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PubMed1998

Parasites and related pathological lesions in the gastrointestinal tract of a seal (Phoka vitulina Linnaeus).

An immature seal, about one-year-old, died a natural death. At autopsy, a large number of Contracaecum osculatum and Pseudoterranova decipiens, as well as some of Anisakis simplex were found in the stomach together with numerous Corynosoma strumosum in the small intestine and colon. Histopathological examination revealed epithelial desquamation, congestion and hemorrhage in the mucosa. There were cellular infiltration and fibroplasia around the nematodes, collapsed nematodes and molted nematode cuticules in the stomach wall. The small intestine and colon underwent severe epithelial desquamation, catarrhal inflammation, and slight inflammatory response consisting mainly of lymhocytes. To the best of our knowledge, this may be the first report on Corynosoma strumosum in Japan.

Animals↗
PubMed2001

Cecal rupture by Anoplocephala perfoliata infection in a thoroughbred horse in Seoul Race Park, South Korea.

A 7-year-old Thoroughbred horse was admitted to the Equine Hospital, Korea Racing Association with signs of colic. Based on the size of impactions, the clinical signs, the results of abdominal paracentesis and medical treatment, the prognosis was poor. The horse died 3 hours later following hopeless discharge. At necropsy, the caecum and large colon were fully filled with fecal contents and there was a rupture (10 cm in dia) in the latero- ventral caecum. The mucosa of the ileo-caecal and caeco- colic valves appeared to the hyperemic, edematous and ulcerous. There were many tapeworms in the affected mucosa. Histopathologically, lesions included hyperaemia, a deep necrotic inflammatory lesion and ulcers in the mucosa and submucosa of ileo-caecal and caeco-colic valves. One hundred thirty four faecal samples were obtained from 16 stables and submitted to parasitic examination. A total of 4 genera of eggs were recovered: Stongylus spp (82.1%), Anoplocephala perfoliata (10.5%), Bovicola equi (0.7%) and Parascaris equorum (1.5%). The major findings in this study are the presence of A perfoliata and its suspected association with the colic which led into an eventual caecal rupture. This study indicates the needs for an epidemiological survey of colic that is associated with Anoplocephala.

Animals↗
PubMed1987

The response of the intestinal epithelium in B10.A mice to infection with Trichinella spiralis.

Previous studies on intestinal trichinosis have dealt mainly with areas other than the intestinal epithelium. Since the epithelium is now known to be the parasite's habitat, its response to infection is important. Infection with Trichinella spiralis in immunologically slow-responding B10.A mice was associated with crypt hyperplasia and villus atrophy. With similar infection levels in both primary and challenge infections, there was no difference in the maximal degree of atrophy or hyperplasia between the 2 groups. However, challenged mice underwent these mucosal changes in about half the time. Expulsion of worms always occurred during regeneration of the intestinal epithelium suggesting that the host's defense mechanism of altering the kinetics of the epithelium was not the prime factor causing expulsion. Pulse labelling of enterocytes with [3H] thymidine showed that there was no significant increase in the relative size of the proliferation zone. This indicates that the crypt cell output was not altered by this parasite. Atrophy of the villus was analysed with respect to its 3-dimensional shape. There was a decrease in both height and width of the villus but not thickness. Thus, there is a real decrease in the size of the enterocyte population per villus. Histochemical staining of the enterocyte brush border by an alkaline phosphatase method showed that (1) hyperplastic crypts have an enlarged maturation zone and (2) the villus epithelium is composed entirely of mature cells. The distribution of the nematode population was compared to these changes in the intestine. Trichinella spiralis showed a marked anteriad (distal to proximal) migration prior to expulsion. Thus, utilizing a novel approach to study intestinal trichinosis, the response of the mucosal epithelium has been characterized.

Alkaline Phosphatase↗
PubMed2006

The rabbit coccidium Eimeria piriformis: Selection of a precocious line and life-cycle study.

