Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “TREMATODE INFECTIONS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,081 records · Page 60Linked to original sources
PubMed1991

Differential diagnosis of opisthorchiid and heterophyid metacercariae (Trematoda) infecting flesh of cyprinid fish from Nam Ngum Dam Lake in Laos.

The examination of flesh of 313 cyprinid fish from the Nam Ngum water reservoir in Vientiane Province, Laos, revealed the presence of four morphologically similar opisthorchiid and heterophyid metacercariae of medical importance. The following morphological characters, visible under dissecting microscope with low magnification, were typical of trematodes recorded in fish: (1) Opisthorchis viverrini, the liver fluke, has oval cysts containing quickly moving C-shaped metacercariae provided with a rather large excretory bladder; (2) metacercariae of Haplorchis pumilio and H. taichui are surrounded by a thin-walled, oval cyst; they are actively motile, C- or S-shaped, and possess a relatively small excretory bladder; (3) cysts of Haplorchoides mehrai are considerably variable in shape, size, and thickness of cyst wall; larvae are slowly moving, C- or S-shaped, or often not folded, and provided with a rather small excretory bladder. Some cysts with dead or degenerated H. mehrai larvae are filled with brownish or yellowish pigment. Morphological variability of some larvae, however, excluded correct identification of all metacercariae during routine examination of fish. Therefore, we consider isolation of several larvae from each fish host as well as all "atypical" metacercariae from fish flesh and their examination under the light microscope to be necessary. Even though this method of examination is rather time consuming, it decreases the possibility of false identification of trematode larvae encysted in flesh of cyprinid fish during field studies on opisthorchosis and heterophyiosis.

Animals↗
PubMed2004

Life cycles shape parasite evolution: comparative population genetics of salmon trematodes.

Little is known about what controls effective sizes and migration rates among parasite populations. Such data are important given the medical, veterinary, and economic (e.g., fisheries) impacts of many parasites. The autogenic-allogenic hypothesis, which describes ecological patterns of parasite distribution, provided the foundation on which we studied the effects of life cycles on the distribution of genetic variation within and among parasite populations. The hypothesis states that parasites cycling only in freshwater hosts (autogenic life cycle) will be more limited in their dispersal ability among aquatic habitats than parasites cycling through freshwater and terrestrial hosts (allogenic life cycle). By extending this hypothesis to the level of intraspecific genetic variation, we examined the effects of host dispersal on parasite gene flow. Our a priori prediction was that for a given geographic range, autogenic parasites would have lower gene flow among subpopulations. We compared intraspecific mitochondrial DNA variation for three described species of trematodes that infect salmonid fishes. As predicted, autogenic species had much more highly structured populations and much lower gene flow among subpopulations than an allogenic species sampled from the same locations. In addition, a cryptic species was identified for one of the autogenic trematodes. These results show how variation in life cycles can shape parasite evolution by predisposing them to vastly different genetic structures. Thus, we propose that knowledge of parasite life cycles will help predict important evolutionary processes such as speciation, coevolution, and the spread of drug resistance.

Analysis of Variance↗
PubMed1998

First report of the isolation of an adult worm of the genus Brachylaima (Digenea: Brachylaimidae), from the gastrointestinal tract of a human.

A 78-year-old woman presented with an 18-month history of intermittent diarrhoea. Examination of her stools revealed brachylaimid eggs, which were present in three separate specimens over a week. After treatment with praziquantel a degenerate adult Brachylaima species was recovered from her faeces. She lived in a rural area of South Australia and ate vegetables grown in her own garden which had been infested with helicid snails. In south Australia these introduced European helicid snails are commonly infected with brachylaimid intermediate larval stages and are considered to be the source of the human infection.

Aged↗
PubMed1991

Comparative pathological study of hepatic changes induced by Fasciola gigantica and Gigantocotyle explanatum in Javanese thin-tailed sheep.

