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PubMed1963

[DISTOMIASIS].

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Humans↗
PubMed2005

Exacerbation of Plasmodium yoelii malaria in Echinostoma caproni infected mice and abatement through anthelmintic treatment.

The effect of chronic intestinal trematode infection on malaria was examined in a murine model of co-infection using Echinostoma caproni and Plasmodium yoelii. BALB/c mice (n = 32) infected with a low dose of E. caproni (approximately 10 cysts) 25-35 days before malaria infection displayed significantly increased malaria parasitemia (P = 0.01), extended patency of malaria (P = 0.03), and increased fatality (47%; P < 0.001) compared to mice infected only with P. yoelii (17X nonlethal strain) (n = 18). Further analysis revealed that differences in malaria parasitemia between fatal co-infections and infections with P. yoelii only were highly significant (P < 0.0001), whereas nonfatal co-infections were not statistically different. Exacerbation of malaria was demonstrated to be reversible through clearance of E. caproni worms by praziquantel treatment administered 10 days before malaria infection. No deaths were observed during malaria infection in mice cleared of their E. caproni infection (n = 10), and parasitemia was significantly reduced from that of untreated co-infected mice (P = 0.03) and was not different from that of mice infected with P. yoelii only. Further studies examining parasite-parasite interactions and host immune response in the echinostome model are warranted to understand the mechanisms affecting the course and outcome of malaria infection during concomitant helminth infection.

Animals↗
PubMed2002

Spatial and temporal variations in the trematode component community of the mudsnail Hydrobia ventrosa in relation to the occurrence of waterfowl as definitive hosts.

The component community of larval trematodes infecting the mudsnail Hydrobia ventrosa (Montagu) was examined in coastal lagoons of the southern Baltic Sea among different host subpopulations in relation to the structure of the waterfowl community. The 10 trematode species observed represent the families Notocotylidae (1), Echinostomatidae (1 or 2), Heterophyidae (2). Monorchidae (1). Microphallidae (3 or 4), Psilostomatidae (1), and Hemiuridae (1). Eight of these species infect waterfowl as adults. The structure of the trematode communities was similar between sampling sites. Seven trematode taxa were commonly found at all sampling sites. Prevalence values of the 6 most abundant taxa, which infect birds as final hosts, were significantly different between neither sampling sites nor across year. Overall trematode prevalence in H. ventrosa fluctuated seasonally. Prevalence usually peaked in summer between July and September or October. Low prevalences were observed in late winter and early spring. In contrast, the seasonal maximum in waterfowl numbers differed between areas because of significant spatial differences in the bird community structure. The species composition of the component trematode community of H. ventrosa in the coastal lagoons of the southern Baltic Sea is more or less independent of the species composition of the waterfowl community. This independence presumably results from the lack of host specificity in most of the observed trematode species. Otherwise, the low host specificity in combination with the enormous waterfowl diversity in the coastal lagoons might explain the stability of the prevalence pattern of the component trematode community.

Animals↗
PubMed1997

The suppressive excretory-secretory product of Trichobilharzia ocellata: a possible factor for determining compatibility in parasite-host interactions.

Factors which may determine trematode-snail interactions were assessed in the present study. Compatibility was examined using a bacterial clearance assay to detect the modulatory effects of both compatible and incompatible trematode infections on the activity of haemocytes from Lymnaea stagnalis, during the early stages of infection. Exposure to and injection with Trichobilharzia ocellata, a compatible trematode, or the incompatible Schistosoma mansoni, resulted in modulation of haemocyte activity. However, T. ocellata activated haemocytes 1.5 h post-infection (p.i.) and then suppressed activity 24-72 h p.i. whereas with S. mansoni no suppression, only activation of haemocytes was observed throughout the test period (1.5-72 h p.i.). In previous studies, modulation of the haemocyte clearance activity by T. ocellata was found to be mediated by 2 E-S fractions, an activating fraction and a suppressing one. Investigations to assess whether the lack of suppression of haemocyte activity, observed in the S. mansoni-L. stagnalis incompatible trematode-snail interaction studied, was due to either the absence or ineffectiveness of the suppressing E-S fraction, were performed on a second incompatible combination, T. ocellata-Planorbis corneus. Using this combination it was revealed that only the activating E-S fraction had modulatory effects on P. corneus haemocytes, indicating that the suppressing E-S fraction, which actively interferes with the clearance activity of haemocytes from L. stagnalis, appears to act in a host-specific manner. In conclusion, the suppressing E-S fraction determines, at least in part, compatibility in the trematode-snail association studied. This is also probably likely in other trematode-snail combinations.

Aeromonas↗
PubMed1984

Comparative Morphology Of Eggs Of Heterophyids And Clonorchis Sinensis Causing Human Infections In Korea.

