• Parasites, Hosts and Diseases
• /
• v.23 no.1
• /
• pp.102-110
• /
• 1985

In order to determine the epidemiological pattern of the Paragonimus westermani, the infestation rates for the cercarial and metacer-carial larvae of digenetic trematodes in the snail and crayfish hosts, 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 from 5 to 25, with an 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 m 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 relatively high.

• Parasites, Hosts and Diseases
• /
• v.43 no.1 s.133
• /
• pp.33-37
• /
• 2005

Eosinophil degranulation is considered to be a key effector function for the killing of helminthic worms and tissue inflammation at worm-infected lesion sites. However, relatively little data are available with regard to eosinophil response after stimulation with worm-secreted products which contain a large quantity of cysteine proteases. In this study, we attempted to determine whether the degranulation of human eosinophils could be induced by the direct stimulation of the excretory-secretory products (ESP) of Paragonimus westermani, which causes pulmonary paragonimiasis in human beings. Incubation of eosinophils for 3 hr with Paragonimus-secreted products resulted in marked degranulation, as evidenced by the release of eosinophil-derived neurotoxin (EON) in the culture supernatants. Moreover, superoxide anion was produced by eosinophils after stimulation of the ESP. The ESP-induced EDN release was found to be significantly inhibited when the ESP was pretreated with protease inhibitor cocktail or the cysteine protease inhibitor, E-64. These findings suggest that human eosinophils become degranulated in response to P. westermani-secreted proteases, which may contribute to in vivo tissue inflammation around the worms.

• Parasites, Hosts and Diseases
• /
• v.51 no.6
• /
• pp.683-687
• /
• 2013

Among Paragonimus species, P. paishuihoensis is one of the most mysterious and poorly understood species. Metacercariae are characterized by having a unique dendritically branched excretory bladder. However, the morphology of the adult worm remains unknown. To date, metacercariae of this species have been reported only in China and Thailand. In this study, we first found P. paishuihoensis metacercariae in freshwater crabs, Potamon lipkei, in Hinheub District, Vientiane, Lao PDR, with a prevalence of 77.7% and the average intensity of 10.3 (range 1-28) metacercariae per crab. The molecular data based on ITS2 and CO1 markers indicated that P. paishuihoensis from Laos and Thailand were almost completely identical and were close to members of the Paragonimus bangkokensis/Paragonimus harinasutai complex. Attempts to infect experimental animals (cats, dogs, and rats) with P. paishuihoensis were unsuccessful, suggesting that these animals might be unsuitable definitive hosts for the species. Further studies are necessary to elucidate the taxonomic status and life cycle of P. paishuihoensis.

• Parasites, Hosts and Diseases
• /
• v.41 no.1
• /
• pp.47-55
• /
• 2003

We compared patterns of intraspecific polymorphism of two markers with contrasting modes of evolution, nuclear ribosomal DNA (rDNA) and mitochondrial DNA (mtDNA), in the lung fluke, diploid and triploid Paragonimus westermani from three geographical regions of Korea. The genetic distances between three populations of Korean diploid and triploid P. westermani showed no significant difference in the nucleotide sequences of the mitochondrial cytochrome c oxidase subunit 1 (mtCOI) and ribosomaal second internal transcribed spacer (ITS2) genes. A highly resolved strict-consensus tree was obtained that illustrated phylogenetically useful information of the ITS2 and mtCOI sequences from diploid and triploid P. westermani.

• Parasites, Hosts and Diseases
• /
• v.40 no.2
• /
• pp.89-92
• /
• 2002

The cysteine proteases of Paragonimus westermani metacercariae are involved in metacercarial excystment, host immune modulation, and possibly in tissue penetration. In order to clarify the origin of the enzymes, 28 and 27 kDa cysteine proteases in metacercarial excretory-secretory products were purified through the FPLC system using Mono Q column chromatography. The polyclonal antibodies to the enzymes were produced in BALB/c mice. Immunolocalization studies revealed that both cysteine proteases were distributed at the linings of excretory bladder and excretory concretions of the metacercariae. It was suggested that the excretory epithelium of P. westermani undertake the secretory function of metacercarial cysteine proteases, in addition to its role as a route for eliminating waste products.

• Parasites, Hosts and Diseases
• /
• v.41 no.4
• /
• pp.221-231
• /
• 2003

To gain information on retrotransposons in the genome of Paragonimus westermani, PCR was carried out with degenerate primers, specific to protease and reverse transcriptase (rt) genes of long-terminal-repeat (LTR) retrotransposons. The PCR products were cloned and sequenced, after which 12 different retrotransposon-related sequences were isolated from the trematode genome. These showed various degrees of identity to the polyprotein of divergent retrotransposon families. A phylogenetic analysis demonstrated that these sequences could be classified into three different families of LTR retrotransposons, namely, Xena, Bel, and Gypsy families. Of these, two mRNA transcripts were detected by reverse transcriptase-PCR, showing that these two elements preserved their mobile activities. The genomic distributions of these two sequences were found to be highly repetitive. These results suggest that there are diverse retrotransposons including the ancient Xena family in the genome of P. westermani, which may have been involved in the evolution of the host genome.

