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The Korean Journal of Parasitology Aug 2016To know the infection status of zoonotic trematode metacercariae in brackish water fish, we surveyed mullets collected from 18 coastal areas in the Republic of Korea....
To know the infection status of zoonotic trematode metacercariae in brackish water fish, we surveyed mullets collected from 18 coastal areas in the Republic of Korea. The metacercariae of Pygidiopsis summa were detected in 236 (68.2%) out of 346 mullets examined. They were found in mullets from 15 areas except for those from Boseong-gun (Jeollanam-do), Pohang-si, and Uljin-gun (Gyeongsangbuk-do). Especially in mullets from Taean-gun (Chungcheongnam-do) and Geoje-si (Gyeongsangnam-do), their prevalences were 100% and 95.5%, and the average metacercarial density was more than 1,000 per fish. They were also detected in mullets from 3 coastal lakes, Gyeongpoho, Songjiho, and Hwajinpoho, in Gangwon-do, and their average densities were 419, 147, and 672 per infected fish, respectively. The metacercariae of 5 other heterophyid species, including Heterophyes nocens, Heterophyopsis continua, Metagonimus sp., Stictodora fuscata, and Stictodora lari, were found in the mullets examined. The metacercariae of H. nocens were detected in 66.7, 100, 28.6, 81.6, 3.9, 61.5, and 27.3% of mullets from Muan-gun, Shinan-gun, Haenam-gun, Gangjin-gun, and Boseong-gun (Jeollanam-do), Hadong-gun, and Geoje-si (Gyeongsangnam-do), and their metacercarial intensities were 64, 84, 119, 99, 1, 24, and 24 per fish infected, respectively. From the above results, it has been confirmed that P. summa metacercariae are heavily infected in mullets from coastal areas of Korea. It is suggested that residents who frequently consume raw mullet dish can be easily infected with heterophyid flukes.
Topics: Animals; Fish Diseases; Heterophyidae; Metacercariae; Parasite Load; Prevalence; Republic of Korea; Smegmamorpha; Trematode Infections
PubMed: 27658602
DOI: 10.3347/kjp.2016.54.4.497 -
Brazilian Journal of Biology = Revista... 2017Pleurolophocercous cercariae found in the invasive gastropod Melanoides tuberculata (Müller, 1774) collected in a stream of the Vila do Abraão, Ilha Grande, Angra dos...
Pleurolophocercous cercariae found in the invasive gastropod Melanoides tuberculata (Müller, 1774) collected in a stream of the Vila do Abraão, Ilha Grande, Angra dos Reis, Rio de Janeiro, Brazil were used for experimental infection that enabled the identification of the heterophyid trematode Centrocestus formosanus (Nishigori, 1924). The parasite has been found in the locality since 2007, after two years of the introduction of M. tuberculata. Recently, from a sample of 483 specimens collected in June 2013, 101 (21%) were found infected with parasite. The potential environmental impacts caused by the parasite occurrence could be underestimated in the country, and actions to monitor and control both the parasite and the mollusk are necessary.
Topics: Animals; Brazil; Heterophyidae; Host-Parasite Interactions; Introduced Species; Metacercariae; Snails
PubMed: 27599102
DOI: 10.1590/1519-6984.13615 -
Emerging Infectious Diseases Feb 2016Trematodes are recognized as a group of emerging parasites in tropical countries. We identified a trematode as a cause of ocular granulomas that developed in children...
Trematodes are recognized as a group of emerging parasites in tropical countries. We identified a trematode as a cause of ocular granulomas that developed in children who bathed in ponds or rivers in South India. DNA was isolated from patients' surgically excised granulomas and from the trematode cercariae (larvae) released by the snail Melanoides tuberculata in water in which the children bathed. Real-time and conventional PCRs were performed that targeted ribosomal DNA regions spanning the internal transcribed spacer 2 and 28S sequences of this trematode. The PCR-amplified products were subjected to bidirectional sequencing. Analysis of sequences for the granuloma samples and the trematode cercariae showed maximum sequence similarity with Procerovum varium (family Heterophyidae). Our results confirmed the etiology of the ocular infection, implicating snail vectors as environmental risk factors for ocular parasitosis.
Topics: Adolescent; Animals; Base Sequence; Child; DNA, Helminth; Eye Infections, Parasitic; Female; Geography; Granuloma; Humans; India; Male; Molecular Sequence Data; Sequence Alignment; Sequence Analysis, DNA; Snails; Trematoda; Trematode Infections
PubMed: 26812231
DOI: 10.3201/eid2202.150051 -
Parasites & Vectors Dec 2015Adults and larvae of generalist parasites are exposed to diverse hosts and local environmental conditions throughout their life cycles, thus local adaptation is expected...
