Prevalência de trematódeos do gênero Clinostomum em Jundiás (Rhamdia quelen) e desenvolvimento de um método de diagnóstico através de PCR

Clinostomum complanatum Rudolphi, 1814 é um trematódeo digenético que infecta moluscos, diversas espécies de peixes de água doce e pássaros piscívoros. Em seu ciclo de vida, o C. complanatum possui como segundo hospedeiro intermediário alguns peixes de água doce, dentre os quais o Jundiá (Rhamdia quelen). Desse modo, o objetivo do presente estudo foi avaliar a prevalência de infecções por Clinostomum em Jundiás capturados na região estuária de Pelotas/RS e padronizar a Reação em Cadeia da Polimerase (PCR) para diagnóstico da presença de metacercárias em amostras de tecidos de peixes capturados neste estuário. Para a realização do estudo transversal e padronização da PCR, utilizou-se 174 amostras de Jundiás (Rhamdia quelen), capturados por pescadores amadores em 5 diferentes pontos em locais próximos à Laguna dos Patos, Lagoa Mirim ou o Canal São Gonçalo. A prevalência de parasitismo por Clinostomum spp. com diagnóstico através de chaves parasitológicas foi de 36,21%, com variações da prevalência de acordo com os pontos relatados de captura dos espécimes de Jundiá, sendo confirmado a partir da PCR padronizada. Conclui-se que a prevalência é alta nos jundiás analisados e a PCR pode ser uma ferramenta auxiliar no diagnóstico desse parasita elevando não só a sensibilidade, mas também a rapidez do teste. Tais fatores serão de grande importância para futuros estudos epidemiológicos, assim como para saúde pública, visto que o consumo de peixes de água doce, típico da culinária oriental, encontra-se em expansão no Rio Grande do Sul e no Brasil.

Prevalence and Infection Intensity of Zoonotic Trematode Metacercariae in Fish from Soyang-cheon (Stream), in Wanju-gun, Jeollabuk-do, Korea

We surveyed on the infection status of zoonotic trematode metacercariae (ZTM) in freshwater fishes from Soyang-cheon (a branch stream of Mangyeong-gang) in Wanju-gun, Jeollabuk-do, the Republic of Korea. A total of 927 fishes were individually examined with the artificial digestion method during 2013-2015 (462 fish in 15 spp.) and 2018-2019 (465 fish in 25 spp.). Clonorchis sinensis metacercariae were detected in 207 (31.4%) out of 659 fishes in 14 positive fish species (PFS), and their mean intensity was 114 per fish infected (PFI). Metagonimus spp. metacercariae were found in 302 (37.4%) out of 808 fishes in 21 PFS, and their mean intensity was 12 PFI. Centrocestus armatus metacercariae were detected in 222 (59.0%) out of 376 fishes in 12 PFS, and their mean intensity was 383 PFI. Echinostoma spp. metacercariae were found in 139 (22.1%) out of 628 fishes in 10 PFS, and their mean intensity was 7 PFI. Clinostomum complanatum metacercariae were detected in 14 (6.5%) out of 214 fishes in 4 PFS, and their mean intensity was 2.4 PFI. Metorchis orientalis metacercariae were detected in 36 (13.5%) out of 267 fishes in 5 PFS, and their mean intensity was 4.3 PFI. Conclusively, the prevalence and infection intensity of ZTM is generally not so high in fishes from Soyang-cheon. However, those of C. sinensis metacercariae are more or less higher in 2 fish species, Pungtungia herzi and Sarcocheilichthys variegatus wakiyae.

Survey of Zoonotic Trematode Metacercariae in Fish from Water Systems of Geum-gang (River) in Republic of Korea

The infection status of zoonotic trematode metacercariae (ZTM) was surveyed in freshwater fishes from the water systems of Geum-gang (River) in the Republic of Korea (Korea). A total of 1,161 freshwater fishes from 6 local sites of Geum-gang were examined with the artificial digestion method for 4 years (2012-2015). Clonorchis sinensis metacercariae were detected in 122 (37.2%) out of 328 fishes in the positive fish species from 4 surveyed areas, and their mean intensity was 43 per fish infected. Metagonimus spp. metacercariae were found in 432 (51.7%) out of 835 fishes in the positive fish species from all 6 surveyed areas, and their mean intensity was 30 per fish infected. Centrocestus armatus metacercariae were detected in 285 (75.0%) out of 380 fishes in the positive fish species from 6 surveyed areas, and their mean intensity was 2,100 per fish infected. Echinostoma spp. metacercariae were found in 56 (19.7%) out of 284 fishes in the positive fish species from 5 surveyed areas, and their mean intensity was 10 per fish infected. Clinostomum complanatum metacercariae were detected in 98 (57.3%) out of 171 fishes in the positive fish species from only 2 surveyed areas, and their mean intensity was 11 per fish infected. Conclusively, the endemicity of ZTM is not so high in fishes from water systems of Geum-gang in Korea although it is more or less different by fish species, surveyed areas and ZTM species.

