Paragonimiasis

Paragonimiasis misdiagnosed as liver abscess: A case report

BACKGROUND

Paragonimiasis is a typical food-borne zoonotic disease. Hosts acquire Paragonimus infection through the ingestion of raw or undercooked crayfish and crab. The clinical manifestations of the disease are varied, and it is often misdiagnosed or missed. The diagnosis of paragonimiasis should be considered comprehensively. Praziquantel is the first choice for treatment, and albendazole can be used in combination with repeated courses in severe cases.

CASE SUMMARY

We report a case of liver paragonimiasis that was misdiagnosed as an abscess. The patient presented with fatigue and poor appetite for 2 months, and was diagnosed with liver abscess in the local hospital. After 6 months, the patient visited our hospital because of recurrent abdominal pain and was diagnosed with liver paragonimiasis based on epidemiological history, clinical presentations, and laboratory findings. He was treated with praziquantel (25 mg/kg) three times a day for 3 days; however, the symptoms still presented after treatment. He was treated with oral praziquantel and albendazole for one further course. Follow-up suggested that the treatment was effective and the symptoms improved.

CONCLUSION

The combination of albendazole and praziquantel may improve the therapeutic efficacy of paragonimiasis.

[Case of Abdominal Colicky Pain Caused by Hepatic Paragonimiasis]

In Korea, the prevalence of paragonimiasis has decreased markedly since 1970 and is now rarely encountered. Although the lung is the primary site of paragonimiasis, ectopic infestation can occur in other sites. The central nervous system is the most commonly involved ectopic site, accounting for only approximately 1% of all paragonimiasis patients. Therefore, the liver is an extremely rare site of ectopic infestation. The authors experienced the case of a 55-year-old female with hepatic paragonimiasis who presented with abdominal colicky pain.

Emerging and Re-Emerging Parasitic Infections of the Central Nervous System (CNS) in Europe

In a rapidly evolving global landscape characterized by increased international travel, migration, and ecological shifts, this study sheds light on the emergence of protozoal and helminthic infections targeting the central nervous system (CNS) within Europe. Despite being traditionally associated with tropical regions, these infections are progressively becoming more prevalent in non-endemic areas. By scrutinizing the inherent risks, potential outcomes, and attendant challenges, this study underscores the intricate interplay between diagnostic limitations, susceptibility of specific population subsets, and the profound influence of climate fluctuations. The contemporary interconnectedness of societies serves as a conduit for introducing and establishing these infections, warranting comprehensive assessment. This study emphasizes the pivotal role of heightened clinician vigilance, judicious public health interventions, and synergistic research collaborations to mitigate the potential consequences of these infections. Though rare, their profound impact on morbidity and mortality underscores the collective urgency required to safeguard the neurological well-being of the European populace. Through this multifaceted approach, Europe can effectively navigate the complex terrain posed with these emergent infections.

Exudative pleural effusion caused by lung fluke infection: A practical diagnostic approach

OBJECTIVES

Pleural effusion caused by lung fluke is a rare etiology of exudative pleural effusion (EPE), which is often misdiagnosed or delayed. We aim to summarize the diagnosis and treatment course of EPE caused by lung fluke infection and put forward a practical diagnosis approach.

METHODS

We retrospectively analyzed the diagnosis and treatment of 14 cases of EPE caused by lung fluke infection diagnosed by enzyme-linked immunosorbent assay of serum antibodies or egg detection.

RESULTS

All patients (100%) with an absolute count of eosinophils in peripheral blood exceeded 0.5 × 109/l, and 10 patients (71.4%) had a history of special ingestion. Eosinophilic PE occurred in 11 patients (78.6%), pleural biopsy of medical thoracoscopic demonstrated eosinophils infiltration in nine patients (64.3%), and parasite eggs in one patient. All patients showed positive intradermal tests for Paragonimus-specific antigens and enzyme-linked immunosorbent assay of serum antibodies to Paragonimus.

CONCLUSION

For patients with unexplained PE, lung fluke infection should be highly suspected when pleural fluid or pleural biopsy shows eosinophilic PE or eosinophils infiltration, especially for patients with certain diet history.

Pediatric paragonimiasis: a retrospective analysis of cases from a county in south-west China

Introduction

The clinical manifestations of paragonimiasis are diverse and non-specific, and can easily lead to misdiagnosis. We aimed to analyze the clinical manifestations, laboratory features, treatment, and clinical outcome of children with paragonimiasis in order to improve recognition of this disease and avoid misdiagnosis.

Methods

Children diagnosed with paragonimiasis from August 2016 to July 2022 were included in the study. Information on population informatics, medical history, and laboratory features was extracted from case data. The clinical features of paragonimiasis were retrospectively analyzed.

