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PubMed2006

Migration of Neodiplostomum leei (Digenea: Neodiplostomidae) neodiplostomula to the livers of various mammals.

Of morphologically indistinguishable small-sized neodiplostomula in the grass snake Rhabdophis tigrina in the Republic of Korea, some, such as Neodiplostomum seoulense, mature into adults in the intestines of rodents, whereas others, such as Neodiplostomum leei, migrate to rodent livers and mature in the intestines of chicks. In the present study, we aimed to observe in more detail the extraintestinal migration and development of N. leei by using various animal models, i.e., mice, rats, hamsters, rabbits, cats, and chicks. In mammals, small-sized neodiplostomula (N. leei) inoculated orally penetrated the intestinal wall, entered the peritoneal cavity, and oriented to the liver without passing through any other organ. In rodent livers, the neodiplostomula were surrounded by host inflammatory cells and fibrotic tissues from day 10 postinfection (PI); the worms were found dead by day 56 PI. When neodiplostomula from rodent livers were transferred orally to mammals, they reoriented to the liver, although they were able to develop into adults in the chick intestine by day 6-7 PI. The possibility of human infections, i.e., liver migration, by N. leei neodiplostomula, among snake consumers, warrants investigation.

Animals↗
PubMed1993

Intestinal parasite infections in the inhabitants along the Hantan River, Chorwon-gun.

The prevalence of intestinal parasite infections in inhabitants at the reaches of the Hantan River, Chorwon-gun, Korea, was observed from August 12 to September 14, 1993. Of 465 people observed by cellophane thick smear and formalin-ether concentration method, 2 Ascaris lumbricoides (unfertilized), 1 Trichuris trichiura, 39 Clonorchis sinensis and 16 Metagonimus egg positive cases were found. After treatment, the Metagonimus egg positive cases passed out flukes of Metagonimus Miyata type. Of 68 fish caught in the Hantan River, 14 (20.6%) were infected with metacercariae of Metagonimus, while no metacercaria of C. sinensis was found. At this area, soil-transmitted nematodes are very low, but clonorchiasis and metagonimiasis are prevalent by modernate endemicity.

Adolescent↗
PubMed1986

Gyrodactylus salmonis (Yin and Sproston, 1948) parasitizing fry of Salvelinus fontinalis (Mitchill).

Fry of brook trout, Salvelinus fontinalis (Mitchill), were infected under controlled conditions with Gyrodactylus salmonis (Yin and Sproston, 1948) and the course of infection followed for 22 days in four groups of 40 fish and for 60 days in a group of 200 fish. Between 15 and 44% mortality occurred among infected groups compared with less than 5% in noninfected control groups. Intensely infected moribund fish were cachexic, lethargic, and often darkened in color. Histologic studies revealed that intensely infected fish had a thinner epidermis with fewer goblet cells than control fish. Internally the only obvious lesions involved the kidney where there was extensive tubular degeneration and necrosis. It is hypothesized that attachment and grazing activity by G. salmonis can lead directly to death of fry through disruption of the osmotic permeability of the epidermis. There was no evidence of secondary invasion by bacteria or fungi.

Animals↗
PubMed1996

Redescription of Macroorchis spinulosus Ando, 1918 (Digenea: Nanophyetidae) encysted in the fresh water crayfish, Cambaroides similis.

Macroorchis spinulosus Ando, 1918 (Digenea: Nanophyetidae) is redescribed based on adult flukes recovered from experimental mice, rats and cats which were fed with metacercariae encysted in the muscle of the crayfish. Cambaroides similis. A total of 117 adult flukes were harvested from the small intestine of the experimental animals at 5-21 days post-infection. The worm recovery rate was 31-37%, not significantly different among the three kinds of animals. The metacercariae were round, 0.18 mm in average diameter, encysted with two layers of thick walls, and possessing a stylet on the oral sucker and Y-shaped excretory bladder. The adult flukes were oval, 0.66-0.71 mm long and 0.36-0.41 mm wide, and characterized by the presence of a stylet on the oral sucker, variable location of the ovary near the mid-portion of the body, bilobed seminal vesicle, and anterolateral location of two testes. These morphological features were a little different from the original description, hence, an emended version of M. spinulosus was given. M. spinulosus is a new intestinal trematode of animals and possibly man in Korea.