Pathological changes in the liver induced by Fasciola gigantica and Gigantocotyle explanatum were readily distinguishable from each other. Lesions associated with the migration of immature flukes through the parenchyma were a prominent feature of infection with Fasciola gigantica, whereas lesions induced by Gigantocotyle explanatum were confined to the large bile ducts. The size of the hepatic lesions increased during the course of infection with Fasciola gigantica and was associated with the formation of progressively larger areas of scar tissue in the parenchymal migration tracts as the flukes grew. This was also as a result of the progressively increasing cellular infiltration, proliferation of bile ductules and fibrosis which occurred in adjacent portal triads and interlobular septa. The absence of signs of migration through the hepatic parenchyma by Gigantocotyle explanatum, was regarded as evidence that these flukes gain entry to the bile ducts from the intestine via the common bile duct. In bile ducts infected with Fasciola gigantica there was more extensive desquamation of the epithelium, more intense mucosal infiltration with lymphoid cells and fewer eosinophils, less severe glandular hyperplasia, more free blood in the lumen and a thicker duct wall than in bile ducts infected with Gigantocotyle explanatum.

Animals↗
PubMed1984

The population dynamics of Gyrodactylus bullatarudis (Monogenea) within laboratory populations of the fish host Poecilia reticulata.

Experiments were undertaken to investigate the factors which influence the transmission dynamics of Gyrodactylus bullatarudis within populations of laboratory guppies. The parasites possess a number of biological attributes which are almost unique amongst helminth parasites of vertebrates. These include the ability to reproduce viviparously and directly on the surface of the host, the ability to survive death of the host (for a short period of time) and the ability to transfer between hosts (despite the absence of a specialized transmission stage in the parasite's life-cycle). Long-term laboratory experiments demonstrated the inability of the parasite to persist within populations of the host in the absence of the continual introduction of naive susceptible fish. With regular addition of susceptible fish, the parasite population exhibited recurrent epidemic behaviour. The magnitudes of the epidemics and the time interval between them, were dependent on the rate at which fish were added to the populations. The parasite was over-dispersed in its distribution within the experimental fish populations and was a significant cause of host mortality (in a manner related to parasite burden). The experimental results suggest that acquired resistance to infection is an important factor determining epidemic behaviour.

Animals↗
PubMed2005

Parasitism of Cichlasoma paranaense Kullander, 1983 and Gymnotus carapo Linnaeus, 1814 by Clinostomum complanatum (Rudolphi, 1814) metacercariae in the Taquari river.

The infection, known as yellow spot disease, produced by metacercariae of Clinostomum spp. was studied in fishes of the Taquari river, located in Jataizinho, Paraná State, Brazil. A total of 1,582 specimens, belonging to 36 species, were collected between March 1999 and April 2001. Yellow spot disease was observed only in Gymnotus carapo Linnaeus, 1814 (Gymnotiformes, Gymnotidae) and Cichlasoma paranaense Kullander, 1983 (Perciformes, Cichlidae). This parasitism was generated by metacercariae of Clinostomum complanatum (Rudolphi, 1814) (Digenea, Clinostomidae). Among the 88 specimens of G. carapo examined, 7 (prevalence = 8%) had cysts of the parasite. Four of them were captured in July 1999 and three in October 1999. In the other months, no specimen found was infected. Using relative condition factor (Kn) analysis, it was determined that both infected and non-infected specimens had a total weight equal to the theoretically expected value for each total length (Kn = 1.0). Among 56 individuals of Cichlasoma paranaense, 6 (prevalence = 10.7%) had between 1 and 27 metacercariae of C. complanatum (mean intensity of infection = 9.3 +/- 9.6). In March 1999 and April of both 2000 and 2001, the specimens examined were not infected. The infected fish had a total weight higher than the expected value (Kn > 1.0), while the non-infected fish had a weight equal to the expected value (Kn = 1.0).

Animals↗
PubMed2004

Two new species of Cardicola (Digenea: Sanguinicolidae) in drums (Sciaenidae) from Mississippi and Louisiana.

Two new species of Cardicola (Digenea: Sanguinicolidae) are described from the heart of drums (Perciformes: Sciaenidae) in and off Mississippi and Louisiana. Cardicola palmeri n. sp. infects the black drum, Pogonias cromis, and, in mature individuals, is distinguished from its congeners by the combination of a body 1.9-2.9 times longer than wide, an esophagus 44-52% of the body length, posterior ceca 1.0-1.8 times longer than the anterior ones, a gland encircling the seminal vesicle that is 30-37% of maximum body width in diameter, and a sinistral and nearly medial male pore. Cardicola currani n. sp. infects the red drum, Sciaenops ocellatus, and is distinguished from its congeners by the combination of posterior ceca 1.8-4.2 times longer than anterior ones, a male pore located well posterior to the ootype, a female pore and transverse metraterm located just anterior to the level of the ootype, and a medial and posttesticular ovary located at the level of the terminal ends of the posterior ceca. No adult blood fluke had been described previously from the northern Gulf of Mexico west of Florida. Each of the 2 flukes infected only 1 host species despite the hosts being sympatric.