Results

A total of 45 children were included in this study. All children had, at least, one risk factor. The clinical features mainly included fever, cough, pleural effusion, peritoneal effusion, and subcutaneous nodules. The main imaging findings were alveolar exudation, peritoneal effusion, pleural thickening, and local nodules. The "tunnel sign" finding on computed tomography (CT)/magnetic resonance imaging (MRI) was helpful in establishing the diagnosis of paragonimiasis. After praziquantel treatment, most of the children improved, and one child with cerebral paragonimiasis experienced sequelae.

Conclusion

Most children with paragonimiasis have a good prognosis, but few children can experience sequelae. Avoidance of untreated water and raw food is a simple, feasible, and effective preventive measure.

A clinical review of human disease due to Paragonimus kellicotti in North America

Human autochthonous infections with the trematode Paragonimus kellicotti are increasingly being reported in North America, but the true prevalence and geographic distribution are unknown. Ingestion of raw crayfish is reported in most human cases, typically in the context of alcohol intoxication. Risk of infection varies depending on what part of the crayfish is ingested as metacercariae of P. kellicotti (>50% mature to adults) localize to the heart and pericardium of the crayfish. Reported human cases have manifested primarily in otherwise healthy young adults presenting with severe eosinophilic pneumonia, pleuritis, systemic symptoms, dermatologic lesions and cerebral involvement. However, it is likely that many infections go unreported due to lack of awareness, mild illness or the absence of rapid commercially available diagnostic tests. Promising advances have been made related to novel diagnostic targets. Conservation of these antigen targets among at least four Paragonimus species could make these antigens viable for diagnostic testing of P. kellicotti specifically as well as other Paragonimus species, but additional studies and funding investments are required. Public and physician awareness may have improved due to targeted education campaigns, but ongoing activities to raise awareness are needed, particularly in areas where cases have not been frequently reported to date.

Computed Tomography and Magnetic Resonance Imaging in the Diagnosis of Cerebral Paragonimiasis in Children

Objective

To investigate the computed tomography (CT) and magnetic resonance image (MRI) manifestations of cerebral paragonimiasis (CP) in children and to improve the understanding of the disease.

Methods

The cranial CT and MRI data of 12 children with positive intradermal tests for Paragonimus-specific antigens were retrospectively analyzed. Additionally, the lesion locations, morphology, and imaging characteristics were analyzed.

Results

The lesions were located in the cerebral parenchyma in 12 cases, with 10 in the supratentorial area and two in the subtentorial area, among which three cases included involvement of the meninges. The morphology of the lesions was mainly nodular and striated, with clear or indistinct borders and varying degrees of surrounding edema. The lesions showed isodense or slightly hyperdense opacities on the CT scans, heterogeneous equal or slightly decreased signal intensities on the T1-weighted images (T₁WI), heterogeneous equal or slightly increased signal intensities on the T2-weighted images (T₂WI), and equal or slightly increased signal intensities on the diffusion-weighted images (DWI) in MRIs. In four cases, the cyst wall showed equal T1 and short T2 signals, and in six cases, the characteristic “tunnel sign” and “worm-eaten sign” were visible. The contrast-enhanced MRI showed strip-shaped enhancement in five cases, nodular or ring-shaped enhancement in three cases, linear enhancement in two cases, and uneven enhancement in two cases. The meninges adjacent to the lesions were thickened with significant enhancement in four cases.

Conclusion

CP was mostly located in the cerebral parenchyma with involvement of the adjacent meninges. CT and MRI scans had certain imaging characteristics, and the MRI may particularly be of great value for the diagnosis of CP.

A case of cerebral paragonimiasis misdiagnosed as eosinophilic granulomatosis with polyangiitis

Paragonimiasis is a parasitic disease caused by Paragonimus westermani infection, and migration to the brain results in cerebral paragonimiasis. Cerebral paragonimiasis is now extremely rare, but a few cases are still reported. A 48‐year‐old Japanese woman presented with right‐hand convulsion, right‐hand numbness, sputum, and fatigue. Chest computed tomography demonstrated multiple nodular lesions, and head computed tomography revealed a hemorrhagic lesion in the left motor cortex. Magnetic resonance imaging revealed multiple small ring‐shaped lesions with surrounding edema. Laboratory evaluation demonstrated peripheral eosinophilia. We considered eosinophilic granulomatosis with polyangiitis and started steroid treatment as a diagnostic therapy since we wanted to avoid cerebral lesion biopsy if possible. However, the patient underwent craniotomy surgery after steroid treatment for four months because a new intracerebral mass lesion had appeared. Trematode eggs were detected in the sample, and the final diagnosis was cerebral paragonimiasis. The patient was successfully treated with praziquantel. Cerebral paragonimiasis is extremely rare but should be considered in the differential diagnosis if atypical intracranial hemorrhage and peripheral eosinophilia are observed.

