Epizootic hemorrhagic disease virus infection of type I interferon receptor deficient mice

Type I interferon receptor deficient (IFNAR-/-) mice were infected with an Israeli isolate of serotype 7 of epizootic hemorrhagic disease virus (EHDV; Orbivirus, Reoviridae). Two out of two mice that received 5 × 105 50% tissue culture infectious doses (TCID50) by intraperitoneal injection died or were euthanized in a moribund state on day 5 after infection. One mouse out of three that had been inoculated with 5 × 102 TCID50 died on day 7 while the remaining mice did not show any clinical signs and survived until the end of the experiment. Spleens of all dead mice were highly positive in an EHDV real-time RT-PCR (quantification cycle values =15) and contained =105.8 TCID50 of virus per ml of homogenate. The viral RNA content and virus titer in the spleens of the two surviving mice, on the other hand, were over 100-fold lower. Different from data reported for BTV, the outcome of EHDV infection of IFNAR-/- mice is dose-dependent and subclinical infections can occur.