Outbreak Investigation

Transcription

1 Outbreak Investigation Joyce Chung Santa Clara County Public Health Department Steps of an outbreak investigation 1) Establish the existence of an outbreak 2) Verify the diagnosis 3) Define and identify cases Establish a case definition Identify and count cases 4) Perform descriptive epidemiology Describe and orient the data in terms of time, place, and person 5) Develop and evaluate hypotheses 6) Refine hypotheses and carry out additional studies 7) Implement control and prevention measures 8) Communicate findings A phone call Another phone call Early September 2004 Infectious Disease physician calls to report to the health dept 17 yr old with multiple nodules on both legs, Cx pos for Mycobacteria, rapid grower Worked as lifeguard at water ride at Great America Late September 2004 Dermatologist calls to report 3 women seen with nodules on legs; all had pedicures AND, 2 of the 3 women said they went to the same nail salon End of September persons with nonhealing leg lesions and history of pedicure reported to us Interesting. Clinically: Mycobacterial furunculosis Mycobacteria - Well known strains: M. tuberculosis, M. leprae Non-tuberculous mycobacteria (NTM) Furunculosis - Also known as boils Skin disease caused by the infection of hair follicles, resulting in the localized accumulation of pus and dead tissue generally attributable to S aureus 1

2 Background: Mycobacteria and nail salons Outbreak of M. fortuitum furunculosis among customers of same nail salon in Watsonville, CA (2000) 110 cases; 34 culture positive Shaving prior before pedicure increased risk by 4.8 times; 1/3 of cases hadn t shaved M. fortuitum isolated from all 10 footbaths Prompted regulatory change Health and Safety Rules for Board of Barbering and Cosmetology (BBC) required procedures for cleaning and disinfecting the footspas Background: Mycobacteria and nail salons cases of M. mageritense from same nail salon in Georgia cases of M. fortuitum and M. abcessus furunculosis at 2 nail salon in southern CA Unpublished: Texas 12 cases Dallas County Texas adopted regulations in July 04 Illinois Others (references to cases in AZ, FL, DC) Methods: Enhanced case finding Establish the existence of an outbreak Word-of-mouth among dermatologists Physician Alerts sent in Nov and Dec Extensive media coverage starting 11/17/04 TV and newspaper SJ Merc ran story 8 times Verify diagnosis Methods: Case Investigation Standardized case investigation Phone interview with each reported case Questionnaire development Attempt to collect skin samples from each culture positive case Sent to the labs for confirmation 2

3 Questions Who, what, where, when? Define and identify cases Establish a case definition Identify and count cases Methods: Case Definition Case Definition: Suspect Case Onset of non-healing leg lesions after 1/1/04 H/o pedicure prior to onset of lesions MD evaluation: clinically c/w mycobacterial infection Cx not done, pending, or negative Confirmed Case Cx of swab or punch biopsy positive for nontuberculous mycobacteria Excluded 114 (66%) Suspect Cases investigated Sept 2004 May (86%) Interviewed 29 (17%) Confirmed 173 reports 5 (3%) Excluded 25 (14%) Lost to follow-up or refused Status unknown Who was infected? (n=143) Descriptive epidemiology Time, place, person Majority women (98%) Majority white (78%) Age: <15 8% % % % % % 3

4 What were their habits? Frequent pedicure goers 63% had a pedicure monthly or more 14% had a pedicure every 2-3 months 10% had a pedicure occasionally 74% shaved before pedicure 95% used the whirlpool footspa 94% had leg massages How ill were they? 73% had lesions on both legs Average 8 lesions/leg (range 0 100) Source: Almaden Times Weekly Pedicure-associated Mycobacterial furunculosis by month of iilness onset Santa Clara County, 2004 (n = 143) No. Cases Reported Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec 11/18 salon investigation Suspected Confirmed Outbreak characteristics Peak symptom development July-Nov 2004 Mean incubation time 16 days 2004 Lab results - Cases 28 culture confirmed (23 typed) Sensitivities 95% amikacin sensitive 100% clarithomycin sensitive Generally resistant to Cipro, Minocycline, TMP/SMX Where were they exposed? Total of 43 different salons named!! 68% (98/143) named one of the Big Three salons 21% named Salon #1 11% named Salon #2 37% named Salon #3 10 additional salons mentioned > once 30 additional salons mentioned once 4

