Doniger said this week about 25 percent of calls to the Health Department were from people who got the illness from someone they came in close contact with, often a preschooler. About 90 percent of the 358 people in Monroe County who have reported getting sick were young children, Doniger said.
"We don't want this to continue to propagate in this community," he said.
The parasite can be passed only by extremely close contact with another individual, such as changing a diaper or caring for a sick child. The parasite does not live well outside water, so getting it by touching surfaces shared with strangers is not likely.
The number of people who have reported getting sick from contaminated water at the Spraypark in Seneca Lake State Park near Geneva, Ontario County, in July and August has climbed past 3,000, and stretched through30 New York counties. The Health Department is still taking reports of illness connected with the park, but some of those who were sick have since recovered.