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PubMed1989

[Studies on ecology of Fasciolopsis buski and control strategy of fasciolopsiasis].

The development of eggs of Fasciolopsis buski requires oxygen and the eggs cannot survive anaerobic conditions. The eggs have some resistance to low temperature and can be maintained at 4 degrees C for 3 to 4 months; however, the eggs are killed at 50 degrees C in four hours. The presence of salts can influence the development time of the eggs and reduce their hatching rate. Encysted cercariae exist not only on aquatic plants, but also on the surface of the water. The number of encysted cercariae floating on the water surface is about 3.6% of that of the total encysted cercariae. By inquiring into the case history we found that 10.3-12.8% of the patients and 35.1-40% of the infested pigs were possibly infected by drinking water contaminated with encysted cercariae. The authors suggest the use of fermented silage to feed pigs instead of fresh aquatic green fodders to prevent infection in the animals. In addition, aquatic plants such as water chestnut should be boiled for 1 to 2 minutes before eating to kill the encysted cercariae on the plants.

Animals↗
PubMed1995

Histopathology of cultured sea bass (Lates calcarifer) (Centropomidae) infected with Cruoricola lates (Trematoda: Sanguinicolidae) from Pulau Ketam, Malaysia.

Cruoricola lates are found throughout sea bass (Lates calcarifer), most commonly in the mesenteric blood vessels, kidney, pericardial vessels, and eye. Eggs of C. lates were predominantly found in the gills, ventricle, hepatopancreas, and kidneys, but only develop to miracidia regularly in the gills and heart. Single miracidia escaping appear to cause little damage, but groups induce an inflammatory response and haemorrhage. Endocardial macrophages encapsulate eggs trapped between trabeculae in the heart. The reaction to eggs in the kidneys, hepatopancreas and spleen consists of fibrocytic encapsulation. Infection at the levels observed in this study were insufficient to cause lethal pathological changes, but could result in reduced food conversion ratios or impaired immunological capacity.

Animal Husbandry↗
PubMed2003

Gyrodactylus derjavini infection elicits IL-1beta expression in rainbow trout skin.

Specific gene expression of the pro-inflammatory cytokine IL-1beta and the type II IL-1beta receptor (IL-1RII, 'decoy receptor') was studied in skin of rainbow trout Oncorhynchus mykiss (Walbaum, 1792) fry during infection with the ectoparasitic monogenean Gyrodactylus derjavini Mikailov, 1975. Cytokine expression was studied in both primary and secondary infections using a semi-quantitative RT-PCR technique. Generally, low levels of specific IL-1beta1, IL-1beta2 and IL-1RII gene transcription were found in uninfected hosts. In contrast, a clear induction of both IL-1beta isoforms could be observed during the initial phases of primary G. derjavini infections. A less obvious induction of IL-1beta expression was seen in secondary infections imposed just after recovery from the priming infection. However, challenge infections given one-month post full recovery of the primary infections did not elicit transcription levels above those seen in skin samples from uninfected hosts. Despite this, hosts carrying a secondary infection elicited a stronger response toward G. derjavini thus expelling parasites quicker than their nai;ve counterparts. When induced, indications of a more tight regulation of the IL-1beta1 isoform compared to IL-1beta2 could be observed. Increased expression of IL-1RII was seen later during the course of a primary infection and could be involved in the observed down regulation of IL-1, especially the beta1 isoform. The current study represents the first example of cytokine expression in fish induced by an ectoparasitic infection and indicates the importance of localised mucosal immune reactions in responses of fish towards gyrodactylids.

Animals↗
PubMed2005

Second intermediate host land snails and definitive host animals of Brachylaima cribbi in southern Australia.

