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Locations of provinces in Thailand and Myanmar from which freshwater crabs were sampled for this study. Myawaddy: Myanmar (1; present study), Thailand: Phitsanulok (2; present study), Phetchabun (3; present study), Saraburi (4; present study and Thaenkham and Waikagul, 2008), and Surat Thani (5; present study). In addition, provinces from which P. pseudoheterotremus has been reported in previous studies are shown: Kanchanaburi (6; Thaenkham and Waikagul, 2008) and Loei (7; Intapan et al., 2012).
Source publication
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 fo...
Similar publications
Human paragonimiasis is caused by the Paragonimus species of lung flukes. These are widely distributed worldwide including East and Southeast Asia. The first ever case of paragonimiasis was reported by Kerbert from the lungs of a Bengal tiger more than a century ago.1 In India the first case was reported from Manipur in 1982. Subsequently, endemic...
To determine that Paragonimus sp. is actively transmitted in a tropical area of the Pacific region of Ecuador where human cases of pulmonary paragonimiasis have recently been documented, a total of 75 freshwater crabs were collected from 2 different streams in the Pedernales area of Manabí Province, Ecuador. All collected crabs were identified as H...
Paragonimiasis is an infection caused by Paragonimus, a lung fluke and is acquired by eating raw or undercooked crustaceans containing the infective metacercariae. Herein, we report a case of paragonimiasis in a Malaysian man who presented with incidental findings from chest radiographs. Examination of his biopsied lung tissue and sputum specimen r...
A review of national and international publications on paragonimiasis in Ecuador, epidemiological records from the Ministry of Public Health and unpublished research data was conducted to summarise the current status of the parasite/disease. The purpose of the review is to educate physicians, policy-makers and health providers on the status of the...
Se ha estudiado el proceso del desarrollo de Parogonimus peruvianus Miyazaki, Ibóñez y Miranda, 1969 en el gato doméstico, Felis cati L. infectado experimentalmente mediante la administración oral de metacercarias del parasito extraídas de ejemplares de Pseudothelphusa chilensis Milne Edwards, 1843 procedentes de áreas endémicas.
Citations
... This species is morphologically distinct from all other Paragonimus species in having a very short excretory bladder, once used as a character for a different genus, Euparagonimus (Waikagul, 1997). Later, however, this species is considered a geographical variation of the P. heterotremus complex, based on molecular studies using ITS2 and cox1 sequences (Sanpool et al., 2013;Doanh et al., 2015;Tantrawatpan et al., 2021). Human infection with P. heterotremus was first identified by the recovery of an adult worm from a 13-year-old boy in Nakorn-Nayok Province, Thailand in 1965 (Miyazaki and Harinasuta, 1966). ...
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.
... However, we observed that genetic variations between closely related species were lower than the mitochondrial DNA genetic markers. Previous studies have also revealed lower levels of sequence variation among closely related trematode species using the ITS2 region than the mitochondrial genes [33,34]. Despite the comparable inter-species genetic distances of the ITS2 region to the mitochondrial DNA genetic markers, the comparatively lower sequence variation between closely related trematodes could limit the robustness of the ITS2 region for molecular identification among cryptic lineages, conferring an advantage to the mitochondrial rRNA genes. ...
... The COI gene possesses sufficient genetic variation to discriminate between species, including cryptic lineages. Among others, examples include molecular identification of species within the family Heterophyidae, Opisthorchiidae, and the Paragonimus heterotremus complex [17,22,33,35]. In our study, inter-species genetic distances among the three mitochondrial DNA genetic markers are comparable. ...
Background
Genetic markers like the nuclear ribosomal RNA (rRNA) genes, internal transcribed spacer regions, mitochondrial protein-coding genes, and genomes have been utilized for molecular identification of parasitic trematodes. However, challenges such as the design of broadly applicable primers for the vast number of species within Digenea and the genetic markers’ ability to provide sufficient species-level resolution limited their utility. This study presented novel and broadly applicable primers using the mitochondrial 12S and 16S rRNA genes for Digenea and aimed to show their suitability as alternative genetic markers for molecular identification of orders Plagiorchiida, Echinostomida, and Strigeida.
