Diagnosis is confirmed through the recovery of cysts from Cormedstoolsand trophozoites from diarrbeic or watery stools. The consistency of stools dictates how soon the stools are to be examined in the laboratory. If-what we expect to. recover from the stools are t. rophozoil es, the stools must be examined immediately because trnphozoi tes are fragile and they die within 30 to 60 minutes outside the host. Cysts and tropho:w ites can be detected th rougb the direct fecalsmea. r preparation. Nuclei of the cysts are best stained with iodine solution while nuclei of the lropbozo ites with metl1ylene blue solution. Coucent. ratioo techniques like formalin el. }1er concentration (FECT), merthiolate iodine formaldehyde concentration (MIFC) and Zn S04 are very useful in the recovery of the cysts. Skill in the identification of pathogenic amebae from non pathogenic ones can be acquired through proper training. Jt";n he worth while to realiietliatusing microscopic examination the cysts of Entameba histolytica have morphological chnracter istics very similar to tvvo other amebae namely: Entam,eba dispar and 611tameba hartmanni, the latter however happened to be a lot smaller than E. histolytica and E. dispar. Transmission of amoebiasis is related to contaminated water supply, use of night soil as fertilizer and infected food handlers. Moreover, si:uclies have shown that flies and cockroaches carry amoebic cysts as well. Boili~g of drinking water from questiona ble source is a very good practice to avoid infection. Specific drugs must be given to the patients. Health education emphasiz ing environmenta l sanitation must be done. Drinking water and food must be safe for human consumption. There must be regular examination of food handlers, which is now mandated by the provisions in the new Code of Sanitation approved by the Departmen t of Health. Idenlification of cyst passers ~\;II reduce tr:ansmission. In a recent study among food handlers in school canteens in the City of Manila, a high percentage was found to be positive to non-pathogenic amobae by stool examination. Even if the identified cysts were non-pathog enic, their presence indicates a possible danger of transmissio n to the food consumers once personal hygiene is not strictly praclic. ed. Another indication is that, ch;nking water has been contaminated with humnn excreta. Giardia lamblia This is a flagellated protozoan which lives in the duodenum, jejunum and upper ileum of humans. It is also known as Giardia duodenalis, G. duoduenalis, Lamblia <luodenalis or L intestinalis. The clisease caused by this protozoan is called giardiasis or 1ambliasis which has an incubation period of one to fourwecks, averaging nine days. While it is asyrnptomnlic in approxima tely 50% of infected individuals, itis manifested in mild cases as moderate and protracted diarrihen followed by spontaneous recovery in six weeks. In acute cases symptoms usually. include cramping, abdominal bloating, nausea, anorexia, diarrheal stools, often with excessiv. e flatus with an odor similar to that of rotten eggs. Chronic infection is characterized by passage of greasy, frothy stools. Transmiss ion of the. Giardia liamblia parasite results from ingestion of mature cysts (infective stage) from feces oi humans or animals (e. g. dogs, rats, horses) via contami nated b:u1<ls, food or water. Ingested cysts pas.,; through the stomach and excyst in the duodenum in about thirty minutes. developing into trophozoites which rapidly multiply and attach to the intestinal villi (Illustration 15. u). They cause pathological 373 