changes like flattened vi. Di tips,sha Uowc,ypts, in Oammation of mucosa and hyperplacia oflymphoid follicles. The trophozoit,es may then be found in the jejunum. As the feces enters the colon and dehydrates, the parasite then encysts. Newly formed cysts have two nuclei while mature ones have four. After encystation, mature cysts are passed out in the feces ancl are ll1cn infective (Beli. ?. ario and Solon 1998, pp. 38-4J). Lllboratory diagnosis is made by demon~tration of tropbowitcs and/or cysts in stool specimen or duodenal aspiration or biopsy. Doud en al aspirates can be collec1cd Uwough the so-called Entero-tcst or tl1c String Test method. Prompt intervention reduces cyst pass;1ge und possible transmission particularly when food handlers, children in day­ care centers, institulionalized patients and hom!Jsexuals are involved. The prevalence of giardiasis is associated with poor environmental sanitation. Poor hygiene, overcrowding, immunodeficiency, bacterial and fungal overgrowth in the small intestines are impc)rtant risk factors. Sanitary disposal of human excreta, proper management of reservoir :mimals, regular cxamina 1ioa of food handlers and i;anitary practices on food prepanllion and stor. ige ;ire cnici. il in the prevention and control of disease transmission. lloiling of drinking water may be required when potability is questionable. 374 Cryptosporidium hominis '11iis is an intestinal protozoan falling under Class Coccidia. There arc about eight recognized species, of which only C. hominis is the only one knovm to cause infection in humans. A wide range of an. imals ]rnve been found to harbor the parasite as well. II has been commonly isob1tecl from both tbe small and 1. irge intestines. Howeve1·, it has also hccn identified from other organs like the esophagus, stomach and appendix. Among the immuno-compromiscd 11. nd immuno-deficient patients, like AIDS victims, infection of the bile duct, gallbladdet ·, liver, pancrens, and lungs have been reported. This was initially thought to be an opportunistic parasite among AIDS patients but eventually it was found even among immuno-competcnt individuals. Among the immuno-compctcnt individuals, diarrheal episodes are sci( limiting but among the immuno-eompromi scd and immuno-suppressed. individ1111. ls, diarrhea crui be prolongcd and m::iy therefore rcsuhs in more serious conditions_ Like any of the toccidian, the parasite undergoes the process of schi:zogony that results in 1110 production of merozoites and sporogony whielt in turn develops oocysts. Both processes of multiplication occur in the extra-cytopla sm of the intestinal cells. When oocysts arc passed out with the feces, they arc already sporulated and are therefore readily infective. Data show that ingestion of even a few ooeysts can already estal>lish infection in man_ Patients with crytosporidiosis often develop acute gastroenteritis possibly due to the ability of the orgnni!;1n as an enterotoxin. With prolonged symptoms, patients mny eventually suffer from malabsorpti,on resulting from villous atro J>hy and cellular infiltration of the lamina propria. From the inteslines, the infection may go up to the bile duct and the pancreatic duct, which would lead to cholangitis and panereatitis. In some occasions, lung infections may be involved, causi. ng the patients to suffer from respiratory symptoms like cough and shortness ofbrcatl1. 