General overview of the current status of human foodborne trematodiasis

Foodborne trematodes (FBT) of public health significance include liver flukes (Clonorchis sinensis, Opisthorchis viverrini, O. felineus, Fasciola hepatica and F. gigantica), lung flukes (Paragonimus westermani and several other Paragonimus spp.) and intestinal flukes, which include heterophyids (Metagonimus yokogawai, Heterophyes nocens and Haplorchis taichui), echinostomes (Echinostoma revolutum, Isthmiophora hortensis, Echinochasmus japonicus and Artyfechinostomum malayanum) and miscellaneous species, including Fasciolopsis buski and Gymnophalloides seoi. These trematode infections are distributed worldwide but occur most commonly in Asia. The global burden of FBT diseases has been estimated at about 80 million, however, this seems to be a considerable underestimate. Their life cycle involves a molluscan first intermediate host, and a second intermediate host, including freshwater fish, crustaceans, aquatic vegetables and freshwater or brackish water gastropods and bivalves. The mode of human infection is the consumption of the second intermediate host under raw or improperly cooked conditions. The major pathogenesis of C. sinensis and Opisthorchis spp. infection includes inflammation of the bile duct which leads to cholangitis and cholecystitis, and in a substantial number of patients, serious complications, such as liver cirrhosis and cholangiocarcinoma, may develop. In lung fluke infections, cough, bloody sputum and bronchiectasis are the most common clinical manifestations. However, lung flukes often migrate to extrapulmonary sites, including the brain, spinal cord, skin, subcutaneous tissues and abdominal organs. Intestinal flukes can induce inflammation in the intestinal mucosa, and they may at times undergo extraintestinal migration, in particular, in immunocompromised patients. In order to control FBT infections, eating foods after proper cooking is strongly recommended.

Pulmonary, liver and cerebral paragonimiasis: An unusual clinical case in Colombia

BACKGROUND

Mainly affecting poorer populations in remote (sub)tropical areas, paragonimiasis is considered one of the world's most neglected tropical diseases by the World Health Organization. It is usually acquired by consuming undercooked freshwater crustaceans and primarily affects the lungs, but may ectopically migrate to other organs to produce a multisystemic clinical presentation. This study details what appears to be the first documented case in South America and particularly in Colombia of cerebral paragonimiasis and infection by the crab Moreirocarcinus emarginatus.

CASE PRESENTATION

After consuming this crab, a 32-year-old Colombian male developed dyspnea and headache. A chest X-ray revealed tension pneumothorax (TPT) and a thoracoscopic lung biopsy bronchiolitis, eosinophilia, and granulomatous reaction due to Paragonimus parasites.

RESULTS

Brain tomography and MRI also showed a configuration typical of Paragonimus parasites, namely a predominantly cystic area near the left cuneus with diffusion restriction, a hemosiderin halo, and linear enhancement characteristic of the tunnel sign, indicating an adult worm moving in the brain.

CONCLUSIONS

Cerebral paragonimiasis can occur in the Colombian population and Moreirocarcinus emarginatus can be its cause. In rural areas, education about raw crab consumption would be beneficial, and physicians addressing lung-related complaints should bear paragonimiasis in mind and ask about raw crab consumption.

Exudative pleural effusion caused by lung fluke infection: case report

The global incidence of lung fluke disease is low, and the infection is a rare cause of pleural effusion in adults. This article reports a case of exudative pleural effusion accompanied by eosinophilia in a 19-year-old male which was finally proven to be caused by lung fluke infection through antibody testing. This case highlights that lung fluke infection is an easily overlooked cause of pleural effusion. Eosinophilia is a potential marker of infection, and serological tests could further confirm the diagnosis.

Transcriptome Analysis Reveals Possible Virulence Factors of Paragonimus proliferus

Objective:

To identify the possible virulence factors (VFs) of P. proliferus.

Methods:

By Illumina HiSeq 4000 RNA-Seq platform, transcriptomes of adult P. proliferus worms were sequenced to predict VFs via screening the homologues of traditional VFs of parasites based on the annotations in the functional databases. Homology analysis was also performed to screen homologous genes between P. proliferus and other four Paragonimus species (i.e., P. kellicotti, P. skrjabini, P. miyazakii and P. westermani) whose transcriptomes were downloaded from the National Center for Biotechnology Information (NCBI) database, and then the differential-expressed homologous genes (DEHGs) were screened via comparisons of P. proliferus and P. kellicotti, P. skrjabini, P. miyazakii and P. westermani, respectively. Finally, an overlap of the predicted VFs and DEHGs was performed to identify possible key VFs that do not only belong to the predicted VFs but also DEHGs.

