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PubMedDate not supplied

Recovery of avian schistosome cercariae from water using penetration stimulant matrix with an unsaturated fatty acid.

Avian schistosome cercariae that emerge from aquatic snails can penetrate human skin causing cercarial dermatitis resulting in serious skin disease in sensitized and immunocompromised people. A trap developed for Schistosoma mansoni cercariae was tested for recovery of avian schistosome cercariae. A matrix with an unsaturated fatty acid, linoleic acid stimulates attachment and penetration of Trichobilharzia spp. cercariae, and the immobilized larvae can be subsequently visualized. The number of trapped cercariae exceeded by 3 to 7 times the number of larvae expected on the surface of the trap, based on their random distribution in the water. Recognition, attachment, and penetration of Trichobilharzia spp. cercariae led to injection of more secretory products into the stimulant matrix than by Schistosoma mansoni cercariae. This method can assist in the identification of waters infected with avian schistosome cercariae so that human exposure to these parasitic larvae can be minimized.

Animals↗
PubMedDate not supplied

Intestinal fluke infections: the heterophyids.

The food-borne small flukes infections are uncommon in Italy, because the parasite is strictly limited to certain areas of the world. Humans become infected by ingestion of parasitized fish that is raw, inadequately cooked or improperly-pickled or salted. Two case reports of intestinal infections by Heterophyies heterophyies are reported.

Adult↗
PubMed2006

[Swimming in summer].

It happens every summer: 'Swimming prohibited because of cyanobacteria'. Blooming of these toxine producing bacteria in warm summer months is a well known risk for swimming human beings. But how big is this risk for swimming dogs? And how big are other risks? In this article these risks are assessed for dogs that occasionally swim in surface water during the summer in the Netherlands. Based on these findings an advice will be given for dog owners to keep these risks for waterborne infections as small as possible.

Animals↗
PubMed2006

Mucosal mast cell responses in rats (Rattus norvegicus) experimentally infected with Centrocestus caninus.

Mucosal mast cell (MMC) responses and worm recovery rates in rats experimentally infected with Centrocestus caninus were investigated. Metacercariae of C. caninus, procured from goldfish, Carassius auratus, were orally administered to twenty-five male rats (300 metacercariae each rat). The infected rats were sacrificed on days 3, 7, 14, 21 and 28 post-infection (PI) along with the control rats. Worm recovery was performed from each part of small intestine. To investigate MMC, duodenal, jejunal and ileal paraffinized-tissue sections were processed and stained with 1% alcian blue and 0.5% safranin-O. The average worm recovery rates were 42.8, 37.7, 21.2, 12.5 and 3.7% on days 3, 7, 14, 21 and 28 PI, respectively. The majority of the worms (98.9%) were collected from the duodenum and jejunum. The MMC numbers in the infected rats were significantly higher than those of the controls (p<0.05). A peak level was observed on days 14 PI and the numbers gradually decreased thereafter. The results reveal that MMC plays an important role in the expulsion of C. caninus from the host intestine. A more precise description of the role the MMC plays in helminth expulsion is still needed to understand the mechanism of host defense against intestinal helminthic infection, along with other effector cells, such as goblet cells.

Animals↗
PubMed1991

Serological differentiation of human small fluke infections using Opisthorchis viverrini and Haplorchis taichui antigens.

Sera from 642 inhabitants of Vientiane Province (Laos) were examined by enzyme-linked immunosorbent assay (ELISA) using cytoplasmic and membranous antigens prepared from adult worms. Worms of Opisthorchis viverrini originated from liver of dissected cats, Haplorchis taichui were obtained from a stool specimen of a Laotian patient after praziquantel treatment. The sera were divided into five groups according to the intensity of infection expressed as egg count per gram of patients stool (EPG). Correlation between intensity of infection and the level of antibodies in serum was recorded. Reactions obtained using the cytoplasmic antigens were more sensitive and more specific compared to those with membranous antigens. Cross-reactions between antigens of both helminth species were found. Highly positive sera were examined using electroimmunotransfer blots (EITB) with cytoplasmic antigens of both species, which enabled the species differentiation. Antigens of both species yielded several shared fractions; however, differences between them were found: homologous sera reacted specifically with O. viverrini antigen in the area of 70 kDa and with H. taichui antigen in the area of 10 kDa. Thirty-one of 122 tested sera had specific antibodies against O. viverrini, 77 sera against H. taichui and 14 sera against both species. The results confirmed our assumption about predominant occurrence of heterophyid flukes in the human population living in studied area, compared with the occurrence of opisthorchid flukes. Hence, serology seems to be helpful tool for correct diagnosis of small fluke infections.