Results
Our results revealed that the mitochondrial 12S and 16S rRNA genes are suitable for trematode molecular identification, with sufficient resolution to discriminate closely related species and achieve accurate species identification through phylogenetic placements. Moreover, the robustness of our newly designed primers to amplify medically important parasitic trematodes encompassing three orders was demonstrated through successful amplification. The convenience and applicability of the newly designed primers and adequate genetic variation of the mitochondrial rRNA genes can be useful as complementary markers for trematode molecular-based studies.
Conclusions
We demonstrated that the mitochondrial rRNA genes could be alternative genetic markers robust for trematode molecular identification and potentially helpful for DNA barcoding where our primers can be widely applied across the major Digenea orders. Furthermore, the potential of the mitochondrial rRNA genes for molecular systematics can be explored, enhancing their appeal for trematode molecular-based studies. The novelty of utilizing the mitochondrial rRNA genes and the designed primers in this study can potentially open avenues for species identification, discovery, and systematics in the future.
... In Asia, P. skrjabini is an important pathogen, along with P. westermani, causing infections in humans throughout Asia. Among the different species complexes, P. skrjabini has been previously reported mainly in East Asia and China [3]. Initially thought to be a pathogen exclusively found in China, it has recently been reported from Japan, India, and Vietnam [4]. ...
Purpose
To perform environmental sampling and molecular identification of Paragonimus in endemic regions, which may help in minimizing transmission among humans.
Methods
Mountain crabs from the genus Potamiscus were collected and the encysted metacercariae were extracted and subjected to morphological identification, followed by animal inoculation in Sprague–Dawley (SD) rats. After 112 days of infection, animals were killed and adult worms were extracted from lungs and muscles. The morphology of adult worms was characterized by microscopy and molecular identification was done by polymerase chain reaction, followed by sequencing of cox1 and ITS2 genes. Phylogenetic analysis was done by maximum parsimony method.
Results
A total of 447 crabs were captured from the streams of Tongchang Town, Jinping County, Yunnan Province, China. The infection rate was found to be 41% (186 out of 447 crabs). The metacercariae of Paragonimus skrjabini was identified by the characteristics round or spherical encysted form measuring 410 to 460 × 400 to 460 µm. After animal infection in SD rats, adults were presumptively confirmed to be P. skrjabini , which was also confirmed by gene amplification and sequence analysis of cox1 and ITS2 regions. Paragonimus skrjabini clustered with previously reported P. skrjabini from Yunnan and Vietnam. The confidence values of their branches were > 95%. Phylogenetic analysis of the ITS2 region revealed two distinct clusters with distinct geographical grouping. Phylogenetic analysis with the combined data sets reiterated the geographical grouping with P. skrjabini from Yunnan clustering with strains from Vietnam.
Conclusion
Metacercariae of P. skrjabini was discovered in freshwater crabs in Yunnan province, China, and the strains were phylogenetically related to P. skrjabini from Vietnam.
... This study revealed that P. heterotremus from Thailand, Vietnam, and China formed a separate distinct phylogenetic clade. Metacercariae from Phitsanulok Province, Thailand, were found to be distinct from all others (Sanpool et al. 2013). However, the results indicated that P. heterotremus and P. pseudoheterotremus are not specifically genetically distinct from each other (Sanpool et al. 2013). ...
... Metacercariae from Phitsanulok Province, Thailand, were found to be distinct from all others (Sanpool et al. 2013). However, the results indicated that P. heterotremus and P. pseudoheterotremus are not specifically genetically distinct from each other (Sanpool et al. 2013). This evidence was supported by a later study which showed that P. heterotremus and P. pseudoheterotremus isolates in Vietnam formed a P. heterotremus complex consisting of three genetic groups with strong geographical origins. ...
A diverse range of human trematodes commonly dwell in the intestine, bile ducts of the liver, lung, and blood vessel infecting millions of people in continental Southeast Asia. Similarly, their life cycles involve a diverse range of intermediate hosts comprising aquatic plants, snails, fish, and other invertebrates. A sound knowledge of the biodiversity of these trematodes and their intermediate hosts is critically important for the development and establishment of future prevention and control programs on trematodiases in Southeast Asia. Therefore, this chapter will focus on the biology, life cycles, species diversity, and genetic diversity of medically important trematodes including their intermediate hosts and their distribution in Southeast Asia. The chapter will also examine the route of transmission via food and water as well as a variety of traditionally cooked dishes and raw attitudes that pose significant risks of trematode infection in people throughout Southeast Asia.
