Fulminant cryptosporidiosis after near-drowning: a human Cryptosporidium parvum strain implicated in invasive gastrointestinal adenocarcinoma and cholangiocarcinoma in an experimental model.

In the present work, we report the characterization of a Cryptosporidium parvum strain isolated from a patient who nearly drowned in the Deule River (Lille, France) after being discharged from the hospital where he had undergone allogeneic stem cell transplantation. After being rescued and readmitted to the hospital, he developed fulminant cryptosporidiosis. The strain isolated from the patient's stools was identified as C. parvum II2A15G2R1 (subtype linked to zoonotic exposure) and inoculated into SCID mice. In this host, this virulent C. parvum isolate induced not only severe infection but also invasive gastrointestinal and biliary adenocarcinoma. The observation of adenocarcinomas that progressed through all layers of the digestive tract to the subserosa and spread via blood vessels confirmed the invasive nature of the neoplastic process. These results indicate for the first time that a human-derived C. parvum isolate is able to induce digestive cancer. This study is of special interest considering the exposure of a large number of humans and animals to this waterborne protozoan, which is highly tumorigenic when inoculated in a rodent model.

Cytologic diagnosis of blastocystis hominis in peritoneal fluid: a case report.

BACKGROUND: Blastocystis hominis is the most common parasite identified in s worldwide. Although it is commonly identified in stool preparations, unusual to encounter B hominis in abdominal fluid. CASE: A 46-year-old woman presented with the clinical impression of acute peritonitis. The initial radiologic evaluation showed free air in the abdominal cavity and an abdominal mass. Abdominal fluid submitted for cytologic examination was diagnostic of acute inflammation with mixed bacteria and abundant cystlike forms of B hominis. The patient underwent an exploratory laparotomy that revealed a poorly differentiated adenocarcinoma involving her bowel and peritoneum. CONCLUSION: The present case highlights the unusual identification ofextraintestinal forms of B hominis in a peritoneal fluid sample from a patient with invasive, poorly differentiated adenocarcinoma and associated bowel perforation.

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.

Pseudocapillaria tomentosa, a nematode pathogen, and associated neoplasms of zebrafish (Danio rerio) kept in research colonies.

Infections with capillarid nematodes were observed in zebrafish (Danio rerio) kept at several research facilities and in a large carcinogen exposure study previously conducted at Oregon State University. We report a morphologic description that identifies the worm as Pseudocapillaria tomentosa, a common nematode of cyprinid and other fishes. Pathologic lesions associated with the infection ranged from inflammatory changes to aggressive neoplasms of the intestine (i.e., intestinal carcinomas and mixed malignant neoplasms). Capillarid nematodes may have intermediate or paratenic hosts. Using a laboratory transmission study, we confirmed that the parasite has a direct life cycle.

Cryptosporidium parvum-induced ileo-caecal adenocarcinoma and Wnt signaling in a mouse model.

Cryptosporidium species are apicomplexan protozoans that are found worldwide. These parasites constitute a large risk to human and animal health. They cause self-limited diarrhea in immunocompetent hosts and a life-threatening disease in immunocompromised hosts. Interestingly, Cryptosporidium parvum has been related to digestive carcinogenesis in humans. Consistent with a potential tumorigenic role of this parasite, in an original reproducible animal model of chronic cryptosporidiosis based on dexamethasone-treated or untreated adult SCID mice, we formerly reported that C. parvum (strains of animal and human origin) is able to induce digestive adenocarcinoma even in infections induced with very low inoculum. The aim of this study was to further characterize this animal model and to explore metabolic pathways potentially involved in the development of C. parvum-induced ileo-caecal oncogenesis. We searched for alterations in genes or proteins commonly involved in cell cycle, differentiation or cell migration, such as ß-catenin, Apc, E-cadherin, Kras and p53. After infection of animals with C. parvum we demonstrated immunohistochemical abnormal localization of Wnt signaling pathway components and p53. Mutations in the selected loci of studied genes were not found after high-throughput sequencing. Furthermore, alterations in the ultrastructure of adherens junctions of the ileo-caecal neoplastic epithelia of C. parvum-infected mice were recorded using transmission electron microscopy. In conclusion, we found for the first time that the Wnt signaling pathway, and particularly the cytoskeleton network, seems to be pivotal for the development of the C. parvum-induced neoplastic process and cell migration of transformed cells. Furthermore, this model is a valuable tool in understanding the host-pathogen interactions associated with the intricate infection process of this parasite, which is able to modulate host cytoskeleton activities and several host-cell biological processes and remains a significant cause of infection worldwide.