[Fluorescence serologic studies for the detection of Trichinella spiralis]

Attempts were made to find out, if Trichinella (Tr.) spiralis could be detected by means of immunofluorescence. An applicable Trichinella antigen was prepared by applying pepsin digestion to trichinous muscular tissue of experimentally infected guinea pig. Different quantities of Trichinae were orally administered to guinea pig and rabbit, and even parenteral infection of rabbit was attempted, with the view to obtain immune sera. Oral infection was followed by the occurrence of antibody titres, between the tenth day from infection and the sixtieth day, when the experiment was disrupted. Highest antibody titres were established in the fourth through sixth weeks after infection. Titres in excess to 1:64 could not be recorded by means of indirect immunofluorescence. No antibody were detected by fluorescence serology after parenteral immunisation. The detection of Trichinella spiralis by fluorescence microscopy was somewhat problematic. When the preparations were evaluated, some secondary fluorescence was observed. It had been caused by remnants of undigested muscular fibrils, contaminants, and cell detritus not removable by the authors' method of preparation and, therefore, also recorded. That secondary fluorescence, however, was eliminated by secondary staining, using methylen blue. Hence, fluorescence should not pose any obstacle to automatic reading of the reaction. Some five or six hours were required to detect by means of indirect immunofluorescence Trichinella antigen as extracted from test animals. Yet, in practice carcass processing would go on in that time. The above results, consequently, appear to suggest that for detection of Trichinella spiralis immunofluorescence cannot even replace trichinoscopy under the condition that the time of antigen preparation was shortened.