Maternal Zika Virus (Zikv) Infection Following Vaginal Inoculation With Zikv-Infected Semen in the Timed-Pregnant Olive Baboon

Abstract

44 45 ZIKV infection is associated with pregnancy loss, fetal microcephaly and other 46 malformations. While Aedes sp. of mosquito are the primary vector for ZIKV, sexual 47 transmission of ZIKV is a significant route of infection. ZIKV has been documented in 48 human, mouse and non-human primate (NHP) semen. It is critical to establish NHP 49 models of vertical transfer of ZIKV that recapitulate human ZIKV pathogenesis. We 50 hypothesized that vaginal deposition of ZIKV infected baboon semen would lead to 51 maternal infection and vertical transfer in the olive baboon (Papio anubis). Timed 52 pregnant baboons (n=6) were inoculated via vaginal deposition of baboon semen 53 containing 10 6 ffu ZIKV (n=3, French Polynesian isolate:H/PF/2013, n=3 Puerto Rican 54 isolate:PRVABC59) at mid-gestation (86-95 days gestation [dG]; term 183dG) on day (d) 550 (all dams), and then at 7 day intervals through three weeks. Maternal blood, saliva and 56 cervico-vaginal washes were obtained at select days post-inoculation. Animals were 57 euthanized at 28 days post initial inoculation (dpi; n=5) or 39 dpi (n=1) and maternal/fetal 58 tissues collected. vRNA was quantified by qPCR. Viremia was achieved in 3/3 FP ZIKV 59 infected dams and 2/3 PR ZIKV. ZIKV RNA was detected in cvw (5/6 dams;). ZIKV RNA 60 was detected in lymph nodes, but not ovary, uterus, cervix or vagina in the FP ZIKV 61 dams but was detected in uterus, vagina and lymph nodes. Placenta, amniotic fluid and 62 all fetal tissues were ZIKV RNA negative in the FP infected dams whereas 2/3 PR 63 infected dam placentas were ZIKV RNA positive. We conclude that ZIKV infected 64 semen is a means of ZIKV transmission during pregnancy in primates. The PR isolate 65 appeared more capable of wide spread dissemination to tissues, including placenta 66 compared to the FP strain. 67 68 69 IMPORTANCE 70 Due to its established link to pregnancy loss, microcephaly and other major congenital 71 anomalies, Zika virus (ZIKV) remains a worldwide health threat. Although mosquitoes 72 are the primary means of ZIVK transmission, sexual transmission in human populations 73 is well documented and provides a means for widespread dissemination of the virus. 74 Differences in viremia, tissue distribution, immune responses and pregnancy outcome 75 from sexually transmitted ZIKV compared to the subcutaneous route of infection are 76 needed to better clinically manage ZIKV in pregnancy. Through our previous work, we 77 have developed the olive baboon as a non-human primate model of ZIKV infection that 78 is permissible to ZIKV infection via the subcutaneous route of inoculation and transfer of 79 ZIKV to the fetus in pregnancy. The current study evaluated the course of ZIKV infection 80 after vaginal inoculation of ZIKV in pregnant baboons at mid-gestation using baboon 81 semen as the carrier and comparing two isolates of ZIKV, the French Polynesian isolate 82 first associated with microcephaly and the Puerto Rican isolate, associated with an 83 increased risk of microcephaly observed in the America...

Potent Restriction of Sexual Zika Virus Infection by the Lipid Fraction of Extracellular Vesicles in Semen

“…This virus likely is present in ejaculated semen ( Govero et al, 2016 ; Ma et al, 2016 ; Joguet et al, 2017 ; Matusali et al, 2018 ; Robinson et al, 2018 ; Stassen et al, 2018 ), arguing against the defective virus explanation. In addition, primate and mouse studies both report successful transmission of ZIKV via semen ( Uraki et al, 2017 ; Gurung et al, 2020 ). On the other hand, our findings here demonstrate that extracellular vesicles from semen are potent inhibitors of ZIKV infection at physiological ratios, providing a plausible reason why sexual transmission of ZIKV is a rare event.…”

“…We do not currently know whether semen from other species contains inhibitory SEV. Mouse studies showing sexual ZIKV transmission use IFN-knockout mice which leads to very high viral titers in semen ( Uraki et al, 2017 ), and a study on vaginal inoculation of ZIKV with semen in primates required more than one exposure ( Gurung et al, 2020 ), implying that sexual transmission of ZIKV is still somewhat limited in animal models. One caveat to our studies is that we used semen and SEV from healthy donors rather than ZIKV infected men.…”

Animal models of congenital zika syndrome provide mechanistic insight into viral pathogenesis during pregnancy

“…Following in utero infection, olive baboon fetuses exhibit neurological damage, with notable defects in radial glia, disorganized migration of neurons to cortical layers, and pathology in immature oligodendrocytes [ 24 ]. In addition to subcutaneous inoculation, intravaginal inoculation using ZIKV-infected olive baboon semen resulted in maternal viremia and vertical transfer, with the Puerto Rico (PRVABC59, 2015) strain being more virulent than the French Polynesia strain and causing more widespread dissemination to reproductive tissues and placenta [ 25 ].…”