Animals↗
PubMed2002

Nasal schistosomes of wildfowl in the Czech Republic.

In Central Europe, the adults of nasal bird schistosomes of the genus Trichobilharzia have only been reported from experimental infections. Our work confirmed a relatively high prevalence of these parasites in wild anatid birds in the Czech Republic. The isolated miracidia were used to infect the Radix peregra (an autochtonous snail species) which proved to be a susceptible intermediate host. Subsequently, the emerged cercariae penetrated the skin of domestic ducks and adults were found in the nasal mucosa. It can be concluded that nasal bird schistosomes occur in the Czech fauna and are able to complete their life cycle under the conditions found in Central Europe.

Animals↗
PubMed1986

Effects of praziquantel on human intestinal flukes (Fasciolopsis buski and Heterophyes heterophyes).

Human intestinal flukes (Fasciolopsis buski and Heterophyes heterophyes) were treated with praziquantel in vivo or in vitro and then studied by transmission (TEM) and scanning (SEM) electron microscopy. F. buski worms recovered from patients, which had been cured by oral treatment of 1 X 15, 1 X 25 or 1 X 40 mg praziquantel/kg body weight, showed typical contraction and alterations together with vacuolization and bleb formation of their tegument. H. heterophyes worms recovered from an experimentally infected dog were incubated in media containing 1 microgram praziquantel/ml for 5-60 min. Their tegument showed lesions the extent and duration of which increased with exposure time, finally leading to death. The damage observed in vitro was very similar to that found in F. buski recovered from cured patients. The cure rate was very high when using 1 X 15 mg praziquantel/kg.

Animals↗
PubMed1999

The influence of temperature on the survival and infectivity of the cercariae of Echinoparyphium recurvatum (Digenea: Echinostomatidae).

Survival and infectivity characteristics are described for cercariae of the echinostome Echinoparyphium recurvatum at 10, 15, 20, 25 and 30 degrees C. Cercarial survival was markedly age- and temperature-dependent, maximum survival time being reduced from 68 h at 10 degrees C to 12 h at 30 degrees C, 50% survival times falling from 47.9 h at 10 degrees C to 8.4 h at 30 degrees C. The mean instantaneous per capita death rate of cercariae increased exponentially with temperature. Cercarial infectivity was also temperature dependent, the main effect of temperature being upon the rate at which infectivity diminished with increasing age of cercariae. Infectivity increased from zero at 10 degrees C to a maximum at 25 degrees C after which it declined to a low level at 30 degrees C. Overall transmission efficiency of cercariae at each experimental temperature was calculated as the ratio of the mean instantaneous per capita death rate (mu) to the mean instantaneous per capita rate of infection (beta). Transmission efficiency of cercariae was found to be maximal at 20 degrees C and at a relatively high level between 10 and 25 degrees C. Transmission efficiency was zero at 10 degrees C and at a very low level at 30 degrees C. These results suggest that the cercariae of E. recurvatum show transmission optima at water temperatures likely to be encountered in natural habitats in Britain and Europe.

Aging↗
PubMed2003

Larval stages of Brachylaima fuscatum in the terrestrial snail Limicolaria aurora from southern Nigeria.

Of 150 specimens of the gastropod snail Limicolaria aurora examined from the Edo and Delta states of Nigeria, 63.4% were infected with larval digeneans comprising mother sporocysts (12.1%) daughter sporocysts (20.4%) cercariae (43.1%) and metacercariae (24.5%). Attempts to experimentally infect three 14-day-old chicks (Gallus domesticus) and two laboratory-bred 4-month-old mice (Mus musculus) by oral feeding and peritoneal injection with cercariae were negative, although experimental infections of chicks via a cloacal drop yielded 62 immature and 37 mature worms from the intestinal caeca and ileum. The worms were identified as Brachylaima fuscatum (Trematoda: Brachylaimidae). The study also revealed that L. aurora acts as an intermediate host for B. fuscatum, in addition to Eulota sp., Helix sp., Helicella sp., Oxychilus sp. and Agrolimax sp.