High Endemicity with Clonorchis sinensis Metacercariae in Fish from Yongjeon-cheon (Stream) in Cheongsong-gun, Gyeongsangbuk-do, Korea

The infection status with Clonorchis sinensis metacercariae (CsMc) was examined in freshwater fishes from Yongjeon-cheon (a branch of Nakdong-gang) located in Cheongsong-gun, Gyeongsangbuk-do, the Republic of Korea (Korea). A total of 750 fishes in 19 species were examined by the artificial digestion method for 2 years (2019 and 2020). CsMc were detected in 378 (51.4%) out of 735 fishes in 14 species (73.7%), and the infection intensity was 666 per fish infected. In 2019, CsMc were found in 172 (68.0%) out of 253 fishes in 10 species, and the infection intensity was 565 per fish infected. In 2020, CsMc were detected in 206 (62.2%) out of 331 fishes in 10 species, and the infection intensity was 751 per fish infected. The other zoonotic trematode, ie. Metagonimus spp., Centrocestus armatus, Echinostoma spp. and Clinostomum complanatum, metacercariae were also detected in fishes from the survey streams, but their endemicities were relatively low. Conclusively, it was first confirmed that CsMc are highly endemic in fishes from Yongjeon-cheon in Cheongsong-gun, Gyeongsangbuk-do, Korea.

Morphological and Molecular Characteristics of Clinostomid Metacercariae from Korea and Myanmar

Morphological and molecular characterization of clinostomid metacercariae (CMc) was performed with the specimens collected in fish from Korea and Myanmar. Total 6 batches of clinostomid specimens by the fish species and geographical localities, 5 Korean and 1 Myanmar isolates, were analyzed with morphological (light microscopy and SEM) and molecular methods (the cytochrome <i>c</i> oxidase 1 gene and internal transcribed spacer 1/5.8S rRNA sequence). There were some morphological variations among CMc specimens from Korea. However, some morphometrics, i.e., the size of worm body and each organ, ratio of body length to body width, and morphology of cecal lumens, were considerably different between the specimens from Korea and Myanmar. The surface ultrastructures were somewhat different between the specimens from Korea and Myanmar. The <i>CO</i>1 sequences of 5 Korean specimens ranging 728-736 bp showed 99.6-100% identity with <i>Clinostomum complanatum</i> (GenBank no. KM923964). They also showed 99.9-100% identity with <i>C. complanatum</i> (FJ609420) in the ITS1 sequences ranging 692-698 bp. Meanwhile, the ITS1 sequences of Myanmar specimen showed 99.9% identity with <i>Euclinostomum heterostomum</i> (KY312847). Five sequences from Korean specimens clustered with the <i>C. complanatum</i> genes, but not clustered with Myanmar specimens. Conclusively, it was confirmed that CMc from Korea were morphologically and molecularly identical with <i>C. complanatum</i> and those from Myanmar were <i>E. heterostomum</i>.

Monogeneans and Trematodes of some Fishes from Lake Hamrin in Diyala Province, Iraq

Between January and December 2019, a total of 368 fish specimens were collected from Lake Hamrin in Diyala province, Iraq. Eight species of these fishes belonged to the family Cyprinidae, five to the family Leuciscidae as well as one species each to Bagridae, Heteropneustidae, Siluridae, Mugilidae and Mastacembelidae. After the laboratory examination these fishes were found to be infected with 30 monogeneans and two trematode species. The monogeneans included one species each of Mastacembelocleidus, Paradiplozoon, Solostamenides, and Thaparocleidus, two species of Dogielius, four species of Gyrodactylus and 20 species of Dactylogyrus, while the trematodes included one species each of Ascocotyle which infects eight fish species and Clinostomum which infect nine fish species. Clinostomum complanatum infected nine host species, also, the results of the present study revealed that 15 parasite species infect only one host species each. Carassius auratus was infected with 18 parasite species and Cyprinus carpio with nine species. Eight fish species are reported here as new host records in Iraq for 13 parasite species.