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).

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.

Paragonimus heterotremus Chen et Hsia, 1964 (Digenea: Paragonimidae): species identification based on the biological and genetic criteria, and pathology of infection.

As a result of the experimental infection of rats with metacercariae of Paragonimus heterotremus Chen et Hsia, 1964 from crabs (Potamiscus tannanti) caught in Yen Bai province, Vietnam, it was found that worms migrated into the lungs, to the liver and less frequently to the tissue that lines body cavities of the hosts, where they reached the adult stage, but in the muscles, worms stayed at the larval stage. Studies have shown that for P. heterotremus, rats can simultaneously play the role of the final and paratenic host; herewith, an infection with the trematode of this species can lead to the development of three forms of paragonimiasis: pulmonary, hepatic and muscular. Eggs from the adult worms localised in the liver, unlike eggs from the adult worms localised in the lungs, were not excreted into the external environment, but accumulated inside the organ. Histology and description of changes, which take place on the external surface of organs affected with P. heterotremus, are given in this study. Based on the behavioural characteristics of worms during rat infection and molecular genetic data, we established that worms from Vietnam and India should be assigned to different species of Paragonimus. P. heterotremus distribution is limited to the territory of the Southeast China, Northern Vietnam, Laos and Thailand.

Prevalence and Risk Factors of Intestinal Parasites in Cats from China.

The prevalence of intestinal parasites in cats from China was largely unknown prior to this study. The aim of the present study was to investigate the presence of intestinal parasites in cats from central China and also identify risk factors for parasitism. Fecal samples from 360 cats were examined using sugar flotation procedure and fecal smear test by microscope. Cats had mixed two or three kinds of parasites infections. Of the 360 cats feces, intestinal parasites positive feces were 149 (41.39%). 64 (17.78%) were infected with Toxocara cati, 61 (16.94%) with Isospora felis, 41 (11.39%) with Isospora rivolta, 33 (9.17%) with Paragonimus, 23 (6.39%) with hookworms, 11 (3.06%) with Toxoplasma-like oocysts, 10 (2.78%) with Trichuris, 4 (1.11%) with lungworm, 2 (0.56%) with Sarcocystis, and 1 (0.28%) with Trematode. The cats' living outdoor was identified as risk factor by statistical analysis. These results provide relevant basic data for assessing the infection of intestinal parasites in cats from central region of China. In conclusion, there was high prevalence of intestinal parasites in cats from China.

Food-borne trematodiases in Southeast Asia epidemiology, pathology, clinical manifestation and control.

The food-borne trematodiases are an important group of neglected tropical diseases (NTDs). Over 40 million people are infected with food-borne trematodes and 750 million (>10% of the world's population) are at risk of these NTDs. Here, we review the life cycles, epidemiology, clinical manifestations, pathology and pathogenesis, diagnosis, treatment, and prevention and control of the major food-borne trematodiases in Southeast Asia. We focus particularly on opisthorchiasis caused by Opisthorchis viverrini and clonorchiasis caused by Clonorchis sinensis, which people contract by ingestion of metacercariae in flesh of raw or undercooked freshwater fishes, on fascioliasis caused by Fasciola species, where infection arises from ingestion of metacercariae on water plants such as watercress, and on Paragonimus species, the lung flukes, which use freshwater crabs and other crustaceans as intermediate hosts. We also include information on the intestinal flukes Fasciolopsis buski, the echinostomes and the so-called 'minute intestinal flukes' of the family Heterophyidae. Ecological information, placing emphasis on reservoir hosts, intermediate snail hosts and secondary hosts where applicable, is also reviewed and research needs are highlighted.

Diversidad enzimática de la fracción soluble de un aislado venezolano de adultos Paragonimus sp / Enzymatic diversity of enzymes in the soluble fraction of adult worms from a Venezuelan isolate of Paragonimus sp

