TYLER — East Texas health care professionals are on notice to be on the alert for cases of Legionnaires’ disease.

The Northeast Texas Public Health District is reporting seven confirmed and five possible cases of Legionnaires’ disease in the Northeast Texas region, all of which could be connected to recent attendance at the East Texas State Fair in Tyler.

NET Health Disease Surveillance Division is working with the fair organizers and local health officials to determine connections of the cases with attending this year’s fair Sept. 20 to 29.

George Roberts, NET Health CEO, said the common element is the East Texas State Fair. NET Health is working with the Texas Department of State Health Services, the Centers for Disease Control and Prevention, event organizers and local health departments to narrow down the location within the fair.

Legionnaires’ disease is spread by inhaling water droplets in the air and caused by the Legionella bacteria, according to a written statement sent out Thursday by NET Health. Breathing in the water droplets can come from water in the air, steam, humidifier, cooling tower, sprinklers, lakes, rivers, streams and stagnant water.

The disease mimics pneumonia symptoms, and about 5,000 to 6,000 cases are reported every year, Roberts said.

Within a week’s time, five cases were noticed by health officials. Roberts said red flags come up when two or more cases occur.

Jason Geslois, epidemiologist with NET Health, said he and other health officials ask patients about where they have traveled recently to find a common denominator of the outbreak’s source. The process of narrowing down the location within the fair is ongoing, but the time frame is Sept. 20 to 29 and two to 10 days afterward.

“Now we narrow down our scope a little further,” Roberts said. “That’s why we’re trying to track this down.”

Roberts said NET Health has a strong confidence that Harvey Convention Center is safe because of the chlorine that disinfects the water for such bacteria as Legionnaires’ disease.

“Just because you went to the East Texas State Fair doesn’t mean you have Legionnaire’s disease,” Roberts said.

NET Health likely will be informing the public on investigation updates weekly, Roberts said.

The health district is urging anyone who attended the fair this year and is sick with Legionnaires’ symptoms to contact their health care provider immediately.

The patient’s primary clinical provider would run a urine-based test to determine if the patient has been infected by the Legionella bacteria, Roberts said.

Symptoms of Legionnaires’ disease could be cough, high fever, weakness, muscle aches, headaches and shortness of breath. People with Legionnaires’ disease are treated with antibiotics in a hospital or as outpatients, and most recover fully. However, according to the Centers for Disease Control and Prevention, about one out of 10 people with Legionnaires’ disease will die from the infection.

The following groups of people are at a higher risk of contracting Legionnaires’ disease: people over the age of 50, current or former smokers (cigarettes and e-cigs), persons with chronic lung disease such as emphysema or chronic obstructive pulmonary disease and those with weakened immune systems from a previous disease or medication.

For information, call the Disease Surveillance Division at NET Health at (903) 595-1350.