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At least 1,387 records · Page 77Linked to original sources
PubMed1997

Control of gastro-intestinal parasitism in sheep with ivermectin delivered via an intraruminal controlled-release capsule.

The efficacy of ivermectin delivered by an intraruminal controlled-release capsule against gastro-intestinal nematodes of sheep was evaluated under controlled conditions. In seven Australian studies involving 170 Merino or Merino x Border Leicester sheep, intraruminal capsules developed for 20-40 kg or 40-80 kg sheep, and delivering 0.8 or 1.6 mg of ivermectin/day respectively for 100 days (minimum dose 20 microg/kg/day), were evaluated. Studies were designed to test the therapeutic efficacy against naturally acquired and induced infections treated at the adult and fourth larval stage, and the prophylactic efficacy against naturally acquired and induced infections with third stage infective larvae. The predominant pathogenic nematodes of sheep were represented. Two studies included known benzimidazole- and levamisole-resistant nematode strains. Sheep were necropsied for total nematode counts 21-8.5 days after treatment. The efficacy of the ivermectin controlled-release capsule was generally >99% against all nematode species tested, including those confirmed to be benzimidazole- and levamisole-resistant. High therapeutic activity was demonstrated against existing adult and fourth larval stage nematode infections at the time of treatment, and high prophylactic efficacy was shown against incoming third stage larvae of all species and strains tested.

Journal Article↗
PubMed2002

Immature stages and re-description of Henneguya suprabranchiae (Myxosporea: Myxobolidae), an intestinal parasite of the catfish Clarias gariepinus in the River Nile, Egypt.

A new morphological description, supported by light microscopy photographs, is presented for various immature stages and for mature Henneguya suprabranchiae Landsberg, 1987 spores infecting the intestine of the Nile catfish Clarias gariepinus, Burchell, 1822 (Syn.: C. lazera). Large cysts of 2 to 4.5 mm diameter, containing immature and mature stages, were present in the outer layer of the intestine. They caused severe damage to the smooth muscle and atrophy due to the increased size and resultant pressure of the plasmodial mass. From September 2000 to April 2001, 21 infected fishes were detected, with a parasite prevalence of 21.2%. Nine immature stages were distinguished, and these have been measured, sketched and described. In addition, caudal process development was recorded. The mature spores are re-described and compared with previous descriptions of H. suprabranchiae spores. The main new morphological characteristics described are the number of polar filament coils, triangular thickening of the sporoplasm base, and a suture line visible only in lateral view.

Animals↗
PubMed2004

Morphological plasticity varies with duration of infection: evidence from lactating and virgin wild-derived house mice (Mus musculus) infected with an intestinal parasite (Heligmosomoides polygyrus; Nematoda).

With chronic parasite infection, host response to the parasite may change throughout the duration of the infection as the host progresses from the acute to the chronic phase. We investigated the effects of parasite infection ranging in duration from 30 to 120 days on host morphology both alone and in combination with lactation by using captive wild-derived house mice (Mus musculus) experimentally infected with a naturally occurring intestinal nematode (Heligmosomoides polygyrus). We found that some changes in host morphology were greatest at 30-60 days post-infection (e.g. spleen mass) followed by a decline towards the control state whereas other morphological changes were greatest at 90-120 days post-infection (e.g. small intestine mass) after a relatively steady increase with infection duration. For all infection durations, the morphological responses to parasite infection were similar for virgin and lactating mice (except for lean body mass). After accounting for changes in body mass with lactation, lactating mice increased organs of the gastrointestinal tract as well as liver and kidney but had less body fat than virgin mice. This is the first study to demonstrate that morphological plasticity of mice parasitized by H. polygyrus varies with infection duration and that this variation is generally similar for lactating and virgin mice.

Analysis of Variance↗
PubMed2005

The intestinal parasite Pomphorhynchus laevis as a sensitive accumulation indicator for the platinum group metals Pt, Pd, and Rh.

Concentrations of the platinum group elements Pt, Pd, and Rh were analyzed by adsorptive cathodic stripping voltammetry (Pt, Rh) and total-reflection X-ray fluorescence (Pd) in the intestinal helminth Pomphorhynchus laevis and its host Barbus barbus. The fish were caught in the Danube river south of the city of Budapest (Hungary) and were exposed to ground catalytic material for 28 days. Following exposure all three precious metals were taken up and accumulated in host organs and the parasites. Interestingly, in all tissues of the unexposed controls Pt was found, whereas Pd was not present in the muscle of the controls and Rh was not detectable in muscle and intestine of unexposed barbel. All metals were found at significantly higher concentrations in the acanthocephalan than in the tissues of barbel. These results are discussed with respect to the application of P. laevis as an accumulation indicator for metals.

