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PubMed1990

[Study of Strongyloides stercoralis in the duodenal juice obtained by the examination of a string capsule or the Enterotest].

We present our experience in the investigation of Strongyloides stercoralis in the duodenal juice obtained by the "string capsule" o Enterotest, in 1,511 patients from the Gastroenterology Service of the National Hospital "Edgardo Rebagliati Martins" IPSS, between January 1985 to July 1990. We found 36 patients parasitized with Strongyloides stercoralis, an incidence of 2.4%. This method was good tolerated and have proved to be simple, fast, effective and allowing to examine simultaneously many patients at a very low cost.

Adolescent↗

PubMedDate not supplied

Prospects for the immunological control of ruminant gastrointestinal nematodes: natural immunity, can it be harnessed?

Current understanding of the mucosal immune response to nematode parasites is briefly reviewed with emphasis on the role of the cytokines interleukins-4 and -12 and gamma interferon (IFN gamma) in the development of T-helper responses in rodents. Data from laboratory animals and ruminants indicate that the events associated with a T-helper 2 (Th2) cell response, notably IgE synthesis, eosinophilia and mucosal mastocytosis are protective. Evidence that effector mechanisms may vary for different parasite species is considered. Current gaps in understanding such as the location in the gut and mechanism of antigen processing and presentation as well as the relative contribution of non-immunological effector responses, such as gut motility and mucus secretion, to worm expulsion are discussed.

Animals↗

PubMed1998

[Intestinal parasites in the vendors and consumers of street food. A study conducted in the Dakar area].

In order to assess the parasitic risk for street-food consumers, the authors conducted two studies from September to August 1996, one on street-food sellers (305) and the other on consumers (235). Among the consumers, 127 were considered as not exposed to risk, since they did not frequent the sector being surveyed, and 108 were exposed because they consumed at least one meal per day cooked by the sellers of this area. Both groups filled out a questionnaire and had their stools analysed according to the RITCHIE method. The infection rate was 60% among sellers and 45.5% among consumers. Protozoans were predominant in both groups. Among the consumers, those exposed were significantly more infected. Even though the sellers represent a parasitic risk due to their level of infection and the typology of parasites they shelter, one cannot assume that consumers are contaminated only by the sellers of street food. However, appropriate measures must be implemented in order to minimize risks for street-food consumers.

Feces↗

PubMed1999

Localization of Toxoplasma gondii in feline intestinal tissue using PCR.

Gametogony of Toxoplasma gondii occurs only in the epithelial cell layers within the intestine of the definitive feline host. Infected feline intestine is required in order to study the physiology, histology, and molecular biology of the gametogenic stages. Therefore, we set out to devise a rapid, conservative, and reproducible technique to determine which portions of the intestine were infected. Several methods of collecting and processing infected material were assessed for their ability to detect T. gondii. Infected and uninfected intestines from domestic cats were used to produce nitrocellulose lift impressions along the entire small intestine. The nitrocellulose was analyzed for the presence of T. gondii DNA using polymerase chain reaction (PCR) primers specific for the T. gondii alpha-tubulin gene. In addition, mucosal tissue scrapings, derived from segments of intestinal tissue, were used to isolate DNA and RNA for subsequent PCR and reverse transcriptase PCR analysis, respectively. The nitrocellulose impression lift method demonstrated distribution of parasite throughout the intestine. Histological staining and indirect immunofluorescence antibody analysis of sections obtained from the same infected tissue confirmed the presence of T. gondii intraepithelial stages. Comparison among the different techniques indicates that the nitrocellulose impression lift technique proved to be effective for easily and quickly assessing presence of T. gondii in infected tissue. This technique does not require a significant amount of the experimental material.

Animals↗

PubMed1984

Interactions between Moniliformis (Acanthocephala) and Nippostrongylus (Nematoda) in the small intestine of laboratory rats.

