γ) and interleukin-4 (IL-4) and their related chemokines. At the late stage of AE, the profile extended to a combined tolerogenic mode including Foxp3, IL-10, and transforming growth factor beta (TGF-β) as key components. In a second step (experiment 2), the effect of T regulatory cell (Treg) deficiency on metacestode growth was assessed in E. multilocularis-infected DEREG (depletion of regulatory T cells) mice upon induction of Treg deficiency with diphtheria toxin (DT). The parasite lesions were significantly smaller in the livers of treated mice than in corresponding control groups. Foxp3⁺ Tregs appear to be one of the key players in immune-regulatory processes favoring metacestode survival by affecting antigen presentation and suppressing Th1-type immune responses. For these reasons, we suggest that affecting Foxp3⁺ Tregs could offer an attractive target in the development of an immunotherapy against AE.

Clinical presentation, diagnosis, therapy and outcome of alveolar echinococcosis in dogs

Alveolar echinococcosis (AE), a parasitic disease primarily of the liver caused by the larval stage of Echinococcus multilocularis, is highly endemic in Switzerland. In contrast to well-established management protocols in people, little is known with regard to optimal treatment strategies in dogs. The objective of this study was to describe the clinical signs and diagnostic procedures in dogs with AE and to evaluate outcome following medical treatment alone or surgery and medical treatment. Of 23 putative AE cases between 2004 and 2014, 20 were classified as confirmed (n=18) or probable (n=2) AE, based on abdominal ultrasound, serology, cytology, histology and/or PCR. Most dogs presented with abdominal distension in an advanced stage of disease. Dogs receiving specific treatment (radical or debulking surgery together with medical treatment, or medical treatment alone) survived longer than dogs left untreated, but no difference was found between treatment types. Survival at one year was associated with absence of free abdominal fluid, absence of abdominal distension and treatment of any type. However, dogs treated with debulking surgery all faced relapse. Findings of this study suggest that in AE-affected dogs for which a therapeutic approach is regarded appropriate by owners and veterinarians, radical surgical resection and medical treatment or, if total resection is not possible, medical treatment alone should be considered. However, studies on larger numbers of dogs are necessary before definitive treatment recommendations can be made.

Comprehensive diagnosis and treatment of alveolar echinococcosis: A single-center, long-term observational study of 312 patients in Germany

Alveolar echinococcosis (AE) is the most Iethal human helminthic infection. The malignancy-like disease is rare, but morbidity and treatment costs are high. Objective of the study was to identify factors at baseline and during specific AE therapy influencing the long-term outcome of the disease.

All patients with AE seen at the specialized treatment unit in Ulm between January 1992 and December 2011 were included in the analysis.

The data of 312 patients were analyzed; 108 were diagnosed before 2000 (series A), 204 since 2000 (series B); 290 received specific AE treatment. Patients of series B were more often symptom-free at diagnosis (44.1% vs. 21.3%), had lower disease stages (50.0% vs. 34.2%) and more complete resections (57.7% vs. 20.0%), but higher rates of side effects and drug toxicity (54.1% vs. 40.8%). In series B, more patients remained relapse- or progression-free after 5 years (90.5% vs. 82.8%); after 10 years, the ratio of relapses converged (70.3% vs. 66.9%, p=0.0507). Relapses or progression occurred more often after incomplete surgery or long treatment pauses. The 5-year and 10-year survival rates were 96.9% and 90.6%, respectively, and 17% of the patients were cured.

We observed a shift towards early diagnosis, earlier initiation of specific therapy and more complete resections after 2000. Although diagnosis and treatment of AE pose a challenge, with an individual interdisciplinary management 88.8% of the patients have a favorable outcome.

