Zika virus (ZIKV) is a potential threat to male reproductive health but the mechanisms underlying its influence on testes during
ZIKV infection remain obscure. To address this question, we perform single-cell
RNA sequencing using testes from ZIKV-infected mice. The results reveal the fragility of spermatogenic cells, especially spermatogonia, to
ZIKV infection and show that the genes of the
complement system are significantly upregulated mainly in infiltrated S100A4 + monocytes/macrophages. Complement activation and its contribution to testicular damage are validated by ELISA, RT‒qPCR and IFA and further verify in ZIKV-infected northern pigtailed macaques by
RNA genome sequencing and IFA, suggesting that this might be the common response to
ZIKV infection in primates. On this basis, we test the
complement inhibitor C1INH and S100A4 inhibitors
sulindac and
niclosamide for their effects on testis protection. C1INH alleviates the pathological change in the testis but deteriorates
ZIKV infection in general. In contrast,
niclosamide effectively reduces S100A4 + monocyte/macrophage infiltration, inhibits complement activation, alleviates testicular damage, and rescues the fertility of male mice from
ZIKV infection. This discovery therefore encourages male reproductive health protection during the next ZIKV epidemic.