Rats harbouring a 35-day-old primary infection of Moniliformis dubius were inoculated with constant doses of Nippostrongylus brasiliensis and 10 days later, after post mortem examination, rats with concurrent infections harboured significantly fewer Nippostrongylus than rats with single infections. Similar infections of Moniliformis were carried out, but with post mortem taking place on days 8, 9, 12 and 14 of the Nippostrongylus infections. On days 8 and 9 of infection, rats with concurrent infections did not harbour significantly fewer Nippostrongylus compared with single infections. Both single and concurrent infections of 12- and 14-day-old Nippostrongylus were found to harbour lower numbers of worms. In the single infection this corresponds to the timing of the typical immune expulsion of a primary single infection which takes place on approximately day 12 of infection. The Moniliformis population was not significantly affected, in terms of numbers, dry weight and length, although each parasite population did show a slight shift in site in the presence of the other. A significant reduction in egg production by Nippostrongylus was detected throughout concurrent infection. The possible role of non-reciprocal cross-immunity is discussed as an explanation for the apparent early expulsion of the Nippostrongylus population in the presence of Moniliformis.

Animals↗

PubMed1992

[Decreased intraepithelial lymphocytes in the intestinal mucosa in children with malnutrition and parasitic infections].

In Gabon, 15 children aged 13 to 36 months admitted for malnutrition with chronic diarrhea underwent a small bowel biopsy for detection of parasites in the duodenal contents and histologic evaluation of the intestinal mucosa. In every case, intraepithelial lymphocyte counts (IELC) were under the lower limit of normal for children and adults, regardless of whether or not parasites were found. Partial villous atrophy was a consistent finding. Proportion of lymphocytes among intraepithelial cells was 7.4% in the 6 children with no parasitic infection, 7.9% in the children with giardiasis, and 8.1% in the children with strongyloidiasis. Appropriate treatment of the parasitic infections was quickly followed by resolution of the diarrhea in the nine patients with demonstrable intestinal parasites. These data should be compared with the well documented lymphocyte function anomalies associated with protein-calory malnutrition. The fall in IELC and lack of response to local anigenic stimulations are features of malnutrition.

Atrophy↗

PubMed2002

Eimeria organisms develop in the epithelial cells of equine small intestine.

Histopathologic and immunohistochemical examinations were performed to determine the origin of host cells parasitized by Eimeria in the small intestines collected from five foals. Eimeria organisms at various stages (mainly microgametes and macrogametes) were frequently found in the cytoplasm of hypertrophied host cells in the lamina propria at the tips of villi of the jejunum and ileum. The cytoplasm of the host cell was immunohistochemically positive for cytokeratin AE1/AE3 and cytokeratin 13 and was negative for vimentin, desmin, alpha-smooth muscle actin, chromogranin A, neuron-specific enolase, and factor VIII. The host cells parasitized by Eimeria species had the immunostaining characteristics of epithelial cells but not of mesenchymal cells, endothelial cells of lacteals or capillaries, smooth muscle cells or neuroendocrine cells. These results suggest that the host cell of Eimeria species is possibly derived from intestinal epithelial cells and then displaced into the lamina propria of the small intestine.

Actins↗

PubMed2005

Evidence of Haplorchis taichui infection as pathogenic parasite: three case reports.

Haplorchis taichui is the minute intestinal fluke which parasitizes the small intestine of humans and other mammals. We present the pathology in the small intestine of 3 human cases caused by H. taichui. Microscopic examination revealed mucosal ulceration, mucosal and submucosal haemorrhages, fusion and shortening villi, chronic inflammation, and fibrosis of the submucosa. This finding clearly indicated H. taichui as pathogenic; thus prevention of infection and treatment should be paramount.

Adult↗

PubMed1996

Ascaris lumbricoides infestation as a cause of intestinal obstruction in children: experience with 87 cases.