Specific pathogen-free (SPF) rabbits were inoculated with oocysts of an original strain (OS) of Eimeria piriformis and the first newly developed oocysts recovered from the intestine were used for infection of other rabbits. The prepatent period (PP) was shortened after 12 passages from 194 to 170 hours and remained stable after 5 passages without any selection pressure. Oocysts of the precocious line (PL) exhibited peculiar morphology. Besides refractile bodies (RB) within sporozoites, one huge RB joined with a residual body was present inside each sporocyst. The parasite developed in the proximal colon and, to a lesser extent, in other parts of the large intestine. All stages were seen in the epithelium of crypts. In OS, four asexual generations preceded gamogony and, like in other rabbit coccidia, two types of meronts were observed: meronts of type A that develop into polynucleate merozoite, in which endomerogony takes place, and meronts of the type B that form uninucleate merozoites. The endogenous development of PL was identical with that of OS except for the last merogony which was absent. This resulted in earlier appearance of gamogony and shortening of PP. These observations of the life cycle of E. piriformis substantially improve on its description made 50-60 years ago.

Animals↗
PubMed2003

Effect of host age in the distribution of adult Trichinella zimbabwensis in the small intestines of golden hamsters (Mesocricetus auratus) and Balb C mice.

Golden hamsters (Mesocricetus auratus) and Balb C mice were experimentally infected with Trichinella zimbabwensis to determine the effect of host age in the distribution of adult stages in the small intestines. The hamsters and mice were divided into two groups of young and old animals. Hamsters aged 90 days were designated as young and those aged 360 days were designated as old while mice of 30 days of age were designated as young and those aged 90 days as old. To recover the adult parasites of T. zimbabwensis, the small intestines of each animal were separated and divided into four equal parts and each part was slit open longitudinally. The contents were incubated in 0.85% saline for 4 h at 37 degrees C before the adult worms were recovered from the saline. They were fixed in 70% alcohol and counted under a dissecting microscope. In both young and old hamsters and mice, T. zimbabwensis adult worm counts were significantly higher (P < 0.05) in the second segment of the intestines thus invariably reflecting a significantly high count (P < 0.05) in the first (anterior) half of the small intestines. From this study it was demonstrated that host-age had no effect on the distribution of T. zimbabwensis adult worms in the different segments of the small intestines of golden hamsters and Balb C mice.

Age Factors↗
PubMed2005

Prevalence and diagnosis of parasites of the stomach and small intestine in horses in south-west England.

Parasites were extracted from the stomach and small intestine of 118 horses at slaughter. The most abundant species was the tapeworm Anoplocephala perfoliata. Maximum likelihood analysis was used to investigate the relationship between the number of worms and their total weight, and the ability of an antibody-based elisa to diagnose the level of infection. The total weight of tapeworms increased towards a maximum as the number of worms increased, suggesting a population density-dependent constraint on the weight. The number of A perfoliata present could be predicted approximately from the results of the elisa. Although wide variation in elisa optical densities confound interpretation in individual animals, tests on groups of animals could provide a useful reflection of overall levels of infection.

Abattoirs↗
PubMedDate not supplied

[Experimental imaginal Echinococcus multilocularis infestation of golden hamsters].

The imago stage of Echinococcus multilocularis development (prior to maturation of parasite oocysts) has been described in the intestine of golden hamsters infected by parenteral penetration of an Alveococcus agent and given hydrocortisone subcutaneously for 3 days before the infection and on the day of the infection, mean total drug dose being about 250 mg/kg. The number of helminths developed on days 8-35 of postinvasion ranged from 432 to 1863, their length was 1.0 to 4.0 mm and the number of segments did not exceed 2. Oocyst maturation was noted on day 20 of postinvasion. High oocyst invasiveness was confirmed by a biological test on 32 cotton rats aged 1-1.5 months who were administered parenterally 2-3 helminths containing 86 to 284 oocysts. All the rats died of severe hepatic alveococcosis on days 24-43 of postinfection.

Animals↗
PubMed2006

A new species of Capillaria (Nematoda: Capillariidae) parasitizing Conger orbignianus (Pisces: Congridae) from Argentina.

