SUMMARY: The growth in the chick embryo yolk sac of trachoma and inclusion conjunctivitis (TRIC) strains which differ in virulence for the chick embryo was measured in terms of ELD 50 inclusion forming units in HeLa cells and total particles. Observed differences in rates of growth are consistent with the assumption that greater virulence depends on a higher rate of multiplication in the chick embryo. All strains were equally labile when heated at 37° in vitro but only the more virulent kill chick embryos at 37°.
BellS. D.Jun.,
MurrayE. S.,
CarrollT. J.,
SnyderJ. C.1963; Studies on trachoma. III. Comparison of virus infectivity for man and chick embryos Amer. J. trop. Med. Hyg. 12:902
GearJ. H. S.,
GordonF. B.,
JonesB. R.,
BellS. D.Jun.1963; Nomenclature of isolates of virus from trachoma and inclusion blennorrhoea. Nature, Lond. 197:26
HannaL.,
JawetzE.,
ThygesonP.,
DawsonC.1960; Trachoma viruses isolated in the United States: I. Growth in embryonated eggs. Proc. Soc. exp. Biol., N.Y. 104:142
JawetzE.,
HannaL.,
ChinoS.,
ZichoschJ.1962; Trachoma viruses isolated in the United States. V. Growth rates and drug inhibition patterns in embryonated eggs. Proc. Soc. exp. Biol., N.Y. 109:205
MurrayE. S.,
BellS. D.Jun.,
HannaA. T.,
NicholsR. L.,
SnyderJ. C.1960; Studies on trachoma. 1. Isolation and identification of strains of elementary bodies from Saudi Arabia and Egypt Amer. J. trop. Med. Hyg. 9:116
T’angF. F.,
ChangH. L.,
HuangY. T.,
WangK. C.1957; Studies on the etiology of trachoma with special reference to isolation of the virus in chick embryo. Chin. med. J 75:49