[Tularemia seroprevalence in the risky population living in both rural and urban areas of Erzurum].

Tularemia which is a zoonotic infection, caused by Francisella tularensis, has become a re-emerging disease in Turkey. Infection is often transmitted to human by handling animal tissues and products, but it is also possible to acquire the disease from contaminated water or food. Recently several cases and epidemics of tularemia have been reported in the northwest areas of Turkey, particularly in Marmara and West Black Sea regions. Erzurum is a city in Eastern Anatolia Region, Turkey and animal husbandry is the main agricultural activity in that area. However, neither tularemia cases were reported from this province nor seroprevalence studies were performed. In this study we aimed to determine F.tularensis antibody seropositivity in the risky population living at both rural and urban area of Erzurum. Blood samples from 240 volunteer subjects (134 male with mean age: 36.2, age range: 17-75 years and 106 female with mean age: 39.1, age range: 16-77 years) whose occupations were farming and animal husbandry, were included in the study. Serum samples were screened for the presence of F.tularensis antibodies by slide agglutination method (BD, USA) and Serazym ELISA kit (anti-F.tularensis IgG/IgA/IgM, Seramun, Germany). The positive samples with those tests were also retested by microagglutination test (MAT) in National Tularemia Reference Laboratory of Refik Saydam Hygiene Center, using antigen prepared in the same laboratory from the local strain. The serum samples were also searched for the presence of Brucella and Salmonella antibodies in terms of cross-reactivity. Seropositivity was detected in 71 (29.6%) out of 240 subjects by slide agglutination test (SAT), whereas only 5 (2.1%) gave positive result for total antibody by ELISA. Twenty-five of the 71 SAT positive samples yielded F.tularensis antibodies by MAT, of which 21 were between 1/20-1/40 and four were between 1/80-1/160 titers. However, all of the MAT positive samples (n= 25) were found reactive in Brucella and/or Salmonella antibody tests. One of the four MAT positive samples with 1/40 titer and all of the four MAT positive samples with ≥ 1/80 titer yielded positive results in ELISA. Since MAT gave very high cross reactive results, the five subjects (2.1%) found positive with ELISA were evaluated as seropositive for tularemia. Of those subjects (four were female, one was male; age range: 27-38 years), four were the inhabitants of the same village, and one from another neighboring village. All of the seropositive subjects were dealing with raising livestock and two were also farming. No history of contact with rat and wild animals or tick bite were detected, however it was noted that non-chlorinated fountain water has been used in both of these villages. In conclusion, our data emphasized that, populations inhabiting especially in rural area and dealing with farming and stock raising in our region are at risk for tularemia.