OCCURRENCE OF GIARDIA AND CRYPTOSPORIDIUM IN THE KAU-PING RIVER AND ITS WATERSHED IN SOUTHERN TAIWAN BING-MU HSU 1 , CHIHPIN HUANG 1 * * M , CHIH-LI LILIAN HSU 2 , YEONG- FUA HSU 3 and J. H. YEH 4 1 Institute of Environmental Engineering, National Chiao Tung University, Hsinchu, Taiwan; 2 Department of Parasitology, Medical College National Cheng Kung University, Tainan, Taiwan; 3 National Institute of Environmental Analysis, Environmental Protection Administration, Taipei, Taiwan and 4 Bureau of Environmental Sanitation and Toxic Substances Control, Environmental Protection Administration, Taipei, Taiwan (First received July 1998; accepted in revised form October 1998) AbstractÐGiardia and Cryptosporidium are important waterborne parasites. Thirteen water samples and 32 fecal specimens were collected from the Kau-Ping River and its watershed to test for Giardia cysts and Cryptosporidium oocysts. The detection methods are immuno¯uorescence assay and enzyme- linked immunosorbent assay for water samples and fecal specimens, respectively. Seven out of eight samples collected from raw water samples showed the presence of cysts, while six out of eight raw water samples contained oocysts. Cryptosporidium was present in 40% of the treated water, while Giar- dia occurred in all of them. Four out of 32 fecal specimens, collected from the hog farming region, tested positive for Giardia, and seven specimens tested positive for Cryptosporidium. Giardia was related only to Cryptosporidium but not to the others. # 1999 Elsevier Science Ltd. All rights reserved Key wordsÐGiardia, Cryptosporidium, water supply, Kau-Ping River INTRODUCTION Parasites Giardia and Cryptosporidium are common pathogenic protozoa of the gastrointestinal tract (Cook, 1995). Members of the genus Giardia infect the proximal small intestine in humans and other mammals, causing giardiasis with symptoms include diarrhea, stomach cramps, nausea, and fatigue. Many outbreaks of giardiasis have been reported in the last few decades (Smith et al., 1995). Members of the genus Cryptosporidium also cause gastroen- teritis in humans and animals and are often respon- sible for waterborne outbreaks. For instance, a signi®cant outbreak in Milwaukee, WI, during 1993 was caused by Cryptosporidium, infecting 400,000 people (MacKenzie et al., 1994). The ®rst case of giardiasis in Taiwan was discovered in 1975 on an oshore island. Thirty two percent of the children residing on the island were diagnosed with Giardia in their stool specimens (Chung and Cross, 1975). Another survey showed that over 50% of the avian species in Taiwan were infected with Cryptosporidium spp. (Wang and Liew, 1990). However, information pertaining to Giardia and Cryptosporidium in the drinking water supply sys- tems in Taiwan is very limited. Majorities of Giardia cysts are oval in shape, ran- ging from 8 to 14 mm in diameter. Cryptosporidium oocysts, which range from 4 to 6 mm in diameter, are characteristically spherical. These thick-walled cysts and oocysts are extremely resistant to com- monly used disinfectants such as chlorine (Korich et al., 1990). They can remain viable for several months in water between 4 and 108C (Medema et al., 1997). The most commonly used laboratory protocols for identifying cysts and oocysts in stool specimens or environmental water samples are immuno¯uorescent microscopic examination and enzyme-linked immunosorbent assay (EIA) (Leng et al., 1996). The Kau-Ping River is the major raw water source for the great Kaohsiung area of 2.5 million people, approximately 12% of Taiwan's total popu- lation. Another water source in this region is groundwater. A survey on the Kau-Ping River shows that the watershed in the upper region is used for recreation. The middle and lower regions are heavily polluted, due to inputs of domestic sew- age, industrial and farm wastewaters. Although conventional prechlorination, coagulation, sedimen- tation, and ®ltration processes are employed by Wat. Res. Vol. 33, No. 11, pp. 2701±2707, 1999 # 1999 Elsevier Science Ltd. All rights reserved Printed in Great Britain 0043-1354/99/$ - see front matter PII: S0043-1354(98)00478-3 *Author to whom all correspondence should be addressed. [Tel: +886-35-726463; fax: +886-35-725958, e-mail: cphuang@green.ev.nctu.edu.tw]. 2701