BACKGROUND
Adults and larvae of generalist parasites are exposed to diverse hosts and local environmental conditions throughout their life cycles, thus local adaptation is expected to occur through phenotypic plasticity and/or natural selection. We investigated how the combined effect of cryptic host specificity and local selective pressures could shape reproductive traits of a putative generalist parasite in the oceanic realm.
METHODS
The LSU rDNA, ITS2 and the mt-COI of individuals of the digenean Pholeter gastrophilus (Kossack, 1910) Odhner, 1914 (Heterophyidae Leiper, 1909) from oceanic striped dolphins, Stenella coeruleoalba Meyen, and coastal bottlenose dolphins, Tursiops truncatus Montagu, in the western Mediterranean were used to elucidate whether worms were conspecific. Infection parameters were compared between both dolphin species. General Linear Mixed Models were used to analyse the influence of host species on four reproductive traits of P. gastrophilus: body size, maturity stage (non-gravid/gravid), egg size, and number of eggs in utero. AIC values were used to rank competing models, and p-values to assess the effect of specific predictors.
RESULTS
Evidence indicated that worms collected from both dolphin species were conspecific. All worms collected were gravid and infection parameters did not differ between dolphin species. However, body size and egg size of individuals of P. gastrophilus were significantly larger in striped dolphins. The number of eggs in utero did not significantly differ between dolphin species but, for a given body size, worms in bottlenose dolphins harboured more eggs. A trade-off between egg size and egg number was found in worms from both dolphin species, with a higher slope in striped dolphins.
CONCLUSIONS
Apparently, striped dolphin is a more suitable host for P. gastrophilus, but reproductive investment seems to be adapted to the habitat where the life-cycle develops. Worms from striped dolphins likely face the problem of finding intermediate hosts in the oceanic realm and apparently invest into offspring size to enhance the early survival of larvae and the potential to multiply asexually within the first intermediate host. The small-sized worms from bottlenose dolphins would be adapted to reproduce early because of higher adult mortality, generating smaller and numerous eggs in a coastal habitat where chances of transmission are presumably higher.
Topics: Adaptation, Physiological; Animals; Bottle-Nosed Dolphin; DNA, Helminth; DNA, Ribosomal; DNA, Ribosomal Spacer; Electron Transport Complex IV; Environmental Exposure; Host Specificity; Mediterranean Sea; Molecular Sequence Data; RNA, Ribosomal; Sequence Analysis, DNA; Stenella; Troglotrematidae; Zygote
PubMed: 26701345
DOI: 10.1186/s13071-015-1273-8 -
Parasites & Vectors Dec 2015Fish-borne zoonotic trematodes (FZT), such as Clonorchis sinensis, Opistorchis viverini (Opisthorchiidae) and intestinal trematodes of the family Heterophyidae,...
BACKGROUND
Fish-borne zoonotic trematodes (FZT), such as Clonorchis sinensis, Opistorchis viverini (Opisthorchiidae) and intestinal trematodes of the family Heterophyidae, constitute a public health hazard in Vietnam and infections with these trematodes has been linked to consumption of raw or undercooked fish from aquaculture. The FZT transmission pathways, however, are more complicated than just the presence of intermediate snail hosts in aquaculture ponds as ponds may exchange water with surrounding habitats such as rice fields and irrigation canals and thereby these surrounding habitats may be a source of snails and cercariae and contribute to FZT infection in cultured fish.
METHODS
This is a longitudinal descriptive study on selected farms (n = 30) in Nam Dinh Province which is endemic for FZT. At each farm, we sampled one pond, a small irrigation canal used to supply the pond with water, and a nearby rice field. At each of these three sites, we estimated the density of the FZT intermediate snail hosts and determined their trematode infection status. Comparative analysis was performed for the prevalence and density of FZT infections in fish and snails.
RESULTS
Species of the Thiaridae, and most notably Melanoides tuberculata, the most important host species for FZT belonging to the Heterophyidae, were particularly abundant in ponds and small canals, i.e. M. tuberculata was found in 27 ponds and 13 small canals. Bithynia fuchsiana, a potential host for both Heterophyidae and Opisthorchiidae, was rarely found in fish ponds but common in rice fields. A total of 12 types of cercariae were found in the snails and pleurolophocercous cercariae, primarily FZT, constituted about 40 % of all cercarial infections. The fish species cultured were mainly carp species and Haplorchis pumilio was the dominating trematode species infecting fish. Clonorchis spp. were not recorded in any of the ponds. FZT transmission to fish was intense during the summer period (May-June to November) but less intense during the winter months (December-January) partly because cercarial emergence ceases due to the low temperature.
CONCLUSION
Our findings highlight the complexity of FZT transmission within aquaculture farm settings and suggest that efforts to control these infections must take a holistic approach using interventions against all stages of the transmission cycle.