• Tuberculosis and Respiratory Diseases
• /
• v.56 no.5
• /
• pp.550-554
• /
• 2004

A paragonimiasis infestation is caused by the paragonimus species. It is commonly found in the lung but has also been found to exist extrapulmonary infestations including cerebral, spinal, subcutaneous, hepatic, splenic, abdominal, urinary, and gynecologic infestation. On the other hand, a cutaneous infestation is extremely rare. Human infestation is caused by ingesting raw or undercooked intermediate hosts. Because paragonimus westermani larva mature to an adult worm in the lung, the possibility of identifying the adult worm of paragonimus westermani at extrapulmonary region is very rare. Case : After ingesting a fresh-water crab 1 month prior to the hospital visit, a 45-year old female patient was suffering from right pleuritic chest pain during that 1 month. The patient also complained of a palpable mass that was movable and migrating, and it was localized at the right upper quadrant of the abdomen. The eosinophil fraction of the white blood cell of peripheral blood and pleural fluid was elevated to 55.1% and 90%, respectively. Parasite eggs were not found in her sputum and stool examination. By using the enzyme-linked immunosorbent assay (ELISA), the paragonimus-specific IgG antibody titer was elevated to 0.28. During incisional biopsy, we were able to find the young adult worm of paragonimus westermani. We experienced the rare case of ectopic paragonimiasis with pleural effusion that was confirmed by identifying the adult worm of paragonimus westermani within the abdominal subcutaneous tissue. We report a case with brief literature reviews.

• Parasites, Hosts and Diseases
• /
• v.51 no.6
• /
• pp.677-681
• /
• 2013

Paragonimiasis is an important food-borne parasitic zoonosis caused by infection with lung flukes of the genus Paragonimus. Of the 7 members of the genus known in Thailand until recently, only P. heterotremus has been confirmed as causing human disease. An 8th species, P. pseudoheterotremus, has recently been proposed from Thailand, and has been found in humans. Molecular data place this species as a sister species to P. heterotremus, and it is likely that P. pseudoheterotremus is not specifically distinct from P. heterotremus. In this study, we collected metacercariae of both nominal species (identification based on metacercarial morphology) from freshwater crabs from Phetchabun Province in northern Thailand, Saraburi Province in central Thailand, and Surat Thani Province in southern Thailand. In addition, we purchased freshwater crabs imported from Myanmar at Myawaddy Province, western Thailand, close to the Myanmar-Thailand border. The DNAs extracted from excysted metacercariae were PCR-amplified and sequenced for ITS2 and cox1 genes. The ITS2 sequences were nearly identical among all samples (99-100%). Phylogenies inferred from all available partial cox1 sequences contained several clusters. Sequences from Indian P. heterotremus formed a sister group to sequences from P. pseudoheterotremus-type metacercariae. Sequences of P. heterotremus from Thailand, Vietnam, and China formed a separate distinct clade. One metacercaria from Phitsanulok Province was distinct from all others. There is clearly considerable genetic variation in the P. heterotremus complex in Thailand and the form referred to as P. pseudoheterotremus is widely distributed in Thailand and the Thai-Myanmar border region.

• Journal of Chest Surgery
• /
• v.12 no.4
• /
• pp.312-317
• /
• 1979

1] During the period of Jan. 1959, to Aug. 1979, 47 patients of paragonimiasis have been treated in the department of Chest Surgery. 2] The total number of patients who has been admitted and treated in the department of Chest Medicine are 262 and annual distribution of number of patients has been decreased. However, since 1964, the number of patients has been stationary. On the other hand, the total number of patients who has been admitted and treated surgically in the department of Chest Surgery are 47 and the annual distribution of number of patients has not been decreased. 3] The peak age incidence lies in fourth decade [34%], and over halves of patients is in third to fifth decade. Male to female is 8.4 to 1. 4] The symptoms, which are mainly cough, chest pain, dyspnea and blood tinged sputum, developed mostly in two to five years after infestation by Paragonmius westermani. 5] Sputum tests for eggs of Paragonimus westermani were positive in 16 out of 43 patients [37%]. The 93% of patients were positive in skin test for Paragonimus westermani. The patients with negative skin test were 7%, but sputum or stool examination for Paragonimus westermani`s eggs were positive in these negative group of skin test. 6] Chest roentgenogram revealed pleural effusion [41 cases], hydropneumothorax [1 case], atelectasis [1 case] and mediastinal mass [1 case]. 7] All patients were preoperatively treated with Bithionol. The mode of surgery were decortication only [31 cases], pleuropneumonectomy [3 cases], decortication & lobectomy [2 cases], decortication & closure of bronchial fistula [1 case], thoracentesis [1 case] and postural drainage [1 case]. 8] Paragonimiasis is primarily medical disease and well treated by the administration of Bithionol. But the delayed diagnosis and missed diagnosis, especially as pulmonary tuberculosis, make the disease aggravated and chronic. Subsequently, surgical treatment is infrequently required. Chronic empyema due to Paragonimus westermani is much benign than tuberculous empyema thoracis.

• Parasites, Hosts and Diseases
• /
• v.24 no.2
• /
• pp.194-200
• /
• 1986

A study on the population density of crayfish intermediate hosts and infestation status of crayfish with encysted larvae of Paragonimus westermani in Ulchin county, Kyungpook Province, Korea was conducted from May to October in 1986. The population density of the crayfish ranged from 1 to 13, with an average of 4 per man-hour. Among the six habitats, Ducheon had a somewhat higher density than that of the others. Of eight hundred and seventeen crayfish examined, 127 or 15.5 per cent harboured the metacercarial larvae of Paragonimus westermani. The majority of the larvae were found in three parts of the body: most frequently in the cephalothorax, next in the gills, and then in the liver. The average number of metacercarial larvae per infected crayfish ranged from 1.0 to 1.9, with an average of 1.7. Summarizing the results, this study indicates that the population density of crayfish intermediate host and infestation rates for the crayfish with encysted larvae of Paragonimus westermani in Ulchin county of Kyungpook Province is relatively high.