OBJECTIVE: To investigate the sequences of internal transcribed spacer 2 (ITS2) and cyclooxygenase 1 (COX1) genes of Paragonimus metacercariae in freshwater crabs in Henan Province, identify the species of Paragonimus and evaluate its genetic relationships with Paragonimus isolates from other provinces in China. METHODS: Freshwater crabs were collected from 8 survey sites in Zhengzhou, Luoyang, Pingdingshan, Nanyang and Jiyuan cities of Henan Province from 2016 to 2021, and Paragonimus metacercariae were detected in freshwater crabs. Genomic DNA was extracted from Paragonimus metacercariae, and the ITS2 and COX1 genes were amplified using PCR assay, followed by sequencing of PCR amplification products. The gene sequences were spliced and aligned using the software DNASTAR, and aligned with the sequences of Paragonimus genes in the GenBank. Phylogenetic trees were created using the MEGA6 software with the Neighbor-Joining method based on ITS2 and COX1 gene sequences, with Fasciola hepatica as the outgroup. RESULTS: The detection rates of Paragonimus metacercariae were 6.83% (11/161), 50.82% (31/61), 18.52% (5/26), 8.76% (12/137), 14.29% (9/63), 17.76% (19/105), 18.50% (32/173) and 42.71% (41/96) in freshwater crabs from 8 survey sites in Zhengzhou, Luoyang, Pingdingshan, Nanyang and Jiyuan cities of Henan Province, with a mean detection rate of 19.46% (160/822), and a mean infection intensity of 0.57 metacercariae/g. The amplified ITS2 and COX1 gene fragments of Paragonimus were approximately 500 bp and 450 bp in lengths, respectively. The ITS2 gene sequences of Paragonimus metacercariae from 8 survey sites of Henan Province showed the highest homology (99.8% to 100.0%) with the gene sequence of P. skrjabini (GenBank accession number: MW960209.1), and phylogenetic analysis showed that the Paragonimus in this study was clustered into the same clade with P. skrjabini from Sichuan Province (GenBank accession number: AY618747.1), Guangxi Zhuang Autonomous Region (GenBank accession number: AY618729.1) and Hubei Province (GenBank accession number: AY618751.1), and P. miyazaki from Fujian Province (GenBank accession number: AY618741.1) and Japan (GenBank accession number: AB713405.1). The COX1 gene sequences of Paragonimus metacercariae from 8 survey sites of Henan Province showed the highest homology (90.0% to 100.0%) with the gene sequence of P. skrjabini (GenBank accession number: AY618798.1), and phylogenetic analysis showed that the Paragonimus in this study was clustered into the same clade with all P. skrjabini and clustered into the same sub-clade with P. skrjabini from Hubei Province (GenBank accession numbers: AY618782.1 and AY618764.1). CONCLUSIONS Paragonimus species from freshwater crabs in Henan Province were all characterized as P. skrjabini, and the ITS2 and COX1 gene sequences had the highest homology to those of P. skrjabini from Hubei Province. The results provide insights into study of Paragonimus in Henan Province and China.
Animals ; Paragonimus/genetics* ; Brachyura/genetics* ; Cyclooxygenase 1/genetics* ; Phylogeny ; China/epidemiology* ; Sequence Analysis, DNA ; Paragonimiasis

