Pittsburgh water crisis raises possibility of contracting parasite that can lead to intestinal problems
When it comes to the giardia parasite, a little can go a long way.
Giardia is a microscopic parasite that causes cramps and diarrhea and is found in soil, food or water contaminated with feces from infected humans or animals. In many cases, an antibiotic is needed to treat the condition associated with infection, known as giardiasis.
The parasite is in the news because of low levels of chlorine found in Pittsburgh water that could impact 100,000 Pittsburgh Water and Sewer Authority customers. Low chlorine levels found at the Highland Park reservoir could enable giardia to grow in the water.
PWSA issued the temporary advisory Tuesday, urging customers in the affected areas to flush and boil water before using.
Dr. Bernard Macatangay, a UPMC parasitic disease specialist and assistant professor of infectious diseases at the University of Pittsburgh School of Medicine, said that an incubation period for giardia is generally one to two weeks.
“It doesn't take a lot of the parasite to cause infections,” he said. “It's a waterborne parasite, and the main way to get sick is through ingestion.”
Untreated symptoms such as diarrhea can lead to malabsorption, weight loss and dehydration, he said. Doctors generally diagnose a giardiasis infection through a stool test.
Subsequent treatment can include a one-dose antibiotic pill called tinidazole or a five- to seven-day cycle of an antibiotic known as flagyl.
Boiling water will kill the parasite, Macatangay said.
Dr. Marc Itskowitz, an Allegheny Health Network internal medicine physician, noted that many people's immune systems can clear giardia without symptoms.
“I would be most concerned about people with weakened immune systems or very young and very old people,” he said. “Those are the ones who tend to have more severe infections.”
Itskowitz said he senses that the current water boil is precautionary.
“If there would be an actual diagnosis in Pittsburgh, of course, our level of concern would increase,” he said.
According to the Centers for Disease Control and Prevention, less common symptoms include itchy skin, hives and swelling of the eyes and joints. Sometimes symptoms might seem to resolve only to come back after several days or weeks, according to the CDC.
Giardia infection is the most common intestinal parasitic disease affecting humans in the United States, the CDC says.
Macatangay, who lives in Shadyside, a neighborhood impacted by the water crisis, is paying close attention for his own reasons.
“I was a little concerned when I read about it because I live in the area,” he said. “I'll definitely be paying attention.”
Dr. Karen Hacker, director of the Allegheny County Health Department, said Wednesday that giardia has not been detected in the water thus far.
“But given its unique nature, there is still some concern,” she said. “Again, there is no evidence of giardia in the system, and, if there is, the PWSA filtration system should remove it from the system. The precautions put in place are appropriate to assure protection. Should you develop symptoms, please contact your health care provider.”
Ben Schmitt is a Tribune-Review staff writer. Reach him ator 412-320-7991.