PATHOGENICITY OF Blastocystis sp. TO THE GASTROINTESTINAL TRACT OF MICE: RELATIONSHIP BETWEEN INOCULUM SIZE AND PERIOD OF INFECTION / Histopatogenicidade de Blastocystis sp. para o trato gastrointestinal de camundongos: relação com inóculo e tempo de infecção

The pathogenic potential of Blastocystis sp. in experimental models requires further investigation. In this work, the pathogenicity of this parasite in the gastrointestinal tract of male Swiss mice was evaluated according to the inoculum size and period of infection. Animals were infected intragastrically, with 100, 500, 1,000, 5,000 and 10,000 Blastocystis sp. vacuolar forms obtained from a mixture of eight human isolates cultured axenically in Jones' medium. After seven, 14, 21, 28 and 60 days of infection, the animals were sacrificed and fragments of the small intestine (duodenum), large intestine, and cecum were subjected to histopathological analysis. Blastocystis sp. triggered an inflammatory response in the different tissues analyzed, with a predominance of mononuclear cells. The parasite was found in the muscular layer of the cecum, showing its invasive character. Larger inocula triggered inflammatory processes earlier (seven days) than smaller ones (from 21 days). We conclude that, in the proposed model, the pathogenicity of Blastocystis sp. isolates that were studied is related to inoculum size and period of infection.

Pouco é sabido sobre o potencial patogênico de Blastocystis sp. em modelos experimentais. Neste trabalho a patogenicidade desse parasito para o trato gastrointestinal de camundongos Swiss machos foi avaliada de acordo com o inóculo e tempo de infecção. Os animais foram infectados, via intragástrica, com 100, 500, 1.000, 5.000 e 10.000 formas vacuolares de Blastocystis sp. obtidos a partir de uma mistura de oito isolados humanos cultivados axenicamente em meio Jones. Após 7, 14, 21, 28 e 60 dias de infecção os animais foram sacrificados e fragmentos do intestino delgado (duodeno), grosso e ceco foram retirados para análise histopatológica. Blastocystis sp. desencadeou resposta inflamatória nos diferentes tecidos analisados, com predominância de infiltrado mononuclear. No ceco o parasito foi encontrado na túnica muscular mostrando seu caráter invasivo. Inóculos maiores desencadearam processos inflamatórios mais precocemente (7 dias) e inóculos menores mais tardiamente (a partir de 21 dias). Conclui-se que no modelo proposto a patogenicidade dos isolados de Blastocystis sp. estudados tem relação com o inóculo e tempo de infecção.

Cochlosoma Infection in a Turkey in Iran

Cochlosoma sp. infection was identified in a single case among 60 stunted diarrheic native turkey poults, Meleagris galopavo. A large number of the flagellated parasites was found free or within the intervillous spaces of the jejunum, ileum and cecum. Moderate enteritis was associated with the parasites. In TEM studies of the parasagittal sections of the parasite, a prominent ventral sucker like disc and flagella emerging from an opening on the ventrodorsal surface of the pyriform uninuclear parasite were found. The morphological characteristics of this protozoan match with those described for Cochlosoma anatis. The parasite could be considered as an intestinal pathogenic protozoan causing stunting and diarrhea in turkeys in Iran.

Anchitrema sanguineum (Digenea: Anchitrematidae) Accidentally Found during Colonoscopy of a Patient with Chronic Abdominal Pain: A Case Report

In November 2007, a 46-year-old male Thai patient presented with chronic abdominal pain for over 3 years. Colonoscopy revealed a small parasite of about 2 x 1 mm in size attached to the cecum mucosa. The worm was removed endoscopically, fixed, and stained for morphological observations. The specimen was identified as Anchitrema sanguineum (Digenea: Anchitrematidae), a trematode first reported in a reptile, Chamaeleo vulgaris, from Egypt, and then sporadically found in the intestines of insectivorous bats and other mammals. The patient was treated with praziquantel but no more worms were found in his stool. His symptoms improved slightly but not cured completely. It remains unclear whether the chronic abdominal pain of the patient was caused by this trematode infection. Whatever is the pathogenicity of this trematode, this is the first human case of A. sanguineum infection in the literature.

Hydatidiarrhea.

