SUMMARYPersistent and latent Japanese encephalitis virus (JEV) infection was studied in pregnant and non-pregnant mice. Following intraperitoneal inoculation into pregnant mice JEV persisted for 16 weeks in contrast to 4 weeks in non-pregnant mice. This was followed by a higher frequency of latent infection in pregnant mice. The virus could be reactivated during pregnancy or by cyclophosphamide treatment, the latter being more effective.
Pregnant rats were utilized to study the effect of maternal hyperthermia on fetal development. Eight groups of six to eight rats were exposed to ambient temperatures of 43-44 degrees C at various stages of pregnancy. All rats were killed on day 20 of gestation. Edema, microencephaly and microphthalmia followed heat treatment on day 4, 6, or 8 and skeletal defects occurred on day 10 of gestation. Apparently heat stress of dams after day 14 of gestation had little or no effect on embryos. Most placentas from day 6-10 treatment groups were significantly heavier than control and exhibited extensive thickening and necrosis of decidua basalis. Our results suggest that the rat is a useful model for investigating maternal hyperthermia as a possible cause of human placentophathies and fetal retardation.
Transplacental transmission of Japanese encephalitis virus (JEV) when given intraperitoneally was demonstrated in pregnant mice as shown by isolation of the virus from placenta and fetal tissues. Furthermore, JEV could be isolated from the brain, liver, and spleen of newborn mice. The effect of JEV at different periods of gestation in pregnant mice was demonstrated for the first time, and the consequences of maternal infection on fetuses and neonates were studied. JEV infection during the 1st week of gestation caused a significantly higher number of fetal and neonatal deaths (66%) than during the 3rd week of gestation (13.8%). The number of abortions, stillbirths, and neonatal deaths was higher in infected mothers than in controls. No congenital abnormalities were found in any of the newborn mice. Sera obtained from 5-week-old health mice delivered by mothers infected during the 3rd week of gestation contained JEV hemagglutination inhibiting and immunoglobulin M antibodies. The results of these preliminary experiments show the usefulness of mice as a model for further elucidation of JEV infection during pregnancy and its effects on the fetus.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.