Seroprevalence of Francisella tularensis in patients with neck mass complaints

Abstract

Aim: Tularemia is a zoonotic disease endemic in the northern hemisphere. The causative agent of the disease is Francisella tularensis. F.tularensis is endemic in Turkey, predominantly in the Marmara and Black Sea regions, and causes small outbreaks. This study aimed to investigate the seroprevalence of F.tularensis in patients admitted to the Otorhinolaryngology outpatient clinic with the complaint of neck mass by using two different methods.Methods: Serum samples were collected from patients who were admitted to the Otorhinolaryngology outpatient clinic of Dicle University Faculty of Medicine Hospitals between January 2021 and December 2021 with the complaint of neck mass. A commercially available immunochromatographic lateral flow test (ICT) and a single-assay chemiluminescence test (CHT) were used to detect F.tularensis antibodies. Rose-Bengal test was performed on all sera to determine cross-reactions with antibodies produced in brucellosis. Brucella immunocapture agglutination tests (BCT) were performed on the sera of patients with positive screening tests.Results: The ages of patients diagnosed with neck mass ranged between 14–70 years, with a mean age of 44.5±12.1 years. Sixty two (62%) of the patients were male, and 38 (38%) were female. When the test results were evaluated, two sera were positive for F.tularensis by both ICT and CHT methods. The first serum tests were negative for Brucella. The titer of the second serum in the chemiluminescence test was low positive.Conclusion: Tularemia should be considered in the differential diagnosis of patients presenting with neck mass complaints, especially in patients living in rural areas, and specific diagnostic tests should be performed. In addition, a more comprehensive seroprevalence study supported by molecular testing techniques to be conducted in Diyarbakır will provide clearer data on the extent to which tularemia affects our region and which subspecies is the causative agent.