Temperature-driven Campylobacter Seasonality in England and Wales
Valérie R. Louis, Iain A. Gillespie, Sarah J. O'Brien, Estelle Russek-Cohen, Andrew D. Pearson, and Rita R. Colwell
Published in Appl. Environ. Microbiol. 2004:
71(1):85-92 .
ABSTRACT
Campylobacter incidence in England and Wales between 1990 and 1999 was examined in conjunction with weather conditions. Over the ten-year interval the average annual rate was determined to be 78.4±15.0 cases per 100,000, with an upward trend. Rates were higher in males than in females regardless of age, and highest in children less then 5 years old. Major regional differences were detected, with highest rates in Wales and the Southwest and lowest in the Southeast. The disease displayed a seasonal pattern, and increased campylobacter rates were found to be correlated with temperature. The most marked seasonal effect was observed for children under the age of five. The seasonal pattern of campylobacter infections indicated a linkage with environmental factors rather than food sources. Therefore, public health interventions should not be restricted to food-borne approaches, and the epidemiology of the seasonal peak in human campylobacter infections may best be understood through studies in young children.
Color figures (in pdf):
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| Figure 1. (A) Map of England and Wales showing 104 Health
Authorities (thin outlines), 20 numbered districts (thick outline),
and 6 regions (gray shading) with corresponding population in millions
for 2000 (42), surface area (km2), and number of Health
Authorities. Districts are: 1, N. London; 2, S. London; 3, Kent; 4,
Surrey & Sussex; 5, Berkshire, Hampshire & Isle of Wight; 6, Avon,
Somerset, Dorset & Wiltshire; 7, Devon & Cornwall; 8, Essex &
E. Anglia; 9, Central counties; 10, S. Humber and Lincolnshire; 11,
Central Midlands; 12, S.W. Midlands & Gloucestershire; 13,
N. W. Midlands;14, Greater Liverpool & Manchester; 15, East Midlands;
16, W. & S.Yorkshire; N.Yorkshire & Lincolnshire; 17, Cumbria &
Lancashire; 19, North East; 20, Wales. (B) Map of annual
campylobacter incidence (annual cases per 100,000) by district, shown
with district numbers and, in parenthesis, corresponding campylobacter
rates. |
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| Figure 2. Time series of weekly campylobacter incidence (weekly cases per 100,000) and environmental factors, by region. Black (thick line)= campylobacter rates per 100,000; red= temperature; blue= precipitation; green = sunshine |
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| Figure 3. Time series of campylobacter incidence (weekly cases per 100,000). (A) by gender: male= blue; female= red. (B) by age category (years): <1= blue; 1 to 4= red; 5 to 19= aqua; 20 to 34= green; 35 to 49= brown; 50 to 69= orange; =70= gray. The smooth lines represent spline interpolation. For clarity, original data points (+) are shown only in panel A. |
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| Figure 4. Campylobacter incidence annual pattern by area. Solid line= average campylobacter rates (weekly cases per 100,000); dotted line= 95% confidence interval around the ten-year mean; vertical line= onset of the annual peak around May 1st. |
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| Figure 5. Linear regression of weekly campylobacter rates versus average temperature by geographical area. Red (circle)= no rain (<1mm in the week); blue (plus)= rain (>=1mm in the week). Linear regression line is shown for each case (solid red and dotted blue, respectively). |
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