United States Office Of Water September 2000 Environmental Protection Agency 4304

LEGIONELLA : DRINKING WATER FACT SHEET

Early symptoms include muscle GENERAL INFORMATION pain, loss of appetite, headache, high fever, dry cough, chills, Legionella are small gram-negative rod- confusion, disorientation, nausea, shaped bacteria. diarrhea, and vomiting. Over 40 individual species of Legionella Later symptoms include chest pain are known. and difficulty breathing. The majority of human infections It is difficult to distinguish this are caused by the species Legionella disease from other pneumonias. pneumophila. Early diagnosis and treatment are Legionella pneumophila was first extremely important. discovered following a pneumonia Treatment consists of intravenous outbreak at the 1976 Convention of the administration of antibiotics. American Legion in Philadelphia. HEALTH EFFECTS IN ANIMALS The species Legionella pneumophila is divided into sixteen subgroups (called There are no reports of naturally serogroups). infected animals. Scientists may artificially infect experimental animals (such as HEALTH EFFECTS IN HUMANS guinea pigs and gerbils) with There are two forms of Legionellosis, Legionella to study disease. pontiac fever and the more severe Legionnarires’ Disease. ENVIRONMENTAL PROFILE

Pontiac Fever: Ecology: Pontiac fever is a less severe Legionella are most form of Legionellosis which is commonly found in water, charaterized by flu-like including groundwater, fresh symptoms (fever, chills, and marine surface waters, headache, and muscle pain) and potable (treated) water. lasting 2-5 days. Legionella are protected againist standard water Legionnaires’ Disease: disinfection techniques, by Legionnaires’ disease is a their symbiotic potentially fatal illness involving relations with later pneumonia. microorganisms.

Occurrence: These bacteria have been found in water distribution Legionella are relatively resistant to systems of hospitals, hotels, standard water disinfection procedures clubs, public buildings, homes, and, can occur in potable water. and factories. Other waters in which Legionella have been found include cooling towers, evaporative condensers RISK FACTORS and whirlpools. These bacteria may be The general population (healthy transported from potable water to individuals) is fairly resistant to air by faucets, showerheads, infection. cooling towers, and nebulizers. Certain groups of people are at increased risk for contracting Transmission to Humans: legionnaires’ disease, including: Legionella are transmitted directly from hospital patients who require the environment to humans. intubation, have received There is no evidence of human-to- human ventilation assistance, or are or animal-to-human transmission of these receiving respiratory therapy bacteria. people taking corticosteroids or Potable water is the most important other immunosuppressive source of Legionella. drugs Humans may inhale contaminated solid organ transplant patients, aerosols or aspirate small amounts of especially those requiring contaminated drinking water. dialysis No vaccine is available to prevent people with certain chronic infection. health conditions (chronic obstructive pulmonary Outbreaks: diease,diabetes, head or neck Cases of legionellosis (any disease cancer, or end-stage kidney caused by Legionella) have been reported disease) in North and South America, Asia, heavy smokers or drinkers Australia, New Zealand, Europe, and Legionnaires’ disease in these people Africa. may be associated with more severe National surveillance programs are illness and increased mortality. conducted in the United States, 24 European countries (including England), ANALYTICAL METHODS Australia, and New Zealand. Legionellosis outbreaks most frequently Environmental samples should be have been attributed to contaminated collected by swabbing areas where potable water, cooling towers, or water flows (such as faucets and components of water distribution systems. shower heads). Outbreaks in hospitals have been linked The specimen should be concentrated to hospital potable water supplies, air by filtration, treated with an acid buffer conditioning systems, and cooling towers. to enhance Legionella recovery, and Travelers can be exposed to Legionella in cultured on a selective buffered contaminated hotel potable water or charcoal yeast extract (BCYE) agar contaminated whirlpool spas. medium. Community outbreaks are caused by Culture assays are the most common exposure to a wide variety of sources, but tests used to detect Legionella in potable water and cooling towers are the environmental and biological samples. most common. WATER TREATMENT

Control methods designed to disinfect an entire water distribution system include thermal (super heat and flush) hyperchlorination copper-silver ionization Control methods designed to disinfect only a specific portion of a water distribution system include ultraviolet light sterilization ozonation instantaneous steam heating Selecting one or a combination of these two types of control methods would be best for eradicating Legionella colonies and preventing recolonization of the water distribution system.

REGULATORY INFORMATION

EPA has established a Maximum Contaminant Level Goal (MCLG) of zero organisms for drinking water. An MCLG is a non-enforceable guideline based solely on an evaluation of possible health risks, taking into consideration a margin for public safety.

ADDITIONAL HELP • EPA has established the Safe Drinking Water Hotline, a toll-free number for further information on drinking water quality, treatment technologies, and for obtaining Health Advisories or other regulatory information. • Safe Drinking Water Hotline: 800-426-4791 9:00 a.m. - 5:30 p.m. (Eastern Time) Monday-Friday (excluding holidays) • Your state or county health officials or experts in your state’s Department of Environmental Protection or Natural Resources may also be of assistance.