In order to provide some clues for differential diagnosis of trematode infections in fecal examination, the comparative morphology of eggs of 5 kinds of heterophyid flukes (Metagonimus yokogawai, Heterophyes heterophyes nocens, Heterophyopsis continua, Stellantchasmus falcatus and Pygidiopsis summa) and Clonorchis sinensis was studied. The eggs were obtained from distal portion of uteri of worms which were recovered from men after treatment. The characteristic shape and apperance of each kind of eggs were observed in detail under light microscope, and their length and width measured and compared one another. The results are as follows: Eggs of C. sinensis are elongated ovoidal in shape with attenuated anterior end, 25.3-33.2 (28.3 in average) micrometer long and 14.2-17.4(15.9) micrometer wide with length /width ratio of 1.60-2.00 (1.78). They differ from all heterophyid eggs in that they have prominent wrinkling (muskmelon pattern) at their shell surface. P. summa eggs are ovoid to pyriform in shape and characterized by the smallest size of all kinds examined, 19.8-22.9(21.6) micrometer long and 11.1-13.4 (12.1) micrometer wide and the ratio 1.63-1.99 (1.78). Eggs of S. falcatus are elongated ovoidal and most slender form, 25.3-29.2 (27.2) micrometer long and 11.1-13.4 (12.5) micrometer wide with the ratio of 2.00-2.57 (2.17). Eggs of M. yokogawai are ellipsoid to elliptical in shape with round both ends, 26.9-31.6 (28.5) micrometer long and 14.2-18.2 (16.8) micrometer wide with the ratio of 1.48-2.11(1.70). H. continua eggs are oval in shape, sometimes similar to M. yokogawai or H. h. nocens eggs, however, the relative breadth is broadest among all kinds, with maximum width at posterior half portion. They are 23.7-27.7 (25.0) micrometer long, 15.8-18.9 (16.4) micrometer wide with the ratio of 1.33-1.75 (1.53). Eggs of H. h. nocens are ellipsoid to ovoid in shape but sometimes more slender than M. yokogawai and have slightly pointed both ends. They are 23.7-29.2 (25.7) micrometer long, 14.2-15.8 (15.4) micrometer wide, and the ratio 1.50-2.06 (1.67). From the results, it is concluded that eggs of 5 kinds of heterophyids and C. sinensis can be morphologically differentiated one another, however, careful observation and measurement on sufficient number of eggs are needed.

Journal Article↗
PubMed2006

Where in Europe should we look for sources of the cutaneous trematode Collyriclum faba infections in migrating birds?

Cutaneous cysts with trematodes of Collyriclum faba have been found in birds during their spring and post-breeding migrations in the Czech Republic. During spring migrations, C. faba was found in one dunnock Prunella modularis, two European robins Erithacus rubecula, three common nightingales Luscinia megarhynchos, one song thrush Turdus philomelos and one great reed warbler Acrocephalus arundinaceus. During post-breeding migration, the same parasite was found in one garden warbler Sylvia borin, one whitehroat S. communis, three goldcrests Regulus regulus and one Eurasian treecreeper Certhia familiaris. The newly identified hosts of C. faba are dunnock, common nightingale, song thrush, great reed warbler and Eurasian treecreeper. Geographical areas of the birds' infection were identified from an analysis of reports on ringed birds of the same species, the time necessary for the development of cutaneous cysts with C. faba and the time of their survival, and hitherto known geographical areas of endemic occurrence of C. faba. It is presumed that birds trapped during spring migrations were infected in some montane and submontane regions in south-western Europe (the Alps, the Apennines). Birds infected during autumn migration or post-breeding vagrancy could have been infected in the Central European Carpathians, the region of C. faba endemic occurrence. For migrating birds, the impact of C. faba infections has not been hitherto assessed.

Animal Migration↗
PubMed2003

Egg size variability in trematodes: test of the bet-hedging hypothesis.

The hypothesis according to which egg size variability in hermaphroditic parasites results from bet-hedging was investigated in a comparative analysis using trematodes as a model. We hypothesized that the species reproducing mainly by self-fertilization should produce smaller eggs than those species that regularly practice cross-fertilization. Indeed, because self-fertilization is usually associated with inbreeding depression, selection should favor individuals spreading the risk of genetically disturbed development across more but smaller eggs, instead of producing fewer eggs, each possessing a large resource supply, of which many may fail to develop because of genetic deficiencies. On the basis of earlier theoretical and empirical studies, we assumed that the ratio length of testis-length of ovary positively correlates with the mating group size and, hence, with opportunities for cross-fertilization. In accordance with the bet-hedging hypothesis, we found, across trematode species, a positive relationship between this ratio and the mean egg volume produced by adults. This result was, however, observed only for the trematodes infecting birds and not for the species infecting fishes and mammals. In addition, once the influence of trematode phylogeny was taken into account, there was no significant trend, suggesting that phylogenetic legacies played a large role in generating the previous signal. Experimental tests of the bet-hedging hypothesis will be necessary to clarify the matter.

Animals↗
PubMed1987

[Therapeutic possibilities in diseases caused by intestinal parasites].

