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PubMed1992

Heterophyids: experimental chemotherapy and immunotherapy.

Heavy infections with the tiny flukes heterophyids can cause intestinal pain and mucous diarrhea, thus the study of praziquantel (Pzq) and the new drug cyclosporin A (CsA) as antiparasitic drugs were undertaken in this work, as well as the effect of matecercarial and adult antigens as immunizing agents. To assess the result of our work, the number and length of the recovered heterophyids were studied. Description of the surface by SEM was carried out for the groups: treated by cyclosporin A and immunized by adult heterophyid antigen (third fraction) which gave the highest percentage reduction.

Animals↗
PubMed1989

Sexual, seasonal and tissue variation in the encystment of Cotylurus variegatus metacercariae in perch, Perca fluviatilis.

All of the 267 perch sampled from Lough Neagh between 1981 and 1983 were infected with the metacercarial cysts of Cotylurus variegatus. Sites of infection were the swim-bladder, pericardium, septum transversum and, to a lesser extent, the visceral cavity. The swim-bladder, particularly the anterior portion, was the site of heaviest infection. Visceral cysts were found chiefly in female fish and this may be related to reduced immunological defence and/or thinner body wall during the breeding season. The number of cysts recorded was not related to host length, suggesting that further parasite invasion is offset by cyst mortality possibly as a result of the host immunological response to the parasite. Highest mean worm burden was recorded between May and June. This corresponded to increased water temperature necessary for development of eggs and the breeding season (April-June) of the perch.

Animals↗
PubMed2000

Genetic difference in susceptibility and fatality of three strains of mice experimentally infected with Neodiplostomum seoulense.

The genetic influence on host susceptibility to Neodiplostomum seoulense infection and fatality of the host was studied in 3 inbred strains of mice (BALB/c [H-2d], C3H/He [H-2k], and C57BL/6 [H-2b]). The survival of the mice, worm expulsion kinetics, worm size, number of eggs produced per day (EPD), and number of uterine eggs were observed from day 1 to day 40 postinfection (PI) with 100 or 200 metacercariae per mouse. Infection with N. seoulense was highly lethal to all 3 strains of mice, but the lethality was dose-dependent and varied according to the genetic backgrounds of the mice. The C3H/He mice exhibited the highest mortality, the lowest worm burdens and EPD, and the quickest expulsion of worms. It is suggested that different genetic backgrounds of mice appear to affect the host's capacity to expel N. seoulense and the fatality of the hosts themselves.

Animals↗
PubMed1990

[Distomatosis: diagnosis and treatment].

Distomatosis caused by Fasciola hepatica is fairly common in France. It is due to the ingestion of contaminated watercress or wild dandelions. Fever is frequent. Jaundice and liver pain are inconstant. The disease is often revealed by an isolated eosinophilia. Ultrasonography and/or computerized tomography are useful to evaluate the hepatic lesions. The diagnosis is confirmed by the finding of eggs in the stools or by serological tests. Numerous other flukes may infect people living overseas and particularly in South-East Asia. Clonorchis sinensis and other Opisthorchidae are responsible for distomatosis of the liver and digestive tract. Several types of intestinal distomatosis may also be acquired. Paragonimiasis (a pulmonary fluke) is particularly frequent in that part of the world. The diagnosis rests on the finding of eggs in the stools (digestive tract distomatosis) or in the airways (paragonimiasis) or on serological tests. The prognosis has been improved by treatment with praziquantel, a drug which in most cases stops the development of the disease within a few days.

Animals↗
PubMed1989

The ecology of Crepidostomum species (Allocreadiidae: Digenea) in the salmonoids of Lake Yli-Kitka in northeastern Finland.