PURPOSE: The purpose of this study is to describe the occurrence and management of bowel obstruction caused by Ascaris lumbricoides, a common parasite in warm climates that affects children with limited socioeconomic means. METHODS: Eighty-seven patients with intestinal infestation owing to Ascaris lumbricoides were treated in the past 10 years (1984-1994). There were 48 (55.2%) girls and 39 (44.8%) boys. The mean age was 4.6 years, with peak occurrence at 2 years of age. Half the patients had a history of passing worms by mouth or anus. The majority of patients, 64 (73.5%), presented with a subacute clinical course; 23 (26.5%) had acute presentation, with severe abdominal pain, fever, dehydratation, vomiting, and abdominal distension and required vigorous fluid resuscitation and emergency surgical intervention. Diagnosis was achieved with plain abdominal roentgenograms, which showed a "whirlpool" pattern of intraluminal worms in most cases. RESULTS: Six patients had been incorrectly diagnosed as having appendicitis; two cases had appendicitis owing to Ascaris in the cecum and distal ileum. The majority of cases with a subacute presentation respond to medical (anthelmintic) management using oral administration of racine oil and piperazine. Of the 23 patients taken to the operating room, 11 required external "milking" of the obstructing bolus of worms from the ileum into the colon, six required intestinal resection and end-to-end anastomosis, six had an appendectomy, and three needed an enterotomy to manually extract the worms. In one case, initial management consisted of an ileostomy because of intraoperative instability owing to sepsis. Subsequently, after stabilization and treatment with anthelmintic agents, closure of the stoma with an end-to-end ileocolostomy was performed. There was no significant postoperative morbidity or mortality. CONCLUSION: These observations suggest that physicians should have a high index of suspicion for parasitic infestation in warm climates where economically deprived children present with symptoms of intestinal obstruction. Ascaris lumbricoides may be the cause of these events in endemic areas. Oral piperazine and racine oil can successfully resolve most subacute cases; however, aggressive resuscitation and prompt surgical intervention in patients with intestinal obstruction result in a satisfactory outcome.

Adolescent↗

PubMed2003

Massive gastrointestinal bleeding in infants with ascariasis.

Although infestation with Ascaris lumbricoides causes various intestinal complications, massive gastrointestinal bleeding is rare. The authors report on 2 infants who presented with massive hematemesis. In the first patient, a gastroduodenoscopy was performed. Roundworms were found adhering to an oozing duodenal ulcer. Duodenal perforation occurred after extraction of the parasites. The second case was hematemesis together with peritonitis. Exploration found volvulus and a gangrenous segment of the distal ileum. Both infants previously passed roundworms with their stool. The authors conclude that the intestinal ascariasis can be a cause of massive gastrointestinal bleeding, especially in temperate and tropical countries.

Animals↗

PubMed1997

In vivo and in vitro studies on the sonographical detection of Ascaris lumbricoides.

Intestinal ultrasound, a frequently applied diagnostic tool in industrialized nations, has recently also been introduced in tropical regions. This study attempts to describe the anatomical and sonographical features of Ascaris lumbricoides in the human intestine. In the course of a schistosomiasis morbidity study in Madagascar, 581 inhabitants of a rice-farming village on the high plateau of the island had their stools examined by means of a modified Kato-Katz thick smear technique (four slides per sample); 53% had eggs of Ascaris lumbricoides in their stools. Twenty-two individuals underwent intestinal ultrasound examination and, in six cases, Ascaris lumbricoides was visualized. All six patients showed eggs upon stool examination. At ultrasound, the parasite was seen as a large, curved echogenic strip (4-6 mm in diameter) with an inner, anechoic, longitudinal canal. The image resembled a winding highway, the central structure representing the pseudocoel of the parasite. Patients were treated with mebendazole. The excreted worms of one patient were scanned under water, showing the same characteristics as in vivo. We conclude that Ascaris lumbricoides has a characteristic sonographical appearance and should not be a confounding factor in studies using intestinal ultrasound.

Aged↗

PubMed2001

Stat6 dependent goblet cell hyperplasia during intestinal nematode infection.

