[Atypical alveolar echinococcosis with systemic involvement in a patient treated with dupilumab]

INTRODUCTION

Alveolar echinococcosis is an endemic parasitic disease prevalent in certain cold regions of the Northern Hemisphere, including Eastern France, Switzerland, Germany, Canada, and the United States. Widely underdiagnosed, it is associated with infection by Echinococcus multilocularis, a small tapeworm belonging to the cestode class, capable of causing multi-systemic involvement, particularly in elderly or immunocompromised patients.

CASE REPORT

We present the case of an 82-year-old patient, immunocompromised due to prolonged corticosteroid therapy and treatment with dupilumab. She was referred to our department for a diagnostic assessment of atypical hepatic and pulmonary lesions, initially suspected of tuberculosis or an IgG4-related disease. The hypothesis of alveolar echinococcosis caused by E. multilocularis was eventually considered based on a set of arguments, further confirmed by molecular diagnosis. We discuss the role of dupilumab in the systemic evolution and atypical presentation of the disease, through the induction of a specific immunosuppression.

CONCLUSION

Alveolar echinococcosis should be systematically considered in case of systemic disease with prominent hepatic and pulmonary involvement, especially in immunocompromised patients.

Two Cases of Disseminated Alveolar Echinococcosis: The Diagnosis, Management, and Differential Considerations for Liver Lesions

Alveolar echinococcosis (AE), caused by Echinococcus multilocularis, is an aggressive and potentially critical infestation that primarily affects the liver and can metastasize to any part of the body. We herein report two cases of echinococcosis, which could be differentiated from malignancy on imaging studies, with infections of the liver and mediastinal lymph nodes, and also associated with systemic disseminated lesions. AE is a very invasive infectious disease, and in order to detect such lesions at an early stage when they are still resectable, it is necessary to understand the characteristic imaging findings and determine the patient's current medical history.

Comprehensive Diagnosis, Treatment, and Outcome of Taenia crassiceps Cysticercosis in a Ring-Tailed Lemur (Lemur catta) from a Croatian Zoo: No Longer Unusual?

Taenia crassiceps is a zoonotic tapeworm of the genus Taenia that is distributed throughout the Northern Hemisphere. Wild and domestic carnivores are final hosts, while rodents and rabbits are primarily intermediate hosts, although many other mammals may harbour the larval stage, Cysticercus longicollis. This case report aims to describe C. longicollis infection in a lemur and molecularly characterise the isolated parasite. The excised lesion was subjected to morphological and histopathological examination, which revealed cysticerci of the tapeworm. Formalin-fixed and paraffin-embedded block (FFPEB), as well as the cysticerci fixed with formalin stored for one year, were subjected to molecular analysis, which aimed at detecting the partial mitochondrial cytochrome c oxidase subunit 1 (cox1) gene of Taenia sp. Based on the morphological characteristics, the parasite was identified as a metacestode of T. crassiceps. The presence of the cox1 gene was detected using polymerase chain reaction (PCR) in all samples. A randomly selected PCR product was sequenced and compared with other sequences from the GenBank database, confirming that the detected parasite was T. crassiceps. This article reports the first case of T. crassiceps cysticercosis in a lemur (Lemur catta) in Croatia and emphasises the potential risk of transmission from wild carnivores.

Human diphyllobothriosis in Taiwan: A review of cases and molecular evidence of Dibothriocephalus nihonkaiensis

Diphyllobothriosis is an infectious disease caused by the consumption of raw freshwater or marine fish containing larvae of broad tapeworms (Diphyllobothriidae). In the present study, we critically reviewed all cases of human diphyllobothriosis reported from Taiwan, including unpublished reports from hospitals in Taipei. Genotyping based on mitochondrial DNA marker (cox1) confirmed that two of the recent cases were caused by Dibothriocephalus nihonkaiensis, which is not native to Taiwan and was probably imported with Pacific salmon infected with larvae of D. nihonkaiensis. The causative species previously reported in Taiwan could not be definitively confirmed. However, considering the distribution of Dibothriocephalus latus, which is not endemic in Taiwan, past cases diagnosed as D. latus are questionable.