Crepidostomum spp. were studied from 417 whitefish (Coregonus acronius Rapp, 1854), 220 vendace (Coregonus albula L.) and 38 brown trout (Salmo trutta m. lacustris (L.)) from Lake Yli-Kitka in northeastern Finland during 1980-1983.12.7% of the whitefish were infected with Crepidostomum with a mean intensity of 4.6 worms per infected fish. The species involvedare C. farionis (Müller, 1784) and Crepidostomum wikgreni Gibson et Valtonen, 1988, which differed from C. farionis in the number and size of the eggs. Both types were encountered in the gall-bladder and intestine, but were unable to be distinguished as immature stages. 21% of the brown trout harboured C. farionis in the intestine with a mean number of 1.5 worms per infected fish. Two C. farionis specimens occurred also in the intestine of one vendace. Whitefish smaller than 150 mm did not harbour Crepidostomum specimens, but in bigger fish the prevalence and the mean intensity of infection increased to a certain limit as the fish got larger. The prevalence of Crepidostomum infection also clearly increased during the three seasons in the three size-groups studied. The seasonal pattern of Crepidostomum in whitefish of the size greater than or equal to 150 mm was variable in that the lowest values, both in the prevalence and mean intensity of infection, occurred between September and December in 1980 and between April and August in 1982. Reinvasion was found throughout the year, although the main recruitment occurred during autumn and early winter. Eggs matured between late spring and early autumn. The smallest worms occurred mainly in the gall-bladder, and most of the gravid specimens were located in the intestine. Both the variance-to-mean ratio and the low values of the parameter k of the fitted negative binomial distribution reveal the Crepidostomum specimens are overdispersed in the whitefish of Lake Yli-Kitka.

Animals↗
PubMed2004

Expression of immune response genes in rainbow trout skin induced by Gyrodactylus derjavini infections.

By means of semi-quantitative RT-PCR, expression of a number of immune relevant genes was studied in skin of small rainbow trout Oncorhynchus mykiss (Walbaum, 1792) fry during both primary and secondary infections with the ectoparasitic monogenean Gyrodactylus derjavini Mikailov, 1975. The target genes studied included the cyto- and chemokines TNF-alpha1, TNF-alpha2, TGF-beta and IL-8, the inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX-2) genes and finally, two cell markers, the beta-chains of TCR and MHC II, from the adaptive arm of the immune system. In general, constitutive expression of all studied genes was apparent. Significant increases in expression of the TNF-alpha1 isoform could be observed at day 8 p.i. in primary infections and although less marked, the alpha2 isoform of TNF showed a similar trend. With the cytokine TGF-beta, 8-10 times increase in the transcription levels was observed in secondary infections compared to uninfected hosts. However, no parasite related changes in expression patterns could be observed for IL-8. Parasite infections elicited strong iNOS expression by 4 days p.i., but significant differences were not detected before day 8 p.i., when transcript levels were increased 5.5-9.6 times compared to uninfected controls. Augmented expression of COX-2 could also be observed in primary, but not secondary, infections at later stages of infections. No clear parasite related changes in transcript levels of the two cell markers TCRbeta and MHC IIbeta could be observed. Although the cellular source(s) was not determined, most of the examined factors appear to take part in a local signalling network of pivotal importance for the initiation, orchestration, effectuation and modulation of immune responses in rainbow trout against the ectoparasite G. derjavini.

Animals↗
PubMed2004

The effect of various metals on Gyrodactylus salaris (Platyhelminthes, Monogenea) infections in Atlantic salmon (Salmo salar).

Atlantic salmon (Salmo salar) parr (age 0+), infected by the ectoparasite Gyrodactylus salaris, were exposed to aqueous aluminium (Al), copper (Cu), zinc (Zn), iron (Fe) and manganese (Mn), at 4 different concentrations. There was a negative correlation between G. salaris infections and metal concentrations in both Zn- and Al-exposed salmon. In the Zn-experiment, all 4 concentrations tested caused a decrease in the G. salaris infections, while in the Al-experiment the G. salaris infection did not decline at the lowest concentration. The number of G. salaris increased continuously during the experiments in all control groups, and in all groups exposed to Cu, Fe and Mn. At the highest concentration, however, copper seemed to impair the growth of G. salaris infection. The results show that aqueous Al and Zn are environmental factors of importance controlling the distribution and abundance of the pathogen G. salaris. Other pollutants might also have an influence on the occurrence of G. salaris. Finally, the results demonstrate that aqueous Al and Zn have a stronger effect on the parasite than on the salmonid host, suggesting that both metals may be used as a pesticide to control ectoparasites such as G. salaris.