To identify the role of signal transducer and activator of transcription factor 6 (Stat6) in the development of intestinal goblet cell hyperplasia during nematode infection, we compared the number of goblet cells in Stat6 deficient (Stat6 -/-) mice with that generated in wild-type (Stat6 +/+) mice in Trichinella spiralis infection. The number of goblet cells significantly increased with infection in wild-type mice. However, Stat6 -/- failed to generate infection-induced goblet cell hyperplasia and a significantly lower number of goblet cells was observed in Stat6 -/- mice on days 14 and 21 postinfection compared to Stat6 +/+ mice. In addition to suppressed goblet cell numbers, Stat6 -/- mice exhibited severe impairment in their ability to produce IL-4 and IL-13 and to expel the parasites from the gut. Our study clearly shows an essential role of Stat6 in intestinal goblet cell hyperplasia which accompanies this infection. We postulate that Th2 cytokines regulate the development of goblet cell hyperplasia in gut during nematode infection via Stat6 activation and that the increased number of goblet cells plays an important role in host protective immunity against the infection.

Animals↗

PubMed1995

A report of intestinal sarcocystosis in the bullsnake (Pituophis melanoleucus sayi) and a re-evaluation of Sarcocystis sp. from snakes of the genus Pituophis.

We report a severe enteric infection of Sarcocystis sp. from a wild-caught bullsnake (Pituophis melanoleucus sayi). The animal was collected in October 1988 by a commercial dealer, imported into the United Kingdom during November 1988 and purchased by the London Zoo, in December 1988. The animal was not fed after capture and was anorexic from the time of purchase to the time of death in January 1989. On necropsy, the animal was emaciated and the mucosa of the proximal intestine was markedly thickened. The lamina propria was packed with oocysts, and enterocytes were parasitized by an organism which closely resembled Sarcocystis roudabushi and Sarcocystis idahoensis, two bisporocystid coccidia described previously from Pituophis melanoleucus. We propose that Sarcocystis idahoensis and Sarcocystis roudabushi are synonymous since both occur in the same host species, both invade the intestinal lamina propria and entreocytes, and sporocyst measurement ranges of both species overlap. This is the first report of death believed to be due to sarcocytosis in a naturally-infected definitive host.

Animals↗

PubMed1991

Isospora corvi Ray, Shivnani, Oommen and Bhaskaran, 1952 from the common house crow (Corvus splendens Vieillot) of Selangor, peninsular Malaysia.

Faecal samples of 56 common house crows (Corvus splendens Vieillot) were collected from the Petaling Jaya and Kelang districts of Selangor, peninsular Malaysia, and examined for coccidia. Intestinal tracts of 8 of the above crows wee histologically examined under light microscopy to determine the site of coccidial infection and the endogenous stages present. Fifty three (94.6%) crows had coccidial oocysts morphologically conforming to only one species of Isospora in their faeces at the time they were examined. The sporulated oocysts were found to be Isospora corviae (Ray et al. 1952) which has been emended to I. corvi. These oocysts are redescribed in greater detail. Corvus splendens is a new host record for I. corvi. Coccidial infection was observed in all the intestinal tracts and generally confined to the anterior two thirds of the intestine. The parasites occurred within intestinal epithelial cells, located usually above the host cell nucleus. Developmental stages of both the asexual and sexual phases were found in the epithelium, and are deemed to be the endogenous stages of I. corvi on the basis of the oocysts recovered from the same crows used for histological study. These stages are described here for the first time. The prevalence of I. corvi, its relationship with the host C. splendens, and its probable transmission from C. macrorhynchus are discussed.

Animals↗

PubMed1998

The effect of nematode infection upon intestinal smooth muscle function.

Nematode infections are useful in studying both host defence and inflammation induced changes in intestinal physiology, including increased contraction by intestinal muscle. Our initial studies of the heightened muscle function found during T. spiralis infection led to investigations of the role of immune and inflammatory cells and mediators in the immunodulation of intestinal muscle function. By infecting various immunodeficient mouse strains, as well as gene transfer to the intestine, T lymphocytes, and in particular the CD4+ve subset were found to be responsible for altering smooth muscle function. However, eosinophils as well as the cytokine interleukin-4 may also be involved. Investigations also indicate a potential role for increased muscle function and propulsive activity in expelling nematode parasites. Mutant mice which suffer aberrant intestinal propulsion, or based upon an immunodeficiency, undergo reduced changes in muscle function during infection, undergo prolonged infections. While increased muscle function may be an adaptive host response, the changes in muscle function may persist long after the resolution of the infection. Thus understanding the mechanisms behind the immunomodulation of intestinal muscle function may also impact upon clinical gastroenterology, since motility disturbances in man often occur following enteric infections, or other inflammatory conditions of the bowel.

