Marked campylobacteriosis decline after interventions aimed at poultry, New Zealand

Abstract

Beginning in the 1980s, New Zealand experienced rising annual rates of campylobacteriosis that peaked in 2006. We analyzed notification, hospitalization, and other data to explore the 2007-2008 drop in campylobacteriosis incidence. Source attribution techniques based on genotyping of Campylobacter jejuni isolates from patients and environmental sources were also used to examine the decline. In 2008, the annual campylobacteriosis notification rate was 161.5/100,000 population, representing a 54% decline compared with the average annual rate of 353.8/100,000 for 2002-2006. A similar decline was seen for hospitalizations. Source attribution findings demonstrated a 74% (95% credible interval 49%-94%) reduction in the number of cases attributed to poultry. These reductions coincided with the introduction of a range of voluntary and regulatory interventions to reduce Campylobacter spp. contamination of poultry. The apparent success of these interventions may inform approaches other countries could consider to help control foodborne campylobacteriosis.

Figure 1

Campylobacteriosis notification rates per 100,000 population by year, 1980–2009, and hospitalization rates per 100,000 population by year, 1996–2009, New Zealand. Arrows indicate key interventions.

Figure 2

Rate ratios of campylobacteriosis notifications in New Zealand by grade of rurality for 2002–2006 and 2008. Main urban area was used as reference value for rate ratios. Error bars indicate 95% confidence intervals.

Figure 3

Annual campylobacteriosis notification rates per 100,000 population compared with annual notification rates per 100,000 population for salmonellosis, cryptosporidiosis, and yersiniosis, New Zealand, 1997–2008.

Figure 4

Number of cases attributed to source by year as determined by the modified Hald model in the Manawatu region of New Zealand. Error bars indicate 95% credible intervals. *2005 data are March through December only.