| Cryptosporidium is an enteric protozoan parasite that infects a wide range of vertebrate hosts including mammals, birds, fish, and reptiles and an important waterborne pathogen in humans. A common mode of transmission is through the consumption of fecal contaminated water. For this reason it is important for water treatment facilities to monitor their source water. This study developed a small-scale (2 L) hollow fiber ultrafiltration method to determine the feasibility of using a reusable ultrafilter to monitor Cryptosporidium. Following the optimization of the small-scale system, a large-scale (10 L) procedure was developed and optimized for the hollow fiber ultrafiltration of oocysts from surface water. To further improve oocyst recoveries from immunomagnetic separation modifications were studied and incorporated. The last part of this study was to investigate potential significance that migrating wild ducks have on the oocyst densities found in the Rio Grande. The results of this study indicate that the overall recovery efficiency of the small-scale hollow fiber ultrafilter ranged from 60 to 81%, with the filter performance increasing as the turbidity of the sample increases. The transition from the small-scale to the large-scale did not require any further modification. Results of the large-scale hollow fiber system indicates that the mean oocyst recovery efficiency was slightly higher than that of the current standard method. Examination of the factors affecting the efficiency of the IMS process included the influence of magnetic material in the concentrate and the effect of pH. Results indicate that magnetic material may not be a major source of variation in the IMS. Results of pH experiments indicate that when the pH was not near its optimum of 7.0 during oocyst capture, oocyst recovery was lower on average by 30%. Ultrafiltration combined with adjustment of the pH during the IMS improved oocyst recovery by improving the efficiency and reproducibility of the recovery of oocysts from a wide variety of water characteristics. Migratory ducks appear to contribute little to the oocyst loads seen in the Rio Grande during their southern migration because of the relatively low numbers of organisms (<30/g of feces). However, relatively large numbers of individual ducks were found to harbor (oo)cysts (59%). |