... P. ohirai complex lineage consisted of P. ohirai and P. iloktsuenensis, P. bangkokensis complex lineage contained P. bangkokensis and P. harinasutai. Although the P. heterotremus complex lineage showed incomplete lineage sorting of P. heterotremus and P. pseudoheterotremus, which was previously observed by mitochondrial and nuclear DNA sequences analyses (Doanh et al., 2015;Sanpool et al., 2013). Therefore, Fig. 3. Phylogenetic tree of Paragonimus spp. ...
Southeast Asian lung flukes, the causative agents of human and animal paragonimiasis, comprise at least 14 species. Of these, seven species; Paragonimus bangkokensis, P. harinasutai, P. macrorchis, P. siamensis, P. westermani, P. heterotremus and P. pseudoheterotremus were studied. Two regions of domain 1 of taurocyamine kinase; TkD1 (exon) and TkD1Int2 (intron 2), were used as genetic markers for elucidating their genetic differentiation, genetic variation, and heterozygosity. The TkD1 region was conserved between these species but can potentially be used to differentiate all seven species. However, the TkD1Int2 region had a high level of polymorpHism, which is suitable for investigation of genetic variation within or between closely related species, especially P. heterotremus and P. pseudoheterotremus as well as for a phylogenetic analyses of the genus Paragonimus. Heterozygosity was mostly observed in DNA samples extracted from adult P. heterotremus including samples taken from sputum of paragonimiasis patients, whereas DNA extracted from metacercariae was not, except in the samples from Myanmar. Our findings provide evidence of DNA recombination and incomplete lineage sorting of P. heterotremus and P. pseudoheterotremus in TkD1Int2, which suggesting gene flow between these two species.
... It is not always easy to determine where and when patients acquired paragonimiasis, especially among foreigners, because they often go back to their home countries and ingest traditional dishes there. Paragonimus heterotremus, another lung fluke species in Asia, is distributed through the Southeast to Southern Asia, causing human infections in China, Thailand, Laos, Vietnam and India [1,[10][11][12]. Although case reports from Cambodia are absent so far, the present outbreak clearly indicates that people in Cambodia are at risk of contracting paragonimiasis. ...
We encountered an outbreak of paragonimiasis among Cambodian technical intern trainees (TITs) at a food-processing factory in Fukuoka, Japan. The patients were 20–28 years old, seven females and two males, who had been in Japan for one to four years. All of them had consumed raw or undercooked Japanese mitten crab they purchased at a local grocery store near their training place. CT images showed multiple lesions not only in the lungs but in the extrapulmonary organs as well, such as subcutaneous tissues, abdominal muscles, and mesentery, in most of the patients. Their medical records indicated that all of them acquired infection in Japan, not in Cambodia. Diagnosis was made serologically and the patients were treated with praziquantel successfully. Foreign workers and TITs are increasing in Japan so rapidly, that food borne-infections, including paragonimiasis, should be considered in people from developing countries who have exotic dietary habits.
... Paragonimus westermani complex is the most commonly reported species complex that has been reported from south and south east Asia (7). Paragonimus heterotremus species has been predominantly isolated and reported from South East Asia and Paragonimus skrjabini complex has been reported from China and East Asia (6,8,9). The allelic diversity and ontogenetic changes have been previously studied with isozymes which has been superseded with molecular approaches (10). ...
Background
Paragonimus species are highly prevalent in ethnic minority areas of Yunnan, China. The objective of the study is to isolate and identify Paragonimus from natural habitat and compare the phylogenetic diversity of Paragonimus in Yunnan province, China.
Methods
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 112 days, adult worms and eggs were isolated from multiple organs. Morphologic identification confirmed the initial identification. DNA was extracted from the adult worms and molecular characterization was performed by amplification and sequencing of CO1 and ITS2 regions followed by phylogenetic analysis.