Long-term Follow-up of a Patient with Portal Hypertension and Hepatic Failure Due to Hepatic Hydatid Disease

We observed liver failure with a presumed etiology of echinococcosis in an 89-year-old woman. Our patient had been born and then resided on Rebun Island until she was 12 years old. At 46 years old, she had been referred to our hospital due to right abdominal pain. Ultrasound had revealed multilocular cysts in the right lobe of the liver. At 84 years old, the hepatic cyst occupied nearly the entire liver with ring-shaped calcification along the cyst wall. The patient was diagnosed with decompensated cirrhosis and hepatic hydatid disease based on typical imaging and the long-term natural clinical course.

Current situation of human Taenia asiatica taeniosis in Japan

This report describes 33 confirmed cases of "Taenia asiatica" taeniosis in Tokyo, Japan, and six adjacent prefectures between 2010 and 2019. Of the 33 cases, 28 were domestic infections. Thirty patients had histories of eating raw pork and/or beef liver. It was highly suspected that the sources of infection were foreigners from T. asiatica-endemic countries who had worked on pig farms in these prefectures. We postulated that the rate of domestic infection has decreased as a result of legal regulations that have banned the serving of raw and undercooked pig and cattle viscera in restaurants in Japan. Haplotype analyses of genetic markers revealed that "T. asiatica" in Japan are the descendants of hybrids of T. asiatica and Taenia saginata that originated from the Philippines and/or Taiwan. It is critical that close attention continues to be paid to domestic recurrences and imported cases of T. asiatica taeniosis, with the goal of communicating information on risk factors for this infection to consumers, pig farmers, restaurant owners, physicians, and visitors coming to Japan.

Spirometra species from Asia: Genetic diversity and taxonomic challenges

Despite considerable controversy concerning the taxonomy of species within the genus Spirometra, human sparganosis and spirometrosis mainly in Asia and Europe has long been confidently ascribed to Spirometra erinaceieuropaei. Recently, the mitochondrial genomes of purported "S. erinaceieuropaei", "Spirometra decipiens" and "Spirometra ranarum" from Asia have been determined. However, it has been pointed out that the morphological criteria used for identifying these species are unsuitable and thus these identifications are questionable. In the present study, therefore, Spirometra samples from Asia were re-examined based on mitochondrial cytochrome c oxidase subunit 1 gene sequences and the identification of these species was discussed. Haplotype network and phylogenetic analyses revealed that: i) two distinct Spirometra species, Type I and Type II, are present in Asia and neither of which is close to likely European "S. erinaceieuropaei"; ii) Type I is genetically diverse and widely distributed, however Type II is known so far from Japan and Korea; iii) "S. decipiens" and "S. ranarum" reported from Asia are conspecific with Type I; iv) Type I is probably conspecific with Spirometra mansoni, and Type II may represent an undescribed species.

Simple liver cysts and cystoid lesions in hepatic alveolar echinococcosis: a retrospective cohort study with Hounsfield analysis

BACKGROUND

Alveolar echinococcosis (AE) is a rare zoonosis caused by the larval stage of the tapeworm Echinococcus multilocularis. AE lesions affect the liver in more than 98% of cases. AE lesions have various morphological characteristics that are described in the Echinococcus multilocularis Ulm classification for computed tomography (EMUC-CT). One of these characteristics is a cystoid portion. The aim of the study was to compare the density of simple hepatic cysts with cystoid portions of AE lesions classified on the basis of the EMUC-CT.

RESULTS

Hounsfield Unit (HU) measurements of the cystoid portions of all EMUC-CT type I-IV AE lesions (n = 155) gave a mean of 21.8 ± 17.6, which was significantly different from that of 2.9 ± 4.5 for the simple hepatic cysts (p < 0.0001). The difference between each of the individual AE types and simple hepatic cysts was also significant. In addition, the HU values of the cystoid portions in types I, II and IIIa/b and simple cysts were each significantly different from type IV (p < 0.0001). The HU measurements in type IV presented by far the highest mean.

CONCLUSIONS

The significantly higher density measured in the cystoid portions of hepatic AE lesions offers a good means of differentiation from simple hepatic cysts.

Epidemiology of Diphyllobothrium nihonkaiense Diphyllobothriasis, Japan, 2001-2016

The threat from this disease, the most common cestodiasis in Japan, is increasing because of globalization and lack of awareness.

