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

Infection and biogeographical characteristics of Paragonimus westermani and P. skrjabini in humans and animal hosts in China: A systematic review and meta-analysis

BACKGROUND

Paragonimiasis, primarily caused by Paragonimus westermani and P. skrjabini in China, is a common food-borne parasitic zoonosis. However, the national distribution of Paragonimus spp. infection and its associated environmental determinants remain poorly understood. In this paper, we summarize the infection of P. westermani and P. skrjabini and describe key biogeographical characteristics of the endemic areas in China.

METHODS

Data on Paragonimus infection in humans and animal hosts were extracted from eight electronic databases, including CNKI, CWFD, Chongqing VIP, SinoMed, Medline, Embase, PubMed, and Web of Science. A random-effects meta-analysis model was used to estimate the pooled prevalence. All survey locations were georeferenced and plotted on China map, and scatter plots were used to illustrate the biogeographical characteristics of regions reporting Paragonimus infection.

RESULTS

A total of 28,948 cases of human paragonimiasis have been documented, with 2,401 cases reported after 2010. Among the 11,443 cases with reported ages, 88.05% were children or adolescents. The pooled prevalence of P. skrjabini is 0.45% (95% CI: 0.27-0.66%) in snails, 31.10% (95% CI: 24.77-37.80%) in the second intermediate host, and 20.31% (95% CI: 9.69-33.38%) in animal reservoirs. For P. westermani, the pooled prevalence is 0.06% (95% CI: 0.01-0.13%) in snails, 52.07% (95% CI: 43.56-60.52%) in the second intermediate host, and 21.40% (95% CI: 7.82-38.99%) in animal reservoirs. Paragonimus are primarily distributed in regions with low altitude, high temperature, and high precipitation. In northeastern China, only P. westermani infections have been documented, while in more southern areas, infections of both P. westermani and P. skrjabini have been reported.

CONCLUSIONS

Paragonimiasis remains prevalent in China, particularly among children and adolescents. Variations exist in the intermediate hosts and geographical distribution of P. westermani and P. skrjabini. Additionally, altitude, temperature, and precipitation may influence the distribution of Paragonimus.

Epidemiologic evaluation of pulmonary paragonimiasis in Japan using a Japanese nationwide administrative database

BACKGROUND

Paragonimiasis is a parasitic disease primarily contracted through consumption of undercooked freshwater crustaceans or wild boar meat. Large-scale nationwide epidemiological data on paragonimiasis are lacking. In this study, we aimed to investigate the nationwide epidemiology of hospitalized patients with paragonimiasis in Japan using a comprehensive nationwide Japanese administrative database.

METHODS

We evaluated the Japanese Diagnosis Procedure Combination (DPC) data of patients diagnosed with pulmonary paragonimiasis between April 1, 2012 and March 30, 2020. The patients' address and information, including age, sex, treatment (medication: praziquantel; surgery: open thoracotomy or intracranial mass extirpation), Japan coma scale, comorbidities, and length of hospital stay, were extracted.

RESULTS

Of the 49.6 million hospitalized patients, data were extracted on 73 patients with paragonimiasis, of whom 36 were male and 37 were female. The mean age was 49.7 years and the mean length of stay was 12.5 days. The most frequent comorbidity was pleural effusion (31.5 %), followed by pneumothorax (13.7 %). The sites of ectopic paragonimiasis in organs other than the lung included the liver (5.5 %), skin (4.1 %), and brain (2.7 %). Geographically, most patients were from the Kyushu region (54.8 %), followed by the Kanto region (22.0 %). Fukuoka Prefecture had the highest number of patients (22.0 %) by prefecture. During the study period, an average of 9.1 patients/year were hospitalized with lung paragonimiasis in Japan.

CONCLUSION

Paragonimiasis has not completely disappeared in Japan; thus, physicians should be aware of paragonimiasis in the Kyushu region, especially in the Fukuoka Prefecture.

