[Dientamoeba fragilis infection as cause of severe abdominal discomfort and flatulence]. / Dientamoeba fragilis-infektion som årsag til meteorisme og flatulens.

The clinical significance of Dientamoeba fragilis infection is controversial. We describe a case-history of a 16-year-old patient, who had suffered severe abdominal discomfort and flatulence through his lifetime. He was eventually diagnosed with D. fragilis infection, and eradication of D. fragilis with high-dose metronidazole kept him without symptoms for one year. Recurrence of the symptoms and recurrence of the D. fragilis infection was thereafter treated successfully with paromomycin.

Infección experimental de aislados humanos de Blastocystis sp. en ratones inmunosuprimidos con dexamentasona / Experimental infection using human isolates of Blastocystis sp. in dexamethasone immunosurpressed mice

Blastocystis sp. es un protozoario controversial en cuanto a su papel patogénico, asociado a enfermedad gastrointestinal, con alta prevalencia. A fin de evaluar signos, síntomas y hallazgos de laboratorio producidos por Blastocystis sp., ratones inmunosuprimidos con dexametasona fueron infectados con morfologías del parásito obtenidos de pacientes sintomáticos y asintomáticos. Los parásitos se aislaron empleando gradiente de densidad con lymphoprep™, se realizó semicuantificación de las morfologías presentes en las muestra de heces, y se inocularon 1,6 × 105 parásitos en ratones Balb/c, vía intragástrica. En heces de pacientes sintomáticos se encontraron seis veces más vacuolares que granulares, mientras que en asintomáticos la relación fue apenas dos veces mayor. Los síntomas más frecuentes en los pacientes fueron: flatulencia (85%), dolor de cabeza(62%), dolor abdominal (55%), fiebre (30%) y estreñimiento (8%). La semicuantificación de parásitos por campo en humanos no encontró relación directa entre carga parasitaria y sintomatología gastrointestinal, mientras que en la cuantificación de parásitos por gramo de heces si existió. Los ratones presentaron signos variables luego de la infección, todos aquellos infectados con muestras de pacientes sintomáticos presentaron signos, mientras que solo algunos de los infectados con muestras de pacientes asintomáticos los desarrollaron. Se demostró que no existe relación estadísticamente significativa (p= 0,8) entre la morfología del parásito y los signos manifestados por el ratón; sin embargo hubo una relación estadísticamente significativa (p=0,02) entre las formas vacuolares del parásito y la aparición de síntomas en los pacientes. Se concluye que Blastocystis sp. tiene capacidad de producir signos sugestivos de patología en ratones.

Blastocystis sp. is a controversial protozoan in terms of its pathogenic role associated with high-prevalence gastrointestinal disease. To evaluate signs, symptoms and laboratory findings produced by Blastocystis sp., dexamethasone immunosuppressed mice were infected with parasite morphologies obtained from symptomatic and asymptomatic patients. The parasites were isolated using density gradient with lymphoprep™, semi-quantification of the morphologies present in the stool sample was performed and 1.6 × 105 parasites were inoculated into Balb/c mice, intragastrically. In the faeces of symptomatic patients, vacuolar morphology was six times greater than granular morphology, whereas the ratio in asymptomatic patients was only two times greater. The most common symptoms in patients were flatulence (85%), headache (62%), abdominal pain (55%), fever (30%) and constipation (8%). The semi-quantification of parasites per field in humans evidenced no direct relationship between parasite burden and gastrointestinal symptoms, while in parasite quantification per gram of feces, a direct relationship was found. The mice showed variable signs after infection; all those infected with samples from symptomatic patients showed signs, while only some of those infected with samples from asymptomatic patients developed them. It was demonstrated that no statistically significant (p = 0.8) relationship exists between the morphology of the parasite and the signs manifested by the mouse; nevertheless, there was a statistically significant (p = 0.02) relationship between the vacuolar forms of the parasite and onset of symptoms in patients. Conclusions are that Blastocystis sp. is capable of producing signs suggestive of pathology in mice.

