[Comparison of usefulness of commercial ELISA Virion/Serion, homemade ELISA and tube agglutination test in serodiagnosis of tularemia].

INTRODUCTION

Tularemia is a highly infectious zoonotic disease caused by Gram-negative bacterium Francisella tularensis. The microbiological diagnosis of tularemia is based on bacteriological, molecular and serological investigations. In the present study we compared of usefulness of commercial ELISA Virion/Serion, home-made ELISA and tube agglutination test in serodiagnosis of tularemia.

METHODS

Serum samples from 57 patients with clinical symptoms of tularemia, 13 patients with yersiniosis and 20 blood donors were tested. The cut-off limit of IgA, IgG and IgM serum antibodies in home-made ELISA was set at mean antibody titer determined in sera of healthy blood donors exceeded by the three standard deviations. The cut-off for positivity in tube agglutination test was titers 25. The IgG and IgM antibodies to lipopolysaccharides of F. tularensis in Virion/Serion ELISA were measured and results interpreted according to the instructions by the manufacturer.

RESULTS

The results of the study showed that 39 (68.4%) serum samples obtained from the patients suspected for tularemia were positive by tube agglutination test and Virion/Serion ELISA assay for IgG and IgM antibodies. Home-made ELISA was slightly more sensitive and detected the IgA/IgG antibodies in 42 (73.7%) and IgM antibodies in 39 (68.4%) of serum samples. The positive reactions were not detected by the tube agglutination test and home-made ELISA in serum samples from patients with yersiniosis and blood donors. The Virion/Serion ELISA detected IgG antibodies in diagnostically significant level only in one blood donor.

CONCLUSIONS

In conclusion, all three serological tests can be successfully used in routine serodiagnosis of tularemia.