An epidemiological study searches for the origins of Legionella cases in Cáceres

Two technicians analyze river water.Getty Images

Extremadura Health Services (SES) Confirmed New confirmed cases of infection Legionella, This increases the number of infected people detected in recent weeks. This time the person affected was a 77-year-old woman who was admitted to the San Pedro de Alcantara Hospital in Cáceres. So far, due to the epidemic that emerged in August last year, Ten people have been infected and an 86-year-old man has died.

The health department is conducting Epidemiological studiesSamples are collected in different parts of the city to determine the source of infection and whether cases are related to each other. In 2022, an outbreak of Legionnaires’ disease occurred in the capital Cáceres, killing 5 people and infecting 20 others.

Legionnaires’ disease or Legionnaires’ disease It is named after an incident that occurred in Philadelphia in the summer of 1976, The 58th Annual American Legion Veterans Convention was held at the Bellevue Stratford Hotel in Philadelphia. The meeting was attended by two thousand legionnaires and their families. During the event, an infectious disease broke out, resulting in 182 patients and 29 deaths from an unknown type of pneumonia that did not respond to antibiotics. In the face of widespread confusion, the media dubbed the disease “Legionnaires’ disease.” Months later, investigations determined that the disease was caused by a new disease-causing bacterium.

Named as Legionella pneumophila.

Where is the bacteria that causes Legionella?

Legionella pneumophila It is a ubiquitous bacterium found in natural and artificial aquatic environments. Bacteria survive and grow between 20°C and 50°C, with the optimal temperature being 35°C. Pathogens are able to survive in water storage tanks and cooling systems, so exposure to the bacteria is often through inhalation of contaminated aerosols from equipment such as cooling towers, humidifiers, hot tubs, jacuzzis, showers and faucets, and by vacuuming contaminated water Occurs from vacuuming. . conditions most conducive to growth Legionella Includes water temperatures between 25 and 42 °C, Stagnant water with sediment accumulation and low biocide levels.

how disease appears

The clinical manifestation of the disease is atypical pneumonia. The incubation period is 2 to 14 days, and the most common symptoms are high fever, cough, chills, difficulty breathing, neurological abnormalities, Myalgia or joint pain, diarrhea, chest pain, nausea or vomiting. Generally, the disease exhibits symptoms similar to those of the flu.

The highest risk groups arePeople over 50, smokers, and people with chronic lung disease or who are immunocompromised. Mortality rates are estimated at 10%, although in some cases the mortality rate is as high as 30%. In July this summer, an outbreak of Legionnaires’ disease was declared in the Polish town of Rzeszów, about 80 kilometers from the Ukrainian border. So far, at least 19 people have died and a total of 166 people have been infected. Authorities have confirmed the presence of bacteria in the city’s water system and are investigating whether the contamination was intentional.

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World’s largest outbreak in Murcia

To date, the world’s largest outbreak of Legionnaires’ disease occurred in the Spanish city of Murcia in 2001. From July 7 to 22, more than 800 suspected cases were registered, including 449 confirmed cases. Six of them died.

Possible sources of transmission are four cooling towers located in commercial and residential buildings in the central neighborhood of Santa María de Gracia.

European situation

2021, The European Union (EU) and European Economic Area (EEA) have recorded their highest annual rates of Legionnaires’ disease notifications to date, There are 2.4 cases per 100,000 inhabitants, with four countries (Italy, France, Spain and Germany) accounting for 75% of all reported cases. The number of global cases is unknown as many countries lack adequate methods to diagnose the infection or adequate surveillance systems. In Europe, Australia and the United States, 10 to 15 cases per million inhabitants are detected each year. Of the reported cases, 75% to 80% are over 50 years old, and 60% to 70% are male. Smoking, excessive alcohol consumption, lung disease, immunosuppression, and chronic respiratory or renal disease are important risk factors.

how to control it

Recommend execution Regular inspections and measurements controlling To prevent cases of Legionnaires’ disease in tourist accommodations, hospitals, long-term care facilities, or other settings where high-risk populations may be exposed to aerosols containing bacteria.

The likelihood of contracting Legionnaires’ disease depends on the concentration of the bacteria in the water source, aerosol generation and transmission, host-related factors (such as age or preexisting medical conditions), and the virulence of the specific strain. Legionella.

Preventive measures greatly reduced risk of contamination Legionella Actions should be included to ensure that water systems, cooling towers, hot tubs, and decorative fountains are regularly maintained, cleaned, and disinfected. Keeping cold water systems below 20°C and hot water systems above 50°C can also prevent bacterial growth. Legionella. It is also important to ensure there is adequate flow and circulation in the water system to minimize the risk of standing water, such as by opening unused faucets in the building. Hot water systems can also be disinfected with high-concentration chlorine for 2 to 4 hours before the start of each warm season.

Of course, regular cleaning and disinfection of water filters, cooling towers, and ducts associated with your air conditioning system is recommended. Control and prevention measures must be complemented by adequate surveillance of community health services to detect cases.