PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “INTESTINAL DISEASES, PARASITIC”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 487 records · Page 27Linked to original sources
PubMed2005

Strongyloides ratti infection in the large intestine of wild rats, Rattus norvegicus.

The large intestine of a rat has been neglected almost completely as a site of Strongyloides sp. infection. We reported that adult Strongyloides ratti remained in the large intestine for more than 80 days, producing more number of infective larvae than small intestine adults, and therefore hypothesized that parasitism in this site could be a survival strategy. In wild rats, however, no study has focused on large intestine infections of Strongyloides. The present study revealed that 32.4% of 68 wild rats, Rattus norvegicus, had the infection of S. ratti in the large intestine, with an average of 4.7 worms. These worms harbored normal eggs in the uterus. In a laboratory experiment with S. ratti and Wister rats, daily output of infective larvae by 4.7 females in the large intestine was estimated to be 4,638.4, suggesting that a few parasites could play a role in the parasite transmission. Five species of nematode found in the wild rats showed seasonality in infection intensity, with highest intensities in March-May. The number of S. ratti in the large intestine was also highest in these months.

Animals↗
PubMed2005

Biological variation between two Brazilian geographical isolates of Echinostoma paraensei.

The biological behaviour and morphometric data from two allopatric isolates of Echinostoma paraensei (Rio Bonito - RB and Sumidouro - SU) collected from naturally infected Nectomys squamipes from two secluded Atlantic Forest fragments were studied. Mice that had been experimentally infected with ten encysted metacercariae of each isolate were monitored weekly in two trials to analyse worm burden and the kinetics of worm distribution along the intestine. The total number of uterine eggs, wet weights and measurements of the worms and body, acetabulum, testes and ovaries were also analysed. The RB isolate showed a higher worm burden, 7.7+/-0.8, and a longer life span, 16 weeks, compared to a worm burden of 5.8+/-1.1 and life span of 9 weeks for the SU isolate. Worms of the RB isolate were clustered in the duodenum and in the bile duct while the SU isolate worms were dispersed along the small intestine of infected mice. Both isolates developed similarly as regards morphometric data and wet weight, although the total number of uterine eggs was greater in RB. The degree of intraspecific variation observed in the worm distribution along the intestine, worm burden and life span raises questions regarding the use of these criteria for species differentiation. These findings suggest that variation in biological parameters found between the E. paraensei isolates could result from geographical isolation and, in particular, the environmental conditions of transmission. Further studies on E. paraensei polulations from different forest fragments will contribute towards an understanding of the speciation of this parasite.

Animals↗
PubMed2003

The rabbit coccidium Eimeria flavescens Marotel and Guilhon, 1941: an electron microscopic study of its life cycle.

The endogenous cycle of Eimeria flavescens was studied in specific pathogen-free rabbits by means of histology and transmission electron microscopy. In total, five asexual generations were observed and two types of meronts and merozoites were found in each generation. Type A gave rise to a smaller number of thick polynucleate merozoites in which daughter merozoites were formed by endomerogony, while in the type B meronts slender uninucleate merozoites arose from ectomerogony. The first generation meronts were found in the crypts and proximal part of the villi of the duodenum and jejunum, whereas the three following generations developed in the superficial epithelium of the large intestine (cecum, vermiform appendix and colon). The last merogony as well as gamogony took place in crypts of the large intestine.

Animals↗
PubMed1984

Chronic infections with Trichostrongylus colubriformis in lambs: influence of anthelmintic treatment on intestinal morphology and mucosal cell populations.

