1.   Fear and anger among city residents has continued since the dangerous parasites were found.

2.   Some scientists have argued that the bugs are harmless algae mistaken for the dangerous parasites, but the water company has denied that.

3.   The warning followed the discovery of high levels of the dangerous microscopic parasites giardia and cyptosporidium in the water system.

4.   They were told they would be otherwise risking serious illness from dangerous parasites.