Increased incidence of Lyme borreliosis in southern Sweden following

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http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_uids=16810531&query_hl=16&itool=pubmed_docsum

Eur J Clin Microbiol Infect Dis. 2006 Jun 30;

Increased incidence of Lyme borreliosis in southern Sweden
following
mild winters and during warm, humid summers.

Bennet L, Halling A, Berglund J.

Department of Clinical Sciences, General Practice/Family Medicine,
University Hospital of Malmo, Lund University, 205 02, Malmo, Sweden.

The aim of the present study was to investigate the long-term
incidence rate of Lyme borreliosis and, additionally, to determine
whether a correlation exists between climatic factors and summer-season

variations in the incidence of Lyme borreliosis. Climatic variability
acts directly on tick population dynamics and indirectly on human
exposure to Lyme borreliosis spirochetes. In this study, conducted in
primary healthcare clinics in southeastern Sweden, electronic patient
records from 1997-2003 were searched for those that fulfilled the
criteria for erythema migrans. Using a multilevel Poisson regression
model, the influence of various climatic factors on the summer-season
variations in the incidence of erythema migrans were studied. The mean
annual incidence rate was 464 cases of erythema migrans per 100,000
inhabitants. The incidence was significantly higher in women than in
men, 505 and 423 cases per 100,000 inhabitants, respectively (p<0.001).

The summer-season variations in the erythema migrans incidence rate
correlated with the monthly mean summer temperatures (incidence rate
ratio 1.12; p<0.001), the number of winter days with temperatures below

0 degrees C (incidence rate ratio 0.97; p<0.001), the monthly mean
summer precipitation (incidence rate ratio 0.92; p<0.05), and the
number
of summer days with relative humidity above 86% (incidence rate ratio
1.04; p<0.05). In conclusion, Lyme borreliosis is highly endemic in
southeastern Sweden. The climate in this area, which is favourable not
only for human tick exposure but also for the abundance of host-seeking

ticks, influences the summer-season variations in the incidence of Lyme

borreliosis.

PMID: 16810531 [PubMed - as supplied by publisher]

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