Paragonimus sp. es un trematodo que causa inflamación crónica del pulmón en mamíferos carnívoros y en el hombre, constituyendo un problema de salud pública en países asiáticos y latinoamericanos. Los trematodos poseen enzimas que facilitan la penetración y migración en diferentes hospederos a fin de garantizar su ciclo evolutivo. Con el objetivo de evaluar la diversidad enzimática de la fracción soluble (FSPA, 100.000 g) de un aislado venezolano de adultos de Paragonimus sp. se realizaron determinaciones enzimáticas a diferentes pH, usando curvas de calibración (A 405 nm vs. nmol) para interpolar la absorbancia de grupos p-nitrofenol o p-nitroanilina liberados por la hidrólisis de sustratos sintéticos; se utilizaron también sustratos 2-naftilamídicos y 2-naftólicos para determinar esterasas, peptidasas, fosfomonoesterasas y glicosidasas. Se demostró que fosfohidrolasas, glicosidasas y peptidasas están presentes en la FSPA, destacándose la β-NAG (0,55 μmol/h/mg, pH 5,5) y la cistein proteasa (0,4 μmol/h/mg, pH 5,5) como las actividades más elevadas, señalando la importancia funcional de la actividad glicosídica y peptídica en este parásito, las cuales están probablemente relacionadas con su hábitat y su necesidad de degradación de secreciones pulmonares. Estos resultados representan los primeros estudios enzimáticos registrados en vermes adultos de un aislado venezolano de Paragonimus sp. obtenidos del reservorio Didelphis marsupialis

Paragonimus sp. is a trematode that causes chronic inflammation of the lung in carnivorous mammals and humans, which constitute a public health problem in Asian and Latin American countries. Trematodes have enzymes that facilitate their penetration and migration through different host organs to ensure their life cycle. To evaluate the enzymatic diversity of the soluble fraction (FSPA, 100,000 g) of a Venezuelan isolate of Paragonimus sp. adult worms, several enzyme determinations were conducted at different pH. The activities of enzymes releasing p-nitrophenol or p-nitroanilina from the corresponding dye-related synthetic peptides were assessed by interpolating absorbance (A 405 nm) values in the corresponding calibration curve (A 405 nm vs. nmol); on the other hand, absorbances82 Bol. Mal. Salud Amb.Diversidad enzimatica de Paragonimus sp. en Venezuelaof 2-naphtylamine and 2-naphtols released from another series of synthetic substrates were read at different wavelengths between 450 nm and 620 nm to assess for the activity of the corresponding hydrolases. Phosphohydrolase, glycosidase and peptidase activities were detected in FSPA, β-N-acetyl-β-D-glucosaminidase (0.55 μmol/h/mg, pH 5.5) and cystein protease (0.4 μmol/h/mg, pH 5.5) being higher than all the other detected activities. These activities are probably related to the adult worm habitat and its need for glycan and peptide degradation of lung secretions. These results represent the first enzymatic study done with a Venezuelan isolate of adult Paragonimus sp. worms collected from the common reservoir Didelphis marsupialis

[Paragonimosis in the peri-urban zone of Medellín, Antioquia]. / Estudio de foco de paragonimosis en Fuente Clara, Robledo, área periurbana de Medellín, Antioquia.

INTRODUCTION: Human paragonimosis in Colombia was assumed to be restricted to the sylvatic areas. However, in 2005, crabs infected with Paragonimus were found in Fuente Clara, an urban sector in Medellín. OBJECTIVE: A study was designed to understand the ecoepidemiology of paragonimosis. Programs were initiated to educate the community in the suitable use of wetland ecosystems. MATERIALS AND METHODS: Infection rates of Paragonimus in human and wild hosts was documented in the Fuente Clara sector. The presence of larvae and digenic adult worms was detected in mollusks (1,312), crabs (27) and mammals (4). Sputum diagnosis was performed on samples from 18 volunteer individuals. The following determinants of water quality were measured in the stream La Puerta: total fecal/coliform, pH, conductivity and dissolved oxygen were measured. Recreational workshops were conducted with children and teenagers for educational purposes. RESULTS: The percentage of infections found in hosts was as follows: snails, 0.07%; crabs, 55.5%; (wild) mammals, 25%; humans, 0%. During the workshops, children and teenagers identified the Paragonimus hosts and the risk factors for acquiring the disease. The water of the stream was found to be unsuitable for consumption and recreation (the most probable number of total coliforms/100 ml was in a scale of 104). CONCLUSIONS: Fuente Clara is the first urban locality in Colombia where a focus of Paragonimus was found. Exposure to and consumption of crabs may constitute a risk for human infection.