This study of infection of southern Australian land snails with Brachylaima cribbi metacercariae has shown that all commonly encountered native and introduced snails are susceptible second intermediate hosts. The range of infected snails is extensive with metacercariae-infected snails being present in all districts across southern Australia. C. virgata has the highest average natural metacercarial infection intensity of 6.1 metacercariae per infected snail. The susceptibility of birds, mammals and reptiles to B. cribbi infection was studied in South Australia by capturing, dissecting and examining the intestinal tract contents of animals which commonly eat land snails as a food source. Indigenous Australian little ravens (Corvus mellori), which are a common scavenger bird, and two other passeriform birds, the black bird (Turdus merula) and the starling (Sturnus vulgaris), which are both introduced European birds, were found to have the highest infection rates of all animals examined. Other birds found infected with B. cribbi were an emu (Dromaius novaehollandiae), chickens (Gallus gallus) and a pigeon (Columba livia). Natural infections were also detected in field mice (Mus domesticus) and shingleback lizards (Tiliqua rugosa) although the intensity of infection was lower than that observed in birds. Susceptibility studies of laboratory mice, rats and ducks showed that mice developed patent infections which persisted for several weeks, rats developed a short-lived infection of three weeks' duration and ducks did not support infection. This study has shown for the first time that a brachylaimid can infect a wide host range of birds, mammals and reptiles in nature.

Animals↗
PubMed1982

Spirorchidiasis in loggerhead sea turtles (Caretta caretta): pathology.

Loggerhead sea turtles (Caretta caretta) from the Atlantic seaboard (Florida to Massachusetts) were examined at the Marine Pathology Laboratory, University of Rhode Island, from March through December, 1980. Three genera of blood flukes (spirorchids) were found in 14 (33%) of the 43 turtles. Gross signs in heavily infected animals included cachexia, anemia and enteritis. Histopathological lesions were similar to those present in homeotherms with schistosomiasis. Granulomatous gastritis, enteritis, hepatitis, pneumonitis, and nephritis were present. Acute and chronic vasculitis accompanied metastasis of eggs. Infected animals had severe hepatic hemosiderosis, indicative of the anemia observed grossly. Evidence is presented that spirorchidiasis is prevelent in sub-adult loggerhead sea turtles, is responsible for extensive lesions and may be responsible for significant debilitation and mortality.

Animals↗
PubMed1995

Investigation of the life cycle and adult morphology of the avian blood fluke Austrobilharzia variglandis (Trematoda: Schistosomatidae) from Connecticut.

This study was undertaken to expand the current knowledge of the life cycle and adult morphology of the avian schistosome Austrobilharzia variglandis, which causes a marine cercarial dermatitis in New England. The specific objectives were to: (1) investigate the seasonality of the infection in the molluscan intermediate host, Ilyanassa obsoleta; (2) determine which bird species are acting as natural definitive hosts for the parasite; and (3) characterize the morphology of the parasite using scanning electron microscopy (SEM). One-thousand individuals of I. obsoleta were collected each month for 14 consecutive months and examined for the parasite. Ten to 15 specimens of each of the following avian species, Larus argentatus, Larus delawarensis, Larus marinus, Phalacrocorax auritus, and Branta canadensis, and 2 individuals of Larus atrilla, were collected and examined for schistosomes. Twenty adult male and 10 adult female specimens of A. variglandis were processed for SEM. Ilyanassa obsoleta was found to maintain a relatively low prevalence of infection (0.7-5.1%) throughout the 14-mo study, but no fully developed cercaria were visible in sporocysts recovered from snails collected in winter months. The Larus species had both the highest prevalence (85-92.8%) and highest mean intensity (12.1-34.5 male worms) of infection with A. variglandis. These data suggest that overwintering snail populations can harbor viable infections and in the spring infect shore birds (or humans) with cercaria. The snail and definitive host data suggest that A. variglandis is a year-round resident of the state.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2001

Ammonia-induced cellular and immunological changes in juvenile Cyprinus carpio infected with the blood fluke Sanguinicola inermis.

Immunological and structural changes in the thymus and pronephros of Cyprinus carpio infected with the blood fluke, Sanguinicola inermis for 30 days, and exposed to 0.5 mg NH4+/1 for 48 and 168 h were investigated. Ultrastructural observations revealed cell disruption and highly vacuolated cytoplasm in the thymus. Of the cells that remained intact there was a significant increase in thrombocytes after 48 h exposure to the pollutant. In addition, there was a decrease in lymphocytes following exposure to ammonia at both time-periods studied. In contrast the pronephros of fish exposed to the pollutant underwent relatively mild changes in cellular architecture although ammonia and time of exposure had significant effects on the proportions of several leucocyte types. A significant decrease in neutrophils, thrombocytes and lymphocytes occurred in fish exposed to the pollutant for 168 h. Pronephric lymphocyte stimulation (cpm) by Con A and PWM increased in vitro, whereas the stimulation index was reduced in infected fish exposed to ammonia. Changes in the immune organs of S. inermis-infected carp treated with pollutant were both organ- and time-specific. The possible reasons for this are discussed and significance in relationship to parasitization assessed.