Unusual pediatric lung infections: imaging findings

Pediatric lung infections continue to be a leading cause of pediatric morbidity and mortality. Although both pediatric and general radiologists are familiar with typical lung infections and their imaging findings in children, relatively rare lung infections continue to present a diagnostic challenge. In addition, the advances in radiological imaging and emergence of several new lung infections in recent years facilitated the need for up-to-date knowledge on this topic. In this review article, we discuss the imaging findings of pediatric lung infections caused by unusual/uncommon and new pathogens. We review the epidemiological, clinical, and radiological imaging findings of viral (coronavirus disease 2019, Middle East respiratory syndrome, bird flu), bacterial (Streptococcus anginosus, Francisella tularensis, Chlamydia psittaci), and parasitic lung infections (echinococcosis, paragonimiasis, amoebiasis). Additional disorders whose clinical course and imaging findings may mimic lung infections in children (hypersensitivity pneumonitis, pulmonary hemorrhage, eosinophilic pneumonia) are also presented, to aid in differential diagnosis. As the clinical presentation of children with new and unusual lung infections is often non-specific, imaging evaluation plays an important role in initial detection, follow-up for disease progression, and assessment of potential complications.

Pancreatic Paragonimiasis in Children: A Case Report

ABSTRACT

A few pediatric cases of abdominal paragonimiasis have been described. Here we describe a case of pulmonary and abdominal paragonimiasis with involvement of the pancreas in a 9-year-old boy. The aim of this study was to analyze the clinical and radiological features of pancreatic paragonimiasis in children and raise the awareness of this disease.

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. 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. Human paragonimiasis occurs primarily in the tropics and subtropics of Asia, Africa, and the Americas, with different species being responsible in different areas (Table 6.1).

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 the present 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.

Massive secretions in paragonimiasis pleural effusion: a new finding concerning clinical recognition and treatment

Some paragonimiasis patients in Chongqing, southwest China, have recently exhibited pleural effusions (PEs) with massive viscous secretions. This study aimed to investigate their clinical characteristics, thereby promoting effective treatments. A 3-year retrospective review of paragonimiasis patients who were admitted for nonhomogeneous PEs at Chongqing University Three Gorges Hospital was conducted. Epidemiological data, symptoms, laboratory and imaging findings, treatments, and outcomes were analyzed. Twenty-eight patients were identified, of which 22 (78.6%) were males and 22 (78.6%) were rural residents. Respiratory (85.7%) and constitutional (57.1%) symptoms were common. Paragonimus-specific ELISA was positive in all patients. Eosinophilia was detected in all patients in peripheral blood and PEs. Irregular hyperdense signals were observed in PEs by chest CT scans (96.4%) and ultrasonography (100.0%). Thoracic closed drainage failed in 10 patients (conservative group) because of tube blockage and was eventually replaced by video-assisted thoracoscopic surgery (VATS). Eighteen patients (surgery group) initially underwent VATS, or thoracotomy surgery, without complications. Massive secretions, described as "bean-dregs" or "egg-floccule," were detected intraoperatively, which explained the imaging findings and tube blockage. All patients recovered well after 2-3 courses of postoperative praziquantel treatment. Viscous secretions in paragonimiasis patients warrant great concern. Irregular hyperdense signals in effusions are important characteristics in CT scans and ultrasonography. Treatments such as thoracic closed drainage may fail due to viscous secretions blocking the tube; therefore, surgeries should be considered. In-depth multidisciplinary research may help determine the optimal treatment strategy and reveal the origin of these secretions.

