Evaluation of the intestinal microbial diversity in miniature pig after orally infected with Entamoeba histolytica.

The objective of this study was to analyze the difference in intestinal microbial diversity between healthy and (Entamoeba histolytica) orally infected minipig. Enterobacterial repetitive intergenic consensus (ERIC)-PCR was applied to analyze this diversity and dynamic change, including the duodenum, jejunum, ileum, cecum, and rectum from healthy and orally infected minipig at different time points. The results showed that the intestinal microbial community of the control minipigs was stable and the ERIC-PCR band numbers of the control minipigs were the lowest in the rectum and highest in the cecum. ERIC-PCR bands of orally inoculated minipigs showed no obvious change until 24 h after postinoculation (hpi). The numbers of the ERIC-PCR bands gradually decreased from 24 to 72 hpi, then, with the development of disease, the band numbers gradually increased until 6 days postinoculation. The prominent bacteria had changed in the presence of E. histolytica infection and the DNAstar of staple of ERIC-PCR showed that obligate aerobes and facultative aerobes (Escherichia coli, Shigella, Salmonella) became the preponderant bacilli in the intestine of orally infected minipigs with E. histolytica. This study has provided significant data to clarify the intestinal microbial diversity and dynamic change of healthy and E. histolytica orally infected minipigs.

Broad early immune response of porcine epithelial jejunal IPI-2I cells to Entamoeba histolytica.

Amoebiasis caused by Entamoebahistolytica triggers an acute inflammatory response at early stages of intestinal infection. The patho-physiological study of intestinal amoebiasis requires the development of powerful animal models. Swine provide robust model for human diseases and they could be used to study intestinal amoebiasis. Here, we introduce an in vitro model of swine intestinal epithelial cell (IPI-2I) co-cultured with E. histolytica. Intestinal epithelial cells (IECs) have crucial roles in sensing pathogens and initiating innate immune response, which qualitatively influence adaptive immune response against them. The contact between the two cells induces marked macroscopic lesions of IEC monolayer and striking alteration of the IPI-2I cell phenotype including blebbing, such as loss of attachment before to be phagocyte by the trophozoite. Increase in Lactate Dehydrogenase (LDH) levels in the culture supernatant of IECs was observed when ameba is present and could reflect the cellular cytotoxicity exerted by the parasite. Using quantitative real-time PCR, we identified the up-regulation of cytokines/chemokines implicated in neutrophil chemoattraction and inflammation, such as CCL2, CCL20, CXCL2, CXCL3, GM-CSF, IL1 alpha, IL6 and IL8, in response to the parasite that can further regulate the immunoregulatory functions of the immune cells of the host. The study points a cardinal role of these pro-inflammatory compounds as central mediators in the interaction IECs/ameba and suggests mechanisms by which they coordinate intestinal immune response. This will focus future efforts on delineating the molecular and cellular mechanisms of other cell partners by the way of in vivo infection of swine.

A case report: Entamoeba histolytica infections in the rhesus macaque, China.

A case of amebic dysentery due to a natural infection of Entamoeba histolytica in the rhesus macaque (Macaca mullata) was reported. A fecal specimen was isolated and identified by the polymerase chain reaction technique. A daily dose of 750 mg of metronidazole was given orally for 10 days, and good results were observed. The early diagnosis of an E. histolytica infection allowed a proper antiamoebic treatment in an early stage of infection resulting in a successful outcome after therapy.

Entamoeba histolytica and Entamoeba dispar infections in cynomolgus monkeys imported into Japan for research.

Three hundred and three stool samples of cynomolgus monkeys (Macaca fascicularis) imported from China and the Philippines were examined for Entamoeba histolytica/Entamoeba dispar infections. Microscopy detected E. histolytica/E. dispar cysts in 41 samples. Positive rates were higher in the monkeys from China (37.5%) than in the monkeys from the Philippines (3.7%). PCR analysis of 25 samples successfully cultured from the cysts demonstrated that 24 were E. dispar, one of the samples from China was E. histolytica. The one sample was also identified as E. histolytica by an antigen detection kit, although the monkey was asymptomatic and serology was negative. To our knowledge, this is the first report of E. histolytica isolation from cynomolgus monkeys based on the discrimination between E. histolytica and E. dispar.

