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PubMed1997

Localization of worm antigen in Neodiplostomum seoulense by immuno-electronmicroscopy.

The localization of worm antigen of Neodiplostomum seoulense was examined by immuno-electronmicroscopic observation. Not only the immunized serum of mice with crude worm extract of N. seoulense but also serum of infected mouse were reacted to the worm section. Using immunized serum as primary antibody, the gold particles were deposited on the rough endoplasmic reticulum of the cell of tribocytic organ, spermatozoa in the seminal vesicle, microvilli of the caecum and vitelline follicle. Using infected serum, gold particles were deposited only on the vitelline follicle prominently. This finding suggested that the tribocytic organ, seminal vesicle, caeca and vitelline follicles may play a role of antigen to immunized serum with crude worm extract of N. seoulense, whereas the vitelline follicle, to the infected serum.

Animals↗
PubMed1988

Ecological studies on Cyathocotyle bushiensis (Digenea) and Sphaeridiotrema globulus (Digenea), possible pathogens of dabbling ducks in southern Québec.

Over the past 20 yr, recurrent late-summer mortality of dabbling ducks in southern Québec has been attributed to the digenean parasite Cyathocotyle bushiensis. This study attempted to determine whether this parasite was still implicated in the epizootics, and examined aspects of the ecology of the parasite in the definitive host. Comparison of prevalence and mean intensity of infection of all species of Digenea between salvaged carcasses and hunter-shot ducks revealed that C. bushiensis and a second digenean Sphaeridiotrema globulus were both significantly more prevalent in salvaged ducks. Mean intensity of infection was consistently higher for S. globulus in the salvaged carcasses than in hunter-shot ducks. These data provide strong circumstantial support for the hypothesis that C. bushiensis continues to contribute to the annual mortality, but also strongly suggest that S. globulus may be involved. Comparison of the relative numbers of each species of duck between the salvaged carcass sample and the hunter-shot sample revealed that blue-winged teal (Anas discors) occurred significantly more frequently in the salvaged carcass sample whereas wood ducks (Aix sponsa) were common in the hunter-shot sample but were never found in the salvaged carcass sample. A comparison of susceptibility to experimental infection with C. bushiensis revealed that mallards (Anas platyrhynchos), black ducks (Anas rubripes), blue-winged teal, pintail (Anas acuta) and lesser scaup (Aythya affinis) had similar susceptibilities but that wood ducks were significantly less susceptible to infection. Experimental infections also showed that age of mallards significantly influenced the number of parasites obtained 7 days postinfection; ducklings were most heavily infected. Significant differences were detected in the gross pathology caused by C. bushiensis among duck species. Data obtained from sentinel ducks placed in the field for 24 hr revealed that transmission of both C. bushiensis and S. globulus occurs at least between mid-May and mid-September and that large, potentially lethal, infections can be acquired in as little as 24 hr. Finally evidence is presented to suggest that ducks acquire resistance to challenge infections of C. bushiensis.

Age Factors↗
PubMed1976

Evaluation of fecal technics for the diagnosis of cat liver fluke infection.

The comparative efficiency of 5 standard technics for the detection of feline liver fluke ova in feces was evaluated. The formalin-ether technic proved superior to direct smear, sugar flotation, zinc sulfate flotation, or detergent sedimentation technics. The formalin-ether technic correctly diagnosed all Platynosomum concinnum-infected cats studied, as confirmed by necropsy findings.

Animals↗
PubMed2005

Effects of host habitat quality on the viability of Cryptocotyle lingua (Trematoda: Digenea) cercariae.

In an earlier study it was shown that Cryptocotyle lingua cercariae, matured in Littorina littorea from a polluted marine lagoon, displayed slower horizontal swimming rates, and reduced longevity compared to cercariae released by periwinkles from a cleaner environment. This work investigated whether the pollution-induced reduction in swimming rates was due to an inefficient swimming action or the adoption of a less direct swimming path. In addition, cercariae from L. littorea that had been transferred from an 'unpolluted' to a 'polluted' site for 1 month provided information on the speed with which pollutants affect cercariae through their intermediate hosts. Results indicated that, in general, horizontal swimming rates were reduced due to slower swimming rather than disorientation and longer swimming pathways. Effects of host transplantation to a polluted site were clearly evident after 1 month. Evidence suggested that the pollutants accumulated by the cercariae via their first intermediate host affected the neuromusculature associated with swimming performance rather than sensory structures. Bearing in mind the reduced viability of C. lingua cercariae in polluted sites it is assumed that high prevalence of this digenean in gastropods (at such sites) must be due to their continual introduction by infected birds attracted to these habitats from other areas.