Morphological and Molecular Characterization of Paragonimus Species Isolated from Freshwater Crabs in Southern Yunnan, China

Paragonimus species are highly prevalent in various regions of China. The study's objective is to isolate and identify Paragonimus from natural habitats and compare the phylogenetic diversity of Paragonimus in southern Yunnan province, China. Metacercariae of Paragonimus was isolated from crabs, and morphologic identification was performed by microscopy. Metacercariae were injected into experimental Paragonimus free Sprague Dawley rats. After 114 days, adult worms and eggs were isolated from multiple organs. Morphologic identification confirmed the initial identification. DNA was extracted from 5 adult worms, and molecular characterization was performed by amplification and sequencing of CO1 and ITS2 regions, followed by phylogenetic analysis. Out of 447 crabs captured, 186 crabs were found to be infected. A total of 4 species of Paragonimus was observed from naturally infected crabs. Paragonimus microrchis (2), Paragonimus heterotremus (1), Paragonimus proliferus (1), and Paragonimus skrjabini (1) were isolated and identified. A total of 32 sequences were downloaded from the National Center for Biotechnology Information, and 5 sequences generated in the study were used for phylogenetic analysis. In the phylogenetic tree of the CO1 gene, Paragonimus proliferus, Paragonimus heterotremus, and Paragonimus skrjabini were clustered with the same species, and the confidence values of their branches were >95%. A congruent phylogenetic relationship was observed with the ITS2 phylogenetic tree. In the phylogenetic tree constructed with the combined dataset of CO1 and ITS2 datasets, Paragonimus proliferus, Paragonimus heterotremus, and Paragonimus skrjabini clustered with the same species, and their branch confidence values were >94%. Paragonimus microrchis clustered with Paragonimus bangkokensis in both datasets. Phylogenetic analysis revealed robustness of the double loci method as against the single-locus method with either CO1 or ITS2 alone. Paragonimus species isolated from the southern Yunnan province, China, was phylogenetically diverse, and the analysis revealed the clustering of multiple species of Paragonimus isolated from different geographic locations.

Case Report: Intermittent Chest Pain With Cough, Fever, and Pericardial Effusion Over the Course of 1 Year in an 11-Year-Old Girl

An 11-year-old girl presented with frequent chest pain, fever, and a cough that she had had for more than 13 months, as well as pleural effusion and large pericardial effusion. She was misdiagnosed with tuberculosis and received anti-tuberculosis drugs for 6 months. Within the past year, she also underwent two more thoracotomies and a thoracoscopic partial pericardiectomy. The final diagnosis of pulmonary paragonimiasis was established once it was known that she had eosinophilia, always drank stream water, and tested positive for antibodies against Paragonimus. Since antiparasitic praziquantel therapy was effective, paragonimiasis should be considered as a possibility in the differential diagnosis of tuberculosis in children.

Paragonimus infection: Rare manifestation with pericardial effusion: A Case report and Literature review

Background

Paragonimus, is a globally distributed trematode, with human disease limited to endemic regions. It can be transmitted to humans through ingestion of intermediate hosts that are crustaceans. Most symptomatic infections consist of pulmonary disease, and in aberrant migration of immature flukes, extrapulmonary manifestations may occur. These presentations are relatively uncommon and may affect various organs with atypical Clinico-radiological pathologies that are often challenging to diagnose. Pericardial involvement has scarcely been reported before. Furthermore, the management, clinical outcomes and potential complications of this involvement remain unclear.

Case report

Our patient is a 31-year-old Nepalese male who presented with abdominal distension and lower limb oedema. Initial work up revealed pericardial effusion, and analysis was suggestive of exudative lymphocytic effusion. Supported by positive QuantiFERON result along with his demographic data, the patient was treated presumptively as a case of tuberculous pericarditis, despite the negative initial Mycobacterial Tuberculosis work up. During follow up, the patient lacked clinical response and repeated echocardiography showed signs of tamponade with concomitant pleural effusion. subsequently video-assisted-thoracoscopy pericardial window along with pericardial and pleural biopsy were performed. Histopathological examination of the biopsied tissue revealed non-necrotizing granulomas containing a parasitic egg suggestive of Paragonimus. Fortunately, the patient received treatment with praziquantel and subsequently made good clinical recovery.

