Interactions of preimplantation mouse embryos with reovirus serotypes 1 and 3.

Mouse two-cell embryos were infected in vitro with reovirus serotypes 1/Lang and 3/Dearing, and the embryos were either implanted into pseudopregnant mice or observed in vitro for cytopathic effects. The reovirus serotypes 1/Lang and 3/Dearing differed in their capacity to kill embryos in vitro and in vivo: when embryos were infected in vitro with reovirus serotype 1/Lang and then transferred to foster mothers, pups resulted only at multiplicities of infection of a few particles per embryo. In contrast, infection of embryos with as much as 6 X 10(4) reovirus type 3 particles per embryo resulted in viable pups. In vitro, reovirus serotype 1/Lang was more virulent than serotype 3/Dearing. The infection of ovum with reovirus offers a unique model for the study of congenital infection and should yield important information concerning the molecular basis of virus virulence to maturing fetuses.

The growth of reovirus 3 in cultured rat embryos and implications for human reproductive failure.

Ten-day rat embryos were exposed to different concentrations of reovirus 3, heat-inactivated virus or diluent and then cultured for 48 h. An effect on embryonic growth and development was observed that required live virus. Virus concentrations of 10(6.0) TCID50 were embryolethal while 10(5.0) TCID50 killed about 20% of embryos and caused varying degrees of growth retardation in the remainder. Growth of the agent in the visceral yolk sac and embryonic tissues was confirmed by virus titration and immunofluorescent studies. Infectious virus was detected in the medium after 6-8 h and increased exponentially throughout the 48 h culture period, except for a check around 18 h. The significance of the findings in relation to previous animal studies and the potential importance of reovirus as a cause of human reproductive failure are discussed.

[Experimental study of the influence of reovirus infection on the course and outcome of pregnancy]. / Eksperimental'noe izuchenie vliianiia reovirusnoi infektsii na techenie i iskhod beremennosti

The possibility of intrauterine infection of fetuses of random-bred white mice with reovirus type 3 at various periods of pregnancy has been demonstrated. The unfavourable effect of reovirus infection on the course and outcome of pregnancy in some cases was manifested by impairment of embryogenesis, stillbirths and subsequent death of defective offsprings. Morphological examinations revealed marked pathological alterations in the lungs, brain, liver, and kidneys of suckling mice infected in utero.