Two cases of Legionnaires' disease have been confirmed at a senior housing complex in East Baltimore, city health officials said Friday.
A pair of residents at the 149-unit Apostolic Towers Apartments at 201 N. Washington St. tested positive for the bacteria that cause Legionnaires', city health officials said.
One case occurred in March and the other this week; the residents were hospitalized. One person remains in the hospital with pneumonia.
Health officials said two cases are considered a "cluster," leading them to test the water system in the building and warn residents not to shower or use the tap. Bottled water has been provided for drinking and cooking.
Legionnaires' disease spreads through the inhalation of small, airborne droplets of contaminated water. The bacteria are often found in the warm waters of cooling towers or the air-conditioning units found in large buildings. The disease is not contagious, and healthy people don't always show symptoms.
Legionnaires' typically sickens older people, smokers and those with weakened immune systems. The disease can incubate in a person for two weeks, so residents have been asked to watch out for symptoms including a fever, a dry cough, muscle aches, abdominal cramps and diarrhea.
A milder form of the disease, called Pontiac fever, does not lead to pneumonia and is more akin to the flu.
The city Health Department is working with building management to inform residents, and officials said a consultant will test the building's potable water system. Health officials took water samples Friday, but results will not be known for at least a week.
"It's not always the case that we find the source, even after testing," said Dr. Mark Clanton, who started this week as the city's deputy commissioner for chronic disease and chief medical officer. "So we will remediate anyway."
That means using high doses of chlorine in the water system or heating the water at very high temperatures, he said.
Including these two cases, the city reports that 11 people have contracted Legionnaires' disease this year. There were 30 cases in the city last year and 28 in 2012.
Nationally, 8,000 to 18,000 people are hospitalized with the disease annually, according to the U.S. Centers for Disease Control and Prevention.
Apostolic Tower management could not be reached for comment.