Results:

A total of 1,509 genes of P. proliferus homologous to traditional VFs, including surface antigens (SAGs), secreted proteins (SPs), ATP-Binding Cassette (ABC) Transporters, actin-related proteins (ARPs), aminopeptidases (APases), glycoproteins (GPs), cysteine proteases (CPs), and heat shock proteins (HSPs), were identified. Meanwhile, homology analysis identified 6279 DEHGs among the five species, of which there were 48 DEHGs being mutually differentialexpressed among the four pairs of comparisons, such as MRP, Tuba 3, PI3K, WASF2, ADK, Nop56, DNAH1, PFK-2/FBPase2, Ppp1r7, SSP7. Furthermore, the overlap between the predicted VFs and DEHGs showed 97 genes of the predicted VFs that simultaneously belonged to DEHGs. Strikingly, of these 97 genes, only 26, including Chymotrypsin, Leucine APases, Cathepsin L, HSP 70, and so on, were higher expressed in P. proliferus while all the remaining were lower expressed than in the four other species.

Conclusions:

This work provides a fundamental context for further studies of the pathogenicity of P. proliferus. Most of the predicted VFs which simultaneously belonged to DEHGs were lower expressed in P. proliferus.

A case of paragonimiasis inducing bilateral pneumothorax with lung and liver involvement

Pulmonary paragonimiasis can occasionally induce bilateral pneumothorax and cause lesions in ectopic organs such as the liver. We report the case of a 26-year-old man who had been treated for bilateral hydropneumothorax one month earlier and returned to the emergency center complaining of epigastric pain that had persisted for four months. After being diagnosed with pulmonary and hepatic paragonimiasis, he was treated with praziquantel and his condition improved without complications.

Differentially Expressed Homologous Genes Reveal Interspecies Differences of Paragonimus Proliferus based on Transcriptome Analysis

Paragonimus proliferus (P. proliferus), one of 46 Paragonimus species registered in the National Center for Biotechnology Information database, may be much more widely distributed in Southeast Asia than previously thought, as its reported natural foci have increased in the past decades. However, very little is known about its molecular biology, especially at the transcriptome level. For the first time, the transcriptome of this species was sequenced and compared with four other common Paragonimus species, namely Paragonimus skrjabini, Paragonimus kellicotti, Paragonimus miyazakii, and Paragonimus westermani, to predict homologous genes and differentially expressed homologous genes to explore interspecies differences of Paragonimus proliferus. A total of 7393 genes were found to be significantly differentially expressed. Of these, 49 were considered to be core genes because they were differentially expressed in all four comparison groups. Annotations revealed that these genes were related mainly to "duplication, transcription, or translation", energy or nutrient metabolism, and parasitic growth, proliferation, motility, invasion, adaptation to the host, or virulence. Interestingly, a majority (5601/7393) of the identified genes, and in particular the core genes (48/49), were expressed at lower levels in P. proliferus. The identified genes may play essential roles in the biological differences between Paragonimus species. This work provides fundamental background information for further research into the molecular biology of P. proliferus.

Extraintestinal Foodborne Pathogens

In general, foodborne diseases present themselves with gastrointestinal symptoms caused by bacterial, viral, and parasitic pathogens well established to be foodborne. These pathogens are also associated with extraintestinal clinical manifestations. Recent studies have suggested that Escherichia coli and Klebsiella pneumoniae, which both cause common extraintestinal infections such as urinary tract and bloodstream infections, may also be foodborne. The resolution and separation of these organisms into pathotypes versus commensals by modern genotyping methods have led to the identification of key lineages of these organisms causing outbreaks of extraintestinal infections. These epidemiologic observations suggested common- or point-source exposures, such as contaminated food. Here, we describe the spectrum of extraintestinal illnesses caused by recognized enteric pathogens and then review studies that demonstrate the potential role of extraintestinal pathogenic E. coli (ExPEC) and K. pneumoniae as foodborne pathogens. The impact of global food production and distribution systems on the possible foodborne spread of these pathogens is discussed.

Intraspinal Paragonimiasis in Children: MRI Findings and Suggestions for Pathogenesis

BACKGROUND AND PURPOSE

Intraspinal paragonimiasis is a rare entity for which imaging findings have seldom been described. The present study investigated the MR imaging features of spinal paragonimiasis, thus providing diagnostic imaging evidence and exploring the possible pathogenesis of intraspinal paragonimiasis.