Conclusion

Diagnosis of extrapulmonary Paragonimus infection can be challenging given its rarity and clinical picture mimicking other infectious aetiologies. Pericardial involvement is seldom reported in the literature and clinical suspicion should be raised particularly when dealing with atypical presentations and relevant demographic data.

Pulmonary Manifestations of Parasitic Diseases in Children

Parasites can cause respiratory symptoms through focal or diffuse lung involvement, depending on the location of the parasite and the host's immune response. Pulmonary involvement can be a major feature of some parasitic infections or a complication during transpulmonary larval migration. Parasites should be included in the differential diagnosis of common lung diseases, especially in the presence of peripheral eosinophilia or extrapulmonary symptoms (abdominal pain, diarrhea, jaundice, skin lesions).

A retrospective clinical analysis of pediatric paragonimiasis in a Chinese children's hospital from 2011 to 2019

Diagnosis of pediatric paragonimiasis is difficult because of its non-specific clinical manifestations. We retrospectively reviewed the records of pediatric paragonimiasis in Children's Hospital of Fudan University from January 2011 to May 2019. The confirmed diagnosis of paragonimiasis was based on positive anti-parasite serological tests from the local Center for Disease Control (CDC). A total of 11 patients (mean age: 7.7 ± 3.1, male-female ratio: 7:4) diagnosed as paragonimiasis were included. 81.8% were from endemic areas such as Sichuan and Yunnan, and 36% had a clear history of raw crab or crayfish consumption. The characteristic clinical features of pediatric paragonimiasis were eosinophilia (100%), pleural effusion (81.8%), hepatomegaly (54.5%), ascites (54.5%), and subcutaneous nodules (45.5%). Misdiagnosed with other diseases including tuberculosis (18.2%), pneumonia (9.1%), intracranial space-occupying lesions (9.1%) and brain abcess (9.1%) led to rehospitalization and prolonged hospitalization. For treatment, a 3-day course of 150 mg/kg praziquantel (PZQ) didn't show ideal treatment effectivity and 63.6% needed more than one course of PZQ, while triclabendazole in a total dose of 10 mg/kg had a better efficacy to stubborn manifestations. This study indicated that pediatric paragonimiasis was often misdiagnosed, and the treatment with a 3-day course of 150 mg/kg PZQ had a high rate of failure.

Distinguishment of parasite-infected children from pediatric inpatients with both eosinophilia and effusion

Patients with both serous effusion and eosinophilia are rarely reported and geographically distributed; their early diagnosis is difficult.According to the ultimate diagnosis, patients (≤14 years) in West China Second hospital with serous effusion and eosinophilia were divided into two groups including a parasitic group and a non-parasitic group. Clinical data were collected and analyzed between the two groups. Subsequently, significant measurement indicators were evaluated by receiver operating characteristic (ROC) curve to explore the optimal cut-off points for the most appropriate sensitivity and specificity.A total of 884 patients were diagnosed with serous effusion and 61 of them displayed co-morbidity with eosinophilia during enrolled time. Among 61 patients, 34 patients had parasitic infection and 27 had non-parasitic diseases. There were statistical difference in effusion position, the levels of white blood cell count (WBC), eosinophil (EOS), EOS%, C-reactive protein (CRP) between parasitic group and non-parasitic group. ROC curve demonstrated that the areas under the curve of EOS count and EOS% were >80%, and the corresponding optimal cut-off values were 1.71 × 10/L and 25.6% for distinguishing between parasitic and non-parasitic infections in our patients.This study provided a quantified index for potentially quick and convenient indicators of pediatric patients presenting with both eosinophilia and effusion. Eosinophils were helpful to improve the initial diagnosis with awareness of parasitic diseases. For the cases with EOS > 1.71 × 10/L or EOS% > 25.6%, parasitic infection should be considered and serological tests are recommended in our region.