Capillaria (Procapillaria) navoneae n. sp. is described from the congrid fish Conger orbignianus from waters off Mar del Plata, Argentina (38 degrees 08'S, 57 degrees 32'W) (prevalence 29.17%, mean intensity +/- SD 6.07 +/- 6.59). The new species is assigned to the subgenus Procapillaria Moravec, 1987, despite the absence of vulvar appendages in gravid females. Of the 3 species so far known in the subgenus, the new one most closely resembles C. (P.) margolisi, from which it is distinguished by lacking a medial expansion in the spicule and a slightly elevated anterior lip of vulva, and by having a shorter esophagus, a larger number of stichocytes, and a shorter tail.

Animals↗
PubMed2000

Prevalence of sarcocystis species sporocysts in wild-caught opossums (Didelphis virginiana).

Sarcocystis sporocysts were found in intestinal scrapings from 24 (54.5%) of 44 opossums (Didelphis virginiana). The number of sporocysts varied from a few (< 10,000) to 245 million. Sporocysts from 23 of 24 opossums were fed to captive budgerigars (Melopsittacus undulatas), and the inocula from 21 opossums were infective, indicating the presence of Sarcocystis falcatula. Sporocysts from 24 opossums were fed to gamma-interferon-knockout (KO) or nude mice; inocula from 14 opossums were infective to mice. Sarcocystis neurona was detected in tissues of KO mice by specific staining with anti-S. neurona antibodies, and the parasite was cultured in vitro from the brains of KO mice fed sporocysts from 8 opossums. Sarcocystis speeri was identified by specific staining with anti-S. speeri antibodies in tissues of KO mice fed inocula from 8 opossums; 3 opossums had mixed S. neurona and S. speeri infections. Thus, the prevalences of sporocysts of different species of Sarcocystis in opossums were: S. falcatula 21 of 44 (47.7%), S. neurona 8 of 44 (18.1%), and S. speeri 8 of 44 (18.1%) opossums. Sarcocystis neurona alone was found in 1 opossum, and S. speeri alone was found in 1 opossum. Mixed Sarcocystis infections were present in 21 opossums.

Animals↗
PubMed2000

Expression of interleukin-9 leads to Th2 cytokine-dominated responses and fatal enteropathy in mice with chronic Schistosoma mansoni infections.

Mice infected with Schistosoma mansoni develop Th2 cytokine-mediated granulomatous pathology that is focused on the liver and intestines. In this study, transgenic mice constitutively expressing IL-9 were infected with S. mansoni and the outcome of infection was determined. Eight weeks after infection, transgenic mice with acute infections had a moderate increase in Th2 cytokine production but were overtly normal with respect to parasite infection and pathological responses. Transgenic mice with chronic infections died 10 weeks after infection, with 86% of transgenic mice dead by week 12 of infection, compared to 7% mortality in infected wild-type mice. Stimulation of mesenteric lymph node cells from infected transgenic mice with parasite antigen elicited elevated interleukin-4 (IL-4) and IL-5 production and reduced gamma interferon and tumor necrosis factor alpha production compared to the responses in wild-type mice. Morbid transgenic mice had substantial enlargement of the ileum, which was associated with muscular hypertrophy, mastocytosis, eosinophilia, goblet cell hyperplasia, and increased mucin expression. We also observed that uninfected transgenic mice exhibited alterations in their intestines. Although there was hepatic mastocytosis and eosinophilia in infected transgenic mice, there was no hepatocyte damage. Death of transgenic mice expressing IL-9 during schistosome infection was primarily associated with enteropathy. This study highlights the pleiotropic in vivo activity of IL-9 and demonstrates that an elevated Th2 cytokine phenotype leads to death during murine schistosome infection.

Animals↗
PubMed1986

The occurrence and abundance of helminth parasites of the mountain hare Lepus timidus (L.) and the wild rabbit Oryctolagus cuniculus (L.) in Aberdeenshire, Scotland.