Animals↗
PubMed1997

Observations of fibropapillomatosis in green turtles (Chelonia mydas) in Indonesia.

OBJECTIVE: To determine the prevalence and manifestations of fibropapillomatosis in green turtles in Indonesia, to identify any relationship between fibropapillomatosis and concurrent parasitic infection, to ascertain the effect of fibropapillomatosis on health, and to examine whether environment might have an effect on the prevalence of fibropapillomatosis. PROCEDURE: 4407 green turtles (Chelonia mydas) and 401 hawksbill turtles (Eretmochelys imbricata) were examined. The occurrence of fibropapillomatosis was correlated with sex, maturity, curved carapace length, body weight/curved carapace length ratio, the number and distribution of tumours on the skin, parasite burdens, some haematological variables and the region of capture. RESULTS: Fibropapillomatosis was seen only in green turtles, and the overall prevalence in these was 21.5%. This prevalence increased with the curved carapace length up to 85 cm. The average number of tumours per affected turtle was 5 +/- SD 4.1 (range, 1 to 29), and was negatively correlated with the body weight/curved carapace length ratio (rs = -0.8; P = 0.001). The red blood cell count in turtles with fibropapilloma was lower than in non-fibropapilloma turtles captured and examined at the same time (P = 0.001). The prevalence of fibropapilloma in turtles captured near densely populated, industrial regions (26.3%) was greater than in turtles from sparsely populated areas (17.7%). CONCLUSION: Fibropapillomatosis in green sea turtles in Indonesia is of moderate occurrence: young mature turtles (curved carapace length = 85 cm) are most frequently affected. Fibropapilloma adversely affects health of turtles. Fluke infestation seems not to be a causal factor, but viral infection, perhaps with concurrent stress of environmental origin, seems likely.

Age Distribution↗
PubMed2002

Trickle and single infection with Discocotyle sagittata (Monogenea: Polyopisthocotylea): effect of exposure mode on parasite abundance and development.

Experimental infection of rainbow trout Oncorhynchus mykiss (Walbaum) with the monogenean Discocotyle sagittata (Leuckart, 1842) allowed comparison between trickle and single exposure, two infection modes demonstrated to occur in the wild. Both types of infection resulted in mean larval attachment success around 50%, which was significantly dependent on dose of infective larvae used (P < 0.0001), but was not affected by mode of infection (P = 0.244). Worms recovered from fish exposed to the same number of oncomiracidia but different mode of infection differed in their rate of development. The developmental stage attained by parasites was significantly affected by number of infective larvae used (P = 0.005), and by the interaction between dose and mode of infection (P = 0.026), suggesting competition among attached larvae. Statistical analysis demonstrated that in the early stages of infestation, worm distribution over the gill arches can be explained by the relative amount of water flowing over them. One, two and three months post-infection parasite numbers were comparable (P = 0.805), but their observed distribution gradually decreased in gill arches III and IV and increased in gill arch I, suggesting that parasites migrate after initial attachment. These results reproduce phenomena observed in the field, indicating that the experimental infection system could be employed to study infection dynamics and host-parasite interactions under controlled conditions.

Animals↗
PubMed2001

Acanthoparyphium tyosenense: the discovery of human infection and identification of its source.

Acanthoparyphium tyosenense Yamaguti, 1939 (Digenea: Echinostomatidae), was originally reported as an avian intestinal parasite; here, its presence is reported in 10 humans in the Republic of Korea. The patients were 9 adults aged 35-66 yr (males and females) and a young girl aged 7 yr residing in 2 coastal villages in Puan-gun, Chollabuk-do. The worms were recovered after treatment with praziquantel and purgation with magnesium salts. A total of 158 specimens (1-107 specimens/individual) was collected, together with varying numbers of other intestinal flukes. The patients had eaten various kinds of brackish water mollusks caught in an estuary near their villages. Five bivalves and a gastropod species suspected as sources of human infection were collected and examined. Two bivalves (Mactra veneriformis and Solen grandis) and the gastropod (Neverita bicolor) were found to be infected with the metacercariae of A. tyosenense; adult flukes were confirmed after the experimental infection of chicks. The results show that A. tyosenense infects humans and that brackish water mollusks are the source of human infection.

