Legionellosis Overview ELC Epidemiology Workshop IRIDVPD Breakout Session
Legionellosis Overview ELC Epidemiology Workshop IRID/VPD Breakout Session February 25, 2016 Lesley Brannan, MPH IRID Team Leader
Legionella Ecology • Legionella bacteria live in water (primarily) and soil, can live inside protozoa • Favorable conditions: • Stagnant water (dead legs in plumbing) • Warmer water (prefers: 77°F-108°F) • Presence of organic matter • Absence of residual disinfectant 2 February 25, 2016
Infection and Prevention • Transmission/infection: • Legionella can be a problem in manmade water systems • Need amplification, aerosolization (or aspiration), and infection of susceptible host • Occasionally acquired from compost or potting soil exposure (L. longbeachae) • No person-to-person transmission (limited? ) • Prevention: • Surveillance and outbreak investigation • Identify and control sources • Maintain equipment • Legionella prevention plans • Maintain hot (≥ 140°F) and cold (≤ 68°F) water temperatures • Avoid high-risk behaviors (e. g. , smoking) • Wear PPE if occupational exposures 3 February 25, 2016
Sources of Aerosolized Legionella • Cooling towers • Evaporative coolers (swamp coolers) • Misters (produce, recreational) • Decorative fountains • Spa pools, thermal pools, springs • Humidifiers • Respiratory therapy equipment • Domestic plumbing (hot and cold water) • Etc. 4 February 25, 2016
Legionellosis Disease and Risk Groups • Both of these legionellosis conditions are reportable: 1. Legionnaires’ disease • Incubation period: 2 -10 days • Cough, pneumonia, chest pain, fever, chills, myalgia, fatigue, N/V/D, abdominal pain, AMS; 5%-30% of cases die 2. Pontiac fever • Incubation period: 5 -72 hours • flu-like (milder), some with GI symptoms, no pneumonia, no deaths • Increased risk of infection: • • 5 February 25, 2016 Recent travel with an overnight stay outside of the home, including stay in a healthcare facility Exposure to hot tubs Recent repairs or maintenance work on domestic plumbing Renal or hepatic failure, diabetes, chronic lung disease Systemic malignancy Immune system disorders Smoking (current or former) Age ≥ 50 years
Clinical Laboratory Testing • Legionella pneumophila serogroup 1 (Lp 1) estimated to cause 85% of human cases • Lab confirmation (case criteria) requires one of these: • Culture positive for ANY Legionella species • Primary method of detecting non-Lp 1 cases • Important for outbreaks (link clinical & environmental samples) • Legionella urinary antigen test positive • Detects Lp 1* • Most common test type • Seroconversion by a fourfold or greater rise in specific serum antibody to Lp 1 • Ask clinical labs not to discard Legionella isolates 6 February 25, 2016
Case Investigation and Exposure Tracking • Main purpose of case investigation is to identify possible exposures • Interview patient or surrogate • Obtain medical records • Obtain specific, detailed info on exposures during the 10 -day incubation period • Facility information—full name and address, dates of stay, potential exposures, room numbers/locations, etc. • Specific sources of exposure to aerosolized or aspirated water • Complete “Legionellosis Investigation Report Form” • DSHS Austin • Tracks exposure locations/facilities • Looks for common exposures among reported cases • Handles out-of-jurisdiction and cross-jurisdictional notifications when a facility is in a different jurisdiction than case’s residence 7 February 25, 2016
Definitions • Definitely associated: spent the whole incubation period at the facility p. 156 EAIDB Investigation Guidelines • Possibly associated: spent part of the incubation period at the facility • Outbreaks • One definitely healthcare-associated case OR two or more possibly healthcare-associated cases within 1 year associated with the same healthcare facility • Two or more cases associated with the same facility (e. g. , hotel, gym, etc. ) or other common location (e. g. , amusement park) within 1 year • Considerations: • Cases – Investigate thoroughly!!! • Consider case link to facility (inpatient, outpatient, employee, visitor, staff), length of stay/exposure, and sources of exposures • Do the cases have other potential exposures? • How far apart are the case onsets? • Environmental • Complete and thorough environmental assessment is essential • Use assessment findings and epidemiologic data to determine next steps 8 February 25, 2016
General Outbreak Recommendations • Notification of facility • Active case finding • Retrospective and prospective • Consider illness in staff, visitors, etc. • Possibly notify staff, residents, etc. (depends on situation) • Dual laboratory testing (culture + UA) • Consider restrictions/control measures to prevent further transmission • Hire a competent Legionella consultant Pages 161 -169 EAIDB Investigation Guidelines • Environmental assessment & interpretation, sampling plan, sampling/specimen collection, submission to environmental testing lab, testing results interpretation, remediation • Environmental assessment of water system/sources • MEASURE WATER SYSTEM PARAMETERS – p. H, temp, residual disinfectant • Environmental sampling for Legionella • Address modifiable issues/Remediation • Make/update facility’s Legionella plan 9 February 25, 2016
Environmental Testing for Legionella • What this means: Trying to detect Legionella in bulk water samples and biofilm swab samples from a possible outbreak source • Testing on environmental specimens only done at private labs in Texas • Recommend using ELITE-certified lab: https: //wwwn. cdc. gov/elite/public/memberlist. aspx • Lab should perform “ISO spread plate method” test (culture) • For potable water, 1 liter samples recommended • In addition to water samples, collect and test biofilm swabs • Ask for speciation for any Legionella, and serotyping for L. pneumophila • Ask the environmental laboratory not to discard isolates/positives • Environmental lab will not assume that this is an outbreak 10 February 25, 2016
Resources • Legionellosis investigation toolkits: http: //www. cdc. gov/legionella/healthdepts/index. html • CDC environmental investigation videos: http: //www. cdc. gov/legionella/videos. html • ASHRAE Guideline 12 -2000: Minimizing the Risk of Legionellosis Associated with Building Water Systems • ANSI/ASHRAE Standard 188 -2015 Legionellosis: Risk Management for Building Water Systems 11 February 25, 2016
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