Animals↗
PubMed1998

[An epidemiological survey of schistosome cercarial dermatitis among the residents living along the banks of the Huaihe River system].

AIM: To make an epidemiological survey of schistosome cercarial dermatitis among the residents living along the banks of the Huaihe River. METHODS: Making inquiries about signs and symptoms of schistosome cercarial dermatitis, and physical examinations of manifestation in the residents (fishermen and peasants). Cercariae shed from the Radix auricularia collected in the field were used to infect ducklings. The eggs and miracidia separated from the feces of the full grown ducks bred by fishermen were used to infect Radix auricularia. RESULTS: Schistosome dermatitis locally known as "duck itch" (meaning duck-fecesdermatitis) was discovered among the residents living along the Huaihe River bank. The main signs and symptoms of the dermatitis included diffuse erythema or red papular eruption with areorae, urticae, urticant itch or titillation around the affected areas (including thoracic part, abdomen and lower limbs etc). The cercariae with eye spot were found from Radix auricularia collected from Huaihe riverside and were identified to be the species of Trichobilharzia can both hatch miracidium, which laboratory-reared Radix auricularia were infected with miracidia hatched from the two types of eggs, rhomboid eggs and crescent eggs, found in the feces of full grown ducks bred by fishermen and shed the same cereariae with eye spot. Besides, adult worms of Trichobiharzia were obtained by dissecting both experimentally infected ducklings bred in the laboratory and naturally infected ducks bred in the Huaihe river-side area. The above-mentioned eggs, miracidia, cercariae and adult worms were all identified to belong to the life-phase of Trichobilharzia. CONCLUSION: The epidemic disease known as schistosoma cercarial dermatitis harmful to the health of the residents living along the banks of Huaihe River is caused by the cercariae of Trichobilharzia.

Adult↗
PubMed1999

[Occurrence of metacerkariae Diplostomum sp. in the Siberian turgeon fry (Acipenser baeri Brandt)--preliminary study].

Siberian sturgeon fry coming from three different ponds has been examined. 1. "Dgał" - fish culture conerete-terrestrial pond beloning to D.O.Z. Dgał Inland Fisheries Institute in Olsztyn supplied with fresh water from Great Dgał Lake; 2. "Grzmieca" - fish culture pond terrestrial, natural belonging to fishing farm Grzmieca near Brodnica; 3. "Konin" - fish culture pond near Konin supplied with water utilized by near heat and power generating plant. Total of 80 sturgeons fry with parameters: length 17.5 cm - 38.5 cm, weight 21 g - 134 g, age 0+1+ has been examined. The examinated group of sturgenos had metacercariae Diplostomum sp. in their lenses. Prevalence of infection of sturgeon with metacercariae Diplostomum sp. was high in all this three ponds. Intensity of infection was also high in ponds "Dgal" and "Grzmieca", but low in "Konin". In ponds "Dgal" and "Konin" we have obtained high positive correlation ("Dgal" - r = 0,606, p < 0,05; "Konin" - r = 0,743, p < or = 0,01) between number of metacercariae in sturgeon and temperature of water. Our study confirmed observations other authors susceptibility sturgeon fry on the Diplostomum sp. invasion.

Animals↗
PubMed1990

Transmammary transmission of mesocercariae of Alaria marcianae (Trematoda) in experimentally infected primates.

A lactating primate, Callithrix jacchus, was infected experimentally with 600 mesocercariae of Alaria marcianae 10 days after parturition to determine if she would transmit the mesocercariae to her offspring. Her twin infants were examined 4 wk postinoculation and 16 mesocercariae were found in their tissues. The female was mated again and gave birth to a litter of triplets. She was not given additional mesocercariae. One infant died within hours of birth without suckling and was found negative for any stage of A. marcianae. The other 2 were allowed to nurse for 5 wk, examined and found to be infected with a total of 115 mesocercariae in various tissues, 1 metacercaria in the lungs, and 1 immature and 2 fully formed ovigerous adults in the small intestines. The female was examined at the same time and 246 mesocercariae were recovered. No other stage was found. Histological examination of her mammary glands revealed numerous mesocercariae in the milk-laden alveoli.