Ammonia↗
PubMed2003

Increased susceptibility of Atlantic salmon Salmo salar to infections with Gyrodactylus derjavini induced by dexamethasone bath treatment.

Dexamethasone, a known immunosuppressant, was administered by bath or injection to Atlantic salmon Salmo salar (Conon stock) to study if this treatment could affect the susceptibility of fish to infections with a Danish strain of Gyrodactylus derjavini (Monogenea). Three groups of S. salar (Conon stock) were immersion treated either with 10, 60 or 240 microg dexamethasone l-1 water, respectively. In addition, one group (positive control) was treated intraperitoneally with 200 microg dexamethasone per fish and one negative control group was kept untreated. A single G. derjavini parasite was placed on the anal fin of each fish and the infection was subsequently monitored weekly for 6 weeks. An increase in parasite populations on the salmon was positively correlated with the amount of immunosuppressant used. Infection levels in the group immersion treated with dexamethasone (240 microg l-1 water) and in the i.p. treated positive control group were significantly higher compared to the untreated control group.

Administration, Cutaneous↗
PubMed1995

Invasion of Metagonimus yokogawai into the submucosal layer of the small intestine of immunosuppressed mice.

Metagonimus yokogawai was found deeply invaded into the submucosa of the small intestine of mice (ICR) when they were immunosuppressed by prednisolone injection. Experimental groups consisted of control, fluke infection (1,800 metacercariae per mouse), and fluke infection plus immunosuppression. In fluke infection group, many worms were found sectioned in the intervillous space of the jejunum and ileum at 6 hrs, 12 hrs, and 1 day after infection, and pathological changes characterized by villous atrophy and crypt hyperplasia were observed. After 3 days, only a few worms were found in intestinal sections, and after 7 days, the pathological changes became minimal. No worm was found penetrated beyond the mucosal layer. On the other hand, in immunosuppressed mice, numerous worms were found sectioned in the duodenum and jejunum, irrespective of the infection period up to 14 days. Pathological changes of the mucosa were minimal until 3 days after infection, but at 5 days marked destruction of the mucosal layer was observed. At this time many flukes were found invaded deeply into the submucosa facing the muscular layer. Despite continuous immunosuppression, the mucosal damage was gradually recovered at 7-21 days post-infection. The results showed that immunosuppression of ICR mice can induce, for a short period of time, severe mucosal damage, and allow deep invasion of M. yokogawai into the submucosa of the small intestine.

Animals↗
PubMed1970

Eurytrema procyonis, a pancreatic fluke of North American carnivores.

Eurytrema procyonis is reported from the pancreatic ducts of domestic cats from North Carolina and Virginia. There were extensive histopathological alterations to the pancreas, especially the pancreatic ducts. However, there was no clinical evidence of infections. The incorporation of a synanthropic host in the life history of E. procyonis allows for rapid distribution of this fluke over its potential geographical range.

Animals↗
PubMed2004

Four-year monitoring of parasite communities in gobiid fishes of the south-western BalticII. Infracommunity.

The parasite infracommunity of five goby species (Pomatoschistus minutus, P. pictus, P.microps, Gobiusculus flavescens, Gobius niger) from the south-western Baltic was investigated during spring, summer and autumn of the years 1997-2000. The mean parasite species number in single hosts was high, ranging between 1.1 (P. minutus), 2.1 (P. pictus) to even 3.3 (P. microps). Gobius niger is the only host which lives longer than a year and is infested by almost identical parasites for longer times, i.e. the parasite species composition has greater homogeneity. Most intensity of infestation values peaked in summer and were lowest in autumn; only a few exceptions were found in spring or autumn. Only the Digenea Podocotyle atomon and Cryptocotyle concavum were abundant enough to show a clear seasonal fluctuation in Pomatoschistus minutus, P. pictus and Gobiusculus flavescens. Aphalloides timmi and Apatemon gracilis (Digenea) also attained high intensities in P. microps. These four parasite species and, additionally, Cryptocotyle lingua (Digenea), and Hysterothylacium sp. (Nematoda) can be strongly accumulated from either prey or free-swimming larvae and, thus, decisively influence the structure of the infracommunities. Due to selection by filter mechanisms, rare parasites settle rather by chance after competition with other species. The number of parasite species usually increased significantly with host growth. As many as four parasite species were found at the same time in the intestinal tract microhabitat of Gobius niger and P. minutus; at most three parasite species were present on the skin and fins or in the body cavity. The level of infection is due to the respective life history patterns and the kinds of prey, which harbour different parasites as intermediate hosts. Additionally, it depends on the time of appearance of goby offspring in the course of the year.