Adult↗
PubMed2005

In vivo and in vitro encystment of Echinochasmus liliputanus cercariae and biological activity of the metacercariae.

In vivo and in vitro encystment of the cercariae of Echinochasmus liliputanus and biological activity of the metacercariae were studied. In vivo encystment of cercariae occurred in the gills of goldfish, the second intermediate host. However, the cercariae also encysted in vitro in Locke solution (0.6x to 1.2x strength), 0.7-1.2% NaCI, artificial gastric juice, and human gastric juice. Locke or NaCI solutions were shown to be appropriate for in vitro encystment to occur within 24 hr; however, full-strength Locke solution was shown to be optimal. The 1-day-old metacercariae formed in vivo and treated in 0.1% sodium deoxycholate excystation medium at 37 C for 1 hr showed 88.5% excystation. The metacercariae formed in vitro, however, showed 88.6% and 85.0% excystation for normal and abnormal ones, respectively. Abnormal cysts at room temperature usually die within 10 days. About 70% of the normal cysts, both in vivo and in vitro, can still excyst after being stored in Locke 0.5x solution at 4 C for 3 mo. Cysts formed in vivo and in vitro were equally infective. The encystment of the cercariae in vitro could be inhibited when the cercariae were treated with 1 micromol silver nitrate. Because silver nitrate binds to the papillae, especially to the ciliated papillae, on the cercaria surface, it is suggested that papillary chemoreceptors may be involved in encystment of the cercariae. The finding of E. liliputanus cercariae encysting in vitro, especially in human gastric juice, might be helpful in elucidating mechanisms of the definitive hosts that are directly infected by the cercariae.

Animals↗
PubMed2001

In vitro excystation of Haplorchis taichui (Trematoda: Heterophyidae).

The effects of trypsin, bile extract, temperature and acid-based condition for the in vitro excystation of Haplorchis taichui metacercariae were studied. At 37 degrees C, approximately half the number of metacercariae excysted when exposed to 1% trypsin for 15 minutes with no more excystation found beyond this time. Increasing trypsin concentration seemed to reduce the excystation rate while bile extract was, however, unlikely to be an absolute requirement. A temperature of 37 degrees-41 degrees C yielded a similar excystation result in combination with 1% trypsin; however, less excystation occurred at a lower temperature of 35 degrees C. The acid-based environment of pH 8 gave the best excystation result in association with 1% trypsin at a temperature of 39 degrees C. Higher and lower basicity produced a smaller excystation rate. An environmental condition of 1% trypsin at pH 8 and a temperature of between 37 degrees-41 degrees C was recommended for the in vitro excystation of H. taichui metacercariae. The relatively broad temperature and pH range condition for the excystation of H. taichui corresponded with various definitive hosts that were infected naturally by this fluke.

Animals↗
PubMed2002

High prevalence of Fasciolopsis buski in an endemic area of liver fluke infection in Thailand.

There is a high prevalence of Fasciolopsis buski in Sawasdee Village in the Nam Som District, Udonthani Province in northeastern Thailand, an endemic area of liver fluke infection. From stool examination of 183 villagers participating in the study, the authors detected a fluke parasitic infection rate of 14.8% (27 cases). Of interest, the authors found a similar high prevalence of both Opisthorchis viverrini (16 cases, 8.7%) and F buski (13 cases, 7.1%). This region is the endemic area of liver fluke, not of F buski. The surrounding environment is the hill area of Nayoong Namsom mountain, which is not a suitable area for F buski larvae. However, the village has been inhabited by a number of immigrants from various regions of Thailand over the past few years. The F buski can be carried by these people, possibly explaining the migration of the fluke parasite to this setting. The nonendemic parasite infection was also detected at high prevalence in the community. Wide spectrum control for various parasitic infections in villages like Sawasdee is necessary.

Animals↗
PubMed1993

Gross lesions and hematological changes in domesticated mallard ducklings experimentally infected with Cyathocotyle bushiensis (Digenea).

