Diagnosis of Tsutsugamushi Disease by Indirect Immunofluorescence

Abstract

By means of indirect immunofluorescence method, the antibody against Rickettsia orientalis was, investigated on the sera of five patients with tsutsugamushi disease, who had been infected at the vicinity of the river bank of Shinano river and Agano river, Niigata prefecture, within the year 1966. Used as antigen was the peritoneal smear obtained from mice infected with Gilliam, Karp, and Kato strains of R. orientalis, respectively.
The results were as follows:
As a whole, the patients' sera obtained in the acute stage of illness showed 10-80X positive rate, whereas, the rate in their convalescence was 160-2560X against three types of antigen, Gilliam, Karp, and Kato strains.
Among the sera, especially the convalescent sera, differences of considerable magnitude in the positive rate according to the type of antigen used were observed.
These results led the author to the conclusion that this method has shown outstanding trustworthiness in the specific serological diagnosis of tsutsugamushi disease, and furthermore, by this method its typing is possible to some extent. In the auther's cases, 3 out of 5 patients were presumed to be infected with Gilliam type strains, one, Karp type, and one, Kato type.