The Illinois Department of Public Health (IDPH) linked two cases of Legionnaires’ disease to Northwestern Memorial Hospital in Chicago, according to news reports.

The Centers for Disease Control and Prevention (CDC) notified IDPH last Thursday that an out-of-state patient treated at the hospital in November had contracted the disease. Another patient was treated at the hospital in May with Legionnaires’, according to the IDPH.

When two or more cases of Legionnaires’ disease occur at a single site in a period of six months or more, they are categorized as “linked.” If the two cases had occurred within a six-month period, it would have been considered a Legionnaires’ disease “outbreak” or “cluster.”

The IDPH said it is working with the hospital, the Chicago Department of Public Health and the CDC to ensure that the following protocols occur:

  • providing guidance on what patients to test and when;
  • reviewing all pneumonia cases that occurred on the floors where the two patients stayed;
  • discuss flushing protocols on the floors where the two patients stayed;
  • discuss expanding use of filters for shower heads and sink on the floors where the two patients stayed;
  • reviewing environmental water testing logs and water sampling approaches.

Northwestern is Illinois’ top hospital

Northwestern Memorial Hospital is ranked No. 13 on the 2017-18 U.S. News & World Report Best Hospitals Honor Roll, the sixth consecutive year the hospital made the prestigious honor roll. It is ranked No. 1 in both the Chicago metro area and in the state of Illinois for the sixth consecutive year. It scored high in patient safety and demonstrating a commitment to reducing accidents and medical mistakes.

 Legionnaires’ on the rise in health-care facilities

In June, the CDC released information from a new study of the U.S. health-care industry and found that 76 percent of the facilities studied in 2015 reported cases of Legionnaires’ disease.

The findings are especially alarming for residents living at, or patients admitted to the facilities, as 1 in 4 people infected in a health-care facility will die. The death rate is higher than for people who get the infection elsewhere; 1 in 10 are estimated to succumb to the disease overall.

According to the CDC’s analysis, among the Legionnaires’ disease cases associated with health-care facilities:

  • 80 percent were linked to long-term facilities; 18 percent with hospitals, and 2 percent with both
  • cases were reported from 72 unique facilities, with the number of cases ranging from 1 to 6 per facility
  • 88 percent were in people 60 years of age or older.

What is Legionnaires’ disease? 

Legionnaires’ disease – also called Legionellosis and Legionella pneumonia – is a severe type of pneumonia or lung infection. The CDC estimates that 25,000 cases of pneumonia due to Legionella bacteria (Legionella pneumophila) occur each year, but only 5,000 cases are reported because of the disease’s nonspecific signs and symptoms. Ten percent of those infected will die.

How is Legionnaires’ contracted? 

Inhaling microscopic water droplets in the form of mist or vapor is how Legionella bacteria infect people. The bacteria, which grow best in warm water, are found primarily in human-made environments.

Outbreaks have been linked to a range of sources, such as:

  • cooling towers in air conditioning systems
  • water systems
  • large plumbing systems
  • mist machines
  • hot tubs and whirlpools
  • hot water tanks and heaters
  • showers and faucets
  • swimming pools
  • equipment used in physical therapy
  • decorative fountains.