Epidemiology and Infection

Original Papers

Campylobacter infection

Molecular and spatial epidemiology of human campylobacteriosis: source association and genotype-related risk factors

P. MULLNERa1a2 c1, T. SHADBOLTa3, J. M. COLLINS-EMERSONa1, A. C. MIDWINTERa1, S. E. F. SPENCERa1, J. MARSHALLa1, P. E. CARTERa4, D. M. CAMPBELLa2, D. J. WILSONa5, S. HATHAWAYa2, R. PIRIEa4 and N. P. FRENCHa1

a1 Molecular Epidemiology and Veterinary Public Health Laboratory, Hopkirk Research Institute, Massey University, Palmerston North, New Zealand

a2 New Zealand Food Safety Authority, Science Group, Wellington, New Zealand

a3 MidCentral Public Health, Rata House, Palmerston North Hospital, Palmerston North, New Zealand

a4 Institute for Environmental Science and Research, Kenepuru Science Centre, Porirua, New Zealand

a5 Department of Human Genetics, University of Chicago, Chicago, IL, USA

SUMMARY

The epidemiology of human campylobacteriosis is complex but in recent years understanding of this disease has advanced considerably. Despite being a major public health concern in many countries, the presence of multiple hosts, genotypes and transmission pathways has made it difficult to identify and quantify the determinants of human infection and disease. This has delayed the development of successful intervention programmes for this disease in many countries including New Zealand, a country with a comparatively high, yet until recently poorly understood, rate of notified disease. This study investigated the epidemiology of Campylobacter jejuni at the genotype-level over a 3-year period between 2005 and 2008 using multilocus sequence typing. By combining epidemiological surveillance and population genetics, a dominant, internationally rare strain of C. jejuni (ST474) was identified, and most human cases (65·7%) were found to be caused by only seven different genotypes. Source association of genotypes was used to identify risk factors at the genotype-level through multivariable logistic regression and a spatial model. Poultry-associated cases were more likely to be found in urban areas compared to rural areas. In particular young children in rural areas had a higher risk of infection with ruminant strains than their urban counterparts. These findings provide important information for the implementation of pathway-specific control strategies.

(Accepted December 03 2009)

(Online publication February 09 2010)

Correspondence:

c1 Author for correspondence: Dr P. Mullner, Molecular Epidemiology and Veterinary Public Health Laboratory, Hopkirk Research Institute, Massey University, Private Bag 11 222, Palmerston North, NZ. (Email: petra@epi-interactive.com)

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