WASTE-WATER AND GIARDIA CYSTS

Giardia intestinalis is a protozoon which has generated numerous waterborne outbreaks of giardiasis in the United States. In this study Giardia cysts were searched in raw wastewater after concentration by Bailenger method and quantification with Thoma cell counting. Different parameters were studied : sampling time, sampling day, sampling month. The study of hourly variations shows concentration of Giardia cysts ranged from 9.5 x 10(3) to 1.4 x 10(4)/1 with a significant difference between the samples taken at 10 a.m. and those taken in the afternoon. No significant daily variation has been shown in the mean value of the 6 samples taken every day. The results of monthly variations indicate that it is in February (5.9 x 10(3)/1) and mainly in March (1.2 x 10(4)/1) that the concentrations of the Giardia cysts are the highest. The lowest values are noticed in November (1.3 x 10(3)/1).