GASTROINTESTINAL SYSTEM PROTOZOA -II- CryptosporidiiumIsosporaMicrosporidia Doç.Dr.Hrisi BAHAR

Cryptosporidium History History * 1895 Clarke first to view Cryptosporidium * 1895 Clarke first to view Cryptosporidium *1910 Tyzzer named and described Cryptosporidium muris in mice *Recognized as disease agent in 1976

Cryptosporidium Classification Classification “hidden spore” “hidden spore” Small (2-5µm) single-celled parasitic protist Small (2-5µm) single-celled parasitic protist Invade and grow intracellularly in mucosal epithelial cells of the stomach and intestine Invade and grow intracellularly in mucosal epithelial cells of the stomach and intestine

Cryptosporidium

Cryptosporidium ~ 23 species named ~ 23 species named Human infections: Human infections: C. Baileyi, C. canis, C. felis, C. hominis, C meleagridis, C. muris, and C. parvum Humans are the primary hosts for C. hominis Humans are the primary hosts for C. hominis

Cryptosporidiosis Host Host Occurs naturally in a variety of animals fishesbirdsreptilesmammalshumans Symptoms Most common-watery diarrhea Others include: Abdominal cramps Nausea Low-grade fever Dehydration Weight loss or no symptoms at all

Cryptosporidium Morphology Morphology

Cryptosporidium

Osmotic (primary) characterized by enterocyte malfunction ↓ Na+ absorption ↑ Cl- secretion Inflammatory generally associated with invasion of the mucosa inflammation of the lamina propria leukocytes in the stools Secretory generally associated with bacterial enterotoxins characterized by watery diarrhea Increased intercellular permeability and inflammation in the submucosal layer

Cryptosporidium Transmission Transmission Cryptosporidium lives in the intestines of infected individuals and is released with bowel movements Cryptosporidium lives in the intestines of infected individuals and is released with bowel movements Minimum infective dose – 10 to 100 oocysts depending upon species Minimum infective dose – 10 to 100 oocysts depending upon species Thick cell walls of oocysts enable them to persist in the natural environment for long periods of time Thick cell walls of oocysts enable them to persist in the natural environment for long periods of time C. parvum oocyst is able to survive for several days in mild chlorine C. parvum oocyst is able to survive for several days in mild chlorine

Cryptosporidium Diagnosis Diagnosis Unable to diagnose Crypto from symptoms alone Unable to diagnose Crypto from symptoms alone Stool samples must be submitted for laboratory analysis Stool samples must be submitted for laboratory analysis Common laboratory diagnostic methods of cryptosporidiosis include microscopy, enzyme immunoassays and molecular biology methods Common laboratory diagnostic methods of cryptosporidiosis include microscopy, enzyme immunoassays and molecular biology methods

Cryptosporidium Image courtesy of CDC. Oocysts can be detected with fluorescent antibodies Image courtesy of CDC. Diagnostics can involve PCR detection of C. parvum in stool specimen

Cryptosporidium Treatment Treatment No reliable treatment No reliable treatment Nitazoxanide and paromomycin occasionally used, temporary effects only Nitazoxanide and paromomycin occasionally used, temporary effects only

Isospora Isospora belli Isospora belli Isospora belli, is a protozoal parasite in the class of sporozoa, a group that includes toxoplasma and crytosporidium. Isospora belli, is a protozoal parasite in the class of sporozoa, a group that includes toxoplasma and crytosporidium.

Isospora belli I. belli in humans, has been described as causing chronic diarrhea and acalculous cholecystitis in patients with the acquired immunodeficiency syndrome (AIDS) I. belli in humans, has been described as causing chronic diarrhea and acalculous cholecystitis in patients with the acquired immunodeficiency syndrome (AIDS)

Isospora Isospora belli clinical manifestation Isospora belli clinical manifestation Isosporiasis should be suspected in HIV-infected patients from tropical countries and the organism Isosporiasis should be suspected in HIV-infected patients from tropical countries and the organism ( Isospora belli) has been commonly identified in the small bowel of patients with mucous diarrhoea, weight loss, fever, peripheral eosinophilia, malabsorption and low CD4+ cell counts. ( Isospora belli) has been commonly identified in the small bowel of patients with mucous diarrhoea, weight loss, fever, peripheral eosinophilia, malabsorption and low CD4+ cell counts.

Isospora belli Site of the infection Epithelial cells of small intestine. Disseminated extra- intestinal isosporiosis may sometimes occur in AIDS patient. Epithelial cells of small intestine. Disseminated extra- intestinal isosporiosis may sometimes occur in AIDS patient. Diagnosis: When oocysts cannot be identified in stool or intestinal aspirate, an upper endoscopic small biopsy can be diagnostic.

Life cycle of Isospora

Microsporidium The microsporidia constitute a phylum of spore-forming unicellular parasites The microsporidia constitute a phylum of spore-forming unicellular parasites Approximately 10 percent of the species are parasites of vertebrates, including in humans Approximately 10 percent of the species are parasites of vertebrates, including in humans After infection they influence their hosts in various ways and all organs and tissues are invaded. Some species are lethal, and a few are used in biological control of insect pests. After infection they influence their hosts in various ways and all organs and tissues are invaded. Some species are lethal, and a few are used in biological control of insect pests.

Microsporidium species Enterocytozoon bieneusi Enterocytozoon bieneusi Encephalitozoon intestinalis Encephalitozoon intestinalis Encephalitozoon hellem Encephalitozoon hellem Encephalitozoon cuniculi Encephalitozoon cuniculi Nosema connori Nosema connori Nosema corneum Nosema corneum Pleistophora species Pleistophora species

Microsporidium Humans acquire microsporidiosis through ingestion or inhalation of microsporidia spores. Studies have isolated Humans acquire microsporidiosis through ingestion or inhalation of microsporidia spores. Studies have isolated The spore is the infective form. Spores are environmentally resistant and are surrounded by an outer electron-dense glycoprotein layer and an electron- lucent endospore layer composed primarily of chitin. The spore extrudes its polar tubule and injects the infective sporoplasm into the host cell. The spore is the infective form. Spores are environmentally resistant and are surrounded by an outer electron-dense glycoprotein layer and an electron- lucent endospore layer composed primarily of chitin. The spore extrudes its polar tubule and injects the infective sporoplasm into the host cell.

Microsporidian spore

Microsporidium Clinical manifestation Intestinal or biliary microsporidiosis Intestinal or biliary microsporidiosis Disseminated microsporidiosis Disseminated microsporidiosis Ocular microsporidiosis Ocular microsporidiosis Musculoskeletal microsporidiosis Musculoskeletal microsporidiosis Dermatologic microsporidiosis Dermatologic microsporidiosis

Microsporidium Microsporidiosis is believed to be a zoonosis. Evidence suggests that microsporidia may be water-borne pathogens and may be transmitted from human to human. Microsporidiosis is believed to be a zoonosis. Evidence suggests that microsporidia may be water-borne pathogens and may be transmitted from human to human. Most cases of microsporidiosis in patients with HIV infection occur in those with severe immunodeficiency Most cases of microsporidiosis in patients with HIV infection occur in those with severe immunodeficiency

Microsporidium Life cycle