Animals↗
PubMed1985

Activity of closantel against experimentally induced Fascioloides magna infection in sheep.

The efficacy of closantel against experimentally induced Fascioloides magna infection in sheep was studied. In each of 3 experiments, closantel was administered 8 weeks after the sheep were given (oral inoculation) 100 metacercariae of F magna. In the 1st experiment, closantel was given orally to 5 groups of 6 sheep each at dosages of 0 (nontreated control), 5, 7.5, 10, and 15 mg/kg of body weight. In the 2nd and 3rd experiments, groups of 10 or 12 sheep were treated to confirm the efficacy of the previously determined optimal dosage of 15 mg/kg. An additional group of sheep (n = 10) was used in the 3rd experiment to evaluate the efficacy of closantel given IM at a dosage of 7.5 mg/kg. Closantel given orally at a dosage level of 15 mg/kg was highly effective (94.6% to 97.7%) in reducing F magna burdens. Also, pathologic scores associated with the F magna infection were reduced by 81.3% to 92.6% in sheep given this dosage of closantel. Efficacy of the IM administered dosage of 7.5 mg of drug/kg was equivalent to that of the 15 mg/kg oral dosage. Other than mild, transient lameness of the limbs which were injected with the drug (group 10), side effects were not observed.

Administration, Oral↗
PubMed1993

Decoy effect and host infection by miracidia within snail communities.

The effect of experimental non-host snail (NHS) communities on the infection of Lymnaea truncatula with Paramphistomum daubneyi and Fasciola hepatica miracidia was studied. The results obtained indicated that NHS had variable effects on basic population parameters of host infection. Specifically, NHS were able to produce aggregation of sporocyst number/snail in the experimental host populations. Proposed hypotheses for decoy effect mechanisms failed to explain completely the experimental results. A new mechanism is suggested, based on a distance response of miracidia to snail chemo-attractants, to explain effects of NHS on miracidial host finding behaviour. It is assumed that miracidia have evolved the ability to discriminate among individual snail chemical attractants in a community already at a distance. This attribute of miracidial behaviour allows NHS to induce variations in the effectiveness of individual host localization by miracidia. The resulting aggregation of successful infections/host is assumed to be the specific component of snail decoy effect at the community level. It was also established that NHS affected trematode reproduction in the host inducing a compensatory increase in the intramolluscan population. Intraspecific competition among developmental stages is suggested to be the mechanism of this compensatory reaction.

Animals↗
PubMed1992

Life cycle and structure of the fish digenean Brachyphallus crenatus (Hemiuridae).

Cystophorous cercariae from Retusa obtusa (Montagu) (Gastropoda, Opisthobranchia, Retusidae) develop into adults of Brachyphallus crenatus (Rudolphi, 1802) Odhner, 1905 (Hemiuridae). The free-swimming cercariae were ingested by laboratory-reared Acartia tonsa Dana, and the cercarial body was injected into the hemocoel of the copepod. Two-week-old metacercariae held at 15 C were infective to stickleback Gasterosteus aculeatus Linnaeus. The cercariae of B. crenatus are very similar to the cercariae of Hemiurus luehei Odhner, 1905, and Lecithocladium excisum (Rudolphi, 1819) Lühe, 1901 (Hemiuridae), which develop in closely related opisthobranch snails. Scanning electron microscopy of metacercariae and adults of B. crenatus revealed the annular plications of most of the external surface to be scalelike. The area surrounding the genital pore and the presomatic pit was densely plicated.

Animals↗
PubMed2003

Indirect ELISA for the detection of antibodies against Opisthorchis felineus (Rivolta, 1884) and Metorchis bilis (Braun, 1790) in foxes.

