[Use of the immunofluorescence method to detect the causative agent of tularemia in developing chick embryos]

There was shown a possibility of using the immunofluorescent method for detection of the causative agent of tularemia in the developing chick embryos, infected with the virulent strains 503 (holoarctic race) and Schu (nonarctic race). The greatest accumulation of bacteria was revealed in the yolk sacs, and the least--in the chorionallantoic fliud; the greatest accumulation of bacteria was observed on the 3rd--4th days after the infection. In infection with various doses of the causative agent--from 1 milliard to 1 microbial cell-positive results were noted in 92.3% of cases (according to the data of fluorescent microscopy) and in 77.3% of cases (according to the data of light microscopy), this pointing to a greater sensitivity of the method of fluorescent in comparison with the light microscopy. Immunofluorescent method can be recommended for detection of the causative agent of tularemia in the yolk sacs of chick embryos.