**5. Conclusions**

The immune response to SGEV in lambs appears to involve a combination of microglia and T lymphocytes, suggesting that B lymphocytes proliferate during infection. The proportion of microglia among immune cells was higher in SGEV-infected lambs than in goats, which may reflect the greater lesion severity in sheep. Nevertheless, the relative proportions of four types of cells (microglia, T and B lymphocytes, and astrocytes) in the CNS were similar between infected lambs and goats. Therefore, we may conclude that lambs might be more susceptible to SGEV due to species di fferences or to di fferent immune responses between individuals, rather than to di fferences in the relative proportion of immune cells. Larger studies that analyze flavivirus infections over longer periods may further increase our understanding of the immune response.

**Author Contributions:** Conceptualization, A.B.; methodology, I.Z.M., L.M.S., C.P.-M., J.F.G.M., R.A.J., and A.B.; validation, C.P.-M., J.F.G.M., R.A.J., and A.B.; formal analysis, I.Z.M., C.P.-M., J.F.G.M., R.A.J., and A.B.; investigation, I.Z.M. and A.B.; resources, A.B.; data curation, C.P.-M., J.F.G.M., R.A.J., and A.B.; writing—original draft preparation, I.Z.M. and A.B.; writing—review and editing, I.Z.M., C.P.-M., L.M.S., R.A.J., J.F.G.M., and A.B. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was partially supported by a FEDER co-funded gran<sup>t</sup> from the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (E-RTA2013-00013-C04-04), Ministerio de Ciencia, Innovación y Universidades (MCIU) and the Agencia Estatal de Investigación (AEI) reference project RTI2018-096010-B-C21 (FEDER co-funded) and by the Principado de Asturias, PCTI 2018–220 (GRUPIN: IDI2018-000237 and FEDER). Ms. Ileana Z. Martínez was supported by a Fundación Carolina PhD scholarship (2017 call).

**Acknowledgments:** The authors would like to thank the Vice-Ministry of the Environment of the Principado of Asturias. The authors thank A. Chapin Rodríguez for critically reviewing the manuscript. Authors also thank Red de Investigación en Sanidad Animal (RISA, Spain).

**Conflicts of Interest:** The authors declare no conflict of interest.