Comparison of Echinococcus multilocularis and Echinococcus granulosus hydatid fluid proteome provides molecular strategies for specialized host-parasite interactions

Alveolar and cystic echinococcoses, caused by the metacestodes of Echinococcus multilocularis and E. granulosus, are prevalent in several regions and invoke deleterious zoonotic helminthiases. Hydatid fluid (HF), which contains proteinaceous and non-proteinaceous secretions of the parasite- and host-derived components, critically affects the host-parasite interplay and disease progression. We conducted HF proteome profiling of fully mature E. multilocularis vesicle (nine months postinfection) and E. granulosus cyst (stage 2). We identified 120 and 153 proteins, respectively, in each fluid. Fifty-six and 84 proteins represented distinct species; 44 and 66 were parasites, and 12 and 18 were host-derived proteins. The five major parasite protein populations, which included antigen B isoforms, metabolic enzymes, proteases and inhibitors, extracellular matrix molecules (ECMs), and developmental proteins, were abundantly distributed in both fluids and also exclusively in one sample or the other. Carbohydrate-metabolizing enzymes were enriched in E. granulosus HF. In the E. multilocularis HF, proteins that constitute ECMs, which might facilitate adhesion and cytogenesis, were highly expressed. Those molecules had physical and functional relationships along with their biochemical properties through protein-protein interaction networks. Twelve host-derived proteins were largely segregated to serum components. The major proteins commonly and uniquely detected in these HFs and their symbiotic interactome relationships might reflect their biological roles in similar but distinct modes of maturation, invasion, and the longevity of the parasites in the hosts.

Intense Focus of Alveolar Echinococcosis, South Kyrgyzstan

Human alveolar echinococcosis (AE) is a highly pathogenic zoonotic parasitic disease caused by Echinococcus multilocularis. An ultrasound study in southern Kyrgyzstan during 2012 revealed a prevalence of 4.2% probable or confirmed AE and an additional 2.2% possible AE, representing an emerging situation. The risk for probable or confirmed AE was significantly higher in dog owners.

Public Health Follow-up of Suspected Exposure to Echinococcus multilocularis in Southwestern Ontario

In the 3 years since the first report of canine alveolar echinococcosis (AE) in Ontario, three additional cases have been diagnosed in the province. Of the four cases reported to date, three have had no known history of travel outside the province. It is possible that this development is an indication of previously unrecognized environmental contamination with Echinococcus multilocularis eggs in some areas of the province. If so, there is the potential for an emerging threat to human health. This article describes a local public health department's investigation of the possible exposure to E. multilocularis of a number of individuals who had had contact with the latest of the four cases of canine AE, and summarizes a comprehensive decision process that can be used by public health departments to assist in the follow-up of such exposures.

First identification of Echinococcus multilocularis in golden jackals in Croatia

Alveolar echinococcosis, caused by the tapeworm Echinococcus multilocularis, is one of the world's most dangerous zoonosis and an emerging disease with growing incidence in humans. The disease has been reported in new areas and host species in the last two decades, and the primary hosts of the parasite - red fox, golden jackal and grey wolf - are expanding their distribution in Europe. Here we report the morphological and molecular identification of Echinococcus multilocularis tapeworms in one of 29 carcasses of adult golden jackals in Croatia, where the only previous report of the parasite was in red foxes in 2016. These results suggest that alveolar echinococcosis should be treated as an emerging disease in Croatia.

Metformin Suppresses Development of the Echinococcus multilocularis Larval Stage by Targeting the TOR Pathway