Results
Out of 447 crabs captured, 186 crabs were found to be infected. A total of 5 occurrences of Paragonimus was observed from naturally infected crabs. Paragonimus microrchis (2), P,heterotremus (1), P.proliferus (1) and P.skrjabini (1) were isolated and identified. A total of 32 sequences downloaded from national center for biotechnology information and 5 sequences generated in the study was used for phylogenetic analysis. Phylogenetic analysis revealed robustness of the double loci method as against the single locus method with either CO1 or ITS2 alone. Considerable phylogenetic diversity depending on the geographic location was observed.
Conclusion
Paragonimus species isolated from Yunnan province, China were phylogenetically diverse and the analysis revealed the clustering of multiple species of Paragonimus isolated from different geographic locations.
... In 2007, P. pseudoheterotremus was proposed as a sister species to P. heterotremus in Thailand, based on both morphological (primarily of the metacercarial stage) and molecular differences (Waikagul 2007;Thaenkham and Waikagul 2008). Later studies in Thailand and Vietnam showed that the situation is not clear-cut (Sanpool et al. 2013;Doanh et al. 2015b). Although phylogenies based on a mitochondrial gene identified several distinct geographic clusters within this putative species complex, all Vietnamese samples fell into a single cluster regardless of their metacercarial morphology (Doanh et al. 2015b). ...
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).
... Two year later, Shan et al. (2009) described P. sheni from China. In addition, some species have been reported in new endemic areas, such as P. skrjabini in India ( Singh et al., 2006); P. bangkokensis, P. harinasutai, P. skrjabini, P. proliferus in Vietnam ( Doanh et al., 2008Doanh et al., , 2009aDoanh et al., , 2009bDoanh et al., , 2012Doanh et al., , 2013aDoanh et al., , 2013b; P. paishuihoensis in Laos ( Habe et al., 2013); P. pseudoheterotremus in Myanmar ( Sanpool et al., 2013). ...
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.
... The CO1 sequences of specimens from Medellin and Costa Rica were 91% similar. The genetic variation values agree well with those previously reported of the Paragonimus species/species complexes (Doanh et al., 2013;López-Caballero et al., 2013;Sanpool et al., 2015Sanpool et al., , 2013. Uruburu et al., (2008) demonstrated the wide distribution of Paragonimus in Antioquia, Colombia, through the search for metacercariae. ...
Paragonimiasis is a subacute to chronic inflammatory granulomatous lung disease caused by the genus Paragonimus. In Latin America Paragonimus mexicanus Miyazaki & Ishii, 1968 is the only confirmed species to cause human infections. Paragonimus caliensis Little, 1968 is an uncommon species often regarded as a synonym of P. mexicanus. Recently, the study of two types of Paragonimus metacercariae from Costa Rica has provided new molecular and morphological evidence that P. caliensis is a separate species from P. mexicanus. In the present study, molecular, morphological and phylogenetic tools have been used to characterize two populations of Paragonimus located at west of Medellin, Antioquia and at Pichinde, Valle del Cauca (type locality of P. caliensis), Colombia. Adults and metacercariae obtained from Medellin, and metacercariae from Pichinde were analyzed. For morphological observations we used light microscopy and scanning electron microscopy (SEM). Morphology of metacercariae and adults matched with the holotype of P. caliensis. The number and arrangement of sensory papillae in the acetabulum region differs from the morphotypes reported for P. caliensis in Costa Rica. Two morphotypes in branching patterns of ovary and two morphotypes in branching patterns of testes were identified. The main morphological differences between P. caliensis and P. mexicanus corresponded to the size of gonads and their relative positions in the body, and the occasional presence of a cyst wall in P. caliensis metacercariae. The molecular and phylogenetic analyses (using nuclear ribosomal ITS2 and partial cytochrome c oxidase subunit 1 CO1 sequences) confirmed that P. caliensis from the type locality is the same species from Medellin and Costa Rica. Furthermore, these analyses also suggest genetic as well as geographical separation of P. caliensis populations between Colombia and Costa Rica. Currently, P. mexicanus and P. caliensis are sympatric in the Colombian Pacific bioregion, and specific diagnosis based on their egg size is not possible. Therefore, it is necessary to determine the biogeographic distribution ranges of both species and to implement molecular techniques to establish the role of P. caliensis in human paragonimiasis in Colombia.
