Probes for INS

Animal models of Zika virus (ZIKV) infection have recently been established in mice, guinea pigs, and nonhuman primates. Tree shrews (Tupaia belangeri) are an emerging experimental animal in biomedical applications, but their susceptibility to ZIKV infection has not been explored. In the present study, we showed that subcutaneous inoculation of ZIKV led to rapid viremia and viral secretion in saliva, as well as to typical dermatological manifestations characterized by massive diffuse skin rash on the trunk. Global transcriptomic sequencing of peripheral blood mononuclear cells isolated from ZIKV-infected animals revealed systematic gene expression changes related to the inflammatory response and dermatological manifestations. Importantly, ZIKV infection readily triggered the production of high-titer neutralizing antibodies, thus preventing secondary homologous infection, in tree shrews. However, neonatal tree shrews succumbed to ZIKV challenge upon intracerebral infection. The tree shrew model described here recapitulates the most common dermatological manifestations observed in ZIKV-infected patients and may greatly facilitate the elucidation of ZIKV pathogenesis and the development of novel vaccines and therapeutics.IMPORTANCEThe reemergence of Zika virus (ZIKV) has caused a global public health crisis since 2016, and there are currently no vaccines or antiviral drugs to prevent or treat ZIKV infection. However, considerable advances have been made in understanding the biology and pathogenesis of ZIKV infection. In particular, various animal models have been successfully established to mimic ZIKV infection and its associated neurological diseases and to evaluate potential countermeasures. However, the clinical symptoms in these mouse and nonhuman primate models are different from the common clinical manifestations seen in human ZIKV patients; in particular, dermatological manifestations are rarely recapitulated in these animal models. Here, we developed a new animal model of ZIKV infection in tree shrews, a rat-sized, primate-related mammal. In vitro and in vivo characterization of ZIKV infection in tree shrews established a direct link between ZIKV infection and the immune responses and dermatological manifestations. The tree shrew model described here, as well as other available animal models, provides a valuable platform to study ZIKV pathogenesis and to evaluate vaccines and therapeutics.

Contemporaneous Zika virus (ZIKV) strains can cause congenital Zika syndrome (CZS). Current ZIKV clinical laboratory testing strategies are limited and include IgM serology (which may wane 12 weeks after initial exposure) and nucleic acid testing (NAT) of maternal serum, urine, and placenta for (+) strand ZIKV RNA (which is often transient). The objectives of this study were to determine if use of additional molecular tools, such as quantitative PCR and microscopy, would add to the diagnostic value of current standard placental ZIKV testing in cases with maternal endemic exposure and indeterminate testing. ZIKV RNA was quantified from dissected sections of placental villi, chorioamnion sections, and full cross-sections of umbilical cord in all cases examined. Quantitation with high-resolution automated electrophoresis determined relative amounts of precisely verified ZIKV (74-nt amplicons). In order to localize and visualize stable and actively replicating placental ZIKV in situ, labeling of flaviviridae glycoprotein, RNA ISH against both (+) and (⁻) ZIKV-specific ssRNA strands, and independent histologic examination for significant pathologic changes were employed. We demonstrate that the use of these molecular tools added to the diagnostic value of placental ZIKV testing among suspected cases of congenital Zika syndrome with poorly ascribed maternal endemic exposure.