Intestinal mucosal morphology, topography and populations of crypt intraepithelial globule leucocytes (IGLs), goblet cells and mucosal mast cells were compared in 4 groups of 3-month-old lambs which had been reared worm-free from birth. Groups 1 and 2 were infected daily on 5 days per week with 2500 Trichostrongylus colubriformis larvae for 18 weeks. Group 2 lambs were treated with fenbendazole (5 mg per kg) at week 10 and week 15. Group 3 lambs were infected as above with T. colubriformis for 10 weeks, dosed with fenbendazole and given no further larvae. A fourth group of 4 lambs (Group 4) was maintained worm-free throughout the experiment as controls. All lambs were killed at week 20. Worm populations (range 410 to 30460) and mucosal damage varied considerably between individuals in the untreated Group 1 lambs, but damage was severe, with total villous atrophy, in lambs with large worm burdens. In 3 lambs with moderate worm burdens, worms were seen only in circumscribed flat "finger-print" lesions in the jejunal mucosa. There was no correlation between IGL numbers, mast cell numbers and final worm burdens in Group 1 lambs, though there was a trend towards an association between high worm populations and low IGL numbers. Only trivial pathological changes were detected in the re-infected Group 2 lambs. Low worm egg counts were found in this group 4 weeks after the first anthelmintic treatment, and virtually no eggs were present after the second treatment. Mucosal morphology in Group 3 lambs, which were not re-infected, resembled the controls at the end of the experiment. IGL numbers were greater in both treated groups than in controls, and numbers in the re-infected Group 2 lambs were greater than those in Group 3 lambs. Mucosal mast cell numbers did not differ significantly between groups, but crypt goblet cell numbers were increased in all 3 infected groups, compared with controls.

Animals↗
PubMed1991

The in vivo excystation of Sarcocystis gigantea and S. tenella sporocysts.

In vivo studies on the excystation of Sarcocystis gigantea and S. tenella sporocysts indicated that this process was, as in vitro, a diphasic one involving both pretreatment and treatment phases. The studies also tended to support in vitro observations that the requirements for the excystation of these two species are quite different. The results suggested that for neither species was the pretreatment stimulus likely to be provided by conditions in the rumen alone. However, exposure to abomasal conditions only induced moderate levels of excystation in both when they were subsequently treated with trypsin and bile. For S. gigantea, 0.25 to 4 h abomasal exposure was most effective; for S. tenella, 24 hours. The stimuli necessary to complete the excystation process could, apparently, be provided by 1 h placement in the duodenum for S. gigantea but not for S. tenella.

Abomasum↗
PubMedDate not supplied

Selective alterations in mast cell subsets and eosinophil infiltration in two complementary types of intestinal inflammation: ascariasis and Crohn's disease.

OBJECTIVE: Numbers of mast cells (MCs) of different subpopulations and the extent of eosinophil infiltration were compared in Crohn's disease and ascariasis. These two types of intestinal inflammation are complementary with regard to T cell response (TH1 versus TH2), prevalence and environmental factors. METHODS: Histochemical, immunohistochemical and ultrastructural tools were applied to biopsies of morphologically uninvolved colon, ileum and duodenum from Crohn's and ascariasis patients, as well as resection margins and tissues from an experimental porcine ascariasis model. MC subsets were defined by their dye-binding properties, and their chymase content was analysed using biochemical tools. RESULTS: The TH2 (IgE-mediated) response in ascariasis was characterised by a dramatic increase in mucosal- type MCs (MMCs) and eosinophils in both the mucosa and the deeper layers of the intestinal wall and a simultaneous decrease of connective tissue-type MCs (CTMCs). Uninvolved intestine of Crohn's patients showed moderate proliferation of CTMCs in the deeper layers of the intestinal wall, but a significant decrease of the MMCs, associated with moderate eosinophilia in all layers of the gut. Similar changes were present in the uninvolved duodenum of Crohn's patients. Comparable amounts of chymase could be extracted from mucosal and submucosal duodenum, with similar proportions of its two principal isoforms in each. CONCLUSIONS: Our results indicate that T cell responses (TH1 or TH2) are associated with different MC subsets in intestinal inflammation. Changes remote from the focus of inflammation point to the systemic nature of the different MC responses.

Adult↗
PubMed1992

Life cycle and ultrastructure of Eimeria stigmosa, the intranuclear coccidian of the goose (Anser anser domesticus).