Acanthocephala↗
PubMed2001

Programmed cell death in a human intestinal parasite, Blastocystis hominis.

Although programmed cell death (PCD) has been associated with multicellular organisms, there have been more reports of its presence in some protozoans. Our study shows the existence of PCD in an intestinal protozoan, Blastocystis hominis. Light and electron microscopy, biochemical and flow cytometry studies showed apoptosis-like death in B. hominis cells exposed to a cytotoxic monoclonal antibody (MAb 1D5). B. hominis cells displayed key morphological and biochemical features of apoptosis, namely, nuclear condensation and in situ fragmentation, reduced cytoplasmic volume, some externalization of phosphatidylserine and maintenance of plasma membrane integrity. No oligonucleosomal DNA laddering was observed in gel electrophoresis. This study supports earlier observations that the cellular machinery that is required to carry out PCD may have existed before the advent of multicellularity. Our study also ascribes a novel function for the B. hominis central vacuole in apoptosis; it acts as a repository where apoptotic bodies are stored before being released into the extracellular space.

Animals↗
PubMed1991

Water balance and its relation to fermentation acid production in the intestinal parasites Hymenolepis diminuta (Cestoda) and Moniliformis moniliformis (Acanthocephala).

Water balance and its relation to carbohydrate metabolism was examined in Hymenolepis diminuta in parallel with the putative osmoconformer Moniliformis moniliformis. Worms were removed from rat intestines, weighed, and incubated (37 C) 1 hr in rat serum and various salines, some with mannitol to vary osmotic concentration from 150 to 400 mOsm/L. Worms were removed at 15-min intervals, weighed, and returned to the test solution. Rat serum and a Ringer's saline (pH 7.4 and 300 mOsm/L) with or without 5 mM glucose were isotonic to M. moniliformis, which behaved like an osmometer, shrinking, or swelling in proportion to external osmotic changes. Hymenolepis diminuta rapidly lost 20-25% wet weight in these solutions and regained lost water when 5 mM glucose was added to the saline. Tapeworms maintained constant body weight between 210 and 335 mOsm/L, but they rapidly gained or lost water outside of this range. Glucose metabolism and uptake of [3H]glucose from the medium increased progressively between 210 and 310 mOsm/L, whereas uptake rates of [3H]leucine, 22Na+, and 36Cl- were not affected. Unbuffered saline (initial pH 6.5 and 300 mOsm/L) had a lower pH (5.0) and higher osmolality (307 mOsm/L) after a 1-hr incubation with tapeworms. Such saline was less hypertonic than unconditioned saline to freshly obtained worms. A Ringer's saline (300 mOsm/L) containing 50 mM acetate- was also hypertonic (greater than 20% weight loss) to tapeworms at pH 7.4, but it was hypotonic (greater than 20% weight gain) at pH 5.0. Isotonicity at 300 mOsm/L was achieved with pH 5.0 and 20 mM acetate-, the approximate pH and fermentation acid concentration in an infected rat intestine. Rats infected with tapeworms (12 days old) were fasted for 2 days. Starved worms were smaller but had the same percentage of body water and internal osmolality as controls. These results show that H. diminuta can regulate its body water content and that water balance is closely related to the fermentation acid concentration and pH of the bathing medium.

Animals↗
PubMed1996

[Seasonality of parasites and intestinal bacteria in vegetables that are consumed raw in Costa Rica].

In Costa Rica, a total of 640 samples from eight different vegetables used for raw consumption, were analyzed for the presence of intestinal parasites and fecal coliforms. Eighty samples of each vegetable were analyzed, forty during the dry season and forty in the rainy. A greater, but unsignificant (p > 0.05) level of fecal coliforms was found during the dry season. Levels of Escherichia coli, were higher (p < 0.05) during the dry season in lettuce (Latuca sativa) and cilantro (Coleandrum sativum) leaves. Cysts of Endolimax nana, Entamoeba coli, Entamoeba histolytica, Giardia intestinalis and Cryptosporidium sp. were found in all vegetables. The greater percentage of positive samples was found during the dry season, although these relation was only corroborated (p < 0.05) in radish (Raphanus sativus) and cilantro leaves. Only lettuce and cilantro levels showed a positive linear correlation (p < 0.05) between occurrences of intestinal parasites and fecal coliforms.