Animals↗
PubMed1975

Fascioloides magna (Bassi, 1875) in feral swine from southern Texas.

Between 1971 and 1975, Fascioloides magna was found in 46 of 67 (69%) feral swine (Sus scrofa) in southern Texas. Flukes were recovered from swine in areas where F. magna commonly has been recovered from white-tailed deer and cattle. One to 12 flukes were recovered from each infected animal. Their presence was indicated by black hematin pigment on the liver and various other internal organs. Eggs were not detected in the gallbladder or feces of infected animals although mature flukes and eggs were recovered in the livers suggesting that, like cattle, feral swine can be infected but are aberrant hosts for the parasite and do not disseminate eggs.

Animals↗
PubMedDate not supplied

Infection of Lymnaea truncatula and Lymnaea glabra by Fasciola hepatica and Paramphistomum daubneyi in farms of central France.

Natural infection of Lymnaea glabra and Lymnaea truncatula by Fasciola hepatica and/or Paramphistomum daubneyi was studied at two periods of risk (June-July and September-October) in 11 French farms known for their high prevalences of F. hepatica infection in ruminants. A total of 1,778 L. truncatula and 2,396 L. glabra measuring 6 mm or more in height were collected to determine the prevalence of natural infection with F. hepatica and P. daubneyi. The role of four factors, i.e. season, snail co-infection (F. hepatica-P. daubneyi), ruminant host and the existence of single or mixed intermediate host communities, was investigated. There were no differences in prevalences between the two risk periods. Co-infections in L. glabra were more frequent than expected. The prevalences of infection with F. hepatica or P. daubneyi in L. glabra were higher in farms rearing sheep than in farms rearing cattle. A similar finding was also noted for L. truncatula infected with P. daubneyi only. L. glabra was a much better intermediate host for F. hepatica and P. daubneyi when it was the only available snail, possibly indicating an adaptation of parasites to their less usual host in local conditions. The two trematodes preferably developed in L. truncatula rather than in L. glabra when both host species lived in the same places.

Animals↗
PubMed1989

[The discovery of Melanoides tuberculata as the first intermediate host of Echinochasmus japonicus].

This paper reports on the discovery of cercariae which are similar to those of Echinotomatidae in Melanoides tuberculata in Yunxiao and Zhaoan Counties of Fujian. Encysted metacercariae were found in the gills of fresh-water fish after experimental infection with the cercariae for 3 to 4 hours. Adult worms identified as Echinochasmus japonicus were obtained from Mesocricetus auratus and dove after infection with the metacercariae. Melanoides tuberculata was recorded for the first time as the first intermediate host of E. japonicus and its natural infection rate was found to be 1.1%. The morphological characteristics of the cercaria are described.

Animals↗
PubMed1980

The treatment of fasciolopsiasis with niclosamide and dichlorophen.

Niclosamide and Dichlorophen have been tried in infection with F. buski in an endemic area of Bangladesh. Niclosamide is the commonly used agent for this condition, but was found to reduce the ova count by about 48.5% only and repeat treatment did not improve the result. Dichlorophen is advocated for tape worm, but was found to reduce the ova count by 83.3% and repeat treatment completely eradicated infection with F. buski.

Adolescent↗
PubMed1993

The metazoan parasite community of migrating greater yellowlegs, Tringa melanoleuca, from the Rio Grande Valley, Texas and New Mexico.

Forty-eight migrant greater yellowlegs, Tringa melanoleuca, collected from southwestern Texas and southeastern New Mexico were examined for metazoan parasites. Nine helminth and 7 ectoparasite species were collected. Five new host records were recorded. The helminth fauna showed little diversity, little concentration for dominance, and no significant positive or negative associations between species were found. All species of helminths showed a contagious distribution. The component helminth community consisted of 2 core, 3 secondary, and 4 satellite species, and there was no host specialist. A checklist of metazoan parasites reported from greater yellowlegs in North America is included.

Animals↗