We report 958 cases of cestodiasis occurring in Japan during 2001–2016. The predominant pathogen was Diphyllobothrium nihonkaiense tapeworm (n = 825), which caused 86.1% of all cases. The other cestode species involved were Taenia spp. (10.3%), Diplogonoporus balaenopterae (3.3%), and Spirometra spp. (0.2%). We estimated D. nihonkaiense diphyllobothriasis incidence as 52 cases/year. We observed a predominance of cases during March–July, coinciding with the cherry salmon and immature chum salmon fishing season, but cases were present year-round, suggesting that other fish could be involved in transmission to humans. Because of increased salmon trade, increased tourism in Japan, and lack of awareness of the risks associated with eating raw fish, cases of D. nihonkaiense diphyllobothriasis are expected to rise. Therefore, information regarding these concerning parasitic infections and warnings of the potential risks associated with these infections must be disseminated to consumers, food producers, restaurant owners, physicians, and travelers.

Genetic diversity of Taenia saginata (Cestoda: Cyclophyllidea) from Lao People's Democratic Republic and northeastern Thailand based on mitochondrial DNA

BACKGROUND

Taenia saginata is a tapeworm found in cattle worldwide. Analysis of genetic diversity in different geographical populations of T. saginata not only helps to understand the origin, transmission and spread of this organism, but also to evaluate the selection pressures acting on T. saginata and how it is responding to them. However, there are few reports of the genetic variability of T. saginata populations in different regions of the world, including Lao PDR and Thailand. We report the genetic diversity of T. saginata populations in Lao PDR and northeastern Thailand together with sequences of T. saginata from other countries deposited in GenBank.

RESULTS

Mitochondrial cox1 sequence analysis revealed that 15 and 8 haplotypes were identified in 30 and 21 T. saginata isolates from Lao PDR and northeastern Thailand, respectively. Fifty-three haplotypes were identified from 98 sequences. Phylogenetic tree and haplotype network analyses revealed that global isolates of T. saginata were genetically divided into five groups (A, B, C1, C2 and D). Taenia saginata isolates from Lao PDR and northeastern Thailand belonged to either Group A or B. Taenia saginata from western Thailand clustered in groups C1, C2 and D, and populations from the northeast and western Thailand were found to be genetically distinct. Taenia saginata isolates in Lao PDR and Thailand were also found to be genetically diverse but the degree of genetic differentiation was low.

CONCLUSIONS

Taenia saginata populations from Lao PDR and northeastern Thailand are genetically distinct from the population in western Thailand and it is proposed that T. saginata has been dispersed by different transmission routes in Southeast Asia.

Differential diagnosis and molecular characterization of Hymenolepis nana and Hymenolepis diminuta (Cestoda: Cyclophyllidea: Hymenolepididae) based on nuclear rDNA ITS2 gene marker

Given the widespread distribution and medical implication of members of the genus Hymenolepis, specific identification of the aetiological agent becomes imperative. For precise diagnosis of the species, molecular techniques such as PCR and RFLP of the nuclear ribosomal internal transcribed spacer 2 (rDNA-ITS2) gene marker were carried out. The results showed distinct restriction patterns for both Hymenolepis nana and Hymenolepis diminuta when digested with either of the enzymes RsaI, HaeIII or HhaI. The annotated rDNA-ITS2 sequences from the two species revealed differences in the length; the folded secondary structure also depicted clear demarcation between the two species with variations in length of the helices, pyrimidine-pyrimidine mismatches and sites where motifs occur. In phylogenetic analysis of the evolutionary relationship between the two species as well as with other members of the family Hymenolepididae, the species causing human hymenolepiasis were found to be distantly related as they diverged independently from the ancestral lineage.