Animals↗
PubMed2004

Acanthoparyphium tyosenense (Digenea: Echinostomatidae): experimental confirmation of the cercaria and its complete life history in Korea.

Cercaria yamagutii Ito, 1957, was found in the marine mesogastropods Lunatia fortuni and Glossaulax didyma from the tidelands of Simpo located at the estuary of the Mankyoung River, which runs to the western coast of Korea. Metacercariae were found in a marine bivalve Mactra veneriformis after being infected with C. yamagutii experimentally. When a sea gull, Larus crassiostris, was fed with the metacercariae collected from the infected M. veneriformis, adult worms were recovered 10 days later. It was confirmed that the parasites collected from L. crassiostris were Acanthoparyphium tyosenense Yamaguti, 1939. From the results of this life cycle study, it was determined that the first intermediate hosts of A. tyosenense are L. fortuni and G. didyma. The second intermediate and final hosts are M. veneriformis and L. crassiostris, respectively. Mactra veneriformis was experimentally infected with C. yamagutii isolated from L. fortuni and G. didyma by maintaining them in a water tank for 30 min at about 20 C. The cercariae entered M. veneriformis through their incurrent siphons. Five hours after infection, the cercariae tails began to separate from the bodies, and the cercariae formed cysts. Mature cysts were formed 340 hr (14 days) after infection and identified as the metacercariae of A. tyosenense. The prevalence of A. tyosenense metacercariae was 99.5% in naturally infected M. veneriformis. This is the first report of C. yamagutii as the cercaria of A. tyosenense, and the complete life cycle of A. tyosenense was established in Korea.

Animals↗
PubMed1997

A new endemic focus of Heterophyes nocens, Pygidiopsis summa, and other intestinal flukes in a coastal area of Muan-gun, Chollanam-do.

A small coastal village of Muan-gun, Chollanam-do, was surveyed for intestinal fluke infections, especially heterophyids such as Heterophyes nocens and Pygidiopsis summa by fecal examination on 108 inhabitants. The egg positive rate of heterophyids was very high, 75.0%, and that of other parasites was comparatively low, 0.9-3.7% by parasite species. After treatment of 20 patients showing high E.P.G. with praziquantel and purging with MgSO4, total 3,864 specimens of H. nocens were collected from the diarrheic stools of all the patients treated (3-1,338 individually) and total 703 P. summa were harvested from 18 patients (1-170 individually), together with several other species of flukes. Other flukes included Stictodora fuscata (164 specimens from 4 patients), Heterophyopsis continua (2 from 2 patients), and Gymnophalloides seoi (4 from 3 patients). From this study, the surveyed coastal area of Muan-gun, Chollanam-do was proven to be a new endemic focus of H. nocens and P. summa. The occurrence of a few infected cases suggests that this area should also be a low-grade endemic area of S. fuscata, H. continua, and G. seoi.

Animals↗
PubMed2006

Heterophyid metacercarial infections in brackish water fishes from Jinju-man (Bay), Kyongsangnam-do, Korea.