The oocyst morphology and endogenous development of Eimeria stigmosa Klimes, 1963 in a domestic goose (Anser anser domesticus L.) was studied using light and electron microscopy. The oocyst wall consisted of two layers. The outer layer formed densely accumulated protrusions, whilst the inner layer was smooth and formed a collar structure around the micropyle. Meronts were observed in the posterior part of the jejunum, along the whole length of the ileum and in Meckel's diverticulum within 1-4 days post infection (DPI). Sexual generation was found in the caecum and colon 4-5 DPI. All endogenous stages were located intranuclearly in enterocytes, predominantly in the apical part of the villi in distinct parasitophorous vacuoles. Numerous different developmental stages were frequently found in one nucleus. Current evidence indicates the existence of only one asexual generation formed by ectomerogony. During the development of asexual stages, invaginations into the body of a meront by the host cell nucleoplasm were observed.

Animals↗
PubMed1990

Concurrent cryptosporidium and coronavirus infections in an Arabian foal with combined immunodeficiency syndrome.

Combined immunodeficiency syndrome is an inherited disorder of the Arabian breed of horses. Affected foals usually die of infectious disease within the first few months of life, and the respiratory tract is the commonest site of infection. This report describes the clinical and pathological features of a case which showed signs of alimentary and respiratory infections. Intestinal infection by coronavirus (not previously recorded in cases of the syndrome) and cryptosporidia was identified. Histopathological evidence also suggested the presence of an adenovirus infection.

Animals↗
PubMed1993

Severe moniliformiasis (Acanthocephala: Moniliformidae) in a gray squirrel, Sciurus carolinensis, from Arkansas, USA.

Three hundred and seventy-five acanthocephalans, Moniliformis clarki, were removed from the small and large intestines of a gray squirrel from Arkansas County, Arkansas (USA). This is the first report of M. clarki from Arkansas. Enteric lesions, including distension, perforating ulcers, enteritis, crypt hypertrophy, goblet cell hyperplasia, and occlusions of the intestinal tract were observed, indicating the pathogenic potential of this parasite.

Animals↗
PubMed1993

Pathways to the impairment of human nutritional status by gastrointestinal pathogens.

Gastrointestinal pathogens are of three varieties, those that can, and often do, take the life of the host, those that infect transiently and rarely are life-threatening, and those (parasites) that establish a relatively prolonged residence or colonization of the host's alimentary tract. In the case of the second form, if infections are recurrent, both catabolic effects during the episode and failure to digest foods and/or absorb nutrients results. Similarly, catabolic wastage through activation of the acute phase response, and interference with the host's acquisition of nutrients by maldigestion, malabsorption, intestinal losses and competition with the parasite burden can impair growth and nutrition with helminthic infections. Growth and nutrition with respect to all of the macronutrients and virtually all of the micronutrients have been documented to be adversely affected by gastrointestinal pathogens. For its burgeoning importance as a worldwide health problem, both with the HIV virus as a direct intestinal pathogen and with the opportunistic gut infections occurring in the immunocompromised host, AIDS represents the emerging context of the impairment of nutritional status by intestinal pathogens.

AIDS-Related Opportunistic Infections↗
PubMed1997

Immune responses to intestinal parasites: protection, pathology and prophylaxis.

Aspects of the immune responses made by hosts to infection with intestinal parasites are discussed in relation to data from experimental systems in mice involving infections with the protozoans Eimeria vermiformis and Cryptosporidium spp., and the nematodes Nippostrongylus brasiliensis and Trichinella spiralis. The focus of the review is our knowledge and understanding of the roles played by the intestinal mucosa and the epithelial cells of the mucosa in the induction, regulation and expression of the immune and inflammatory responses that provide the host with protection but which may also lead to pathology. Emphasis is placed on current knowledge of T helper cell and cytokine involvement in these responses. The relationship between pathology and protection is discussed briefly, as are some aspects of the development of vaccines effective against intestinal parasites.

Animals↗