Clinical and epidemiological features of Lyme borreliosis in Bulgaria

Data on disease expression and epidemiological characteristics of Lyme borreliosis in south-eastern Europe are scarce.

To reveal features of Lyme borreliosis in Bulgaria, clinical data and epidemiological characteristics of 1257 patients reported between 1999 and 2002 were analysed.

The most affected age group was 5-9 years, followed by 45-49 years, 50-54 years, and 10-14 years. Most of the patients (68%) lived in a rural area or were attacked by ticks during activities in a rural area. Lyme borreliosis cases occurred throughout the year with two peaks--one in June and second smaller one in September. The most common clinical manifestation was erythema migrans (EM), diagnosed in 868 (69.1%) of the patients. Rashes had a median diameter of 11 cm and were predominantly located on lower extremities. Forty-four per cent of the rashes consisted of homogenous erythema and 56% had central clearing. Multiple EM was detected in 4.3% of the EM cases. Neuroborreliosis was the second most common presentation of Lyme borreliosis, diagnosed in 19% of the patients. Lyme arthritis was found in 8% of the patients. Heart and ocular manifestations were recorded in 1.1% and 0.9% of the patients, respectively. Borrelial lymphocytoma and acrodermatitis chronica atrophicans were very rare (0.3%). Twenty-seven patients (2.1%) had multiple organ involvement.

The results of the study show that the epidemiology and clinical manifestations of Lyme borreliosis in Bulgaria are similar to those in the majority European countries but possess some distinguishing characteristics.