The digenean Cyathocotyle bushiensis has been associated with late summer fatalities of dabbling ducks in southern Québec. The objective of this study was to investigate the intensity- and time-dependent pathogenesis induced by experimental infection with this digenean in domesticated mallard ducklings. Lesions, hemorrhagic spots, plaques, and cores were observed in the ceca. Both affected tissue area and core weight increased with increasing intensity of infection. Magnitude of tissue damage increased with increasing duration of infection. Dye, administered intravenously, was found within the cecal lumen of infected ducks demonstrating increased permeability of the cecal wall to vascular products. The data suggest that infection was associated with decreased weight gain and a minor increase in body temperature. Elevations in hemoglobin concentration and packed cell volume were observed in some infected ducklings.

Animals↗
PubMedDate not supplied

[Seasonal infection by metacercaria of Diplostomum (Austrodiplostomum) mordax (Szidat and Nani, 1951) and Tylodelphys destructor Szidat and Nani, 1951 in the Chilean Silverside, Basilichthys australis Eigenmann, 1927 (Pisces:Atherinidae) in Lake Riñihue].

Between 1993 and 1994, 129 specimens of Basilichthys australis from Lake Riñihue (39 degrees 50 minutes S; 72 degrees 20 minutes W) in the south of Chile were examined, in order to determine the prevalence and mean intensity of infections by Diplostomum mordax and Tylodelphys destructor metacercariae in the brain of fishes. Prevalence and mean intensity of D. mordax and mean intensity of T. destructor not showed seasonal significant differences. Prevalence of T. destructor was higher in summer than in winter, spring and autumn. No association between intensity of infection by D. mordax and T. destructor and body condition of the host was observed.

Animals↗
PubMed1997

Human infection of Centrocestus caninus in Thailand.

Examination of fecal samples, collected after treatment with praziquantel, of the persons positive with opisthorchioid eggs residing in the northern provinces of Thailand, was carried out. Five adults Centrocestus were recovered in one sample from Doi Saket, Chiang Mai and one adult was found in another fecal sample from Wiang Pa Pao, Chiang Rai. The worms had 26-30 spines arranging in two rows around the oral sucker which agreed with the character of C. caninus. This is the first record of natural human infection with Centrocestus in Thailand.

Adult↗
PubMed1988

Treatment of fish parasites. 4. Effects of sym. triazinone (toltrazuril) on Monogenea.

For chemotherapy in fish parasitized by monogeneans, toltrazuril was tested in vivo and in vitro against gill-parasitizing species (Dactylogyrus vastator, D. extensus, D. cornu, Pseudodactylogyrus anguillae, Diplozoon paradoxum, Dip. homoion) as well as the skin-parasitizing species Gyrodactylus arcuatus. Naturally infected fish were incubated at 20 degrees C for 0.3, 1, 2, 3, 4, and 6h in water containing 0.5, 10, 20, 30, and 50 microgram toltrazuril/ml. In general, the damage observed resulted in the vacuolization and lysis of the parasitic tegument. Toltrazuril caused irreversible lesions in the tegument of Dactylogyrus species and Pseudodactylogyrus bini, beginning at a dose of 5 microgram/ml (4-h exposure). In vitro treatment with 10 microgram/ml toltrazuril caused death in Dip. paradoxum and Dip. homoion after 4-80 min, depending on the age of the parasites. Subadult worms were more susceptible to the drug than adults. Specimens of G. arcuatus were severely affected after 1-h exposure to 20 microgram/ml. In all species, the prohaptor and peduncle regions of the specimens were most sensitive to the drug. Treatment of infections of Gyrodactylus species, D. vastator, D. extensus, C. cornu, and P. bini using a water bath with 10 micrograms toltrazuril/ml for 4 h (D. cornu, 15 degrees C; other species, 20 degrees C) is recommended, since then species diagnosis is not needed. Fish with extensive skin lesions caused by net catching or infection by Saprolegnia spp. should be carefully observed during treatment, as these factors decrease their drug tolerance.

Animals↗
PubMed1991

Epidemiology of paramphistomosis in cattle.