Hydatid cysts rarely rupture into the bowel lumen. We describe five patients presenting with passage of hydatid membranes in stool. Early surgical intervention may prevent erosion of such cysts into the hollow viscus.

Phenotypical characterization of intestinal Schistosoma japonicum granulomas in pigs.

The pig has been proposed as a model for human schistosomiasis japonica and the use of this animal model is increasing. The inflammatory response to schistosome infection in the liver and intestine of the pig shows morphological differences, and only the hepatic granulomas have been phenotypically characterized. The aim of the present study was to phenotypically characterize the cellular inflammatory response in the cecum by immunohistochemistry with particular reference to perioval granulomatous reactions in Schistosoma japonicum infected pigs. Six pigs were exposed to 2000 cercariae and examined 9 weeks post-infection. Three uninfected pigs of the same age served as controls. Exposed pigs developed patent infections with the total number of worms between 6 and 110. Cecal granulomas were dominated by CD3 positive T-lymphocytes and IgG positive plasma cells. Despite the difference in the inflammatory response between the liver and the cecum, the results from this study indicate that the phenotypic cellular composition of cecal granulomas appears similar to what has previously been described in the liver.

Caecal amoeboma simulating malignant neoplasia, ileocaecal tuberculosis and Crohn's disease

We report two cases of amoeboma of caecum. The patients were initially diagnosed with acute appendicitis but a large cecal mass was found on surgery, giving the gross impression of tumor, Ileocaecal tuberculosis or Crohn's disease necessitating right hemicolectomy. On histopathological examination, the mass was found to be 'Amoeboma'. Mode of presentation, clinical examination and operative findings are presented along with the review of literature. A 39 years old woman presented to the surgical outpatient department with complaints of right lower abdominal pain and fever for 2 days. Pain was localized to right iliac fossa. It was continuous and severe in intensity with no aggravating or relieving factors. The patient had intermittent fever upto 101 F. On clinical examination, the right iliac fossa was markedly tender. Total leukocyte count was 12.6 x 109 /L. A clinical diagnosis of acute appendicitis was made. Peroperatively, a focal inflammed caecal mass was found, grossly appearing like Crohn's disease. Rest of the abdomen was normal. Limited right hemicolectomy was done. Distal 6 inches of ileum along with proximal ascending colon was resected and an end to end anastomosis made. The postoperative recovery remained uneventful. Histopathological examination of the resected specimen turned out to be caecal amoeboma

Estrutura das infracomunidades de nematoides estrongilídeos (nematoda: strongylidae) do ceco de equus caballus naturalmente infectados, provenientes da regiao metropolitana do Rio de Janeiro, Brasil / Estructure of infracommunities of strongylid nematodes (nematoda: strongylidae) of cecum of equus caballus naturally infected, from metropolitana region of Rio de Janeiro State, Brazil

Analisou-se a estructura das infracomunidades de nematóides stronglidae en equinos, proveniente da Regiao Metropolitana do Rio de Janeiro, observando-se padroes na diversidade parasitária e relacoes interespecíficas. Além disto, a prevalencia a e abundancia dos nematóides strongylidae foram calculados. Trinta e tres equinos foram necropsiados. Coletou-se 8640 helmintos do conteúdo cecal, desde total 6078 espécimes pertencentes a família strongylidae. Coronocyclus coronatus (90,9 por cento; 60), cylicostephanus calicatus (87,9 por cento; 48,9) e strongylus culgaris (84,8 por cento; 24) foram as espécies mais prevalentes e abundantes, respectivamente. Cylicocyclus brevicapsulatus apresentou um dos maiores índices de dispersao e agregacao. Tres infrapopulacoes (2, 3 e 15) apresentaram a mesma riqueza parasitária (3), contudo, os valores obtidos para os índices de Shannon e Pielou foram diferentes, devido a distinta equitabilidade das amostras. De 182 pares de espécies associados, somente oito foram significativos para associacao e correlacao

On atractis species: a nematode from the caecum of dabb-lizard, uromystax aegypticus [anderson 1896] in Saudi Arabia

Six dabb-lizard, Uromystax aegyptius were caught from Riyadh and Jeddah areas and examined for natural helminth parasitic infection. They were all parasites free except for innumerable small nematodes which were identified Atractis species. The parasites were collected from the cecum and lower gut. The whole results were discussed