Alveolar echinococcosis (AE) is a severe disease caused by the larval stage of the tapeworm Echinococcus multilocularis Current chemotherapeutic treatment options based on benzimidazoles are of limited effectiveness, which underlines the need to find new antiechinococcosis drugs. Metformin is an antihyperglycemic and antiproliferative agent that shows activity against the related parasite Echinococcus granulosus Hence, we assessed the in vitro and in vivo effects of the drug on E. multilocularis Metformin exerted significant dose-dependent killing effects on in vitro cultured parasite stem cells and protoscoleces and significantly reduced the dedifferentiation of protoscoleces into metacestodes. Likewise, oral administration of metformin (50 mg/kg of body weight/day for 8 weeks) was effective in achieving a significant reduction of parasite weight in a secondary murine AE model. Our results revealed mitochondrial membrane depolarization, activation of Em-AMPK, suppression of Em-TOR, and overexpression of Em-Atg8 in the germinal layer of metformin-treated metacestode vesicles. The opposite effects on the level of active Em-TOR in response to exogenous insulin and rapamycin suggest that Em-TOR is part of the parasite's insulin signaling pathway. Finally, the presence of the key lysosomal pathway components, through which metformin reportedly acts, was confirmed in the parasite by in silico assays. Taken together, these results introduce metformin as a promising candidate for AE treatment. Although our study highlights the importance of those direct mechanisms by which metformin reduces parasite viability, it does not necessarily preclude any additional systemic effects of the drug that might reduce parasite growth in vivo.

Molecular Characterization of Echinococcus multilocularis and Echinococcus granulosus from Cysts and Formalin-Fixed Paraffin-Embedded Tissue Samples of Human Isolates in Northeastern Turkey

Erzurum province of Turkey is known to be highly endemic for alveolar echinococcosis (AE) and cystic echinococcosis (CE). In this study, we confirmed Echinococcus multilocularis cases, searched genetic variations of the isolates, and-for the first time-determined the genotypes of Echinococcus granulosus s.l. infecting humans in the province. A total of 5 alveolar and 106 hydatid cysts as well as 23 formalin-fixed paraffin-embedded (FFPE) samples that were diagnosed as AE were collected from hospitals between 2015 and 2017. Partial sequences of two mitochondrial genes were amplified to detect E. multilocularis and E. granulosus sensu lato with conventional polymerase chain reactions (PCRs) and genotypes confirmed by sequencing. PCR amplification of a partial 12S rRNA gene on an alveolar cyst and FFPE tissue samples yielded the expected bp in 5 cysts and 19 of 23 FFPE samples; all Erzurum E. multilocularis isolates were confirmed by sequencing. Phylogenetic analysis of the isolates indicated that some of them were identical to European isolates, whereas some of them were identical to Asian isolates. Off all hydatid cyst samples, 101 (95.2%) yielded the expected bp (94 with 12S rRNA-PCR and 7 with COI-PCR). Sequence analysis showed that 98 (97%) of them corresponded to the G1 genotype, whereas 3 (3%) corresponded to the G3 genotype. Results of the study emphasize that E. multilocularis isolates of Erzurum, based on short sequencing, are similar to both European and Asian isolates, and the G1 genotype of E. granulosus is the main causative agent of human CE in Erzurum.

Helminth parasites and zoonotic risk associated with urban coyotes (Canis latrans) in Alberta, Canada

Coyotes (Canis latrans) are resilient, adaptable, cosmopolitan omnivores that are increasingly prevalent in urban environments, where they interact with both humans and domestic dogs. Coyotes potentially transmit zoonotic parasites, including the tapeworm Echinococcus multilocularis, which appears to be increasing in prevalence in western North America. In this study, we analysed the carcasses of 23 urban coyotes in Edmonton, Alberta, Canada. Focusing primarily on the helminth community, we recovered three tapeworm species (E. multilocularis, Taenia pisiformis, T. serialis), four nematodes (Toxascaris leonina, Uncinaria stenocephala, Capillaria sp., Physaloptera sp.), and two trematodes (Alaria arisaemoides and A. americana). Compared to previous studies of urban coyotes conducted in North America, we report one of the highest levels of E. multilocularis infection in North America: 65.2% infection prevalence. These results amplify concerns expressed by others about the increasing prevalence of this zoonotic parasite and the role coyotes may play in parasite transmission. More research is needed to better understand how various ecological factors, urbanization and wildlife management practices influence the transmission of potentially zoonotic parasites such as E. multilocularis.