Animals↗

PubMed2004

Ecological analysis and description of the intestinal helminths present in dogs in Mexico City.

The objective of the present study was to determine the prevalence of parasitoses in stray dogs from Mexico City, as well as to describe the structure of the intestinal helminth communities present in said hosts. One hundred and twenty dog intestines were collected and dissected to evaluate their parasitic load; finding parasites in 102 dogs (85%). The cestodes collected were: Dipylidium caninum in 72 dogs (60%), Taenia hydatigena in three (2.5%), Taenia pisiformis in two (1.6%), Echinococcus granulosus, Mesocestoides vogae and Mesocestoides variabilis in only one animal each (0.83%), the latter two being collected for the first time ever in Mexico City. Nematodes collected were: Ancylostoma caninum in 75 (62.5%) animals, Toxocara canis in 16 (13.3%) and Toxascaris leonina in 5 (4.16%). By age, D. caninum and A. caninum were the most prevalent species in older animals, while T. canis was more prevalent in young animals (P<0.05). By season, T. canis was most common in the dry season (P<0.05). At the parasitic community level, the diversity value was 0.32, while that of equality was 0.1; the dominant species was M. vogae (Berger-Parker index of 0.95). At the infracommunity level, both diversity and equality were low (0.31 and 0.32, respectively) as compared to that observed in wild canines; the dominant species was A. caninum (Berger-Parker index of 0.37). Qualitative similarity was 33.8%, while quantitative similarity was 32.2%. Based upon the low values for mean diversity, equality and species richness, it is possible to deduce that helminth fauna in dogs from Mexico City is weakened, especially if one compares it to that of other wild canines.

Age Factors↗

PubMed1985

Intestinal invasive amebiasis: an experimental model in rodents using axenic or monoxenic strains of Entamoeba histolytica.

A new experimental model for the production of early stages of invasive intestinal amebiasis in hamsters or guinea pigs with axenic or monoxenic cultures of Entamoeba histolytica of the HM1:IMSS strain is reported. The model is called the washed-closed cecal loop, because it involves the washing out of the cecum contents of conventionally raised animals and the formation of a closed loop, into which amebas are inoculated. Colonization occurred in all inoculated animals. After 48 hr, macroscopic ulcerations of the cecal mucosa were found in approximately one-half (5/12) of the animals inoculated with axenic amebas and in more than two-thirds (10/12) of those inoculated with monoxenic parasites. The amebic nature of the mucosal ulcerations was confirmed by light and transmission electron microscopy, as well as by scanning electron microscopy (SEM) of fractured samples of cecal mucosa. SEM provided a rapid and reliable technique to assess both the extent and the nature of the lesions. This model is particularly useful for the study of the pathogenesis of early intestinal lesions produced by virulent amebas, and may also be applied to experimental studies on the immunology of invasive intestinal amebiasis.

Amebiasis↗

PubMed2005

Accelerated intestinal epithelial cell turnover: a new mechanism of parasite expulsion.

The functional integrity of the intestinal epithelial barrier forms a major defense against invading pathogens, including gastrointestinal-dwelling nematodes, which are ubiquitous in their distribution worldwide. Here, we show that an increase in the rate of epithelial cell turnover in the large intestine acts like an "epithelial escalator" to expel Trichuris and that the rate of epithelial cell movement is under immune control by the cytokine interleukin-13 and the chemokine CXCL10. This host protective mechanism against intestinal pathogens has implications for our wider understanding of the multifunctional role played by intestinal epithelium in mucosal defense.

Animals↗