[Detection antigen of Rickettsia tsutsugamushi by using monoclonal antibody]

Dot-ELISA was used with HRP-labelled monoclonal antibodies Kp3 (IgGi) and Kp4-6 (IgM) against antigen of the Karp strain of Rickettsia tsutsugamushi to detect the antigen of R. tsutsugamushi. The positive rate of sera of 56 acute scrub typhus patients and 37 wild rats caught from the countryside of the endemic area as well as 29 batches of chiggers collected from the wild rats were 92.9%, 100% and 89.7%, respectively. No cross reaction was found with antigens of other rickettsia groups such as R. mooseri, R. prowazeki, R.burneti and R. rickettsia. In patients suffering from acute scrub typhus the antigen of R. tsutsugamushi could be detected earlier in the course of illness than the antibody. This method is very sensitive that an amount of antigen of 6.7ng/microliters can be detected. It is easy to perform and the results can be read by naked eye.