Aluminum↗
PubMed2000

Fasciolopslasis--a re-emerging infection in Azamgarh (Uttar Pradesh).

Fasciolopsiasis is endemic in the far east. In India, there have been a few reports of the infection, prior to the 1990's. We report two cases from Azamgarh district of Uttar Pradesh. Both the cases were from nearby villages where water chestnuts are cultivated. These may be a source of infection. Pigs are commonly observed in these areas and and may be the source of ova. The only missing link is the finding of infected snails. Presence of at least three cases (one reported earlier) in the area indicates the potential for the infection to re-emerge. Further epidemiological studies are needed to analyse the various ecological factors of transmission. Fasciolopsiasis is endemic in China, Taiwan, Vietnam and Thailand. In India, (Fascilopsis buski) infections in man have been reported earlier from Assam, Maharashtra, Tamil Nadu and parts of Uttar Pradesh. However, to the best of our knowledge, no such reports have been made since 1990's. We herewith report two recent cases from district Azamgarh, Uttar Pradesh (U.P.), India. Factors, such as cultivation of water chestnuts, presence of snails as intermediate hosts and pigs as definitive host in this geographical area seem to be suggestive of an endemic focus and thus needs further epidemiological survey for preventive and control measures, at the earliest.

Adult↗
PubMed1989

[Experimental control study of fasciolopsiasis in Taiwan].

This study was conducted from March 1985 to September 1987 among the pupils of Chung-Ying Primary School of Hsia-Ying township in Tainan Country, Southern Taiwan. Health education revealed the preferred control method against Fasciolopsis infection in this study. The education method included lectures, demonstrations of parasites and home visits at regular intervals. The subjects included the staff and children of the school and all family members. At the same time, the children infected with Fasciolopsis were treated with praziquantel in June, 1986. Fecal material of the all primary school children of Hsia-Ying township was examined with the antiformin-ether concentration method. One year before control the positive rate of Fasciolopsis was 25.1%. One year after control in March 1986, it was decreased to 9.5%. Two and a half years after control in September 1987, it was farther brought down to 1.0%. The x2-test of positive rate showed statistically different. Health education with medication is recommended for the control of fasciolopsiasis.

Animals↗
PubMed1998

Two endemic foci of heterophyids and other intestinal fluke infections in southern and western coastal areas in Korea.

Two endemic foci of heterophyid infections were discovered in coastal villages of Puan-gun, Chollabuk-do, and Sachon-gun. Kyongsangnam-do, Korea. Fecal examinations were performed on 153 inhabitants of Puan-gun and 138 of Sachon-gun, using cellophane thick smear and formalin-ether sedimentation technique. The helminth egg and/or protozoan cyst positive rate was 21.5% (33/153) in Puan-gun and 39.1% (54/138) in Sachon-gun. In Puan-gun, the egg positive rate of heterophyids was the highest, 17.6%, and that of other parasites was 0.7-2.6% by parasite species. In Sachon-gun, that of heterophyids was 18.8%, followed by Clonorchis sinensis (12.3%), and other parasites (0.7-5.0%). Twenth-two (Puan-gun) and six (Sachon-gun) heterophyid egg positive cases were treated with praziquantel, and adult flukes were collected from their diarrheic stools. A total of 3,284 adult flukes of Heterophyes nocens was collected from all of the 22 patients treated in Puan-gun (3-778 individually), and other trematodes were also collected from 2-15 patients: Pygidiopsis summa, Stellantchasmus falcalus. Metagonimus yokogawai, M. miyatai, Stictodora fuscata. Heterophyopsis continua, Acanthoparyphium kurogamo, and Gymnophalloides seoi. In Sachon-gun, M. yokogawai (3,007 specimens), H. nocens (120), and S. falcatus (46) were collected from 5 of 6 treated patients, and H. continua and S. lari each from one patient. The present study revealed that heterophyid flukes, especially H. nocens and M. yokogawai, are prevalent in the southern and western coastal areas of Korea where fresh and/or brackish water fishes are popularly eaten raw.

