Seropositivity of Borrelia burgdorferi in risky groups in Van region, Turkey

Abstract

Lyme borreliosis, which is more prevalent in the northern hemisphere, is the most common tick-borne contagious disease among people living in the North America and Europe. The causative agent of Lyme borreliosis, Borrelia burgdorferi, is transmitted by the bites of ticks of the genus Ixodes. In Turkey, the seroprevalence of Lyme disease is increased in regions where ticks and tick-bite cases are prevalent. The present study aimed to determine the seroprevalence of Lyme borreliosis in people at risk, living in the rural areas of Van province, which is located in the eastern region of Turkey. No previous study on this topic has been performed in our province. The study included a total of 446 subjects (mean age: 39.6±15.5 years), of them 139 were male and 307 were female, living in the rural areas of Van province between January 2012 and July 2012. The serum samples collected from participants after informed consent were screened for the presence of B.burgdorferi IgG antibodies by ELISA method. Western blot (WB) method was used for the confirmation of positive or borderline positive samples, and also for the investigation of IgM antibodies. During the study, the individuals from whom samples were taken, were questioned whether they have ever been exposed to tick or insect bite. B.burgdorferi IgG positivity was detected in 17 (3.8%) of the cases, whereas it was within the limit values in 14 cases. A total of 31 samples which yielded positive and borderline positive results were retested by WB and 4 (12.9%) were detected as positive while 10 (32.3%) of the samples were indeterminate. B.burgdorferi IgM antibody positivity was not detected in any of the samples. Considering the WB as reference method, the rate of B.burgdorferi IgG seropositivity was estimated as 0.9% (4/446). Three of these four cases were defined as tick or insect bites. The seroprevalence rate of B.burgdorferi detected in the present study was low as compared to the results of the other studies reported from Turkey. The reason of this result might be from the geographical characteristics and the differences of tick fauna in our region. As a result, it was concluded that our province is not endemic for Lyme borreliosis, however for the reduction of tick exposure, emphasis must be placed on preventive health services for the individuals at risk.