Protozoan parasites intestinal

Rendtorff, R. C. (1954). The experimental transmission of human intestinal protozoan parasites, II. Giardia lamblia cysts given in capsules. Am. J. Hyg. 59, 209-220. 

FIGURE 2.9 Scanning electron microscopy reveals the protozoan parasite Giardia lamblia in the small intestine of an animal host. 

GSH S-transferases are widely distributed in animals, being found in both vertebrates (37) and non-vertebrates (38), including helminth and protozoan parasites. Brophy and Barrett (39) have reviewed the distribution of GSH S-transferases in helminths and have observed that digean trematodes and intestinal cestodes generally have higher levels of total GSH S-transferase activity than do nematodes. Of the helminths examined to data, schistosomes show the highest level of activity, some... 

This test identifies the substance to be examined as a salt of antimony(III), Sb +, or antimony(V), Sb +. Antimony(III) and antimony(V) were formerly used in the oral treatment of intestinal worms and topically in the treatment of infections of protozoan parasites in the skin. But since especially tetrava-lent antimony is poisonous, they have generally been replaced by less toxic alternatives. At present, there are no monographs of antimony compounds in the European Pharmacopoeia. Antimony forms both tetra- and pentavalent ions, but the pentavalent is mainly found in oxides containing the antimonate ion, Sb04. Antimony(III), on the other hand, can be found as the free dissociated ion, Sb +, but, as also for example bismuth, since it reacts with water at neutral pH, forming antimonate. 

Balantidiasis (balantidiosis, balantidial dysentery), an intestinal disease seen almost worldwide, is caused by the large ciUated protozoan, balantidium coll The organism is usually found in the lumen of the large intestine of humans and animals. Cysts formed in the lumen of the colon or in freshly evacuated feces of humans or domesticated and wild animals, can colonize the colon and terminal ileum of new hosts by the latter s ingestion of contaminated food or water. The hog has been found to be the most heavily parasitized host. Its association with the rat may be a means for maintaining a reservoir infection in the two animals. 

Giardia lamblia (also known as G. intestinalis or G. duode-nalis), an enteric protozoan, is the most common intestinal parasite responsible for diarrheal syndromes throughout the world. Giardia is the most frequently identified intestinal parasites in the United States, with a prevalence rate of 5% to 15% in some areas. G. lamblia has been identified as the first enteric pathogen seen in children in developing countries, with prevalence rates between 15% and 30%. 

The direct wet mount made from unconcentrated fresh feces is most useful for the detection of the motile trophozoites of intestinal protozoa and the motile larvae of Strongyloides spp. It is also useful for the detection of protozoan cysts and helminth eggs. For fixed feces, the direct wet mount may allow the detection of parasites which do not concentrate well. This method is also useful for the examination of specific portions of feces, such as flecks of blood or mucus. 

The protozoan Entamoeba histolytica causes amebiasis, an infection that is endemic in parts of the United States. The parasite can be present in the host as either an encysted or a trophozoite form. Initial ingestion of the cyst may result either in no symptoms or in severe amebic dysentery characterized by the frequent passage of bloodstained stools. The latter symptom occurs after invasion of the intestinal mucosa by the actively motile and phagocytic trophozoite form of the protozoan. 

IMPORTANCE TO INTESTINAL PARASITES Bile is of particular importance to intestinal parasites, for in many cases it is involved in the trigger mechanisms concerned in the hatching of helminth eggs, excystation of protozoan cysts, evagination of cestode scoleces and excystment of trematode metacercaria. In relation to cestodes, its role in... 

Giardia lamblia. Giardia lamblia is a flagellate parasitic protozoan. This parasite is largely confined to the lining of the intestine. It can colonize the lining and feed and grow there. It is shed in feces in the form of cysts. The cyst, however, cannot multiply outside the host. 

Giardia lamblia (also known as G. intestinalis or G. duodenalis), an enteric protozoan, is the most common intestinal parasite responsible for diarrheal syndromes throughout the world. Giardia is the... 

The compounds of this class are added to animal feed to combat coccidiosis diseases (such as enteritis or cachexie) caused by protozoans living as parasites in intestines. Poultry and rabbits are the animals most often affected. Residues may be found in eggs. 

C. parvum is an opportunistic protozoan infecting individuals with compromised immunity, resulting in severe diarrhea and wasting. The sporozoites of the parasite express a lectin with hemagglutinating activity, inhibitable by Gal and GalNAc, that may be involved in parasite attachment to intestinal epithelium [104-106]. 

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