Baltimore-Area Drinking Water Tests Negative For Parasite: Officials

BALTIMORE, MD — Public works officials said new samples from the Druid Lake Reservoir, one of two open-air reservoirs that provide drinking water to the Baltimore area, tested negative for the parasite Cryptosporidium.

The announcement from the Baltimore Department of Public Works came five days after officials said low levels of Cryptosporidium were detected in the reservoir, prompting a warning to residents with compromised immune systems to boil or filter drinking water before consuming it.

The warning affected the water supply for Baltimore City as well as Baltimore and Howard counties, officials said.

On Tuesday, officials said test results delivered to the Department of Public Works showed no traces of the parasite.

According to health officials, Cryptosporidium is a micro-organism commonly found in lakes and rivers and can cause gastrointestinal problems, especially in children, older adults and immunocompromised people.

While Cryptosporidium poses a low risk for the general population, the Maryland Department of Health encouraged those with severely weakened immune systems to continue to take the following precautions:

• Drink bottled water.
• Boil water for one minute before consuming.
• Filter tap water using a filter labeled to ANSI/NSF 53 or 58 standards, or a filter designed to remove objects 1 micron or larger (i.e. not Brita-type filters.)

The most common symptoms of cryptosporidiosis include diarrhea, vomiting, fever and stomach pain. People with healthy immune systems typically aren't affected and quickly recover without medical treatment.

Examples of people with weakened immune systems include those with HIV/AIDS, those with diseases that affect the immune system, cancer and transplant patients who are taking immunosuppressive drugs.