5 Methods: Environmental Investigation Interdisclipinary team inspected 3 salons named by majority of cases Inspectors from CA Board of Barbering and Cosmetology Environmental Health Specialists Public Health Staff Summary of Outbreak Total of 143 suspect and confirmed cases between 1/1/04-5/1/05 43 different salons, with 3 salons listed more often than others Mycobacteria present in big three salons Pedicure-associated Mycobacterial furunculosis Hypotheses What do think is going on? What would you like to know more about? Hypotheses Contamination of water Footspa pipes create biofilms Recirculated water (chair design) Cleaning is not enough Why? Current regulations not understood (language barrier) Not following instructions Board of Barbering & Cosmetology insufficiently staffed to enforce/educate Pedicure-associated infections underreported, so magnitude of problem unknown As a result... Salon Field Study How and why? Case-control study Case salons (12) mentioned more than once or lab-confirmed patient; includes Top 3 Control salons (23) not named; randomly chosen from BBC SCC salons PH Nurse and assistant April-June

6 Data collection Preliminary results Questionnaire Salon characteristics Cleaning process Changes since outbreak Observation Judged cleaning process Cleaning supplies Samples 1 swab for 3 most frequently used chairs Cleaned correctly (after Removed pedicure) screen (not required) Correct disinfectant* Case Salons 46% 40% 64% Controls 40% 75% 95% All salons 42% 63% 84% Preliminary Results: Cleaning & Labs Incorrect Cleaning AFTER PEDICURE END OF DAY EXTENSIVE BIWEEKLY OR for positive culture % CI 1.2, , , 41.7 Preliminary Results of Salon Field Study Larger capacity salons were more likely to have generated a case patient Salons that were incorrectly cleaning were more likely to have mycobacteria present in the footspa Roughly about 60% of all salons were following BBC rules for cleaning and disinfecting footspas and tools Since the outbreak, 75% of have increased frequency of cleaning and improved education of pedicurists Steps of an outbreak investigation 1) Establish the existence of an outbreak 2) Verify the diagnosis 3) Define and identify cases Establish a case definition Identify and count cases 4) Perform descriptive epidemiology Describe and orient the data in terms of time, place, and person 5) Develop and evaluate hypotheses 6) Refine hypotheses and carry out additional studies 7) Implement control and prevention measures 8) Communicate findings CA Pedicure Industry Over 35,000 salons in California >1,200 in Santa Clara County alone Largely represented by Vietnamese-speakers (80% of nail salon worker population is estimated to be Vietnamese) $6 billion dollar industry and growing 17 inspectors for the Board of Barbering and Cosmetology in CA (in 2004) Mycobacterial infections are the most common pedicure-associated infections in the medical lit 6

7 What happened next for salons... Due to the outbreak... Santa Clara County sting Assemblyman Leland Yee (SF) wrote a bill for more regulatory authority over salons (AB 1263 ) Originally vetoed by Governor Schwarzenegger Commissioned a Footspa Safety Workgroup -Manufacturers - Inspectors -Health officials - Cosmetologists Changes that were made Footspa workgroup recommendations: New requirements for cleaning/disinfecting footspas Gave authoritative power to BBC to close down salons based on violations More money for BBC More education Signed into legislation Fall Bill 409 California Healthy Nail Salon Collaborative Asian Health Services, Asian Pacific American Legal Center, EPA, CDPH, Northern California Cancer Center Center for Environmental Health, WorkSafe Thank you! Thank you! Joyce Chung Joyce.chung@hhs.sccgov.org 7