Legionnaire’s Disease Investigation Update

Chelan-Douglas Health District is providing the following update on the area’s outbreak of Legionnaire’s Disease:

• Seven cases of Legionnaire’s Disease have been reported recently in this area among otherwise unrelated patients. Legionnaire’s Disease is a serious form of pneumonia from which 5% to 30% of patients may die; fortunately, all known patients in this outbreak are recovering.

• The only known factor in common among the first six patients was that they visited the Wenatchee Safeway store. Investigation of the seventh patient was recently completed, and this patient reported being in the area of the Wenatchee Safeway. So far, the source of the exposure is not known, although the Safeway store is taking precautions to assure the safety of its customers.

• The Health District is investigating properties in the area around the Safeway, in addition to the store itself, for possible sources of Legionella exposure.

• Based on the dates when patients first had symptoms, and the incubation period of the disease (2 to 14 days according to CDC), exposure to Legionella probably occurred between the middle of September and the first week of November. We will not be confident that the outbreak is over until two incubation periods have passed since the last known case without the appearance of new cases. At this point, that will be November 28.

News Release – Chelan-Douglas Health District – Legionnaire’s Disease Investigation Update – November 18, 2015

Page 2

• It is often difficult to identify the source of Legionella, especially in relatively small outbreaks, since the outbreak may not become known until weeks after exposures occurred. At that point, the conditions that produced Legionella exposure may have changed and environmental testing for Legionella may not produce results. That has apparently been the situation so far in this investigation.

• The Washington State Department of Health and the US Centers for Disease Control and Prevention are providing valuable assistance to the Health District in the investigation.

• Safeway has been very cooperative and is doing all they can to support the investigation. Please note that it is not certain at this point that the source of the Legionella was within the Safeway store.

Things to know about Legionnaire’s Disease:

• The disease is caught by inhaling tiny aerosolized droplets infected with the Legionella bacterium.

• You cannot catch the disease from another person.

• Most people who are exposed to the bacteria do not get sick. A few – usually people with other health problems or risks – get a serious case of pneumonia. That is when it is called Legionnaire’s Disease.

• Legionella bacteria are very common, but can become a problem when stagnant water and warm temperatures allow the bacteria to grow in high concentrations. Past outbreaks have been caused by poorly maintained cooling towers, fountains, misters and other water sources.