CDC MMWR Report - 2017 Legionella Outbreak Associated with Memphis Hotel Hot Tub

In the January 19th MMWR release, an investigative report into a 2017 Legionella outbreak associated with a hotel hot tub and pool.  While the outbreak came to light because of a few cases, many more were found through old-fashioned investigative work rather than sample analysis.

Initially 3 cases were identified, and this led them to the hot tub.  Through proceeding to survey past guest, 92 cases were identified, including nine laboratory-confirmed (urinary antigen positive) cases, 19 probable (self-reported pneumonia) cases, and 64 suspected (self-reported fever and ≥1 compatible symptom*) cases.  Of these, 70 had required medical care, and 16 people were hospitalized and there was one reported death.

Not the way to meet up with Elvis after going into a Memphis hotel hot tub, or any hotel water for that matter.  But how do you know?  In this case, "environmental health specialists conducted an assessment of the hotel aquatics facility and identified improper water treatment monitoring and low chlorine residuals (0 ppm; acceptable range = 1–3 ppm)."  "Laboratory testing of the aquatics facility water samples identified three Legionella polymerase chain reaction–positive samples from the pool, pool sand filter, and hot tub sand filter, and isolated Legionella pneumophila serogroup 1 from the hot tub sand filter."   Something to be said about that smell of chlorine when poolside.

CDC MMWR
https://www.cdc.gov/mmwr/volumes/67/wr/mm6702a5.htm?s_cid=mm6702a5_e
Notes from the Field: Legionellosis Outbreak Associated with a Hotel Aquatics Facility — Tennessee, 2017

CDC MMWR - Waterborne Disease Outbreaks from Drinking Water - 2013 to 2014

As an important raw material for most food operations, water must be evaluated as part of the hazard analysis. The source of the water as well as how that water is stored and used must be considered. In CDC's report, disease outbreaks associated with drinking water (period 2013-2014) are reviewed. By their definition, "for an event to be defined as a waterborne disease outbreak, two or more cases must be linked epidemiologically by time, location of water exposure, and illness characteristics; and the epidemiologic evidence must implicate water exposure as the probable source of illness."

A summary of key findings:

• "Legionella was implicated in 24 (57%) outbreaks, 130 (13%) cases, 109 (88%) hospitalizations, and all 13 deaths (Table 1). Eight outbreaks caused by two parasites resulted in 289 (29%) cases, among which 279 (97%) were caused by Cryptosporidium, and 10 (3%) were caused by Giardia duodenalis. Chemicals or toxins were implicated in four outbreaks involving 499 cases, with 13 hospitalizations, including the first reported outbreaks (two outbreaks) associated with algal toxins in drinking water."
• "Thirty-five (83%) outbreaks were associated with public (i.e., regulated), community or noncommunity water systems,¶ and three (7%) were associated with unregulated, individual systems. Fourteen outbreaks occurred in drinking water systems with groundwater sources and an additional 14 occurred in drinking water systems with surface water sources. The most commonly cited deficiency, which led to 24** (57%) of the 42 drinking water–associated outbreaks, was the presence of Legionella in drinking water systems"
• "All of the outbreak-associated deaths reported during this surveillance period as well as all of the outbreaks reported in hospital/health care settings or long-term care facilities, were caused by Legionella. A review of 27 Legionnaires’ disease outbreak investigations in which CDC participated during 2000–2014 identified at least one water system maintenance deficiency in all 23 investigations for which this information was available, indicating that effective water management programs in buildings at increased risk for Legionella growth and transmission (e.g., those with more than 10 stories or that house "
• "Cryptosporidium was the second most common cause of both outbreaks and illnesses, demonstrating the continued threat from this chlorine-tolerant pathogen when drinking water supplies are contaminated."

Some background from one of the references (copied below) on Legionella in water systems.

• "Legionnaires’ disease is a lung infection that is fatal for about one in 10 persons who become infected. Legionella, the bacterium that causes Legionnaires’ disease, grows well in warm water, but can be killed by disinfectants, such as chlorine. Persons can get Legionnaires’ disease when they breathe in small droplets of water contaminated with Legionella."
• "Legionella grows best in building water systems that are not well maintained, especially where levels of chlorine or other disinfectants are low and water temperatures are optimal for its growth. Legionnaires’ disease outbreaks most often occur in hotels, long-term care facilities, and hospitals. The most common sources are potable water (e.g., drinkable water used for showering), cooling towers, hot tubs, and decorative fountains."