Susceptibility versus resistance in alveolar echinococcosis (larval infection with Echinococcus multilocularis)

Epidemiological studies have demonstrated that the majority of human individuals exposed to infection with Echinococcus spp. eggs exhibit resistance to disease as shown by either seroconversion to parasite--specific antigens, and/or the presence of 'dying out' or 'aborted' metacestodes, not including hereby those individuals who putatively got infected but did not seroconvert and who subsequently allowed no development of the pathogen. For those individuals where infection leads to disease, the developing parasite is partially controlled by host immunity. In infected humans, the type of immune response developed by the host accounts for the subsequent trichotomy concerning the parasite development: (i) seroconversion proving infection, but lack of any hepatic lesion indicating the failure of the parasite to establish and further develop within the liver; or resistance as shown by the presence of fully calcified lesions; (ii) controlled susceptibility as found in the "conventional" alveolar echinococcosis (AE) patients who experience clinical signs and symptoms approximately 5-15 years after infection, and (iii) uncontrolled hyperproliferation of the metacestode due to an impaired immune response (AIDS or other immunodeficiencies). Immunomodulation of host immunity toward anergy seems to be triggered by parasite metabolites. Beside immunomodulating IL-10, TGFβ-driven regulatory T cells have been shown to play a crucial role in the parasite-modulated progressive course of AE. A novel CD4+CD25+ Treg effector molecule FGL2 recently yielded new insight into the tolerance process in Echinococcus multilocularis infection.

Echinococcus metacestode: in search of viability markers

Epidemiological studies have demonstrated that most humans infected with Echinococcus spp. exhibit resistance to disease. When infection leads to disease, the parasite is partially controlled by host immunity: in case of immunocompetence, the normal alveolar echinococcosis (AE) or cystic echinococcosis (CE) situation, the metacestode grows slowly, and first clinical signs appear years after infection; in case of impaired immunity (AIDS; other immunodeficiencies), uncontrolled proliferation of the metacestode leads to rapidly progressing disease. Assessing Echinococcus multilocularis viability in vivo following therapeutic interventions in AE patients may be of tremendous benefit when compared with the invasive procedures used to perform biopsies. Current options are F18-fluorodeoxyglucose-positron emission tomography (FDG-PET), which visualizes periparasitic inflammation due to the metabolic activity of the metacestode, and measurement of antibodies against recEm18, a viability-associated protein, that rapidly regresses upon metacestode inactivation. For Echinococcus granulosus, similar prognosis-associated follow-up parameters are still lacking but a few candidates may be listed. Other possible markers include functional and diffusion-weighted Magnetic Resonance Imaging (MRI), and measurement of products from the parasite (circulating antigens or DNA), and from the host (inflammation markers, cytokines, or chemokines). Even though some of them have been promising in pilot studies, none has been properly validated in an appropriate number of patients until now to be recommended for further use in clinical settings. There is therefore still a need to develop reliable tools for improved viability assessment to provide the sufficient information needed to reliably withdraw anti-parasite benzimidazole chemotherapy, and a basis for the development of new alternative therapeutic tools.

Development of a rapid diagnostic kit that uses an immunochromatographic device to detect antibodies in human sparganosis

A diagnostic kit using an immunochromatographic device was developed to replace the time-consuming immunodiagnostic methods for human sparganosis. The kit was found to be faster and easier to use than an enzyme-linked immunosorbent assay (ELISA) and showed higher sensitivity and specificity. It will be useful for the laboratory diagnosis of hospitalized cases of sparganosis.

Nine human sparganosis cases in Thailand with molecular identification of causative parasite species

Human sparganosis is one of the neglected diseases but important food-borne parasitic zoonoses. The disease is caused by larvae (spargana) of diphyllobothriidean tapeworm. Here, we describe nine cases of human sparganosis, caused by Spirometra erinaceieuropaei in a hospital in Thailand during 2001-2012. Clinical characteristics, treatment, and outcome of cases were revealed. Diagnosis and identification of causative parasite species was made by histopathological investigations followed by a polymerase chain reaction-based molecular method using formalin-fixed paraffin embedded tissues. The DNA samples were extracted from tissues and a partial fragment of cytochrome c oxidase subunit 1 (cox1) gene was amplified for the detection of parasitic DNA. Infection could be prevented by increasing activities on health communication by responsible public health agencies.