MATERIALS AND METHODS

The clinical and imaging findings of spinal paragonimiasis in 6 children were analyzed retrospectively. Spinal MR imaging was performed in all patients, 5 of whom also underwent enhanced MR imaging. The diagnosis was confirmed by enzyme-linked immunosorbent assay in all cases and postoperative pathology in 4 cases.

RESULTS

All cases manifested as fusiform-shaped or beanlike masses in the extradural space in the thoracic spine. The extradural masses were connected with pleural lesions through the intervertebral foramen. The plain MR imaging scan showed mixed signals with predominant isointensity on T1WI and hyperintensity on T2WI, among which 5 (5/6) masses presented as patchy hemorrhage with hyperintensity on T1WI. On enhanced scans, all masses (5/5) showed heterogeneous marked enhancement, with thickening and enhancement in the adjacent spinal meninges (5/5). Various degrees of spinal cord compression and edema were found in 5 cases (5/6).

CONCLUSIONS

MR imaging is sensitive for detecting and characterizing spinal paragonimiasis. The MR imaging features of intraspinal granulomas included localization to the extradural space and thoracic segment, connections between intraspinal lesions and pleural lesions through the intervertebral foramen, and hemorrhagic foci within the mass. These findings support an intraspinal mode of paragonimiasis pathogenesis: The Paragonimus larvae migrate from the chest into the extradural space through the intervertebral foramen.

Diagnosis of Human Trematode Infections

Digenetic trematodes form a major group of human parasites, affecting a large number of humans, especially in endemic foci. Over 100 species have been reported infecting humans, including blood, lung, liver, and intestinal parasites. Traditionally, trematode infections have been diagnosed by parasitological methods based on the detection and the identification of eggs in different clinical samples. However, this is complicated due to the morphological similarity between eggs of different trematode species and other factors such as lack of sensitivity or ectopic locations of the parasites. Moreover, the problem is currently aggravated by migratory flows, international travel, international trade of foods, and changes in alimentary habits. Although efforts have been made for the development of immunological and molecular techniques, the detection of eggs through parasitological techniques remains as the gold standard for the diagnosis of trematodiases. In this chapter, we review the current status of knowledge on diagnostic techniques used when examining feces, urine, and sputum and also analyze the most relevant characteristics used to identify eggs with a quick key for the identification of eggs.

Parasites and epilepsy: Understanding the determinants of epileptogenesis

There is a large body of evidence suggesting that parasites could be a major preventable risk factor for epilepsy in low- and middle-income countries. We review potentially important substrates for epileptogenesis in parasitic diseases. Taenia solium is the most widely known parasite associated with epilepsy, and the risk seems determined mainly by the extent of cortical involvement and the evolution of the primary cortical lesion to gliosis or to a calcified granuloma. For most parasites, however, epileptogenesis is more complex, and other favorable host genetic factors and parasite-specific characteristics may be critical. In situations where cortical involvement by the parasite is either absent or minimal, parasite-induced epileptogenesis through an autoimmune process seems plausible. Further research to identify important markers of epileptogenesis in parasitic diseases will have huge implications for the development of trials to halt or delay onset of epilepsy.

Trematode Genomics and Proteomics

Trematode infections are among the most neglected tropical diseases despite their worldwide distribution and extraordinary ability to parasitise many different host species and host tissues. Furthermore, these parasites are of great socioeconomic, medical, veterinary and agricultural importance. During the last 10 years, there have been increasing efforts to overcome the lack of information on different "omic" resources such as proteomics and genomics. Herein, we focus on the recent advances in genomics and proteomics from trematodes of human importance, including liver, blood, intestinal and lung flukes. We also provide information on the latest technologies applied to study the biology of trematodes as well as on the resources available for the study of the molecular aspects of this group of helminths.

Climate Change and the Neglected Tropical Diseases

Climate change is expected to impact across every domain of society, including health. The majority of the world's population is susceptible to pathological, infectious disease whose life cycles are sensitive to environmental factors across different physical phases including air, water and soil. Nearly all so-called neglected tropical diseases (NTDs) fall into this category, meaning that future geographic patterns of transmission of dozens of infections are likely to be affected by climate change over the short (seasonal), medium (annual) and long (decadal) term. This review offers an introduction into the terms and processes deployed in modelling climate change and reviews the state of the art in terms of research into how climate change may affect future transmission of NTDs. The 34 infections included in this chapter are drawn from the WHO NTD list and the WHO blueprint list of priority diseases. For the majority of infections, some evidence is available of which environmental factors contribute to the population biology of parasites, vectors and zoonotic hosts. There is a general paucity of published research on the potential effects of decadal climate change, with some exceptions, mainly in vector-borne diseases.