Topics: Agriculture; Animals; Aquaculture; Carps; Fish Diseases; Longitudinal Studies; Trematoda; Trematode Infections; Vietnam; Water
PubMed: 26642755
DOI: 10.1186/s13071-015-1237-z -
The Korean Journal of Parasitology Oct 2015Metagonimus yokogawai (Katsurada, 1912) Katsurada, 1912 (Trematoda: Heterophyidae) is parasitic in the small intestine of mammals including man and birds in Far Eastern...
Metagonimus yokogawai (Katsurada, 1912) Katsurada, 1912 (Trematoda: Heterophyidae) is parasitic in the small intestine of mammals including man and birds in Far Eastern Russia, Korea, Japan, China, and Taiwan. In the present study, the metacercariae and adults of M. yokogawai were redescribed to designate a neotype of this fluke together with reviews of previous studies including study histories from the first discovery to now. We particularly, attempted to review the study histories and morphological descriptions of M. yokogawai for the species validity, and compared with the morphological characteristics and life cycles of the closely related species, Metagonimus takahashii and Metagonimus miyatai. Finally, we proposed a differential key for the 8 known Metagonimus species distributed in East Asia. Metacercariae were obtained from the body muscles of sweetfish (Plecoglossus altivelis) collected in the Asahi River at Takebe-cho, Kita-ku, Okayama City, Okayama Prefecture, Japan. Adults were recovered from the small intestine of Syrian golden hamsters, to which the metacercariae had been fed 14 days before. A neotype was selected out of the present adult specimens. The Asahi River at Takebo-cho became the type locality of M. yokogawai. In conclusion, the present review shows that M. yokogawai, M. takahashii, and M. miyatai are valid and discriminated by means of morphological characteristics.
Topics: Animals; Fish Diseases; Helminthiasis; Heterophyidae; Intestinal Diseases, Parasitic; Japan; Life Cycle Stages; Mesocricetus; Microscopy; Osmeriformes; Rodent Diseases
PubMed: 26537043
DOI: 10.3347/kjp.2015.53.5.627 -
The Korean Journal of Parasitology Apr 2015The present study was performed to survey the infection status of zoonotic intestinal trematode (ZIT) in stray cats from 5 major riverside areas in the Republic of...
The present study was performed to survey the infection status of zoonotic intestinal trematode (ZIT) in stray cats from 5 major riverside areas in the Republic of Korea. Total 400 stray cats were captured with live-traps in riverside areas of Seomjingang ('gang' means river) (203 cats) from June to October 2010, and of Yeongsangang (41), Nakdonggang (57), Geumgang (38), and Hangang (61 cats) from June to October 2011, respectively. Small intestines resected from cats were opened with a pair of scissors in a beaker with 0.85% saline and examined with naked eyes and under a stereomicroscope. More than 16 ZIT species were detected in 188 (92.6%) cats from Seomjingang areas, and the number of worms recovered was 111 per cat infected. In cats from riverside areas of Yeongsangang, Nakdonggang, Geumgang, and Hangang, more than 9, 8, 3, and 5 ZIT species were recovered, and the worm burdens were 13, 42, 11, and 56 specimens per infected cat, respectively. As the members of family Heterophyidae, more than 10 species, i.e., Metagonimus spp., Pygidiopsis summa, Heterophyes nocens, Stellantchasmus falcatus, Heterophyopsis continua, Acanthotrema felis, Centrocestus armatus, Procerovum varium, Cryptocotyle concava, and Stictodora lari, were recovered. More than 5 species of echinostomes, i.e., Echinostoma hortense, Echinochasmus japonicus, Echinochasmus sp., Echinoparyphium sp., and unidentified larval echinostomes, were collected. Plagiorchis spp. were detected in cats from areas of Seomjin-gang and Yeongsangang. From the above results, it has been confirmed that stray cats in 5 major riverside areas of Korea are highly infected with various species of ZITs.
Topics: Animals; Cat Diseases; Cats; Female; Male; Republic of Korea; Trematoda; Trematode Infections; Zoonoses
PubMed: 25925180
DOI: 10.3347/kjp.2015.53.2.209 -
The Korean Journal of Parasitology Apr 2015This study aimed to investigate the infection status, worm development, and phylogenetic characteristics of the intestinal trematode, Stellantchasmus falcatus. The...
This study aimed to investigate the infection status, worm development, and phylogenetic characteristics of the intestinal trematode, Stellantchasmus falcatus. The metacercariae of S. falcatus were detected only in the half-beak (Dermogenus pusillus) out of the 4 fish species examined. Their prevalence was 90.0%, and the intensity of infection was 919 metacercariae on average. Worms were recovered from 33 (97.1%) of 34 chicks that were experimentally infected with 200 S. falcatus metacercariae each, and the average recovery rate was 43.0%. The body size and inner organs of S. falcatus quickly increased in the experimental chicks over days 1-2 post-infection (PI). In addition, ITS2 sequence data of this parasite were analyzed to examine the phylogenetic relationships with other trematodes using the UPGMA method. The results indicated that the ITS2 sequence data recorded from trematodes in the family Heterophyidae appeared to be monophyletic. This study concluded that D. pusillus serves as a compatible second intermediate host of S. falcatus in Thailand and that S. falcatus can develop rapidly in the experimental chicks. Data collected from this study can help to close the gap in knowledge regarding the epidemiology, biology, and phylogenetic characteristics of S. falcatus in Thailand.