This study aimed to determine the status of common parasitic disease in Korea in 2019. Twelve parasitic diseases were selected: toxocariasis, anisakiasis, paragonimiasis, sparganosis, cysticercosis, toxoplasmosis, clonorchiasis, enterobiasis, trichuriasis, trichomoniasis, cryptosporidiosis, and malaria. Their biology, epidemiology, pathogenesis, symptoms and signs, diagnosis, treatment, and prognosis were evaluated. Of the parasitic diseases, toxocariasis was the most prevalent according to serological results. Anisakiasis should be considered when acute gastrointestinal symptoms occur with a recent past history of raw seafood ingestion. Paragonimiasis, sparganosis, and cysticercosis can be diagnosed using an enzyme-linked immunosorbent assay; thus, enzyme-linked immunosorbent assay needs to be performed for suspected cases. Toxoplasmosis and cryptosporidiosis are opportunistic infections. The symptoms and signs are aggravated under immunocompromised conditions. Although the egg positivity rate of Clonorchis sinensis is higher than that of other intestinal parasitic diseases, encountering patients with complaints of symptoms caused by clonorchiasis is rare because the worm burden is low. Trichomoniasis is usually managed by gynecologists; therefore, it should be included in the differential diagnoses of vaginal diseases. The annual number of malaria cases has decreased, although it remains at approximately 500 cases per year. Malaria should be suspected when symptoms such as intermittent fever, headache, and splenomegaly are noted especially when the patients reside near demilitarized zones. Although the prevalence and number of reported cases of parasitic diseases have decreased in Korea, we should consider parasitic diseases in the list of differential diagnoses.
Animals ; Anisakiasis ; Biology ; Clonorchiasis ; Clonorchis sinensis ; Cryptosporidiosis ; Cysticercosis ; Diagnosis ; Diagnosis, Differential ; Eating ; Enterobiasis ; Enzyme-Linked Immunosorbent Assay ; Epidemiology ; Fever ; Headache ; Humans ; Korea ; Malaria ; Opportunistic Infections ; Ovum ; Paragonimiasis ; Parasitic Diseases ; Prevalence ; Prognosis ; Republic of Korea ; Seafood ; Sparganosis ; Splenomegaly ; Toxocariasis ; Toxoplasmosis ; Trichuriasis ; Vaginal Diseases

Paragonimiasis is a food-borne parasitic zoonosis caused by infection with lung flukes of the genus Paragonimus. In Vietnam, research on Paragonimus and paragonimiasis has been conducted in northern and central regions of the country. Using a combination of morphological and molecular methods, 7 Paragonimus species, namely P. heterotremus, P. westermani, P. skrjabini, P. vietnamensis, P. proliferus, P. bangkokenis and P. harinasutai, have been identified in Vietnam. Of these, the first 3, P. heterotremus, P. westermani and P. skrjabini, are known to infect humans in other countries. However, in Vietnam, only P. heterotremus, found in some northern provinces, has been shown to infect humans. Even nowadays, local people in some northern provinces, such as Lai Chau and Yen Bai, are still suffering from P. heterotremus infection. In some provinces of central Vietnam, the prevalence and infection intensity of P. westermani metacercariae in freshwater crabs (the second intermediate hosts) are extremely high, but human cases have not been reported. Likewise, although P. skrjabini was found in Thanh Hoa Province, its pathogenicity to humans in Vietnam still remains uncertain. The results of molecular phylogenetic analyses of Vietnamese Paragonimus species provides new insights on the phylogeny and taxonomy of the genus Paragonimus. Comprehensive molecular epidemiological and geobiological studies on the genus in Vietnam and adjacent countries are needed to clarify the biodiversity and public health significance of the lung flukes.
Animals ; Humans ; Paragonimiasis/*epidemiology ; Paragonimus/classification/genetics/*isolation & purification ; Phylogeny ; Prevalence ; Sequence Analysis, DNA ; Shellfish/parasitology ; Vietnam/epidemiology