Estudio de foco de paragonimosis en Fuente Clara, Robledo, área periurbana de Medellín, Antioquia / Paragonimosis in the peri-urban zone of Medellín, Antioquia

Introducción. La información sobre paragonimosis humana en Colombia llevó a suponer que los focos de la enfermedad estaban localizados en sectores selváticos; sin embargo, durante 2005 se hallaron cangrejos infectados con Paragonimus sp. en Fuente Clara, zona urbana de Medellín. Esto motivó la investigación. Objetivo. Realizar un estudio ecoepidemiológico de la paragonimosis con la participación de la comunidad para promover un manejo adecuado de los ecosistemas acuáticos. Materiales y métodos. Se realizó búsqueda de huéspedes silvestres y humanos de Paragonimus sp. en Fuente Clara. La presencia de formas larvarias y gusanos adultos del digéneo se evaluó en moluscos, crustáceos y mamíferos. En las personas voluntarias se hizo diagnóstico en esputo. Al agua de la quebrada La Puerta se le midieron: coliformes totales/fecales, pH, conductividad y oxígeno disuelto. Con niños y adolescentes se realizaron talleres educativos utilizando técnicas lúdicas. Resultados. Los porcentajes de infección encontrados fueron: caracoles, 0,07 por ciento; cangrejos, 55,5 por ciento; mamíferos, 25 por ciento, y personas, 0 por ciento. Durante los talleres educativos se manifestó la importancia de los recursos naturales del barrio. Los niños identificaron los huéspedes de Paragonimus sp. y detectaron los factores de riesgo para adquirir la enfermedad. Se determinó que el agua de la quebrada La Puerta no es apta para el consumo y la recreación de las personas. Conclusiones. Se señala a Fuente Clara como el primer foco de paragonimosis en zona urbana de Colombia, donde la manipulación y el consumo de cangrejos ponen en riesgo de adquirir la infección a sus habitantes; se sugiere realizar vigilancia de la enfermedad en el sector.

Paragonimiasis: an important food-borne zoonosis in China.

The lung fluke, Paragonimus westermani, is of major socioeconomic importance in Asia. The parasite is transmitted via snails to freshwater crabs or crayfish, then to humans and other mammals, such as cats and dogs, and causes paragonimiasis. This review provides a background on the parasite and its life cycle; summarizes key aspects regarding the pathogenesis, diagnosis and treatment of paragonimiasis; describes the geographic distribution and prevalence of paragonimiasis; and makes some recommendations for future research and the control of this important disease in China.

On a new lung fluke found in Peru, Paragonimus peruvianus sp. n. (Trematoda: Troglotrematidae)

Paragonimus peruvians sp.n was described from two cats captured in La Asunción and El Guayo, Cajamarca, Peru. The new species is allied to P. mexicanus Miyazaki et Ishii, 1968 in morphology, but they are separated by the branching of the ovary and testes as well as by the character of eggs. It is most likely that human paragonimiasis occurring in Cajamarca area is caused by the new species. The metacercaria belonging probably to P. peruvianus was found in a fresh-water crab, Pseudothelphusa chilensis collected in El Guayo, which is not infrequently eaten uncooked by inhabitants in that area. Ultimately, P. peruvianus seems to be very important in the medical field.

Discovery of Paragonimus proliferus in Northern Vietnam and their molecular phylogenetic status among genus Paragonimus.

During an epidemiological survey for Paragonimus and paragonimosis in northern Vietnam, we found extremely large excysted metacercariae (2.50 +/- 0.14 mm in length and 0.72 +/- 0.08 mm in width; mean +/- standard deviation of 20 samples) in mountainous crabs, Potamiscus mieni. Adult worms were successfully obtained by intraperitoneal injection with those large excysted metacercariae in a cat. Morphological and morphometric data of those large excysted metacercariae and the adult worms derived from them are identical to those of Paragonimus proliferus found in Yunnan province, China. However, when second internal transcribed spacer region and cytochrome oxidase subunit 1 gene sequences of those metacercariae and adult worms were compared with those of known Paragonimus spp. deposited in the GenBank, they were almost completely identical to those of Paragonimus hokuoensis metacercariae in China, of which adult worms have never been reported. This is the first record of P. proliferus in Vietnam and the first record from outside of China. Phylogenetic relationship between P. proliferus and P. hokuoensis is discussed.

[Distribution of Paragonimus (Digenea: Troglotrematidae) in Antioquia Province, Colombia, based on metacercariae counts in freshwater crabs]. / Distribución parcial de Paragonimus (Digenea: Troglotrematidae) en Antioquia, por presencia de metacercarias en cangrejos dulciacuícolas.