Serological investigations focused on the detection of specific opisthorchiid liver fluke antibodies in silver foxes (Vulpes vulpes fulva). Animals were experimentally infected with Opisthorchis felineus (nos. 1 and 2) and Metorchis bilis (nos. 3-8) by feeding fish with a counted number of metacercariae. Four foxes remained as non-infected negative controls (nos. 9-12). For the indirect ELISA, an excretory-secretory antigen was produced by in vitro cultivation of O. felineus and M. bilis adults isolated from livers of experimentally infected hamsters. Immunoglobulin G (IgG) seroconversion against homologous antigen took place between weeks 2 and 6 postinfection (p.i.) and foxes remained seropositive up to the end of the trial at week 41 p.i. In contrast, IgG titres against heterologous antigen remained significantly lower and stayed near the cut-off. All infected animals excreted opisthorchiid eggs, starting between weeks 2 and 4 p.i. The number of liver flukes found at necropsy was relatively low, except in one fox that was sacrificed at the week 11 p.i. These results suggest that the ELISA is a suitable tool for the detection of specific O. felineus and M. bilis antibodies in the fox.

Animals↗
PubMed1986

Schistosome infection in the kelp gull, Larus dominicanus, from Port Elizabeth, Republic of South Africa.

A schistosome infection, cf Gigantobilharzia sp., is recorded from a South African coastal bird, Larus dominicanus, for the first time. The histological response to the presence of the worms and their eggs was considered to be unusually mild. These eggs were all immature and were found only in the mucosa of the gut wall. This raises questions about the oviposition behaviour of the female worm.

Animals↗
PubMed2002

Bolbophorus damnificus n. sp. (Digenea: Bolbophoridae) from the channel catfish Ictalurus punctatus and American white pelican Pelecanus erythrorhynchos in the USA based on life-cycle and molecular data.

The common pathogenic prodiplostomulum metacercaria in the flesh, mostly near the skin, of pond-produced channel catfish Ictalurus punctatus has been demonstrated to be Bolbophorus damnificus Overstreet & Curran n. sp. The catfish acquires the infection from the snail Planorbella trivolvis, the only known first intermediate host, and the species is perpetuated through the American white pelican Pelecanus erythrorhynchos, as confirmed by experimental infections with nestling and dewormed adult pelican specimens in conjunction with molecular data. It differs from the cryptic species Bolbophorus sp., also found concurrently in the American white pelican, by having eggs 123-129 microm rather than 100-112 microm long and consistent low values for nucleotide percentage sequence similarity comparing COI, ITS 1/2, 18S rRNA and 28S rRNA fragments. Bolbophorus sp. is comparable but most likely distinct from B. confusus (Kraus, 1914), which occurs in Europe and has eggs 90-102 microm long. Its intermediate hosts were not demonstrated. The adults of neither of the confirmed North American species of Bolbophorus were encountered in any bird other than a pelican, although several shore birds feed on infected catfish, and B. damnificus can survive but not mature when protected in the mouse abdominal cavity. B. ictaluri (Haderlie, 1953) Overstreet & Curran n. comb., a species different from B. damnificus, is considered a species inquirenda.

Animals↗
PubMed2001

A nationwide survey of the prevalence of human Gymnophalloides seoi infection on western and southern coastal islands in the Republic of Korea.

A nationwide survey was performed to know the distribution and prevalence of human Gymnophalloides seoi infection on western and southern coastal islands in the Republic of Korea. A total of 4,178 fecal specimens were collected from residents on 45 (24 western and 21 southern) islands, and examined by Kato-Katz and formalin-ether sedimentation techniques. Eggs of G. seoi were detected from 160 (3.8%) people living on 22 (13 western and 9 southern) islands. The prevalence varied by the location of islands; higher on western islands than on southern islands. The highest prevalence was found on Amtaedo (25.3%), followed by Cheungdo (25.0%), and Anchwado (20.9%) (Shinan-gun). A little lower prevalence was observed on Munyodo (13.3%), Shinshido (12.9%), and Sonyudo (10.3%) (Kunsan-shi). Of the remaining islands, the regions showing the prevalence greater than 5% included Kohado, Dallido (Mokpo-shi), Pyeongildo, Kogumdo (Wando-gun), and Keogumdo (Kohung-gun). A strong age predilection was noted (p < 0.05); 95% of the infected people were over 40 years old. Females showed a little higher prevalence than males. The results indicate that human G. seoi infection is more widely distributed than previously considered. Nine of 11 islands (excluding the 2 known areas Munyodo and Sunyudo) that showed greater prevalence than 5% are regarded as new endemic foci of G. seoi.

Adolescent↗