Animals↗
PubMedDate not supplied

[Opisthorchiasis and pseudamphistomiasis on the territory of the middle Volga valley].

The authors describe cases of opisthorchiasis and pseudamphistomiasis in 5 areas adjacent to the banks of the Volga, Kama, and Belaya. Metacercariae of Opisthorchis and Pseudamphistomum have been detected in the Cyprinidae. The incidence rate of Opisthorchis infection has been notified in these areas since 1957 and that of Pseudamphistomum infection has been recorded since 1989.

Animals↗
PubMed1989

Pathological effects of Echinostoma caproni (Trematoda) in the domestic chick.

Domestic chicks experimentally infected with Echinostoma caproni for 2 weeks showed a dilated ileum, unkempt feathers, watery diarrhoea, and weight loss. The ileum from infected and control chicks was fixed in 10% neutral buffered formalin, and prepared as 10 microns paraffin sections stained in haematoxylin and eosin, Papanicolau, periodic acid-Schiff, picro-ponceau, and alcian blue. The infected ileum showed atrophic villi, hypertrophied circular musculature with collagen-like fibres and haemorrhagic zones. The brush borders of epithelial cells and goblet cells were absent in the mucosa of the infected ileum. Worms in contact with host mucosa showed tissue plugs in the suckers. The cephalic spines of worms abraded the host mucosa.

Animals↗
PubMed2006

Arctic charr (Salvelinus alpinus) is a suitable host for Gyrodactylus salaris (Monogenea, Gyrodactylidae) in Norway.

Gyrodactylus specimens infecting both anadromous Arctic charr (Salvelinus alpinus) from River Signaldalselva (northern Norway) and resident Arctic charr from Lake Pålsbufjorden (southern Norway) were identified as G. salaris using molecular markers and morphometrics. The infection in Pålsbufjorden represents the first record of a viable G. salaris population infecting a host in the wild in the absence of salmon (Salmo salar). G. salaris on charr from Signaldalselva and Pålsbufjorden bear different mitochondrial haplotypes. While parasites infecting charr in Signaldalselva carry the same mitochondrial haplotype as parasites from sympatric Atlantic salmon, G. salaris from charr in Pålsbufjorden bear a haplotype that has previously been found in parasites infecting rainbow trout (Oncorhynchus mykiss) and Atlantic salmon, and an IGS repeat arrangement that is very similar to those observed earlier in parasites infecting rainbow trout. Accordingly, the infection may result from 2 subsequent host-switches (from salmon via rainbow trout to charr). Morphometric analyses revealed significant differences between G. salaris infecting charr in the 2 localities, and between those on sympatric charr and salmon within Signaldalselva. These differences may reflect adaptations to a new host species, different environmental conditions, and/or inherited differences between the G. salaris strains. The discovery of G. salaris on populations of both anadromous and resident charr may have severe implications for Atlantic salmon stock-management as charr may represent a reservoir for infection of salmon.

Animals↗
PubMed2003

Effects of snail size and age on the prevalence and intensity of avian schistosome infection: relating laboratory to field studies.

Both the prevalence and intensity of patent infection by avian schistosomes (Trichobilharzia ocellata) increase with increasing size of lymnaeid snails (Stagnicola elrodi) collected in Flathead Lake, Montana. Because the size and age of a snail are positively correlated, snails of different sizes may have experienced differential duration of exposure to and development of infection. Another possibility is that infection itself induces snail gigantism. Each of these possibilities could lead to increased prevalence and intensity of infection among the oldest-largest snails. To decouple size variation from many correlated effects of age and to test for parasite-induced gigantism, laboratory experiments standardized snail size-age-at-infection, exposure history, inoculating dose, and duration of infection. The positive relationship between size and prevalence was eliminated in the laboratory, but the relationship between size and infection intensity remained. Laboratory results thus suggest that infection intensity is related to snail size per se, whereas prevalence in the field is related to snail size only through the correlation between size and age. In addition, under these experimental conditions, infected snails were no larger than uninfected snails, so the patterns observed in the field might not be attributable to gigantism.