Mountain hares were collected each month between April 1984 and March 1985 and their intestines examined for helminths. 26 rabbits were also collected between July and December 1984 and examined for gastro-intestinal helminths. Three nematode and two cestode species were found in the hares while only two nematode and one cestode species were found in the rabbits. Trichostrongylus retortaeformis was recorded from 88% of the 193 hares and 92% of the rabbits while comparable figures for Passalurus ambiguus were 0.5% and 54% and for Mosgovoyia pectinata 14% and 81%. Seasonal fluctuations were observed in the T. retortaeformis populations in the hare; numbers tended to be low during the winter months and high throughout the summer. Paranoplocephala wimerosa was reported for the first time from the British Isles and Trichostrongylus axei was recorded for the first time in the mountain hare.

Animals↗
PubMed1988

Seasonal fluctuations of gastrointestinal helminths of camels in Kuwait.

Over a period of 1 year, from May 1982 to April 1983, the gastrointestinal tracts of 240 camels were examined for the presence of parasitic helminths. The study quantifies the prevalence of gastrointestinal helminths and the seasonal fluctuations in intestinal worm burdens and faecal worm egg counts. Among the three species of cestodes and eight species of nematodes which were recorded for the first time from Kuwait, Trichostrongylus probolurus (93.8%), T. colubriformis (34.2%) and Stilesia vittata (30.0%) were the most prevalent in the small intestine and Camelostrongylus mentulatus (59.6%) in the abomasum. Estimation of the intestinal worm burdens and faecal worm egg counts showed that Trichostrongylus infections were by far the most predominant. The highest worm and egg counts were recorded in June and August, during the hot dry season. This rise is attributed to infections acquired from February to April, during the cool wet season. Possibly the most effective control can be achieved by a critical treatment at the end of the wet season coinciding with the first rise in nematode population.

Abomasum↗
PubMed1992

Stimuli for acquired resistance to Heligmosomoides polygyrus from intestinal tissue resident L3 and L4 larvae.

L3 and L4 stages of H.polygyrus were prevented from developing further and were probably killed within 24 h of treatment with ivermectin although total parasite burdens, particularly when treatment was given 4-6 days after infection, declined over a longer period lasting several days. Strong resistance to challenge infection was expressed by infected mice dosed with ivermectin during the tissue phase of larval development. Even immunizing infections as brief as 12-36 h (when only L3 larvae would have been present in the mucosa) elicited strong acquired immunity. When infections were terminated 4-6 days after infection, acquired resistance was 95-100%. The stronger resistance of mice exposed to both L3 and L4 stages was associated with the recognition of low molecular weight polypeptides in adult worm homogenate and there was a highly significant correlation between percentage protection and anti-L4/anti-adult worm serum IgG1 antibodies.

Animals↗
PubMed2002

The phylogeny of Goussia and Choleoeimeria (Apicomplexa; Eimeriorina) and the evolution of excystation structures in coccidia.

The phylogenetic relationships of Goussia janae and Choleoeimeria sp. were analyzed using the small subunit ribosomal RNA gene (SSU rDNA). This is a first attempt to study the molecular phylogeny of coccidian genera parasitizing strictly poikilotherm hosts. The biliary Eimeria-like coccidia of reptiles classified into the genus Choleoeimeria form a sister clade to the family Eimeriidae, which confirms the separate generic status of the genus Choleoeimeria. The position of Goussia is less robustly resolved, since it forms a trichotomy with the Eimeriidae and Sarcocystidae, or alternatively constitutes the earliest branch of the coccidian lineage. Morphological similarities, namely the extracytoplasmic location of the endogenous stages, and the presence of sutures in the sporocyst wall are discussed in the context of the traditional classification of eimeriids. In contrast to the morphology-based systematics, the monophyly of Goussia and Choleoeimeria is not supported by the SSU rDNA data.

Animals↗
PubMed1997

Pathologic and clinical findings in patients with cyclosporiasis and a description of intracellular parasite life-cycle stages.

Cyclospora cayetanensis has been observed in the feces of persons with prolonged diarrhea. A description of the symptoms and histopathologic findings for patients with cyclosporiasis is presented. The intracellular life-cycle stages of these parasites in the enterocytes of patients will also be described. Seventeen Peruvian patients positive for Cyclospora organisms were surveyed and underwent endoscopy, and their symptoms were recorded. Patients presented with gastrointestinal symptoms, including diarrhea, flatulence, weight loss, abdominal discomfort, and nausea. Jejunal biopsies showed an altered mucosal architecture with shortening and widening of the intestinal villi due to diffuse edema and infiltration by a mixed inflammatory cell infiltrate. There was reactive hyperemia with vascular dilatation and congestion of villous capillaries. Parasitophorous vacuoles contained sexual and asexual forms. Type I and II meronts, with 8-12 and 4 fully differentiated merozoites, respectively, were found at the luminal end of epithelial cells. These findings demonstrate the complete developmental cycle associated with host changes due to Cyclospora organisms.

