Two guests who stayed at the luxury Wynn Las Vegas hotel have tested positive for Legionnaires' disease, a severe form of pneumonia that kills one in ten patients. The Southern Nevada Health District reported the cases on Tuesday, revealing that one individual stayed at the hotel casino in September 2025 and the other more recently in February 2026.
Following the discovery, health officials collected samples from the Wynn Las Vegas, and multiple samples tested positive for Legionella, the bacterium responsible for causing Legionnaires' disease. The bacterium thrives in warm, wet, and moist environments, often spreading through contaminated water vapor.
In response to the positive samples, the Wynn Las Vegas 'initiated immediate and comprehensive water system remediation measures,' according to the health district, though specific actions were not disclosed. Recent samples taken from the site now 'indicate no detectable levels' of the bacteria. The hotel casino 'has initiated direct guest notifications regarding potential exposure, and is implementing precautionary measures designed to mitigate any further risk of illness.' Both affected individuals have since recovered, the agency added.
Rising Cases Across the United States
News of the Las Vegas cases follows a worrying trend nationwide. Earlier this month, North Carolina officials issued an alert over a 54 percent jump in Legionnaires' disease cases between 2024 and 2025, with 310 cases last year and 48 already recorded in 2026. In south Texas, Ector County officials detected 12 cases and two deaths between late December and early January. Meanwhile, in Baltimore, Maryland, politicians allege the bacteria caused an outbreak at a federal building housing ICE detainees.
Nationally, infections have soared over two decades, rising from 1,100 cases in 2000 to more than 8,000 today. Health experts warn that warmer temperatures allow Legionella to thrive in damp locations, including air conditioning units, hot tubs, water fountains, and misting devices, increasing the risk of infection.
Prevention and Risk Factors
To avoid infection, health officials recommend cleaning and disinfecting home water systems, including air conditioners and spray devices. They advise flushing faucets or shower heads unused for three days or more, deep cleaning hot tubs regularly, and draining standing water from hoses. Those using humidifiers or CPAP machines should clean and replace filters regularly.
People over 50, current or former smokers, and individuals with lung conditions are most at risk. Legionnaires' disease is caused by Legionella bacteria, which thrive in moist environments between 77 and 113 degrees Fahrenheit (25 to 45°C). The bacteria can become airborne in steam or vapor, and infection occurs when droplets are inhaled.
Symptoms and Treatment
Initial symptoms include headache, muscle aches, and fever that may reach 104°F (40°C) or higher. Within three days, patients may develop cough, shortness of breath, chest pain, nausea, vomiting, diarrhea, and confusion or other mental changes. In severe cases, patients can develop pneumonia, and the bacteria can spread to the blood, causing sepsis. The bacteria can also infect the heart. Death may result from lung failure, septic shock, or acute kidney failure.
Doctors treat the disease with antibiotics, which are most effective in early stages before the bacteria spread. Patients are often hospitalized. In milder cases, Pontiac fever may occur, causing fever, chills, headache, and muscle aches without lung infection, and it resolves on its own without treatment.
