Temperature dependence of reported Campylobacter infection in England, 1989-1999

Abstract

Campylobacter is the most common bacterial cause of gastroenteritis in England and Wales, with 45000 cases reported annually. Campylobacter incidence is highly seasonal; the consistent peak in late spring suggests a role for meteorological factors in the epidemiology of this organism. We investigated the relationship between ambient temperature and Campylobacter enteritis using time-series analysis to study short-term associations between temperature and number of Campylobacter reports adjusted for longer-term trend and seasonal patterns. We found a linear relationship between mean weekly temperature and reported Campylobacter enteritis, with a 1 degrees C rise corresponding to a 5% increase in the number of reports up to a threshold of 14 degrees C. There was no relationship outside this temperature range. Our findings provide evidence that ambient temperature influences Campylobacter incidence, and suggest that its effect is likely to be indirect, acting through other intermediate pathways.

Fig. 1

Linear effect of temperature on Campylobacter spp. reports over lags 0–9. Each point indicates the combined effect of temperature in the corresponding lag and all preceding lags and represents the relative increase in number of reports per 1°C increase in temperature, assuming a linear relationship between temperature and Campylobacter reports. Models are adjusted for trend, seasonality (up to the 6th harmonic), public holidays and relative humidity.

Fig. 2

Relationship between temperature and Campylobacter spp. reports, natural cubic spline models with two knots for the temperature series. , Unadjusted model; - - -, the effect of temperature adjusted for trend, seasonality (up to the 8th harmonic), public holidays and relative humidity.