QUINCY -- The Illinois Veterans Home confirmed another diagnosis of Legionnaires' disease on its campus Tuesday.
The resident was taken to the hospital over the weekend and has since been released.
"We're glad the resident is doing well," said Dave MacDonna, Illinois Department of Veterans' Affairs spokesman, "but we're highly concerned. We're following everything the (Centers for Disease Control and Prevention) is telling us to do."
The most recent Legionnaires' case comes after two Illinois Veterans Home residents were diagnosed with the disease last month. One resident died, and the other recovered.
MacDonna described a state of "high alert" at the home, in which any resident who displays symptoms is tested regularly and rigorously and hospitalized if symptoms continue to progress.
"If there are any symptoms, we're taking immediate action so we don't have the most terrible thing happen," he said.
The Veterans Home underwent a nearly $5 million rehabilitation of its water treatment plant in summer 2015 after Legionnaires' disease sickened 53 people there and led to 12 deaths. Three other residents were sickened during another outbreak last year, less than a month after the new water treatment plant and delivery system were unveiled in June 2016.
"The number of cases nationwide is growing each year," MacDonna said.
MacDonna believes the spike in Legionnaires' diagnoses could be due, in part, to the increase in testing for the pneumonia-like disease. The CDC reported 6,000 cases in 2015. Illinois sees about 300 cases each year.
"We cannot get rid of Legionella," MacDonna said, "so we have to be on high alert all the time."
Older populations are among the more susceptible to the disease. Veterans Home Administrator Troy Culbertson told The Herald-Whig after last month's cases that the Veterans Home's water is tested 500 times a week across the campus and "all of our results have been negative."
MacDonna said the home has done everything it can since the 2015 outbreak to curb the number of Legionnaires' cases it sees on its campus.