Tularemia in children caused by Francisella tularensis biovar palaearctica.

Existing data on tularemia infections in children caused by the biovar Francisella tularensis palaearctica (type B) are limited. The case histories of all patients younger than the age of 16 years in northern Finland who had tularemia, based on the antibody response, during the years 1967 to 1986 are reviewed. A total of 67 children, 28 girls and 39 boys, were identified as having had tularemia. The occurrence of the disease varied greatly among years. Most of the cases occurred in July, August and September. The epidemiology differed significantly from that reported for F. tularensis biovar tularensis (type A). This is most probably attributable to the different vector, which was the mosquito in our series, but the tick in areas where type A is common. There were also clear differences in the clinical picture. The ulceroglandular clinical type was the most common. The clinical symptoms and signs were usually quite benign, but the symptoms lasted for a median duration of 26 days. The patients were treated with different antibiotics and there were no differences in the outcome related to the treatment given. Prospective comparative investigations of antibiotic therapy given for tularemia are needed. It is also important to try to identify which strain is causing the disease in each case.