Animals↗
PubMedDate not supplied

Aerobic performance of wild-derived house mice does not change with cold exposure or intestinal parasite infection.

Aerobic performance is affected by numerous endogenous and exogenous factors. We investigated the effects of ambient temperature and parasite infection on resting metabolism and maximal exercise-induced oxygen consumption in wild-derived house mice (Mus musculus). We also collected preliminary data for effects of lactation on these measures of aerobic performance. Mice were experimentally infected with a naturally occurring intestinal nematode (Heligmosomoides polygyrus) and then exposed to cold temperatures for 10 d or allowed to mate and reproduce. Wild-derived house mice did not change their resting metabolism with H. polygyrus infection or cold exposure, which is in stark contrast to similar studies with laboratory mice. Preliminary data also showed no effect of lactation on aerobic performance. Similarly, maximal exercise-induced oxygen consumption and hematocrit and hemoglobin were unaffected by all experimental treatments. We conclude that resting metabolism, maximal oxygen consumption, and hematology of wild-derived house mice are unaffected by exogenous (temperature) and endogenous (H. polygyrus) demands and, therefore, wild-derived mice respond to these demands without incurring potential costs associated with changes in aerobic performance.

Analysis of Variance↗
PubMed2005

Mycotic dermatitis with digital gangrene and osteomyelitis, and protozoal intestinal parasitism in Marlborough green geckos (Naultinus manukanus).

CASE HISTORY: Thirty adult Marlborough green geckos (Naultinus manukanus) were collected from Stephens Island and held over winter, prior to their translocation. Five adult geckos developed skin lesions after husbandry changes affected the humidity of their enclosures. Two geckos underwent ecdysis and recovered. One animal died and two others progressively worsened and were presented for treatment. CLINICAL AND PATHOLOGICAL FINDINGS: The geckos were in poor body condition and had multiple black powdery lesions and solitary raised white nodules on their skin. Both geckos died despite topical and supportive treatment. Histopathology showed the skin nodules contained branching non-septate hyphae infiltrating necrotic epidermal tissue, and associated dermal inflammation. There was necrosis of several digits and mycotic osteomyelitis. Mucor ramosissimus was cultured from skin biopsies from each animal. Large numbers of motile protozoa, resembling Trichomonas, and another unidentifiable, were recovered from fresh faecal smears, and Nyctotherus sp protozoa were present in the lumen of the intestine of one animal post mortem. DIAGNOSIS: Mycotic dermatitis with digital gangrene and osteomyelitis due to Mucor ramosissimus, and enteric protozoal parasitism with Trichomonas sp and Nyctotherus sp. CLINICAL RELEVANCE: The clinical course and pathological findings of mycotic dermatitis in two Marlborough green geckos involved in a wildlife translocation in New Zealand are reported, and also the first record of the Marlborough green gecko as a host for the enteric protozoa Trichomonas sp and Nyctotherus sp.

Animals↗
PubMed1983

Evaluation of intestinal parasite morphology in polyvinyl alcohol preservative: comparison of copper sulfate and mercuric chloride bases for use in Schaudinn fixative.

As a result of disposal problems inherent in the use of mercury compounds, many laboratories have considered using copper sulfate as a substitute for mercuric chloride in polyvinyl alcohol (PVA) preservative. The primary use for PVA-preserved specimens is the permanent stained smear, the most important technique for the identification of intestinal protozoa. A comparison of organism recovery and morphology was undertaken with PVA containing either copper sulfate or mercuric chloride base. Paired fecal specimens (417 pairs) were collected and examined with the Formalin-ether concentration and Trichrome stain techniques. Numbers of organisms recovered and helminth egg and protozoan morphology were assessed from the concentration sediment. Morphology, clarity of nuclear and cytoplasmic detail, overall color differences, and the ease or difficulty in detecting organisms in fecal debris were assessed from the permanent stained smear. No significant differences were found in the numbers and morphology of organisms seen in the concentration sediment. However, when the trichrome stain was used, the overall morphology of the intestinal protozoa preserved in PVA with copper sulfate was not equal to that seen with PVA with mercuric chloride. We do not recommend switching from mercuric chloride base to copper sulfate base unless that is the only option available for the preparation of permanent stained smears.

Copper↗