A Case of Ectopic Peritoneal Paragonimiasis Mimicking Diverticulitis or Abdominal Abscess

Paragonimiasis is a parasitic disease caused by Paragnonimus species. The primary site of infection is the lung, and extrapulmonary involvement is also reported. When infected with Paragonimus westermani, which is the dominant species in Korea, the central nervous system is frequently involved along with the liver, intestine, peritoneal cavity, retroperitoneum, and abdominal wall. Ectopic paragonimiasis raises diagnostic challenge since it is uncommon and may be confused with malignancy or other inflammatory diseases. Here, we report an ectopic paragonimiasis case initially presented with recurrent abdominal pain. The patient developed abdominal pain 3 times for the previous 3 years and the computed tomography (CT) of the abdomen revealed fluid collection with wall enhancement. Recurrent diverticulitis was initially suspected and part of the ascending colon was resected. However, the specimen showed intact colon wall without evidence of diverticulitis and multiple parasite eggs and granulomas were found instead. The size of about 70 μm, the presence of an operculum and relatively thick egg shell suggested eggs of Paragonimus species. With appropriate exposure history and a positive antibody test, the definitive diagnosis was made as peritoneal paragonimiasis.

Recent Incidence of Paragonimus westermani Metacercariae in Freshwater Crayfish, Cambaroides similis, from Two Enzootic Sites in Jeollanam-do, Korea

An epidemiological study was performed to know the recent infection status of Paragonimus westermani metacercariae (PwMc) in freshwater crayfish, Cambaroides similis, from 2 streams in Jeollanam-do, Republic of Korea. Crayfish were collected from creeks in Bogil-do (Island), Wando-gun, and in a creek near Daeheung Temple in Haenam-gun. The infection rate of crayfish with PwMc in Bogil-do was 89.8%, and the metacercarial burden was 37 PwMc per the infected crayfish. Crayfish in a creek near Daeheung Temple were larger and twice heavier than those in Bogil-do. Of them, 96.5% were infected with PwMc. An average of 140 metacercariae was found in the infected crayfish, almost quadruple to those of Bogil-do. There was a strong correlation between the number of PwMc and body weight of the crayfish. These results suggest that P. westermani metacercariae are still prevalent in crayfish of the 2 regions in Jeollanam-do, Korea.

Paragonimiasis in Children in Southwest China: A retrospective case reports review from 2005 to 2016

BACKGROUND

Paragonimiasis infection has no specific symptoms or typical radiologic findings, leading to the possibility of misdiagnosis. Thus, the objective of this study was to analyze clinical and radiological features, and treatment outcome of paragonimiasis in children in Southwest China to improve the awareness of this disease.

METHODS

We retrospectively reviewed the records of children diagnosed with paragonimiasis in West China Second University Hospital between 2005 and 2016. The confirmed diagnosis of paragonimiasis was based on epidemiology history and seropositivity for paragonimiasis and/or detection of paragonimus eggs. Clinical, laboratory, and imaging findings of patients were examined in order to summarize risk factors, clinical characteristics, and treatment outcomes of these patients.

RESULTS

A total of 123 patients were included; of them 112 (91.1%) lived in villages and 72 (58.5%) had a history of consuming freshwater crabs. Patients with paragonimiasis most frequently showed respiratory symptoms, including cough (26.0%, 32/123) and tachypnea (16.3%, 20/123), and gastrointestinal symptoms, including abdominal pain (26.8%, 33/123), abdominal distention (22.8%, 28/123), and vomiting (13.0%, 16/123). Laboratory examination showed elevated white blood cell (WBC) counts in the peripheral blood in 89 (72.4%) patients and eosinophilia in 102 (82.9%) patients. Tuberculosis (TB) coinfection was found in 4 (3.3%) patients. Main imaging findings included: effusions (90.4%), lymphadenopathy (40.4%), pulmonary ground-glass opacities (36.2%), cystic lesions (18.1%), and pleural thickening (17.0%). Twenty-nine patients (23.6%) received more than 1 course of praziquantel (PZQ). Additionally, 4 (19.0%) of 21 patients who were discharged from the hospital without complete treatment required rehospitalization for residual serous effusions. Moreover, patients from pericardial effusion group showed longer hospital stays and less elevated WBC counts than those from nonpericardial effusion group.

CONCLUSION

Paragonimiasis should be considered in patients from endemic areas, especially in those with gastrointestinal and/or respiratory symptoms, elevated WBC count, eosinophilia, and serous effusions. Additionally, longer hospital stay may be necessary in cases of paragonimiasis associated with pericardial effusions.

