Abstract:
The capability of the recently emerged European strain of bluetongue virus serotype 8 (BTV-8) to cross
the ruminant placenta has been established in experimental and field studies in both sheep and cattle.
Seroprevalence rates in goats in North-Western Europe were high during the recent outbreak of BTV-
8; however the capability of the virus to infect goats through the transplacental route has not been established.
In the present study, four Saanen goats were inoculated with the European strain of BTV-8 at 62 days of
gestation; this resulted in mild clinical signs, however gross lesions observed post mortem were more
severe. Viral RNA was detected by real-time RT-PCR in blood and tissue samples from three fetuses harvested
from two goats at 43 days post infection. Conventional RT-PCR and genome sequencing targeting
viral segment 2 confirmed infection of brain tissue with BTV-8 in two of these fetuses. In total, five of six
fetuses demonstrated lesions that may have been associated with transplacental infection with BTV.
Infected fetuses did not demonstrate neurological lesions. Low viral RNA concentrations in fetal blood
and tissue further suggest that the infected fetuses would probably not have been born viraemic. The
implications of these findings with regards to the epidemiology and overwintering of BTV-8 in Europe
remains unclear.