Mutation scanning analysis of genetic variation within and among Echinococcus species: implications and future prospects

Adult tapeworms of the genus Echinococcus (family Taeniidae) occur in the small intestines of carnivorous definitive hosts and are transmitted to particular intermediate mammalian hosts, in which they develop as fluid-filled larvae (cysts) in internal organs (usually lung and liver), causing the disease echinococcosis. Echinococcus species are of major medical importance and also cause losses to the meat and livestock industries, mainly due to the condemnation of infected offal. Decisions regarding the treatment and control of echinococcosis rely on the accurate identification of species and population variants (strains). Conventional, phenetic methods for specific identification have some significant limitations. Despite advances in the development of molecular tools, there has been limited application of mutation scanning methods to species of Echinococcus. Here, we briefly review key genetic markers used for the identification of Echinococcus species and techniques for the analysis of genetic variation within and among populations, and the diagnosis of echinococcosis. We also discuss the benefits of utilizing mutation scanning approaches to elucidate the population genetics and epidemiology of Echinococcus species. These benefits are likely to become more evident following the complete characterization of the genomes of E. granulosus and E. multilocularis.

Current status and perspectives of cysticercosis and taeniasis in Japan

This mini-review describes recent epidemiological trends in cysticercosis and taeniasis in Japan. Some of the topics discussed herein were presented at the first symposium on "Current perspectives of Taenia asiatica researches", that was held in Osong in Chungbuk Province, South Korea, in October 2011 and organized by Prof. K. S. Eom, Chungbuk National University School of Medicine. To better understand the trends in the occurrence of cysticercosis and taeniasis in Japan, clinical cases reported in 2005 have been updated. In addition, the current status of Taenia asiatica infections successively occurring in Japan since 2010 is also discussed.

Molecular approaches to Taenia asiatica

Taenia solium, T. saginata, and T. asiatica are taeniid tapeworms that cause taeniasis in humans and cysticercosis in intermediate host animals. Taeniases remain an important public health concerns in the world. Molecular diagnostic methods using PCR assays have been developed for rapid and accurate detection of human infecting taeniid tapeworms, including the use of sequence-specific DNA probes, PCR-RFLP, and multiplex PCR. More recently, DNA diagnosis using PCR based on histopathological specimens such as 10% formalin-fixed paraffin-embedded and stained sections mounted on slides has been applied to cestode infections. The mitochondrial gene sequence is believed to be a very useful molecular marker for not only studying evolutionary relationships among distantly related taxa, but also for investigating the phylo-biogeography of closely related species. The complete sequence of the human Taenia tapeworms mitochondrial genomes were determined, and its organization and structure were compared to other human-tropic Taenia tapeworms for which complete mitochondrial sequence data were available. The multiplex PCR assay with the Ta4978F, Ts5058F, Tso7421F, and Rev7915 primers will be useful for differential diagnosis, molecular characterization, and epidemiological surveys of human Taenia tapeworms.

Hepatic echinococcosis: Clinical and therapeutic aspects

Echinococcosis or hydatid disease (HD) is a zoonosis caused by the larval stages of taeniid cestodes belonging to the genus Echinococcus. Hepatic echinococcosis is a life-threatening disease, mainly differentiated into alveolar and cystic forms, associated with Echinoccus multilocularis (E. multilocularis) and Echinococcus granulosus (E. granulosus) infection, respectively. Cystic echinococcosis (CE) has a worldwide distribution, while hepatic alveolar echinococcosis (AE) is endemic in the Northern hemisphere, including North America and several Asian and European countries, like France, Germany and Austria. E. granulosus young cysts are spherical, unilocular vesicles, consisting of an internal germinal layer and an outer acellular layer. Cyst expansion is associated with a host immune reaction and the subsequent development of a fibrous layer, called the pericyst; old cysts typically present internal septations and daughter cysts. E. multilocularis has a tumor-like, infiltrative behavior, which is responsible for tissue destruction and finally for liver failure. The liver is the main site of HD involvement, for both alveolar and cystic hydatidosis. HD is usually asymptomatic for a long period of time, because cyst growth is commonly slow; the most frequent symptoms are fatigue and abdominal pain. Patients may also present jaundice, hepatomegaly or anaphylaxis, due to cyst leakage or rupture. HD diagnosis is usually accomplished with the combined use of ultrasonography and immunodiagnosis; furthermore, the improvement of surgical techniques, the introduction of minimally invasive treatments [such as puncture, aspiration, injection, re-aspiration (PAIR)] and more effective drugs (such as benzoimidazoles) have deeply changed life expectancy and quality of life of patients with HD. The aim of this article is to provide an up-to-date review of biological, diagnostic, clinical and therapeutic aspects of hepatic echinococcosis.

