Rolling epidemic of Legionnaires’ disease outbreaks in small geographic areas

C. Raina MacIntyre,Amalie Dyda,Chau Minh Bui,Abrar Ahmad Chughtai

doi:10.1038/s41426-018-0051-z

C. Raina MacIntyre, Amalie Dyda + Show 2 more

Open Access

https://doi.org/10.1038/s41426-018-0051-z

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Abstract

Legionnaires’ disease (LD) is reported from many parts of the world, mostly linked to drinking water sources or cooling towers. We reviewed two unusual rolling outbreaks in Sydney and New York, each clustered in time and space. Data on these outbreaks were collected from public sources and compared to previous outbreaks in Australia and the US. While recurrent outbreaks of LD over time linked to an identified single source have been described, multiple unrelated outbreaks clustered in time and geography have not been previously described. We describe unusual geographic and temporal clustering of Legionella outbreaks in two cities, each of which experienced multiple different outbreaks within a small geographic area and within a short timeframe. The explanation for this temporal and spatial clustering of LD outbreaks in two cities is not clear, but climate variation and deteriorating water sanitation are two possible explanations. There is a need to critically analyse LD outbreaks and better understand changing trends to effectively prevent disease.

Highlights

Legionnaires’ disease (LD) is a cause of communityacquired atypical pneumonia, with sporadic cases and outbreaks reported from many part of the world
The Centres for Disease Control and Prevention (CDC) collects and reports three types of data on LD outbreaks: (i) surveillance for waterborne disease and outbreaks associated with drinking water, (ii) surveillance for waterborne disease and outbreaks associated with water not intended for drinking, and (iii) surveillance for waterborne disease and outbreaks associated with recreational water use
Outbreak 1—LD outbreak related to the Opera House in the South Bronx

Summary

Introduction

Legionnaires’ disease (LD) is a cause of communityacquired atypical pneumonia, with sporadic cases and outbreaks reported from many part of the world. The disease is caused by Legionella bacterium, which was first detected during the investigation of a major pneumonia outbreak in a convention in Philadelphia in 19761. The primary reservoir of Legionella is water supplies, decorative fountains and cooling towers in buildings[2]. The majority of human infections (70–90%) have been caused by L. pneumophila, mainly serogroups 1 and 6. Most cases in humans are asymptomatic or cause a mild illness called Pontiac fever, and complications are rare[3]. Symptomatic and severe disease tends to affect older people, especially those with chronic diseases, and males

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