Development of lateral flow test for serological diagnosis of tularemia

Abstract

Tularemia is a highly contagious zoonotic infection caused by Francisella tularensis. Bacterial culture, serology and molecular methods are used in the diagnosis of tularemia. Th e agent is a dangerous pathogen, and the importance of serological tests in diagnosis has increased because of the difficulty in culturing them. In this study, a practical, fast and reliable lateral fl ow-based immunochromatographic test was planned to detect F. tularensis specific antibodies in the field. Partially purified lipopolysaccharide antigen obtained from the live vaccine strain of F. tularensis was used as antigen. To determine the sensitivity of the test, 17 true positive tularemia serum samples with known Microagglutination test results, and to determine of specificity of the test, used 30 true negative serum samples. In this study also tested Brucella-positive patient sera of various titers from our laboratory"s serum bank to determine possible cross-reactivity with Brucella antibodies. Th e sensitivity and specificity of the Lateral Flow Test (LFT) rapid diagnostic kit were evaluated in comparison to the standard microagglutination test. Th e sensitivity and specificity of the newly developed Lateral Flow Test (LFT) were found at 100% and 93.5%, respectively. Th e tests revealed any possible cross-reaction with positive sera for brucellosis in lateral fl ow test for tularemia and showed 5% cross-reaction with this disease. Cross-reactions were observed at antibody titers of 1:20 and below. In conclusion, it was concluded that the newly developed lateral fl ow test is a fast, reliable, and practical alternative test for the serological diagnosis of tularemia and crossreaction in the serological tests conducted for brucellosis and tularemia should always be considered.

Keywords

• francisella tularensis
• lateral flow test
• serology