An Environmental Investigation of Legionnaires’ Disease among EU Travelers, Khuk Khak, Takuapa, Phangnga, Thailand, 2nd – 5th June 2015

Abstract

Background: On 31st May 2015, the Office of Disease Prevention and Control Region 11 Nakhon Si Thammarat received notification of Legionnaires' Disease (LD) among travelers who stayed at the same hotel in Khuk Khak subdistrict, Takuapa, Phang Nga from Bureau of Epidemiology. We started to investigate and control the outbreak during 2-5 June 2015. The objectives aimed to confirmed outbreak, to describe the epidemiological characteristic of the outbreak, to identify the source and etiology of the outbreak and to implement control and prevent measures.
Methods: Active Case finding was done at Public hospitals in Phang Nga and Private hospitals in Phuket. The water specimens were collected from room and water filters for Legionella culture. We collected urine specimens from hotel staff and then test for Legionella pneumophila by Urinary Antigen Detection technique, and we collected Blood from hotel staff including testing for Legionella pneumophila antibody by Indirect Fluorescent antibody technique.
Result: We identified 2 confirmed cases and 4 suspect cases by 4 male and 2 female, ratio of Male to female 2 : 1, Median of age 50 year (Min=10 Max=71) all were Europeans. Two confirmed cases stayed at the same hotel. Water specimens from the hotel revealed residual chlorine levels below 0.2 ppm. And the boiler were set to only 45°C. Water specimen from the room and products related to water in the hotels revealed Legionella isolates (Legionella pneumophila serogroup 1, Legionella pneumophila serogroup 2-14, Legionella species).
Discussion and Conclusions: The cause of this outbreak had Legionella pneumophila in water and products related of water. It was suggested that, hotel clean must water systems using chlorine concentration of 50 ppm. (Chlorine shock), settings temperatures of water heater and ensure guest room hot water above 50°C, and to educate about Legionnaires' Disease for hotel staff.