Paragonimus and paragonimiasis in Asia: An update

Paragonimiasis, or lung fluke disease, is a typical food-borne parasitic zoonosis caused by infection with trematodes belonging to the genus Paragonimus. More than 50 species of Paragonimus have been reported throughout the world, of which seven valid species infect humans, an estimated one million people annually worldwide. Among the seven species, P. westermani, P. heterotremus, and P. skrjabini/P. s. miyazakii, distributed in Asia, are the most important species as the cause of paragonimiasis. Humans acquire infection through the ingestion of raw, pickled or undercooked freshwater crustaceans, 2nd intermediate hosts, or consuming raw meat of wild boar or deer, paratenic hosts. Infections often occur clustered in foci where dietary habits allow transmission of the parasites. Paragonimiasis typically causes a subacute to chronic inflammatory disease of the lungs. The symptoms, including chronic cough, chest pain, dyspnea and hemoptysis, mimic those of tuberculosis and lung cancer. Serologic tests are commonly used for the diagnosis of paragonimiasis, and Praziquantel is the treatment of choice. In this review, the current status of Paragonimus and paragonimiasis in Asia is outlined based on the latest information and findings. We also summarize current trends of paragonimiasis in Japan, which is one of the most endemic area of paragonimiasis in the world, for the better understanding and control of paragonimiasis.

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.

Diagnosis and surgical management of pericardial effusion due to paragonimiasis

OBJECTIVES

The pericardial effusion (PE) caused by paragonimiasis is rarely reported. This study aims to present experience in the diagnosis and surgical management of PE due to paragonimiasis.

METHODS

Medical records of 57 children who were diagnosed with PE due to paragonimiasis and underwent surgery at Children's Hospital of Chongqing Medical University between January 2012 and August 2018 were retrospectively reviewed.

RESULTS

The average age of this group was 7.6 ± 3.0 years. Patients were mainly from Chongqing and Sichuan areas. ELISA for Paragonimus skrjabini in all 57 patients showed positive results. Moderate or large PE were identified in 12 and 45 patients, respectively. All patients underwent surgery either by pericardectomy or thoracoscopic surgery. Pathological exams indicated massive eosinophil infiltration in all 57 specimens. After 3-4 courses of praziquantel therapy, the clinical outcomes were satisfactory.

CONCLUSIONS

Typical endemic history, eosinophilia and multiple serous effusion raise suspicions of paragonimiasis. Once moderate to large PE is identified in patients with paragonimiasis, surgical treatment is necessary.

Large Pericardial Effusion Due to Paragonimiasis in a 4-Year-Old Chinese Boy

Large pericardial effusion (PE) and bilateral pleural effusion were found in a 4-year-old Chinese boy. An emergent surgery was performed. The biopsy showed massive eosinophil infiltration. Serologic test for Paragonimus skrjabini was positive. Postoperative praziquantel therapy was effective.

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).

Case series of paragonimiasis from Nepal

Paragonimiasis is an important food-borne parasitic zoonosis caused by trematodes of genus Paragonimus. We report case series of paragonimiasis with common symptoms of cough with blood tinged sputum, shortness of breath, chest pain with occasional fever, eosinophilia and radiological findings mimicking pulmonary tuberculosis and had taken anti-tubercular drug despite all investigation negative for tuberculosis without improvement. They all had common history of consumption of raw/undercooked crab. There is a local belief in remote villages of Nepal that eating raw crab helps in healing bone fracture and cure jaundice. Microscopic examination of sputum sample revealed the ova of Paragonimus species. All patients were treated with praziquantel and got improved. Pulmonary paragonimiasis is endemic in Southeast Asia including Nepal. So, it has to be differentiated from pulmonary tuberculosis in the patient with symptoms of cough, chest pain and hemoptysis with eosinophilia and having history of consumption of raw/undercooked crabs or crayfish.