Programme no. 338-OP
Public Health
Incidence of tick borne diseases in Norwegian general practice - an epidemiological study of consultations for erythema migrans and tick bites at list holding GPs and out of hour services.
Dag Berild1, Harald Reiso2, Knut Eirik Eliassen*3, Morten Lindbæk4, Nils Grude5, Karen Sofie Christophersen6, Cecilie Finckenhagen7
1Infectious diseases dept.,Oslo University hospital,Oslo,Norway, 2Norwegian National Advisory Unit on Tick-borne Diseases,Sorlandet Hospital,Kristiansand,Norway, 3Dept. of general practice,University of Oslo,0318 Oslo,Norway, 4Dept. of general practice,University of Oslo,0318 Oslo,Norway, 5Microbiology dept.,Vestfold Hospital,Tonsberg,Norway, 6Faculty of Medicine,University of Oslo,Oslo,Norway, 7Faculty of Medicine,University of Oslo,Oslo,Norway
* = Presenting author
Objectives: To map the incidence of consultations in Norwegian primary care for tick bites and EM. To map whether the increasing incidence of systemic Lyme disease, is matched in general practice.
Background: There are several tick borne diseases in the Nordic countries, but Lyme disease caused by the Borrelia bacterium is the most common. In Norway, systemic borreliosis is notifiable to the health authorities, but it is not known how common early, non-systemic Lyme disease is. This comprises the typical skin rash erythema migrans (EM). Neither is it known how many consultations concern mere tick bites without sign of disease.
Results:

The exact results are still in progress but will be presented at the conference.

We got data from 214 (52,5 %) list holding GPs and from 14 (72 %) of the out of hour services. We found a yearly incidence of EM in the four counties. The national incidence for systemic Lyme was 6,5/100.000 in the same period, and increasing through the period. This pattern of increased incidence was somewhat matched for the EM consultations. Both EM and tick bite consultations showed a male dominance for the younger, and a female dominance for the older patients. Prescription data for EM and tick bite consultations will be presented, also the prescription variation in age groups. Rate of serology testing and referral to specialist care is presented as well.

Material/Methods: All list holding general practitioners (GPs) and out of hour services in Norway’s four most Borrelia exposed counties were asked to participate. As EM has no unique diagnosis code in ICPC-2, a text search for Lyme disease and tick relevant terms were performed in their electronic patient records for the five year period 2005 – 2010.

Age and gender of the patients and any antibiotic prescribed were registered. From the consultation notes we found whether this was a tick bite and/or an EM, whether serology testing was performed and if the patient got referred to specialist care.

Conclusion: We found the incidence of EM and tick bite consultations in four Norwegian counties and figures for antibiotic prescription, referral and testing routine. We could also estimate the yearly incidence of EM in Norway.
Points for discussion: How can the figures from four counties give an estimate for the whole country?

Are the figures comparable to other (Nordic) countries?

Are guidelines being followed when it comes to antibiotic treatment?

Do the GPs perform too many microbiological tests?