Topics: Animals; Chickens; Fish Diseases; Fishes; Heterophyidae; Metacercariae; Phylogeny; Poultry Diseases; Thailand; Trematode Infections
PubMed: 25925179
DOI: 10.3347/kjp.2015.53.2.201 -
Parasites & Vectors Feb 2015The cutaneous monostome trematode Collyriclum faba (Bremser in Schmalz, 1831) is a bird parasite with a hitherto unknown life cycle and highly focal occurrence across...
BACKGROUND
The cutaneous monostome trematode Collyriclum faba (Bremser in Schmalz, 1831) is a bird parasite with a hitherto unknown life cycle and highly focal occurrence across the Holarctic and Neotropic ecozones.
METHODS
Representative specimens of benthic organisms were sampled at multiple sites and dates within the known foci of C. faba occurrence in Slovakia. A combined approach involving detailed morphological examination and sequencing of two independent DNA loci was used for their analysis.
RESULTS
We elucidated the complete life cycle of C. faba, which we determined to include the aquatic gastropod mollusk Bythinella austriaca (Frauenfeld, 1857) as the first intermediate host, the mayflies of the family Heptageniidae, Ecdyonurus venosus (Fabricius, 1775) and Rhithrogena picteti Sowa, 1971 x iridina (Kolenati, 1839), as the second intermediate hosts, and birds (primarily but not exclusively passeriform birds) as the definitive hosts. Bythinella austriaca occurs focally in the springs of tributaries of the Danube in the Alpine-Carpathian region. The restricted distribution of B. austriaca explains the highly focal distribution of C. faba noticed previously in spite of the broad distribution of its second intermediate and definitive host species. Utilization of both larval and adult Ephemeroptera spp. as the second intermediate hosts explains the known spectrum of the definitive host species, with the highest prevalence in species feeding on larvae of Ephemeroptera, such as Cinclus cinclus (Linnaeus, 1758) and Motacilla cinerea Tunstall, 1771, or adults of Ephemeroptera, such as Sylvia atricapilla (Linnaeus, 1758) and Regulus regulus (Linnaeus, 1758). In this study, we also determine the prevalence and DNA sequences of other immature trematode specimens found in the examined benthic organisms (particularly the families Microphallidae, Troglotrematidae and Nanophyetidae and Euryhelmis zelleri Grabda-Kazubska, 1980, Heterophyidae), and describe cercariae of C. faba.
CONCLUSIONS
We determined the full life cycle of the Central European populations of C. faba. We speculate that other species of Bythinella and the closely related genus Amnicola may serve as first intermediate hosts in other parts of the distribution range of C. faba. Similarly, other Ephemeroptera of the family Heptageniidae may serve as the second intermediate hosts of C. faba in the Americas.
Topics: Animals; Bird Diseases; Birds; Ephemeroptera; Female; Host Specificity; Life Cycle Stages; Male; Mollusca; Platyhelminths; Trematode Infections
PubMed: 25889245
DOI: 10.1186/s13071-015-0646-3 -
The Journal of Veterinary Medical... Dec 2014Seven laboratory mammal and bird species were orally inoculated with 200-1,000 encysted Metagonimus hakubaensis metacercariae that had been isolated from naturally...
Seven laboratory mammal and bird species were orally inoculated with 200-1,000 encysted Metagonimus hakubaensis metacercariae that had been isolated from naturally infected lampreys (Lethenteron reissneri) captured in Aomori Prefecture. At 8 and 15 days post-infection, adult flukes were recovered from all of the laboratory animals tested, and therefore, hamster, rat, mouse, dog, cat, chicken and quail were considered as final hosts of M. hakubaensis. Recovery rates of the fluke were higher in dogs and hamsters than in cats, rats, mice, chickens and quails. The flukes recovered from dogs and hamsters showed increased body length and higher fecundity than those recovered from the other hosts. These results indicate that the suitability of dogs and hamsters for M. hakubaensis infection is higher than that of the other laboratory animals.
Topics: Animals; Body Weights and Measures; Cats; Chickens; Cricetinae; Dogs; Fertility; Heterophyidae; Host-Parasite Interactions; Metacercariae; Mice; Quail; Rats
PubMed: 25649951
DOI: 10.1292/jvms.14-0247