Multilocus genotyping of human Giardia isolates suggests limited zoonotic transmission and association between assemblage B and flatulence in children.

BACKGROUND: Giardia intestinalis is one of the most common diarrhea-related parasites in humans, where infection ranges from asymptomatic to acute or chronic disease. G. intestinalis consists of eight genetically distinct genotypes or assemblages, designated A-H, and assemblages A and B can infect humans. Giardiasis has been classified as a possible zoonotic disease but the role of animals in human disease transmission still needs to be proven. We tried to link different assemblages and sub-assemblages of G. intestinalis isolates from Swedish human patients to clinical symptoms and zoonotic transmission. METHODOLOGY/PRINCIPAL FINDINGS: Multilocus sequence-based genotyping of 207 human Giardia isolates using three gene loci: ß-giardin, glutamate dehydrogenase (gdh), and triose phosphate isomerase (tpi) was combined with assemblage-specific tpi PCRs. This analysis identified 73 patients infected with assemblage A, 128 with assemblage B, and six with mixed assemblages A+B. Multilocus genotypes (MLGs) were easily determined for the assemblage A isolates, and most patients with this genotype had apparently been infected through anthroponotic transmission. However, we also found evidence of limited zoonotic transmission of Giardia in Sweden, since a few domestic human infections involved the same assemblage A MLGs previously reported in Swedish cats and ruminants. Assemblage B was detected more frequently than assemblage A and it was also more common in patients with suspected treatment failure. However, a large genetic variability made determination of assemblage B MLGs problematic. Correlation between symptoms and assemblages was found only for flatulence, which was significantly more common in children less than six years of age infected with assemblage B. CONCLUSIONS/SIGNIFICANCE: This study shows that certain assemblage A subtypes are potentially zoonotic and that flatulence is connected to assemblage B infections in young children. Determination of MLGs from assemblages A and B can be a valuable tool in outbreak situations and to help identify possible zoonotic transmission.

The histo-pathology of human giardiasis.

In giardiasis symptomatic group (I) the prevalence of diarrhoea was 5/7 (71.43%), 13/13 (100%) in Grade 0, I, II, III and IV pathology respectively which is statistically insignificant in comparison to each other (P > 0.05). The prevalence of abdominal pain is 71.43%, 73.33%, 95%, 91.67% and 100% in Grade 0, I, II, I & IV pathology respectively which is statistically insignificant to each other (P > 0.05). The prevalence of flatulence is 42.86%, 40%, 80%, 83.33% and 100% in Grade 0, I, II, III & IV pathology respectively, was statistically significant in comparison to each other (P < or = 0.05) So, the prevalence of flatulence is more frequent in patients with marked pathological changes in the duodenum. The prevalence of anorexia was 14.29%, 53.33%, 65%, 50% & 100% in Grade 0, I, II, III & IV pathology respectively, statistically significant in comparison to each other (P < or = 0.05). The prevalence of vomiting was 0%, 13.33%, 15%, 16.67 & 85.71% in Grade 0, I, II, III and IV pathology respectively, significant increased in Grade IV and absent in Grade 0 (P < or = 0.001).

Efficacy of albendazole in giardiasis.

Albendazole and metronidazole were compared in 68 patients diagnosed positive for giardiasis. Albendazole 1200 mg, one dose was given to 24 patients, albendazole 400 mg twice a day for 3 days was given to 23 patients, and metronidazole 400 mg 3 times a day for 5 days to 21 patients. Response to therapy was monitored by clinical examination and analysis of fresh faecal samples on days 0, 3, 7 and 10. Response to the single dose of albendazole was 55%, to the divided dose of albendazole 70%, and to metronidazole 84%. The results show that albendazole, originally recommended for helminthic infection, can also be used in patients with mixed protozoal infection or for infections resistant to metronidazole.

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.