Inactivation of Paragonimus westermani metacercariae in soy sauce-marinated and frozen freshwater crabs

Soy sauce-marinated freshwater crabs (Eriocheir japonicus) are a source of human paragonimiasis. The viability of Paragonimus westermani metacercariae (PwMc) in marinated crabs was investigated in an experimental setting. The PwMc collected from freshwater crayfish were inoculated into freshwater crabs, which were then frozen or marinated in soy sauce. All PwMc in the freshwater crabs were inactivated after freezing for 48 h at -20 °C and after freezing for 12 h at -40 °C. After marinating for 32 days, the survival rate of PwMc in 5% NaCl soy sauce was 50%, in 7.5% NaCl soy sauce it was 33.3%, and in 10.0% NaCl soy sauce it was 31.3%. When marinated for 64 days, all PwMc were inactivated in all experimental groups. These results revealed that freezing and soy sauce marination were detrimental to the survival of PwMc in freshwater crabs. Specifically, freezing crabs for more than 48 h or soaking them in soy sauce containing at least 5.0% NaCl for 64 days can inactivate PwMc. These results can inform the production of the traditional Korean soy sauce-marinated freshwater crabs known as gejang.

Cerebral Paragonimiasis Presenting with Sudden Death

A 58-year-old Korean-born woman with a history of seizures and psychiatric issues was found dead at home. Autopsy was notable for large, calcified nodules that had nearly replaced her right temporal lobe. Histologic examination revealed the presence of Paragonimus eggs. This case demonstrates a rare manifestation of an aberrantly migrated lung fluke that resulted in epilepsy and sudden death years after the initial infection.

Pancreatic paragonimiasis mimics pancreatic cystic-solid tumor--A case report

Paragonimiasis is frequently misdiagnosed owing to its various and complicated clinical manifestations. Although paragonimiasis has diverse manifestations, there is no report of paragonimiasis involving the pancreas. Herein we report the first case of pancreatic paragonimiasis, which was misdiagnosed as pancreatic cystic-solid tumor by CT scan. The pancreatic lesion was finally proved to be pancreatic paragonimiasis by pathological examination and serum antibody detection. The clinical manifestations and imaging features of this patient were analyzed. Pancreatic paragonimiasis should be an important differential diagnosis for pancreatic cyst-solid lesions.

North American paragonimiasis: epidemiology and diagnostic strategies

Paragonimiasis is a zoonotic, food-borne trematode infection that affects around 23 million people in Asia, Africa and the Americas. North American paragonimiasis, caused by Paragonimus kellicotti, is a common infection of crustacean-feeding mammals in parts of the USA and Canada. Although infection rates in crayfish are very high in some areas, human infections are rare and depend on the consumption of raw or undercooked crayfish. Human infections can be easily prevented and treated, but proper diagnosis of paragonimiasis is a problem. Paragonimus lung flukes often cause serious disease symptoms before they produce eggs that may be detectable in sputum, bronchoalveolar lavage, stool or histological sections by microscopy or PCR. Antibodies against selected Paragonimus proteins are detectable as early as 2-3 weeks after infection. Therefore, antibody serology is the most promising diagnostic approach for paragonimiasis in North America and elsewhere.

Systems biology studies of adult paragonimus lung flukes facilitate the identification of immunodominant parasite antigens

Background

Paragonimiasis is a food-borne trematode infection acquired by eating raw or undercooked crustaceans. It is a major public health problem in the far East, but it also occurs in South Asia, Africa, and in the Americas. Paragonimus worms cause chronic lung disease with cough, fever and hemoptysis that can be confused with tuberculosis or other non-parasitic diseases. Treatment is straightforward, but diagnosis is often delayed due to a lack of reliable parasitological or serodiagnostic tests. Hence, the purpose of this study was to use a systems biology approach to identify key parasite proteins that may be useful for development of improved diagnostic tests.

Methodology/Principal Findings

The transcriptome of adult Paragonimus kellicotti was sequenced with Illumina technology. Raw reads were pre-processed and assembled into 78,674 unique transcripts derived from 54,622 genetic loci, and 77,123 unique protein translations were predicted. A total of 2,555 predicted proteins (from 1,863 genetic loci) were verified by mass spectrometric analysis of total worm homogenate, including 63 proteins lacking homology to previously characterized sequences. Parasite proteins encoded by 321 transcripts (227 genetic loci) were reactive with antibodies from infected patients, as demonstrated by immunoaffinity purification and high-resolution liquid chromatography-mass spectrometry. Serodiagnostic candidates were prioritized based on several criteria, especially low conservation with proteins in other trematodes. Cysteine proteases, MFP6 proteins and myoglobins were abundant among the immunoreactive proteins, and these warrant further study as diagnostic candidates.

