Cause of death was therefore considered as unknown, although it cannot be excluded that the animal died due to RVFV infection. Statistical comparison of the detected RVFV RNA levels between goats inoculated with Vero E6-produced virus (n = 12) and goats inoculated with C6/36 cells-produced virus (n = 16) indicated that the developed viremia was higher with faster onset in animals infected

with insect cell-derived virus (P = 0.002) ( Fig. 4A). When the dose 107 PFU/animal of virus of either origin was evaluated separately, the insect-derived virus caused faster onset of the viremia, with the significantly higher RNA levels at 1 dpi (P < 0.001) 3MA ( Fig. 4B). Increase in rectal temperature can be used as one of the parameters in challenge studies in sheep to evaluate efficacy of the vaccine PI3K Inhibitor Library chemical structure candidates, but is unfortunately not applicable for goats. All RVFV inoculated lambs experienced minimum one or two days of increased rectal temperatures, with no significant differences between individual inoculation

approaches (Fig. 5). On the other hand, out of all 28 RVFV inoculated goats only 11 random animals developed increased rectal temperatures for one day. Although antibody development was not the main focus of the study, due to limited knowledge on RVFV infection in goats, the animals were kept for 28–30 dpi, and serum collected during the animal inoculation experiments was analyzed by plaque reduction neutralization assay. Development of neutralizing antibodies against RVFV in goats is summarized in Fig. 6. Significant difference in antibody titers, related to inoculation nearly dose, was observed at 14 dpi. Animals infected with 107 PFU of either Vero E6 or C6/36 cell-produced virus developed at least four-fold higher antibody titers than goats infected with

105 PFU, however a continuous gradual increase in antibody titers until the end of the experiment was observed in serum of animals inoculated with the lower dose. Very interestingly, goats infected with high dose of mosquito cell-produced virus experienced a drop in neutralizing titers by 28 dpi, while goats infected with the Vero E6 cell-produced RVFV maintained their antibody levels at 21 dpi also at 28 dpi. A difference in the onset of antibody response was observed between goats and sheep. While serum samples collected at 4 dpi were all negative, first neutralizing antibodies were detected at 5 dpi in 92.5% of goats, and on day 6 post infection all goats seroconverted. In comparison, only 85% of sheep seroconverted at 6 dpi, with all serum samples collected at 7 dpi being positive for neutralizing antibodies. The antibody titers at 7 dpi for both, goats and sheep were about the same, in range of 20–40, for all the animals.