Pathological Findings in Equine Herpesvirus 9-Induced Abortion in Rats

Time Course-Dependent Study on Equine Herpes Virus 9-Induced Abortion in Syrian Hamsters

“…In contrast, viruses could not be detected in the few aborted fetuses and placentas in this group [ 30 ]. Virus DNA and antigens were [ 5 ] detected in both the placentas and fetuses when EHV-9 was inoculated in rats in both the early and late trimesters; however, in the present study, we failed to detect both antigens and DNA in fetuses but not in the placenta and uterus when the virus was inoculated in the early trimester in hamsters. This inconsistency in the result might be due to species differences, dose, or inadequate sampling, as we did not examine all offspring, and PCR was applied for only the 11th dpi point of time.…”

“…Dead fetuses were 4/32 and 12/30 in the early and late trimester infection groups, respectively. Gross lesions on the gravid uterus as well as aborted fetuses at full term were similar to those previously recorded for EHV-9-induced abortions in hamsters and rats [ 4 , 5 ]. The number of dead fetuses in early trimester infections is lower than that observed for late trimester infections, probably due to infections in the late trimester corresponding with a fully developed placenta that facilitates the transmission of infection from dam to fetus.…”

“…Although EHV-9 has been isolated from natural wild animal infections with nervous and abortive disorders [ 16 , 17 ], its significant role in disease outbreaks has not yet been explained [ 19 ]. EHV-9-induced abortion has been experimentally investigated in mice, rats, and hamsters [ 4 , 5 ] when the placenta was fully developed. In contrast, there is no evidence that EHV-9 can cross the immature placenta.…”

“…At the same time, EHV-9 is distinguishable from EHV-1 by DNA fingerprinting analysis [ 1 ]. EHV-9 can infect various domestic animals and nonhuman primates, causing fatal infections with fulminate encephalitis, which is characterized by neuronal degeneration and necrosis as well as intranuclear inclusion bodies in rodents [ 1 , 3 , 4 , 5 ], marmosets [ 6 ], dogs [ 7 ], cats [ 8 ], goats [ 9 ], pigs [ 10 , 11 ] and cattle [ 12 ]. Intranasal inoculation was the most common method of virus administration in the experimental studies; a strong affinity of EHV-9 for the olfactory system as the site of viral replication has been observed in all animals experimentally expressing encephalitis [ 11 , 13 ].…”

“…Previously, the pathological findings of EHV-9 abortion were investigated in mice, hamsters [ 4 ] and rats [ 5 ] induced in the early and late trimesters. This study aims to follow up the time-course pathogenesis of EHV-9 abortion in both the early and late trimesters to provide detailed descriptive data on the pathogenesis of abortion during EHV-9 infection by monitoring a variety of parameters such as detection of viremia, viral DNA in different fetal and maternal tissues, and pathological changes in fetal tissue, as well as associations with the placenta and cytokines to abortion at different time points.…”