Seroprevalence of the IgG antibodies for Clonorchis sinensis, Paragonimus westermani, Taenia solium metacestode (cysticercus), and Spirometra erinacei plerocercoid (sparganum) was measured using enzyme-linked immunosorbent assay (ELISA) in sera of patients in Korea from 1993 to 2006. A total of 74,448 specimens referred nationwide from 121 hospitals revealed an IgG positive rate of 7.6% for the 4 parasites. The IgG positive rate (18.7%) for the 4 parasites in 1993 decreased gradually to 6.6% in 2006. Individual positive rate decreased from 5.2% (1993) to 1.6% (2006) for C. sinensis, from 2.8% (1993) to 1.1% (2006) for P. westermani, from 8.3% (1993) to 2.2% (2006) for cysticercus, and from 2.6% (1993) to 1.6% (2006) for sparganum. The positive rate was highest (21.2%) in the group of patients who ranged in age from 50-59 yr old, and in the group that was referred from the Seoul area (55.9%). In conclusion, our results suggest that tissue invading parasitic infections should always be included in differential diagnosis for patients with eosinophilia associated lesions of the central nervous system, liver, and lungs in Korea.
Adolescent ; Adult ; Age Factors ; Aged ; Aged, 80 and over ; Animals ; Antibodies, Helminth/*blood ; Child ; Child, Preschool ; Clonorchiasis/diagnosis/*epidemiology ; Clonorchis sinensis/immunology/isolation & purification ; Cysticercosis/diagnosis/*epidemiology ; Cysticercus/immunology/isolation & purification ; Diagnosis, Differential ; Enzyme-Linked Immunosorbent Assay ; Eosinophilia/immunology ; Female ; Humans ; Immunoglobulin G/blood ; Infant ; Male ; Middle Aged ; Paragonimiasis/diagnosis/*epidemiology ; Paragonimus westermani/immunology/isolation & purification ; Republic of Korea/epidemiology ; Seroepidemiologic Studies ; Sparganosis/diagnosis/*epidemiology ; Sparganum/immunology/isolation & purification

The present study investigated the infection status of Paragonimus westermani metacercariae in freshwater crabs (n = 363) and crayfish (n = 31) from October 2007 to October 2008 using the crush method. All of the freshwater crabs, Eriocheir japonicus, were negative for P. westermani metacercariae while 10 (32.3%) of the 31 examined crayfish were positive. The 10 positive crayfish were caught in Haenam, Jeollanam-do, and there were 8-59 (mean 28.4) metacrcariae per infected crayfish. These results suggest that P. westermani metacerariae are still transmitted by crayfish enzootically in southern Korea, and that freshwater crabs may transmit metacercariae only on rare occasions.
Animals ; Astacoidea/*parasitology ; Brachyura/*parasitology ; Humans ; Korea/epidemiology ; Paragonimiasis/epidemiology/parasitology/*veterinary ; Paragonimus westermani/*isolation & purification ; Prevalence

As a part of a broader effort to determine the status of Paragonimus species infection in Lao PDR, an epidemiological survey was conducted on villagers and schoolchildren in Namback District between 2003 and 2005. Among 308 villagers and 633 primary and secondary schoolchildren, 156 villagers and 92 children evidenced a positive reaction on a Paragonimus skin test. Only 4 schoolchildren out of 128 skin test-positive cases had Paragonimus sp. eggs in their sputum, all of which was collected on 1 day. Several types of crabs, which were identified as the second intermediate host of the Paragonimus species, were collected from markets and streams in a paragonimiasis endemic area for the inspection of metacercariae. Among the examined crabs, only "rock crabs" (Indochinamon ou) harbored Paragonimus sp. metacercariae, and it is speculated that the life cycle of Paragonimus sp. was maintained via rock crabs in Namback District, Lao PDR.
Adolescent ; Adult ; Aged ; Animals ; Brachyura/parasitology ; Child ; Female ; Humans ; Laos/epidemiology ; Male ; Middle Aged ; Paragonimiasis/*diagnosis/*epidemiology ; Population Surveillance ; *Skin Tests

OBJECTIVETo investigate the epidemiological factors and tendency of paragonimiasis in Jin Miaopu township in Zezhou county of Shanxi Province, and to understand the current status of public awareness for providing references to paragonimiasis education and prevention.

METHODSA questionnaire survey was conducted among 2172 villagers probing awareness of paragonimiasis and their experiences of eating crabs; Infection screening and antibody test were also performed by means of ELISA.

RESULTSThe paragonimiasis knowledge coverage rate was zero, and 67.7% (1471/2172) of the respondents claimed their histories of crab eating and 96.7% (29/30) of crabs were infected with metacercaria of paragonimus. Of all the study subjects, 11% (241/2172) of them were infected with the positive rate of 4.1% (89/270).

CONCLUSIONThe incidence of paragonimiasis is closely related to dietetic habit in local residents. It is extremely necessary to increase the public awareness of paragonimiasis prevention and control and to improve the living conditions and dietetic habits.