Animals↗
PubMed1996

Classification and host specificity of Metagonimus spp. from Korean freshwater fish.

Taxonomic problems of Metagonimus spp. in Korea were investigated. Metacercariae of various freshwater fish species -- Plecoglossus altivelis, Carassius auratus, Zacco platypus, Zacco temmincki, Opsariichthys bidens -- were collected from different localities in Korea and experimentally fed to golden hamsters. Observation of recovered adult worms showed that Plecoglossus altivelis was infected with metacercariae of both M. yokogawai and M. takahashii. C. auratus was infected with metacercariae of M. takahashii and Z. platypus, Z. temmincki, O. bidens were infected only with metacercariae of Metagonimus Miyata type. From the inferences about the morphological characteristics, host specificities and occurrence patterns in infected animals, Metagonimus Miyata type is considered to be an independent group.

Animals↗
PubMedDate not supplied

[Human parasitizing echinostomatata (Trematoda, Fasciolidae) in mammals in Belorussian forest zone].

Domestic and wild mammals in Byelorussian Polesye have been found to have 3 species of echinostomatates known as human parasites: Echinochasmus perfoliatus (Ratz, 1908), Echinostoma revolutum (Froelich, 1802) and Isthmiophora (= Euraryphium) melis (Schrank, 1788). Human beings may be infected on ingestion of mollusks, fish, and Amphibia (frogs) invaded with larvae of these helminths. Although, cases of human invasion have not been recorded in Byelarus, there is an infection risk group, this should be borne in mind by medical workers.

Animals↗
PubMed2000

Fasciolopsiasis--a persisting problem in eastern U.P.--a case report.

Fasciolopsiasis, or infection by the intestinal fluke, Fascilopsis buski, is endemic in the eastern states of our country. While it is by no means a rarity, especially in the rural set up, awareness regarding this common parasitic infestation is still a much-needed entity. The importance of a strong degree of suspicion and early diagnosis cannot be over emphasised, if a successful campaign is to be launched in its control. With this as our central theme, we proceed to report a case of and unsually heavy Fasciolopsis buski infection in our hospital, which had failed to be diagnosed in a semi urban setup in UP.

Adult↗
PubMed1990

The pathogenicity, localization, and cyst structure of echinostomatid metacercariae (Trematoda) infecting the kidneys of the frogs Rana clamitans and Rana pipiens.

Light and scanning electron microscopy were used to examine the localization and pathogenicity of echinostomatid metacercariae infecting the kidneys of leopard frogs, Rana pipiens, and green frogs, Rana clamitans. Cysts occurred predominantly in the ventrolateral renal cortex, and at least some were confined to the lumen of the Bowman's capsules. Each vermiform metacercarial body was enclosed by a spherical cyst wall that had a uniform thickness. The wall was composed of a homogeneous material containing basic and keratinlike proteins, with sulfated acid mucopolysaccharides on the outer surface. Most cysts were enclosed by a fibrous capsule of host origin, or were surrounded by an inflammatory focus. Fibrosis was always focal, but its degree varied between individual hosts and between different cysts within the same host. Some heavily encapsulated cysts were darkened and contained disintegrating worms. In heavily infected kidneys, confluence of fibrotic or inflammatory foci resulted in the displacement of functional renal tissue. These data suggest that infection by echinostomatids may impair renal function and that the host's response affects parasite viability.

Animals↗
PubMed1984

Parasitological examinations and immunodiagnostic advances in fluke infections.

A reliable diagnosis of fluke infections should be based on the demonstration of parasite eggs in either faeces, duodenal liquid or sputum, depending on the type of infection. Such an examination permits the identification of the species, and counting eggs establishes the intensity of infection. Unfortunately this examination is useful only when intensity is rather high. The diagnosis of slight infections is uncertain and can vary considerably from one sample to another. In this area of parasitological diagnosis no significant progress has been made in the last few years. On the other hand, in serodiagnosis many recent studies have been published. It should be noted that there are cross reactions between various human fluke species and Schistosoma mansoni. The common antigen varies accordingly. There are 4 groups of parasites that are antigenically close: F. hepatica and F. gigantica; Clonorchis sinensis and Opisthorchis viverrini; P. westermani; P. africanus, P. uterobilateralis, P. ecuadoriensis. The cross reactions between these groups are not very intense and forbid the use of heterologous antigens. On the other hand, among the Paragonimus spp., P. westermani is antigenically quite distinct from the others. Antigens extracted from these various species can be purified. The main progress in this area has been made with Fasciola hepatica. Certain authors have suggested the use of excreted-secreted antigens that seem to improve the specificity. For early serodiagnosis, IFI (indirect immunofluorescence) and the ELISA test (enzyme linked immunosorbent assay) are probably the best (positive two weeks after experimental infection of mice with F. hepatica).(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Helminth↗
PubMed2004

