The dispute between officials in Maryland and at the Centers for Disease Control and Prevention (CDC) is over whether new rules requiring water testing at hospitals are needed.
But the CDC reports that recommendations already on the books for handling the dangerous respiratory disease aren't followed: Only one in five hospitals follow federal guidelines to routinely test patients with possible symptoms for Legionnaires'.
Twenty-four years after its discovery, U.S. health officials say it is possible as many as 4,500 Americans die of Legionnaires' disease each year. But since many hospitals do not test their patients, the actual number is not known.
One patient who wasn't initially tested was 70-year-old Ernest Gresko, whose death from Legionnaires' disease three years ago fit an alarming pattern.
Gresko was admitted to a Michigan hospital with symptoms of pneumonia of which Legionnaires' is a particular type but according to his daughter Valerie Greene, he wasn't tested for Legionnaires' for five days. The results came after he died.
"He was so congested he could not breathe," said Greene. "It was the most horrible, painful death that anyone could imagine."
Greene said she faults the hospital for not testing for the disease immediately.
"This disease is very prevalent and most people don't even know," she said.
Dr. Richard Besser of the CDC's Respiratory Diseases Branch agreed that hospitals "need to be testing their patients. That's essential."
Besser said thousands of Legionnaires' cases go undetected every year because 80 percent of hospitals do not follow federal guidelines to test their pneumonia patients for Legionella, the bacteria that causes the disease.
"Legionnaires' disease is greatly underreported, is under-recognized by clinicians, is under-tested for," Besser said. According to the CDC, only five to 10 percent of estimated cases are reported.
Part of the problem is that the symptoms of Legionnaires' high fever, chills, a productive cough, and sometimes muscle aches or a headache mirror other strains of pneumonia closely, and can even resemble the flu.
The antibiotic erythromycin is used to treat Legionnaires'. Some other forms of pneumonia are also treated with the same drug, but in different amounts. Some forms are treated with entirely different drugs.
And if the right treatment isn't started fast, that can mean "prolonged hospitalization, complications, and death" for some patients, according to the Legionnaires' information site legionella.com.
Testing becomes even more important in light of evidence that many people catch the disease in the hospital.
When four patients died last year at the Harford Memorial Hospital in Maryland, officials blamed Legionella bacteria found in the hospital's drinking water.
After the outbreak, a Maryland state task force recommended that all hospitals routinely test their water systems for Legionella.
That finding conflicted with the rules imposed by the CDC, which sets safety standards for hospitals. The CDC feels water testing will miss some Legionella, and take the emphasis off testing patients.
"If you don't find Legionella in your water system, there will be this false sense of security that your hospital is safe and that will lead to even less testing of patients who develop pneumonia in the hospital," Besser said.
Dr. Glenn Morris, the chief of the Maryland task force, argues the CDC approach essentially tells hospitals to wait until patients are already sick before testing the water.
"If you test, if you know what's going on, you can keep the cases from happening," said Morris. "This nation would save lives if hospitals were testing on a routine basis."
According to the CDC, 8,000 to 18,000 people contract the disease annually, and 5 to 30 percent die.
The illness tends to affect people who are middle-aged or older, often striking heavy cigarette smokers or people who have chronic lung disease, a well as those who have suppressed immune systems because they are battling AIDS or cancer or undergoing dialysis.
The disease has never been found to pass from person to person. Legionnaires' is spread when the Legionella bacteria is inhaled in water mist from an air conditioner, spa or shower.
According to OSHA, the bacteria is found in many natural bodies of water, but usually at levels too low to cause health problems for humans.