Gastric amebiasis due to Entamoeba histolytica in a Dama wallaby (Macropus eugenii).

A 1.5-year-old captive female Dama wallaby (Macropus eugenii) died after a 3-month period of progressive weight loss, anorexia, bloat, and diarrhea. Histopathologic examination revealed numerous Entamoeba histolytica trophozoites within the gastric mucosa and, less frequently, gastric submucosa and submucosal vessels. Immunofluorescent antibody testing confirmed the identity of the trophozoites as E. histolytica. The trophozoites were associated with mild glandular epithelial necrosis, mucosal erosions, and lymphoplasmacytic inflammation. E. histolytica most commonly causes necrotizing and ulcerative colitis in humans and captive nonhuman primates, and it causes necrotizing and ulcerative gastritis in nonhuman primates with sacculated stomachs adapted for leaf fermentation. Rare cases of gastric amebiasis also have been been reported in captive macropods, which also have complex sacculated stomachs. To our knowledge, this is the first report confirming E. histolytica as the cause of gastric amebiasis in a wallaby. The zoonotic potential of this infection in macropods is uncertain.

Amebiasis in four ball pythons, Python reginus.

Between September 13th and November 18th in 1999, four ball pythons, Python reginus kept in the same display, showed anorexia and died one after another. At necropsy, all four snakes had severe hemorrhagic colitis. Microscopically, all snakes had severe necrotizing hemorrhagic colitis, in association with ameba-like protozoa. Some of the protozoa had macrophage-like morphology and others formed protozoal cysts with thickened walls. These protozoa were distributed throughout the wall in the large intestine. Based on the pathological findings, these snakes were infested with a member of Entamoeba sp., presumably with infection by Entamoeba invadens, the most prevalent type of reptilian amoebae.

Intestinal protozoa infections.

This article reviews important intestinal protozoal infections in cats. Among intestinal protozoa, Giardia and coccidia are the most important infections. Giardiasis is a common problem in catteries, especially where young kittens run free on the floor. Overcrowding and high humidity favour the survival and transmission of Giardia. Diagnosis is made by fecal examination by direct or concentration methods. Metronidazole is the drug of choice for treating giardiasis. Among the coccidial parasites, Isospora felis and Cryptosporidium sp. are the common infections. Virtually all cats become infected with Isospora felis. The pathogenicity of I. felis is controversial. Cryptosporidium parvum infection is a zoonosis. Cryptosporidium is transmitted by direct fecal-oral cycle. Cryptosporidial infections appear to be clinical in immunosuppressed cats. No drug has been found satisfactory for treatment of cryptosporidiosis.

Invasive amebiasis in a spider monkey (Ateles geoffroyi). Case report and a short review of the literature of amebiasis in non-human primates.

A spider monkey (Ateles geoffroyi) studied at the San Juan de Aragon Zoo died with symptoms of amoebic dysentery verified by coprologic investigation of the parasite, his female partner was cured with conventional antiamoebic treatment. At autopsy widespread ulcerations in the colon and multiple liver abscesses were found, containing trophozoites of Entamoeba histolytica. Both lesions were identical to those observed in human amoebiasis. A short review of the literature in nonhuman primates infections points out that the so-called spontaneous amoebiasis seen in colonies of captive monkeys, and transmission to their newborns within the same species of monkeys, have been in contact with humans. It is proposed that amoebiasis in monkeys should be considered as an excellent model for experimental studies on amoebiasis because other phylogenetically distant species have shown different pathology or are resistant to the infection. Also, it should raise concern that monkeys may become carriers of cysts and trophozoites of virulent strains of E. histolytica. Entamoeba histolytica DNA hybridization techniques should be considered for comparing genomic similarities with other protozoa, including the genera Amoeba to establish its pattern of evolution.

Amebiasis in red-footed tortoises.

Of 500 red-footed tortoises imported to southern Florida, approximately 200 died during a 2-month period. Clinical signs were nonspecific and included anorexia, listlessness, and watery diarrhea, with lingering death. Necropsy consistently revealed thickened duodenum, with necrotic mucosa and multifocal to diffuse areas of hepatic necrosis. Histologic evaluation of tissues demonstrated numerous amebae in intestinal and hepatic lesions.