INTRODUCTION: Paragonimosis or lung fluke disease courses with signs similar to those seen in tuberculosis. The causative agent is a parasite of the genus Paragonimus (Digenea: Troglotrematidae). People become infected by ingesting raw or partially cooked crabs containing metacercariae. The first focus of human paragonimosis in Colombia was recorded in the county of Urrao, where two species of crabs infected with Paragonimus were found. In 2005, crabs with Paragonimus' metacercariae were captured near Medellín, western Colombia. This prompted a search for the parasite in other locations through its presence in the crabs. OBJECTIVE: To establish the distribution of Paragonimus in Antioquia, we evaluated the presence of metacercaria in freshwater brachyuran crabs. MATERIALS AND METHODS: From 2005 to 2007, crabs were captured in 13 counties of Antioquia. The crabs were relaxed and dissected to determine presence of trematodes and then to make the taxonomic identifications. RESULTS: From 52 crabs captured in 9 counties, 42 (80.8%) were found with Paragonimus metacercariae. The crabs were identified as Pseudothelphusidae in 2 genera--Hypolobocera and Strengeriana--and were assigned to four species. Three of the species were recorded for the first time as hosts of Paragonimus. CONCLUSIONS: A Paragonimus' distribution map was constructed for Antioquia; for the first time urban zones were included. Because of the high rate of infection, the handling and consumption of raw and poorly cooked crabs pose risk factors for human infection. Because crabs are affordable and provide means of easy diagnosis, crabs are targeted as primary agents of and diagnostic tools for paragonmosis.

História natural da infecção por Paragonimus: abordagem clínica e ecológica / Natural history of Paragonimus’ infection: clinical and ecological approach

A paragonimíase é uma doença zoonótica, não-contagiosa, produzida por trematódeos do gênero Paragonimus. O homem e outros animais infectam-se ao ingerir crustáceos de água doce — crus, mal cozidos ou em conserva — ou, ainda, água e/ou alimentos contaminados com metacercárias. Apresenta evolução crônica e acometimento predominantemente pulmonar, ainda que sejam descritas descritas alterações extrapulmonares. Podem surgir sinais e sintomas como tosse com expectoração sanguinolenta, febre intermitente, dor torácica, suores noturnos e, mais raramente, astenia, anorexia e perda de peso. Como principais métodos diagnósticos destacam-se o exame a fresco do escarro e/ou das fezes do paciente e os testes imunológicos. O tratamento é realizado com praziquantel. A infecção, habitualmente, tem bom prognóstico.

A rodent model for pulmonary paragonimiasis.

This study reports a model of pulmonary paragonimiasis in outbred Wistar rats using the Indian strain of Paragonimus heterotremus isolated from the fresh water crab Barytelphusa lugubris collected from Arunachal Pradesh, India. Feeding metacercariae to the rats led to encapsulated adult worms in the lungs and pleural cavity. Some flukes migrated to the skeletal muscles of the hosts where they remained underdeveloped as immature flukes.

Paragonimiasis of the breast. Report of a case diagnosed by fine needle aspiration.

BACKGROUND: Paragonimiasis infestation is endemic mostly to Asia, Africa and South and Central America and commonly found in the lung. It is extremely rare in soft tissue. CASE: A case of paragonimiasis occurred in a 66-year-old woman who presented with a left, painful, 2-cm-diameter breast mass and had a history of eating uncooked freshwater crabs. On mammography, an ill-defined, round, isodense mass was detected without calcification. Hemorrhagic material was aspirated by fine needle aspiration (FNA) of the breast mass, which contained many parasitic eggs. They were about 90 microns long, ovoid, yellowish brown, transparent and thick shelled, with a flattened operculum at 1 end. The breast mass was completely excised. Many collapsed eggs of Paragonimus infiltrated the lobules and fibroadipose tissue, with accompanying abscess formation. To confirm the diagnosis, serologic testing for paragonimiasis was performed; it was positive for Paragonimus antibody. CONCLUSION: Paragonimiasis very rarely presents as a breast mass and can be diagnosed by FNA.

Cavitary mass lesion and recurrent pneumothoraces due to Paragonimus kellicotti infection: North American paragonimiasis.

North American paragonimiasis is well described in omnivorous and carnivorous animals on this continent. Humans are rarely infected, largely because of dietary customs, but are at risk for infection if raw or undercooked crayfish are consumed. We describe a patient with a pleuropulmonary infection due to Paragonimus kellicotti that presented as recurrent pneumothoraces and a cavitary lesion. This is the first case of North American paragonimiasis in which the diagnosis was based on the morphology of the eggs present in histologic sections.