Adolescent ; Adult ; Aged ; Animals ; Cats ; Child ; Child, Preschool ; China ; epidemiology ; Dogs ; Feeding Behavior ; Female ; Humans ; Lung Diseases, Parasitic ; epidemiology ; Male ; Middle Aged ; Paragonimiasis ; epidemiology ; Surveys and Questionnaires

The survey on paragonimiasis was made in the communes of An Lac, Dong Quan, Tan Linh, Truc Lau, Khanh Hoa and Khai Trung of the Luc Yen district, Yen Bai province during 2002 - 2003. A total of 1,143 stool samples and 367 sputum samples were examined showing a positive rate of 0.5% (0 - 8%) and 6.8%, respectively. Paragonimus patients were found in three communes of An Lac, Khanh Hoa and Dong Quan. The most of the patients were children (80.8%). The local people were found to have poor hygienic condition with no latrine or under-standard latrine as well as the habit of free defecating. The patients were treated with praziquatel 25mg/kg thrice/day x 2 consecutive days. 92.3% patients were cured with no eggs and clinical symptoms three months after drug administration.
Paragonimiasis ; Epidemiology

OBJECTIVESTo determine the natural crustacean host, the Paragonimus species, and to investigate the potential host-parasite relationship between Manipur Paragonimus and some of the laboratory animals.

METHODSThe laboratory animals such as puppies, albino rats and Swiss mice were infected orally with metacercariae isolated from the fresh water crabs, Potamiscus manipurensis. The fecal specimens of the experimentally infected animals were examined microscopically for Paragonimus eggs at regular intervals. The animals were autopsied on days 35 to approximately 328 after infection and the isolated worms were flattened between glass slides and fixed in 70% alcohol. The worms were stained with carmine and mounted with Canada balsam for morphological studies. The eggs were collected in 5% formol saline solution for microscopy. The flukes were classified into 4 developmental stages.

RESULTSA total of 11 worms, 5 mature, 5 immature and 1 pre-adult were recovered. The morphological features of the metacercariae, worms and eggs were similar to those of Paragonimus heterotremus.

CONCLUSIONManipur is one of the rare areas in the world where Paragonimus heterotremus is prevalent and the puppies are ideal experimental animal host. This species may be one of the important causes of paragonimiasis in animals and humans in Manipur.

Animals ; Animals, Laboratory ; Brachyura ; parasitology ; Dogs ; parasitology ; Host-Parasite Interactions ; India ; epidemiology ; Lung Diseases, Parasitic ; epidemiology ; parasitology ; Mice ; parasitology ; Paragonimiasis ; epidemiology ; parasitology ; Paragonimus ; anatomy & histology ; isolation & purification ; Rats ; parasitology

In order to determine the epidemiological pattern of the Paragonimus westermani, the infestation rates of the cercarial and metacercarial larvae of digenetic trematodes in the snail and crayfish host, and the prevalence of Paragonimus westermani among the residents in the vicinity of the stream Namdae, Wyangpi, and Kwang, in the Ulchin county, Kyungpook province were studied from March to October in 1984. The population density of the snails per square meter of the habitats ranged form 5 to 25, with average of 15. Among the seven habitats, one, Ducheon, had snails infested with the cercariae of Paragonimus westermani, and the proportion of infested snails was very low, the average being 0.152 per thousand. Of six hundred and four crayfish examined, 113 or 18.7 per cent harboured the encysted larvae of Paragonimus westermani. A high infestation rate for the metacercariae in the crayfish was found in two habitats; 39.0 per cent in the Ducheon and 21.6 per cent in the Sokwang. The prevalence of Paragonimus westermani among the residents in Ulchin county was relatively high, 25.8 per cent by the Paragonimus intradermal tests and the difference in the rate of infection between males and females was found to be significant(t>2). The results obtained in this study indicate that endemic foci of Paragonimus westermani exist in Ulchin county and the prevalence of this lung fluke among the residents is relatviely high.
parasitology-helminth-trematoda ; Paragonimus westermani ; paragonimiasis ; epidemiology ; intermediate host ; crayfish ; snail ; metacercaria