Tularaemia outbreak in Bulgaria

During the last 40 y, 2 large tularaemia outbreaks occurred in Bulgaria. We report the second outbreak, in 1998–2003, including a total of 262 laboratory confirmed cases. The majority of the patients presented with oropharyngeal tularaemia (89.7%). Less common were the glandular, pulmonary and oculoglandular forms. The diagnosis of tularaemia was confirmed serologically. In 5 cases, F. tularensis was detected by immunofluorescent assay in lymph node biopsies. By PCR, all 5 samples yielded successful amplification of the tul4 gene and the feredoxin gene of F. tularensis. Cultivation of the biopsies resulted in 2 F. tularensis isolates. Three additional F. tularensis isolates were obtained from an open well, a dead hare and a tick. All 5 isolates were identified as F. tularensis subsp. holarctica seu palaearctica. F. tularensis was detected by PCR amplification of the tul4 gene in spleen samples from 9 (21%) of 42 captured rodents. Our study indicated food and water contamination by rodents as important sou...