CDC MMWR
https://www.cdc.gov/mmwr/volumes/66/wr/mm6644a3.htm?s_cid=mm6644a3_e
Surveillance for Waterborne Disease Outbreaks Associated with Drinking Water — United States, 2013–2014
Weekly / November 10, 2017 / 66(44);1216–1221

MMWR - Outbreaks Associated with Drinking Water - 2011-2012

 We generally regard drinking water safe, and rightfully so.  For the amount of water that is consumed each day, there have been relatively few issues.  An MMWR article reports that in the two year period reviewed, 2011-2012, there have been 32 water related outbreaks resulting in 431 cases of illness, 102 hospitalizations, and 14 deaths.

The biggest culprit was Legionella and this was primarily related to drinking water in hospitals affecting at-risk patients.  While we hear of Legionella in air conditioning systems, such as the current issue in NY where over 100 have become ill and 12 have died (Legionella grows in the cooling water systems and then is inhaled through the water vapors), evidently Legionella is an issue in hospitals (along with other HAIs (hospital acquired infections) including Clostridium difficile, MRSA, etc).  "Legionella outbreaks are particularly challenging to prevent and control, in part because the organism lives and multiplies in building plumbing systems, which usually fall outside water utility and regulatory oversight (6,7). One Legionella outbreak occurred in a hotel that used point-of-entry water filters, which effectively dechlorinated all water entering the building, and illustrates the importance of maintaining sufficient residual disinfectant in plumbing systems."

EPA has a publication on Legionella in drinking water.

The other issue was non-community water systems.  "All five noncommunity outbreaks originated from groundwater sources. Specifically, four occurred in outdoor camp or work settings where a source spring was contaminated directly or by inflow from a stream, and the fifth occurred at a meeting facility where a well was contaminated with septic tank overflow."  In these cases, Norovirus, non-Legionella bacteria, and Giardia (a parasite) were responsible.   (You are probably wondering how you ever made it through summer camp as a kid considering the pond water where you swam and that nasty spigot you drank from....and you are also then wondering why your parents sent you there.)

Here, an elk enjoys a drink of water from a spigot used for filling water bottles at Grand Canyon National Park (photo courtesy of Nika Bucknavage).

CDC MMWR
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6431a2.htm?s_cid=mm6431a2_e
Surveillance for Waterborne Disease Outbreaks Associated with Drinking Water — United States, 2011–2012

Weekly
August 14, 2015 / 64(31);842-848
Karlyn D. Beer, PhD1,2; Julia W. Gargano, PhD2; Virginia A. Roberts, MSPH2; Vincent R. Hill, PhD2; Laurel E. Garrison, MPH3; Preeta K. Kutty, MD3; Elizabeth D. Hilborn, DVM4; Timothy J. Wade, PhD4; Kathleen E. Fullerton, MPH2; Jonathan S. Yoder, MPH, MSW2

Advances in water management and sanitation have substantially reduced waterborne disease in the United States, although outbreaks continue to occur (1). Public health agencies in the U.S. states and territories* report information on waterborne disease outbreaks to the CDC Waterborne Disease and Outbreak Surveillance System (http://www.cdc.gov/healthywater/surveillance/index.html). For 2011–2012, 32 drinking water–associated outbreaks were reported, accounting for at least 431 cases of illness, 102 hospitalizations, and 14 deaths. Legionella was responsible for 66% of outbreaks and 26% of illnesses, and viruses and non-Legionella bacteria together accounted for 16% of outbreaks and 53% of illnesses. The two most commonly identified deficiencies† leading to drinking water–associated outbreaks were Legionella in building plumbing§ systems (66%) and untreated groundwater (13%). Continued vigilance by public health, regulatory, and industry professionals to identify and correct deficiencies associated with building plumbing systems and groundwater systems could prevent most reported outbreaks and illnesses associated with drinking water systems.