Animals↗
PubMed2000

Infection with different Trypanosoma cruzi populations in rats: myocarditis, cardiac sympathetic denervation, and involvement of digestive organs.

We tested four isolates of Trypanosoma cruzi to assess parasite virulence and ability to cause myocarditis, cardiac sympathetic denervation, and histopathologic alterations in organs of the digestive system. The susceptibility of rats depends on the population of T. cruzi, with the ABC strain and the CL-Brener clone killing all animals, regardless of the parasitemic pattern. All tested T. cruzi populations caused acute myocarditis, but failed to induce histologic alterations in the intestine. The Cl-Brener and ABC isolates caused esophageal myositis. The myocarditis caused by the ABC, CL-Brener, and Y isolates was severe, but resolution started at the end of the acute phase. In contrast, the Col 1.7 G2 clone induced mild and sustained myocarditis. Our results also showed that T. cruzi populations able to induce severe acute myocarditis caused marked sympathetic denervation, but recovery of normal cardiac histology and innervation occurred. The sustained myocarditis induced by Col 1.7 G2 clone failed to cause sustained denervation.

Animals↗
PubMed2006

Peyer's patches are required for the induction of rapid Th1 responses in the gut and mesenteric lymph nodes during an enteric infection.

The Peyer's patches (PP) and mesenteric lymph nodes (MLN) are structural components of the gut-associated lymphoid tissues and contribute to the induction of immune responses toward infection in the gastrointestinal tract. These secondary lymphoid organs provide structural organization for efficient cellular interactions and the initiation of primary adaptive immune responses against infection. Immunity against primary infection with the enteric apicomplexan parasite, Eimeria vermiformis, depends on the rapid induction of local Th1 responses. Lymphotoxin (LT)-deficient mice which have various defects in secondary lymphoid organs were infected with E. vermiformis. The relative susceptibility of LTalpha(-/-), LTbeta(-/-), LTalpha(+/-)beta(+/-) mice and bone marrow chimeras, indicated that rapid protective Th1 responses required both PP and MLN. Moreover, the timing of Th1 induction in both MLN and gut was dependent on the presence of PP suggesting a level of cooperation between immune responses induced in these distinct lymphoid structures. The delay in Th1 induction was attributable to the delayed arrival of a broad range of dendritic cell subsets in the MLN and a substantial reduction of CD8alpha(-)CD11b(high) B220(-) dendritic cells in PP-deficient mice.

Animals↗
PubMed1998

Use of monoclonal antibodies against chicken coccidia to study invasion and early development of Eimeria gruis in the Florida sandhill crane (Grus canadensis).

Eimeria gruis and E. reichenowi are common coccidial parasites of a number of crane species. In the present study, monoclonal antibodies (McAbs), elicited against Eimeria spp. of chickens and turkeys, cross-reacted with sporozoites and developmental stages of E. gruis in the tissues of Florida sandhill cranes. These McAbs were used to define the area of the intestine that was invaded by sporozoites of E. gruis and to demonstrate the feasibility of using McAbs to study the early development of E. gruis in the intestines and visceral organs of cranes. At 6 hr postinoculation (PI), E. gruis sporozoites were found primarily from just proximal to Meckle's diverticulum in the jejunum to the ileocecal juncture. Fewer sporozoites were found in the ceca and rectum, and none were found in the duodenum. Most of the sporozoites were in the middle third of the villi and within the lamina propria. At 14 days PI, developmental stages were detected in the ceca, jejunum, liver, and lungs but not in the heart, kidney, or brain. In the ceca and jejunum, the number, location, and maturity of the stages differed markedly.

Animals↗