Conclusions

The transcriptome, proteome and immunolome of adult P. kellicotti represent a major advance in the study of Paragonimus species. These data provide a powerful foundation for translational research to develop improved diagnostic tests. Similar integrated approaches may be useful for identifying novel targets for drugs and vaccines in the future.

Paragonimiasis is a food-borne trematode infection that people acquire when they eat raw or undercooked crustaceans. Disease symptoms (including cough, fever, blood in sputum, etc.) can be similar to those observed in patients with tuberculosis or bacterial pneumonia, frequently resulting in misdiagnosis. Although the infection is relatively easy to treat, diagnosis is complicated. Available diagnostic assays rely on total parasite homogenate to facilitate the detection of Paragonimus-specific antibodies in patients. Though these blot-based assays have shown high sensitivity and specificity, they are inconvenient because total parasite homogenate is not readily available. This study used next generation genomic and proteomic methods to identify transcripts and proteins expressed in adult Paragonimus flukes. We then used sera from patients infected with P. kellicotti to isolate immunoreactive proteins, and these were analyzed by mass spectrometry. The annotated transcriptome and the associated proteome of the antibody immune response represent a significant advance in research on Paragonimus. This information will be a valuable resource for further research on Paragonimus and paragonimiasis. Thus this project illustrates the potential power of employing systems biology for translational research in parasitology.

Parasitic diseases as the cause of death of prisoners of war during the Korean War (1950-1953)

To determine the cause of death of prisoners of war during the Korean War (1950-1953), death certificates or medical records were analyzed. Out of 7,614 deaths, 5,013 (65.8%) were due to infectious diseases. Although dysentery and tuberculosis were the most common infectious diseases, parasitic diseases had caused 14 deaths: paragonimiasis in 5, malaria in 3, amoebiasis in 2, intestinal parasitosis in 2, ascariasis in 1, and schistosomiasis in 1. These results showed that paragonimiasis, malaria, and amoebiasis were the most fatal parasitic diseases during the early 1950s in the Korean Peninsula. Since schistosomiasis is not endemic to Korea, it is likely that the infected private soldier moved from China or Japan to Korea.

Preparation of colloidal gold immunochromatographic strip for detection of Paragonimiasis skrjabini

Background

Paragonimiasis is a food-borne trematodiasis, a serious public health issue and a neglected tropical disease. Paragonimus skrjabini is a unique species found in China. Unlike paragonimiasis westermani, it is nearly impossible to make a definitive diagnosis for paragonimiasis skrjabini by finding eggs in sputum or feces. Immunodiagnosis is the best choice to detect paragonimiasis skrjabini. There is an urgent need to develop a novel, rapid and simple immunoassay for large-scale screening patients in endemic areas.

Methodology/Principal Findings

To develop a rapid, simple immunodiagnostic assay for paragonimiasis, rabbit anti-human IgG was conjugated to colloidal gold particles and used to detect antibodies in the sera of paragonimiasis patients. The synthesis and identification of colloidal gold particles and antibody-colloidal gold conjugates were performed. The size of colloidal gold particles was examined using a transmission electron microscope (TEM). The average diameter of colloidal gold particles was 17.46 nm with a range of 14.32–21.80 nm according to the TEM images. The formation of antibody-colloidal gold conjugates was monitored by UV/Vis spectroscopy. Excretory-secretory (ES) antigen of Paragonimus skrjabini was coated on nitrocellulose membrane as the capture line. Recombinant Staphylococcus protein A was used to prepare the control line. This rapid gold immunochromatographic strip was assembled in regular sequence through different accessories sticked on PVC board. The relative sensitivity and specificity of the strip was 94.4% (51/54) and 94.1% (32/34) respectively using ELISA as the standard method. Its stability and reproducibility were quite excellent after storage of the strip at 4°C for 6 months.

Conclusions/Significance

Immunochromatographic strip prepared in this study can be used in a rapid one-step immunochromatographic assay, which is instantaneous and convenient.

Paragonimiasis

Paragonimiasis is a zoonotic disease caused by lung flukes of the genus Paragonimus. Humans usually become infected by eating freshwater crabs or crayfish containing encysted metacercariae of these worms. However, an alternative route of infection exists: ingestion of raw meat from a mammalian paratenic host. Adult worms normally occur in pairs in cysts in the lungs from which they void their eggs via air passages. The pulmonary form is typical in cases of human infection due to P. westermani, P. heterotremus, and a few other species (Table 5.1). Worms may occupy other sites in the body, notably the brain, but lung flukes have made their presence felt in almost every organ. Ectopic paragonimiasis is particularly common when infection is due to members of the P. skrjabini complex (Table 5.1). Human paragonimiasis occurs primarily in the tropics and subtropics of Asia, Africa, and the Americas, with different species being responsible in different areas (Table 5.1).