The epidemiology of paramphistomosis in cattle was studied using tracer calves in a subtropical location in eastern Australia. Two species of paramphistomes were present; Calicophoron calicophorum and Paramphistomum ichikawai. The former species was the most abundant. Gyraulus scottianus and Helicorbis australiensis acted as intermediate hosts, respectively. Paramphistome burdens varied seasonally and were dependent upon the number of infected host snails. Peak fluke burdens and clinical paramphistomosis occurred in late summer in year 1 and early winter in year 2. The peak fluke burdens coincided with prolonged inundation of the grazing areas resulting in rapid multiplication and infection of host snails, and the period after the inundated areas dried out. The prevalence of infection in snails was high in both years, peaking at 98% in year 1 and 58% in year 2. The main host snail, G. scottianus, aestivated and retained infection for at least 24 weeks in soil, and in vegetable debris on the surface of the soil, resulting in rapid reappearance of host snails and infective metacercariae after the onset of seasonal rain. Metacercariae survived on herbage for up to 12 weeks, depending on the environmental conditions. Paramphistome burdens in calves could be predicted from the prevalence of infection in the host snail, the water levels and an index of surface water on the grazing site. Control of paramphistomosis during and after flooding may be achieved by removal of susceptible cattle from pasture or regular treatment during these periods. Strategic treatment during the dry season may reduce contamination of snail habitats and infectivity of the pasture in the following wet season.

Animals↗
PubMed1991

Hematology and clinical pathology of experimental Fascioloides magna infection in cattle and guinea pigs.

The hematologic and clinico-pathologic response to Fascioloides magna infection in cattle and guinea pigs was investigated. Twelve calves (six infected and six controls) were monitored for 26 weeks after inoculation with 1000 metacercariae. All calves remained healthy and there were no significant differences in weight gains between infected and control groups. Flukes (mean = 9.2, range 1-32) were recovered from the liver and abdominal cavity of all infected calves. The only significant response observed in the complete blood counts was an eosinophilia present in the infected calves extending from Weeks 2 to 26 post-infection. There were no significant differences in serum levels of aspartate aminotransferase and only minor increases in the levels of gamma-glutamyl transferase and sorbitol dehydrogenase. A total of 48 infected and 48 control guinea pigs from three separate experiments were monitored for 16 weeks after inoculation with 20 metacercariae of Fascioloides magna. Infected guinea pigs died between 7 and 114 days after infection, and flukes (mean = 2.5, range 0-13) were recovered from the liver, abdominal cavity, lungs, thoracic cavity, skeletal muscle and subcutaneous tissue. There were no differences in weight gains between infected and control guinea pigs. Complete blood counts showed increases in white blood cells, monocyte and neutrophil counts from between the third and fourteenth weeks post-infection; however, the differences were not consistently significant. Infected guinea pigs developed a significant eosinophilia and basophilia from 2 to 16 weeks post-infection. There were no significant changes in the serum levels of alanine aminotransferase or gamma-glutamyl transferase. There was an increase in the serum levels of aspartate aminotransferase beginning at 5 weeks post-infection. The response observed in the guinea pigs was similar to that reported in sheep, suggesting the suitability of the guinea pig as a model for Fascioloides magna infection in the sheep.

Alanine Transaminase↗
PubMed2000

Skin lesions caused by Dermophthirius penneri (Monogenea: Microbothriidae) on wild-caught blacktip sharks (Carcharhinus limbatus).

Skin lesions caused by the ectoparasite Dermophthirius penneri Benz, 1987 (Monogenea: Microbothriidae) on 2 wild-caught blacktip sharks (Carcharhinus limbatus) from the northern Gulf of Mexico were studied using light and scanning electron microscopy. Grossly, lesions appeared as multifocal, well-demarcated, ovoid or irregularly shaped, light gray patches of skin. Scanning electron microscopy of lesions revealed gaps between placoid scales apparently created by detachment and loss of placoid scales, rotated and tilted placoid scales with blunt distal tips and shallow ridges, and a frayed epithelium that covered some placoid scales and filled some spaces between placoid scales. Light microscopy of lesions revealed epithelial hyperplasia accompanied by dermal infiltrates of moderate numbers of loosely arranged lymphocytes interposed between collagen bundles in the superficial layers of the stratum compactum. This report provides the first details of microbothriid skin lesions on wild sharks. Our results indicate that D. penneri caused chronic skin lesions not associated with bacterial infection or severe, debilitating, skin disease in the studied sharks.

Animals↗