Jet set pets: examining the zoonosis risk in animal import and travel across the European Union

Ownership of companion animals or pets is popular throughout the world. Unfortunately, such animals are susceptible to and potential reservoirs of zoonotic pathogens. Close proximity to and contact with pets can lead to human infections. The distribution of zoonotic diseases associated with companion animals such as dogs and cats is not uniform around the world, and moving animals between regions, countries, and continents carries with it the risk of relocating the pathogens they might harbor. Critical among these zoonotic diseases are rabies, echinococcosis, and leishmania. In addition, the protozoan parasites, Toxoplasma gondii and Giardia duodenalis, are also significant agents for human disease of pet origin. Considerable effort is applied to controlling movements of companion animals, particularly dogs, into the European Union. However, free movement of people and their pets within the European Union is a risk factor for the translocation of diseases and their vectors. This review considers the current distribution of some of these diseases, the risks associated with pet travel, and the controls implemented within Europe to prevent the free movement of zoonotic pathogens.

A case of Budd-Chiari syndrome associated with alveolar echinococcosis

Although alveolar echinococcosis (AE) can cause a serious disease with high mortality and morbidity similar to malign neoplasms. A 62-year-old woman admitted to a hospital located in Sivas, Turkey, with the complaints of fatigue and right upper abdominal pain. On contrast abdominal CT, a 54×70×45 mm sized cystic lesion was detected in the left lobe of the liver that was seen to extend to the posterior mediastinum and invade the diaphragm, esophagus, and pericardium. The cystic lesion was seen to be occluding the inferior vena cava and left hepatic vein at the level where the hepatic veins poured into the inferior vena cava. Bilateral pleural effusion was also detected. We discussed this secondary Budd-Chiari Syndrome (BCS) case, resulting from the AE occlusion of the left hepatic vein and inferior vena cava, in light of the information in literature.

Recurrent hepatic alveolar echinococcosis: report of the first case in Korea with unproven infection route

Human alveolar echinococcosis (AE), a hepatic disorder that resembles liver cancer, is a highly aggressive and lethal zoonotic infection caused by the larval stage of the fox tapeworm, Echinococcus multilocularis. E. multilocularis is widely distributed in the northern hemisphere; the disease-endemic area stretches from north America through Europe to central and east Asia, including northern parts of Japan, but it has not been reported in Korea. Herein, we represent a first case of AE in Korea. A 41-year-old woman was found to have a large liver mass on routine medical examination. The excised mass showed multinodular, necrotic, and spongiform appearance with small irregular pseudocystic spaces. Microscopically, the mass was composed of chronic granulomatous inflammation with extensive coagulation necrosis and parasite-like structure, which was revealed as parasitic vesicles and laminated layer delineated by periodic acid-Schiff (PAS) stain. Clinical and histologic features were consistent with AE. After 8 years, a new liver mass and multiple metastatic pulmonary nodules were found and the recurred mass showed similar histologic features to the initial mass. She had never visited endemic areas of AE, and thus the exact infection route is unclear.

Alveolar echinococcosis in a dog in the eastern United States

An 8-y-old Labrador Retriever was presented to a small animal practice in northern Virginia with a history of recent lethargy. Physical examination findings were unremarkable. Ultrasound revealed several large hepatic masses and multiple smaller masses involving the pancreas. Cytologic findings on fine-needle aspirates of the hepatic masses included inflammation and necrosis with eosinophilic, membranous oval structures consistent with cestode infection. Histopathologic findings for biopsies of these masses included extensive necrosis, inflammation, and PAS-positive hyaline-like membranous material interpreted as metacestode cyst wall. A PCR product was generated from aspirate material using primers specific for Echinococcus multilocularis. Subsequent sequence data were 100% homologous to E. multilocularis NADH dehydrogenase subunit I gene sequences. The dog received daily oral albendazole (10 mg/kg) treatment, but its condition deteriorated, and the dog was euthanized. The dog, born in Mississippi, was brought as a puppy to Virginia with no other travel history. To our knowledge, alveolar echinococcosis has not been reported previously in a dog in the United States; E. multilocularis infection was apparently acquired in the mid-Atlantic region of the United States.