Is the major increase in notified campylobacteriosis in New Zealand real?

Abstract

Notifications of campylobacteriosis by New Zealand medical practitioners have increased steadily in the last two decades. To determine if this increase is real, as opposed to a surveillance artefact, we examined both available notification (1980-2003) and hospitalization data (1995-2003). The similarity in the temporal pattern of increasing hospitalizations for campylobacteriosis, with that of notifications, is suggestive that this increase is indeed real. Although some risk factors for this disease have been identified (e.g. uncooked poultry consumption) it is unclear what the likely causes of the increasing rates are. The overall disease burden is also high compared with other developed countries (an annual notification rate of 396 cases per 100000 population in 2003), with highest rates in children aged 1-4 years, males, Europeans, and those living in urban areas. Given the large disease burden, further research and intervention studies should be public health priorities in this country.

Fig. 1

Campylobacteriosis cases in New Zealand by year, based on notifications (–■–, 1980–2003) and hospitalizations (–●–, 1995–2003).

Fig. 2

Age-specific rates of campylobacteriosis notifications in New Zealand, by year (1995–2003). –■–, <5; –▲–, 5–14; –●–, 15–29; –□–, 30–59; –○–, ⩾60.

Fig. 3

Rates of campylobacteriosis notification by New Zealand district health board (average annual rates for 2001–2003). The abbreviations for the health boards are listed below: [Table: see text]

Fig. 4

Rates of campylobacteriosis notification and hospitalization by New Zealand district health board (average annual rates for 2001–2003). For health-board abbreviations see Figure 3 legend.