Compatible and efficient drugs for the therapy, caused by protozoal- or helminthic-infections, are available today. Many of them are not registered in Austria. Metronidazole, Mebendazole and Praziquantel are particularly effective. Most protozoal-infections can be treated with metronidazole. Mebendazole can be used against numerous nematode-infections (Ascariasis, Trichuriasis, Oxyuriasis, Ancylostomiasis), Niclosamide against cestode-infections (Taeniasis, Hymenolepiasis, Diphyllobothriasis), whereas, Praziquantel is applied against trematode-infections.

Anthelmintics↗
PubMed2001

Histopathology of cultured sea bream Sparus aurata infected with sanguinicolid trematodes.

The present study is the first report of a sanguinicolid infection affecting sea bream Sparus aurata cultured in net cages in the NE of Spain. The disease was associated with trickling mortalities during the cold season (1999 and 2000). Examination of gill wet mounts of the affected population revealed that sanguinicolid infection was present in 82.6 and 100% of the fish sampled in 1999 and 2000, respectively. Adult flukes, which were located in the kidney, were tentatively identified as members of the family Sanguinicolidae, subfamily Cardicolinae. Eggs and miracidia were found in the gill vascular structures. The inflammatory response triggered by the parasites was moderate and the lesions caused by either eggs and miracidia in the gills or adult flukes in the kidney were not extremely severe, possibly because of the moderate intensity of the parasitosis. Histological observations of sanguinicolid infected sea bream presented here are compared with those reported in other fish species. The role played on sea bream morbility and mortality by other factors (occurrence of a simultaneous moderate monogenean infection, immunological impairement related to low water temperatures) is discussed.

Animals↗
PubMed1990

Concurrent infections of the trematode Echinostoma caproni and the tapeworms Hymenolepis diminuta and Hymenolepis microstoma in mice.

Superimposing the intestinal tapeworm Hymenolepis diminuta on an established infection with the trematode Echinostoma caproni or simultaneous infection of mice with H. diminuta and Hymenolepis microstoma caused destrobilation and expulsion of H. diminuta, whereas establishment and growth of H. microstoma under the same infection regimes were not affected. In contrast, simultaneous superimposition of H. diminuta and H. microstoma on an established E. caproni infection caused destrobilation and expulsion of both H. diminuta and H. microstoma.

Animals↗
PubMed2000

Susceptibility of Biomphalaria alexandrina to infection with Schistosoma mansoni: correlation with the activity of certain glycolytic enzymes.

The importance of the glycolytic flux for the success of Biomphalaria-Schistosome sporocyst interaction was acertained in this study. Hexokinase (HK), pyruvate kinase(PK), glucose phosphate isomerase(GPI) and lactate dehydrogenase (LD) as four important glycolytic enzymes were markedly stimulated in trematode infected Biomphalaria alexandrina when measured two weeks post exposure to infection with Schistosoma mansoni miracidia. On the other hand phosphoenolpyruvate carboxy kinase (PEPCK), glucose-6-phosphatase (G6Pase) and fructose 1,6 diphosphatase(FDPase) as three gluconeogenic enzymes were slightly affected which confirm the importance of the glycolytic pathway for schistosome-exposed snails. Effect of LC25 of Solanum nigrum leaves dry powder as plant molluscicide on HK, PK and GPI were tested. Treatment with this plant resulted in a significant inhibition of these three investigated enzymes. LC10 concentrations of S. nigrum reduced considerably the infection rate of B. alexandrina with S. mansoni to be 34% compared to an infection rate of 80% in control, non-treated snails. Longer prepatent period and remarkable decrease in cercarial production was also recorded in snails treated with the sublethal concentrations of the molluscicide. As conclusion, susceptibility of B. alexandrina to infection with the digenetic trematode S. mansoni is correlated to the activity levels of the glycolytic enzymes. Moreover, sublethal and less pollutant concentration of S. nigrum could be recommended to control schistosomiasis by disturbing the intramolluscan environment of the parasite.

Animals↗
PubMed1997

PCR amplification of the mitochondrial DNA minisatellite region to detect Schistosoma mansoni infection in Biomphalaria glabrata snails.

Schistosoma infection in Biomphalaria glabrata can be detected by either exposing snails to light to induce cercarial shedding or by squeezing them between glass slides to detect parasites in the digestive gland and other regions. The methods available are inefficient for identification of prepatent infections and do not allow the diagnosis of infection in snails that die before arriving in the laboratory. Furthermore, infection is undetectable after migration of sporocysts from the head-foot region of the snail. We examined the use of polymerase chain reaction (PCR) amplification of minisatellite repeats from Schistosoma mansoni mitochondrial DNA (mtDNA) to identify snail infection. We found that amplification of mtDNA under low stringency conditions (LS-PCR) allowed for the identification of specific S. mansoni infection in Biomphalaria snails. To confirm these results, specific amplification reactions were performed using 2 sets of primers that allowed for the diagnosis of infection and an internal control of the reaction (multiplex PCR). Results obtained using multiplex PCR demonstrated the ability of the assay to detect S. mansoni-specific infection. Thus, LS-PCR as well as specific multiplex PCR allow for the detection of prepatent infections and show high specificity for S. mansoni in comparison with other trematode infections in either living or dead snails.

Animals↗