Adolescent↗
PubMed1991

Diplectanidae (Monogenea) infestations of sea bass, Dicentrarchus labrax (L.), from the Spanish Mediterranean area. Histopathology and population dynamics under culture conditions.

In the present study, Diplectanum laubieri was redescribed from material obtained from wild and cultured fish. The population dynamics of D. aequans and D. laubieri under culture conditions was studied. The prevalence and mean intensity (average number of worms per parasitized fish) were 80.64% and 112 for D. aequans and 67.74% and 59.61 for D. laubieri, respectively. Both Diplectanidae exhibited seasonal variations, with maximal infection levels occurring in winter, suggesting continuous parasites recruitment, and infection levels tended to increase with host age. Male hosts were more heavily infested than females. The apparent positive association between D. aequans and D. laubieri was not confirmed statistically. The Diplectanidae showed definite and different patterns of gill distribution. Histopathological gill damage mainly consisted of hyperplasia of the epithelium, fusion of branchial lamellae and the presence of hemorrhagic and inflammatory foci with leucocytic infiltration. The results demonstrated the pathological importance of both Diplectanidae for the cultivation of sea bass.

Age Factors↗
PubMed1987

Human intestinal infection with Nanophyetus salmincola from salmonid fishes.

Between 1974 and 1985, 10 patients were studied who presented with either gastrointestinal complaints or unexplained peripheral blood eosinophilia, and had eggs typical for N. salmincola recovered from their stools. Clinical findings in 8 of the 10 included increased frequency of bowel movements or diarrhea (6), peripheral blood eosinophilia (6), abdominal discomfort (5), nausea and vomiting (3), weight loss (2), and fatigue (2). Two were asymptomatic. Eight recalled eating fish prior to the onset of symptoms. Anthelminthic treatment consisting of three 2-g doses of niclosamide (2 patients) or two 50 mg/kg doses of bithionol (1 patient) proved effective. In the remaining individuals symptoms resolved slowly over several months.

Adolescent↗
PubMed1988

Chemotherapy of paramphistomosis in sheep.

Controlled trials were used to assess the efficacy of various anthelmintics against immature and adult paramphistomes in 75 experimentally or naturally infected sheep. Albendazole (20 mg/kg), praziquantel (10 mg/kg), nitroxynil (10 mg/kg) triclabendazole (10 and 100 mg/kg), profenophos (25 mg/kg) and netobimin (15 mg/kg) had little or no activity against adult or immature fluke. Niclosamide at 100 mg/kg had high efficacy (99%) against intestinal fluke but none against adult fluke. A 2- tertiary-butyl benzthiazole compound (CGA 72630) at 25 mg/kg and resorantel at 65 mg/kg had very high efficacy against both adult and immature fluke in the rumen and small intestine respectively. The efficacy of other anthelmintics which have been used against paramphistomes in sheep is reviewed.

Animals↗
PubMed1983

The effects of crowding on adults of Philophthalmus gralli (Trematoda) grown in chickens.

Chickens were infected with six, 10, 30, 50, or 100 metacercariae of Philophthalmus gralli per eye and the adults were harvested 9, 14, 21, 35, and 50 days later. The worms recovered were measured and assessed for maturity. Significantly more adults from infections of six and 10 metacercariae per eye were recovered than from infections of 100 per eye. When metacercariae were placed in one eye, over one-fourth of the resulting adults were found in the opposite eye. Worms recovered from groups of zero to 10 were significantly longer than those in groups of 41 to 50 and 51 to 60 at all ages sampled. The normal movement of worms from the conjunctival sac to the outside of the nictitating membrane was hindered by crowding; when more than 10 were present, some worms developed in the sac to mature adults. Worms in all groups produced eggs in which miracidia developed at the same rate.

Animals↗
PubMed1998

The diversity of the Digenea of Australian animals.