Heterophyid metacercarial infections in brackish water fishes, i.e., perch, shad, mullet, redlip mullet, and goby, of Jinju-man (Bay), Kyongsangnam-do, Korea, were investigated using a digestion technique. Among 45 perch (Lateolabrax japonicus), the metacercariae of Heterophyopsis continua were found in 55.6% (18.5 metacercariae per fish), Stictodora spp. in 28.9% (3.6), and Metagonimus takahashii in 6.7% (17.0). The metacercariae of H. continua were detected in 23 (65.7%) of 35 shad (Konosirus punctatus). Among 15 mullet (Mugil cephalus), the metacercariae of Pygidiopsis summa were found in 100% (105.9 metacercariae per fish), Heterophyes nocens in 40.0% (8.5), H. continua in 13.3%, and Stictodora spp. in 6.7%. Among 12 redlip mullet (Chelon haematocheilus), the metacercariae of P. summa were detected in 91.7% (1,299 metacercariae per fish), H. nocens in 16.7%, and Stictodora spp. in 16.7%. Among 35 gobies (Acanthogobius flavimanus), the metacercariae of Stictodora spp. were found in 82.9% (44.5 metacercariae per fish), and H. continua in 25.7% (2.8). The adult flukes recovered from a cat experimentally infected with metacercariae from perches were compatible with M. takahashii. The results confirm that the estuarine fish in Jinju-man (Bay) are heavily infected with heterophyid metacercariae. Furthermore, it was found for the first time that the perch acts as a second intermediate host for M. takahashii.

Animals↗
PubMed1988

Humoral and cellular response to infection with Echinostoma revolutum in the golden hamster, Mesocricetus auratus.

Laboratory hamsters (Mesocricetus auratus) were infected with Echinostoma revolutum (Trematoda). Immunoelectrophoretic studies of hamster serum showed no demonstrable antibody response to E. revolutum. Histopathologic examination of intestinal tissue of infected hamsters showed erosion of intestinal villi and lymphocytic infiltration as the primary host response. Spleens from infected hamsters were hyperplastic during the first 3 weeks of infection and atrophic from 4 to 8 weeks postinfection. Hamsters were unable to acquire a resistance to E. revolutum infection. Lack of resistance was demonstrated in hamsters where the parasite infection was no longer detected based on the absence of eggs in the faeces; these hamsters were then reinfected. Hamsters treated with the anthelmintic oxyclozanide were also reinfected with E. revolutum.

Animals↗
PubMed1999

Life-cycle and biology of Sychnocotyle kholo n.g., n. sp. (Trematoda : Aspidogastrea) in Emydura macquarii (Pleurodira : Chelidae) from southern Queensland, Australia.

Sychnocotyle kholo n. g., n. sp. (Aspidogastrea: Aspidogastridae) is described from the small intestine of the freshwater turtle Emydura macquarii (Pleurodira: Chelidae). The new genus is distinguished from other aspidogastrids by the possession of the following suite of characters: no cirrus-sac; no hermaphroditic duct; four rows of alveoli on the ventral disc but no prominent papillae; Laurer's canal opening to the exterior. Eggs hatched to cotylocidia within 37-41 days at 17-24 degrees C. The life-cycle is obligate two-host, involving a mollusc and a freshwater turtle. Juvenile forms, almost entirely single worm infections, were found in the molluscs Corbiculina sp. (Bivalvia: Corbiculidae) and Thiara balonnensis (Prosobranchia: Thiaridae). Sychnocotyle is most likely to have evolved in Australia after the separation of Gondwanaland from Laurasia 120- 100 mya.

Animals↗
PubMed2004

Obliterative endophlebitis in mute swans (Cygnus olor) caused by Trichobilharzia sp. (Digenea: Schistosomatidae) infection.

Schistosome infections in mammals cause chronic proliferative vascular lesions associated with the presence of adult parasites in the lumen of mesenteric and portal veins. In birds, however, this has never been reported. In this study, we found obliterative endophlebitis associated with the presence of adult schistosomes (Trichobilharzia sp., probably Trichobilharzia filiformis) as the main pathologic finding in five of eight mute swans (Cygnus olor). On histologic examination, the intestinal and portal veins of these swans showed moderate to severe, diffuse, hyperplastic endophlebitis, characterized by myointimal hyperplasia, often with obliteration of the vascular lumen. In addition, moderate to severe lymphocytic and granulocytic enteritis occurred in all eight swans associated with the presence of schistosome eggs in the intestinal mucosa. Other findings included hepatic and splenic hemosiderosis and high hepatic copper levels. The vascular lesions associated with Trichobilharzia sp. infection may have contributed to the emaciation and death of those mute swans by obstruction of venous return in the intestinal and portal veins.

Animals↗