Epidemiology and Infection

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Epidemiology and Infection (2010), 138:15-20 Cambridge University Press
Copyright © Cambridge University Press 2009
doi:10.1017/S0950268809990835

Short Report

Legionella

An outbreak of Pontiac fever due to Legionella longbeachae serogroup 2 found in potting mix in a horticultural nursery in New Zealand


G. J. CRAMPa1 c1, D. HARTEa2, N. M. DOUGLASa3, F. GRAHAMa4, M. SCHOUSBOEa5 and K. SYKESa1

a1 Te Puna Waiora, Tairawhiti District Health, Gisborne, New Zealand
a2 ESR, Legionella Reference Laboratory, Kenepuru Science Centre, Wellington, New Zealand
a3 Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
a4 Geohealth Laboratory, Department of Geography, University of Canterbury, Christchurch, New Zealand; Population Health Directorate, Ministry of Health, Wellington, New Zealand
a5 Canterbury Health Laboratories, Canterbury District Health Board, Christchurch, New Zealand
Article author query
cramp gj [PubMed]  [Google Scholar]
harte d [PubMed]  [Google Scholar]
douglas nm [PubMed]  [Google Scholar]
graham f [PubMed]  [Google Scholar]
schousboe m [PubMed]  [Google Scholar]
sykes k [PubMed]  [Google Scholar]

SUMMARY

Previous outbreaks of Pontiac fever have invariably been associated with water droplet spread of Legionella spp. In January 2007 three workers from a horticultural nursery were admitted to hospital with non-pneumonic legionellosis. Investigations showed that a working party of ten people had been exposed to aerosolized potting mix; nine of these workers met the case definition for Pontiac fever. The presence of genetically indistinguishable Legionella longbeachae serogroup 2 was demonstrated in clinical specimens from two hospitalized workers and in the potting mix to which they had been exposed. A further seven cases were diagnosed by serological tests. This is the first documented outbreak of Pontiac fever from L. longbeachae serogroup 2 confirmed from inhalation of potting mix. Pontiac fever is likely to be under-diagnosed. We advocate the introduction of an industry standard that ensures the use of face masks when handling potting mix and attaching masks and warning labels to potting mix bags sold to the public.

(Accepted August 19 2009)

(Online publication September 28 2009)

Key Words:Infectious disease epidemiology; legionellosis (Pontiac fever); outbreaks

Correspondence:

c1 Author for correspondence: Dr G. J. Cramp, Public Health Physician and Medical Officer of Health, Te Puna Waiora, Tairawhiti District Health, Private Bag 7001, Gisborne, New Zealand 4040. (Email: geoffreyc@TDH.org.nz)


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