Immunity in rainbow trout, Oncorhynchus mykiss, against the monogenean Discocotyle sagittata following primary infection.

Rainbow trout (Oncorhynchus mykiss) were experimentally infected by continuous or single exposure with the monogenean Discocotyle sagittata. To determine whether immunity follows primary infection, fish were exposed to a secondary challenge by one of two modes: (1) primary infections were cleared with praziquantel (PZQ) and hosts re-infected with 100 oncomiracidia; (2) parasites were allowed to reach maturity and hosts super-infected with 100 oncomiracidia. Fish challenged after initial continuous exposure developed significant partial resistance to re-infection, carrying burdens 35% lower than controls. PZQ treatment controls demonstrated that the drug did not account for the protection observed. Single exposure did not significantly modify the outcome of secondary challenges. Super-infection experiments suggested that no concomitant immunity develops. No correlation was found between initial burdens and the outcome of secondary challenges in the same individual. Significantly elevated anti-D. sagittata antibodies were detected in infected fish, but there was no correlation between immunoglobulin levels and parasite burdens.

Animals↗
PubMed2004

The severity of mouse pathologies caused by the bird schistosome Trichobilharzia regenti in relation to host immune status.

Cercariae of the nasal bird schistosome Trichobilharzia regenti are able to penetrate into mammalian skin and migrate to the mouse central nervous system (CNS) causing tissue injury in certain cases. Our study shows that the severity of T. regenti pathologies in the CNS closely depends on the host immune status. During the primary infection of immunocompetent mice, the parasites evoked an acute inflammatory reaction in the skin and the CNS involving focal oedema and cellular infiltration of the tissue. Challenge infections resulted in the development of extensive inflammatory foci in the host skin which precluded the subsequent migration of the schistosomula to the CNS. On the other hand, during primary as well as challenge infections of immunodeficient mice (SCID), no significant immune response against the parasites was detected in any of the host organs examined; however, in contrast to immunocompetent mice, the infections were frequently manifested by severe leg paralysis.

Animals↗
PubMed2004

The role of Bithynia tentaculata in the transmission of larval digeneans from a gravel pit in the Lower Thames Valley.

The freshwater snail, Bithynia tentaculata (Gastropoda: Prosobranchia), is frequently found in gravel pits and its role in the transmission of larval digeneans was assessed in one of these unstable water bodies from the Lower Thames Valley (UK) from June 1982 to December 1984. Eight species of cercarial and five species of metacercarial infections were reported from B. tentaculata, with up to 7.7% and 4.7% prevalence of infections, respectively, occurring in the snail, making it the most important host at this site. Seasonal peaks in cercarial infections occurred in late autumn/early winter but little seasonality was apparent in the occurrence of metacercarial infections. The life history characteristics of both hosts and parasites, which can affect intramolluscan digenean dynamics, are discussed.

Animals↗
PubMed1978

Chronic diarrhea in returing travelers: intestinal parasitic infection with the fluke Metagonimus yokogawai.

An unusual intestinal infection with the parasite Metagonimus yokogawai was acquired by an American traveling in the Orient. Diarrhea began abroad, and recurred at intervals until she was seen 1 1/2 years later. Stool examinations resulted in the recovery of small operculated ova characteristic of intestinal or biliary fluke infection. Treatment with hexylresorcinol failed to eradicate the infection, but subsequent use of tetrachloroethylene was successful and facilitated recovery of adult parasites, leading to the specific diagnosis of metagonimiasis. Metagonimiasis and related intestinal fluke infections should be considered as a possible cause of persistent diarrhea in travelers returning from endemic areas abroad.

Chronic Disease↗