The first workshop towards the control of cestode zoonoses in Asia and Africa

The first workshop towards the control of cestode zoonoses in Asia and Africa was held in Asahikawa Medical University, Japan on 15 and 16 Feb 2011. This meeting was fully supported by the Asian Science and Technology Strategic Cooperation Promotion Programs sponsored by the Special Coordination Funds for Promoting Science and Technology, the Ministry of Education Japan (MEXT) for 3 years from 2010 to Akira Ito. A total of 24 researchers from 9 countries joined together and discussed the present situation and problems towards the control of cestode zoonoses. As the meeting was simultaneously for the establishment of joint international, either bilateral or multilateral collaboration projects, the main purposes were directed to 1) how to detect taeniasis/cysticercosis infected patients, 2) how to differentiate Taenia solium from two other human Taenia species, T. saginata and T. asiatica, 3) how to evaluate T. asiatica based on the evidence of hybrid and hybrid-derived adult tapeworms from Thailand and China, 4) how to evaluate T. solium and T. hyaenae and other Taenia species from the wild animals in Ethiopia, and 5) how to detect echinococcosis patients and 6) how to differentiate Echinococcus species worldwide. Such important topics are summarized in this meeting report.

Expert consensus for the diagnosis and treatment of cystic and alveolar echinococcosis in humans

The earlier recommendations of the WHO-Informal Working Group on Echinococcosis (WHO-IWGE) for the treatment of human echinococcosis have had considerable impact in different settings worldwide, but the last major revision was published more than 10 years ago. Advances in classification and treatment of echinococcosis prompted experts from different continents to review the current literature, discuss recent achievements and provide a consensus on diagnosis, treatment and follow-up. Among the recognized species, two are of medical importance -Echinococcus granulosus and Echinococcus multilocularis - causing cystic echinococcosis (CE) and alveolar echinococcosis (AE), respectively. For CE, consensus has been obtained on an image-based, stage-specific approach, which is helpful for choosing one of the following options: (1) percutaneous treatment, (2) surgery, (3) anti-infective drug treatment or (4) watch and wait. Clinical decision-making depends also on setting-specific aspects. The usage of an imaging-based classification system is highly recommended. For AE, early diagnosis and radical (tumour-like) surgery followed by anti-infective prophylaxis with albendazole remains one of the key elements. However, most patients with AE are diagnosed at a later stage, when radical surgery (distance of larval to liver tissue of >2cm) cannot be achieved. The backbone of AE treatment remains the continuous medical treatment with albendazole, and if necessary, individualized interventional measures. With this approach, the prognosis can be improved for the majority of patients with AE. The consensus of experts under the aegis of the WHO-IWGE will help promote studies that provide missing evidence to be included in the next update.

Differential diagnosis of Taenia asiatica using multiplex PCR

Taenia asiatica and T. saginata are frequently confused tapeworms due to their morphological similarities and sympatric distribution in Asian regions. To resolve this problem, a high-resolution multiplex PCR assay was developed to distinguish T. asiatica infections from infection with other human Taenia tapeworms. For molecular characterization, the species specificity of all materials used was confirmed by sequencing of the cox1 gene. Fifty-two samples were analyzed in this study, comprising 20 samples of T. asiatica genomic DNA from China, Korea, and the Philippines; 24 samples of T. saginata from Belgium, Chile, China, Ethiopia, France, Indonesia, Korea, Laos, the Philippines, Poland, Taiwan, Thailand, and Switzerland; and 10 samples of T. solium from Cape Verde, China, Honduras, and Korea. The diagnostic quality of the results obtained using PCR and species-specific primers designed from valine tRNA and NADH genes was equal to that based on the nucleotide sequencing of the cox1 gene. Using oligonucleotide primers Ta4978F, Ts5058F, Tso7421F, and Rev7915, the multiplex PCR assay was useful for the differentially diagnosing T. asiatica, T. saginata, and T. solium based on 706-, 629-, and 474-bp bands.