The Digenea is one of five major helminth assemblages represented in Australian animals. History of the study of digeneans in Australia is reviewed briefly to show that it has never been subjected to the kind of sustained study needed to reach an understanding of it. The Australian vertebrate fauna comprises over 5500 species. These have so far been shown to harbour just over 70 families, about 306 genera and 566 species of digeneans. Digeneans occur in all classes of vertebrates in Australia but are distributed very unevenly; aquatic hosts are generally most heavily infected, but many terrestrial species are also infected. Particular weaknesses in knowledge of the fauna concern the bats, cetaceans and teleosts. Another weakness is in knowledge of life-cycles; representative life-cycles are known for only about 20 of the 70 families known in Australia. Estimates of the overall size of the fauna are dependent on an understanding of sampling strategies, the heterogeneity of distribution of the fauna, and the nature of host-specificity. These subjects are reviewed briefly and an estimate of the total fauna is made. There may be as many as 6000 species of digeneans in Australia.

Amphibians↗
PubMed1980

Microscopic pathology of liver of capuchin monkey (Cebus albifrons) infected with Athesmia foxi (dicrocoelidae : trematoda) : a pictorial illustration.

Histopathological changes in the livers of two white fronted capuchin monkeys, Cebus albifrons, associated with Athesmia foxi (Dicrocoelidae : Trematoda) infection are illustrated through photomicrographic plates. The lesions are confined in and around the hepatic biliary system. The bile ducts are greatly distended and thickened because of fibroblastic activity and collagen deposit in its walls. In one of the livers desquamative, necrotic and reorganizational changes are found to be well marked. At places the bile duct lumen contains infiltrating inflammatory cells and shed pieces of biliary epithelia mixed in a scanty necrotic tissue while elsewhere the necrotic changes are more pronounced and the bile duct contents are presented only by homogeneous amorphous debris. The overall picture is that of chronic cholangitis coupled with cholangiectasis.

Animals↗
PubMed1992

Observations on the pigmentation of the monogeneans, Anoplodiscus spp. (family Anoplodiscidae) in different microhabitats on their sparid teleost hosts.

The monogeneans Anoplodiscus australis and A. cirrusspiralis infect the fins of their respective hosts, the yellowfin bream, Acanthopagrus australis, and the snapper, Pagrus auratus. In these habitats the adult parasite contains melanin-like pigment deposits within the body. Very young parasites lack the pigment but deposits of pigment appear and coalesce into dense deposits within the parasite as it grows. The evidence suggests that the pigment is synthesized within the body of the parasite rather than acquired through feeding on the host epidermis. However, adults of Anoplodiscus cirrusspiralis from the nares of snapper lack this pigment, which suggests that environmental cues may promote the production of pigment as a possible aid to camouflage.

Animals↗
PubMed2000

Host-specificity of monogenean (platyhelminth) parasites: a role for anterior adhesive areas?

Monogeneans (flatworms) are among the most host-specific of parasites in general and may be the most host-specific of all fish parasites. Specificity, in terms of a restricted spatial distribution within an environment, is not unique to parasites and is displayed by some fungi, insects, birds, symbionts and pelagic larvae of free-living marine invertebrates. The nature of cues, how "habitats" are recognised and how interactions between partners are mediated and maintained is of interest across these diverse "associations". We review some experiments that demonstrate important factors that contribute to host-specificity at the level of infective stages (larvae of oviparous monogeneans; juveniles of viviparous gyrodactylids) and adult parasites. Recent research on immune responses by fish to monogenean infections is considered. We emphasise the critical importance of host epidermis to the Monogenea. Monogeneans live on host epidermis, they live in its products (e.g. mucus), monopisthocotyleans feed on it, some of its products are "attractants" and it may be an inhospitable surface because of its immunological activity. We focus attention on fish but reference is made to amphibian hosts. We develop the concept for a potential role in host-specificity by the anterior adhesive areas, either the specialised tegument and/or anterior secretions produced by monogeneans for temporary but firm attachment during locomotion on host epithelial surfaces. Initial contact between the anterior adhesive areas of infective stages and host epidermis may serve two important purposes. (1) Appropriate sense organs or receptors on the parasite interact with a specific chemical or chemicals or with surface structures on host epidermis. (2) A specific but instant recognition or reaction occurs between component(s) of host mucus and the adhesive(s) secreted by monogeneans. The chemical composition of fish skin is known to be species-specific and our preliminary analysis of the chemistry of some monogenean adhesives indicates they are novel proteins that display some differences between parasite families and species.

Animals↗