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Seven years after the onset of the Zika virus (ZIKV) epidemic in the Americas, longitudinal studies are beginning to demonstrate that children infected in utero and born without severe birth defects exhibit motor skill deficits at up to 3 years of age. Long term health and socioeconomic impacts of fetal ZIKV infection appear imminent. ZIKV continues to circulate in low levels much as the virus did for decades prior to the 2015 epidemic, and the timing of the ZIKV outbreak is unknown. Thus, in the continued absence of ZIKV vaccines or antivirals, small animal models of ZIKV transplacental transmission have never been more necessary to test antiviral strategies for both mother and fetuses, and to elucidate mechanisms of immunity at the maternal-fetal interface. Here we review the state of ZIKV transplacental transmission models, highlight key unanswered questions, and set goals for the next generation of mouse models.

Zika and the four serotypes of dengue are closely related flaviviruses that share a high degree of structural and sequence homology and co-circulate in many regions of the world. Here, we review recent studies investigating antigenic cross-reactivity between the two viruses. We discuss the pathogenic and protective roles of cross-reactive anti-viral antibody and T cell responses, respectively, in modulating the outcome of secondary dengue or Zika infection. Based on recent findings and increased incidence of severe disease in seronegative recipients of the first dengue vaccine to be licensed, we propose that the time has come to focus on developing pan-flavivirus vaccines that protect against Zika and four dengue serotypes by eliciting protective cross-reactive T cell responses while concomitantly reducing production of cross-reactive antibodies that can exacerbate disease.

Summary Background In low- and middle-income countries (LMICs), the burden of healthcare-associated infections (HCAIs) is not known due to a lack of national surveillance systems, standardized infection definitions, and paucity of infection prevention and control (IPC) organizations and legal infrastructure. Aim To determine the status of IPC bundle practice and the most frequent interventional variables in LMICs. Methods A questionnaire was emailed to Infectious Diseases International Research Initiative (ID-IRI) Group Members and dedicated IPC doctors working in LMICs to examine self-reported practices/policies regarding IPC bundles. Responding country incomes were classified by World Bank definitions into low, middle, and high. Comparison of LMIC results was then made to a control group of high-income countries (HICs). Findings This survey reports practices from one low-income country (LIC), 16 middle-income countries (MICs) (13 European), compared to eight high-income countries (HICs). Eighteen (95%) MICs had an IPC committee in their hospital, 12 (63.2%) had an annual agreed programme and produced an HCAI report. Annual agreed programmes (87.5% vs 63.2%, respectively) and an annual HCAI report (75.0% vs 63.2%, respectively) were more common in HICs than MICs. All HICs had at least one invasive device-related surveillance programme. Seven (37%) MICs had no invasive device-related surveillance programme, six (32%) had no ventilator-associated pneumonia prevention bundles, seven (37%) had no catheter-associated urinary tract infection prevention bundles, and five (27%) had no central line-associated bloodstream infection prevention bundles. Conclusion LMICs need to develop their own bundles with low-cost and high-level-of-evidence variables adapted to the limited resources, with further validation in reducing infection rates.

The recent re-emergence of Zika virus (ZIKV)1, a member of the Flaviviridae family, has become a global emergency. Currently, there are no effective methods of preventing or treating ZIKV infection, which causes severe neuroimmunopathology and is particularly harmful to the developing fetuses of infected pregnant women. However, the pathology induced by ZIKV is unique among flaviviruses, and knowledge of the biology of other family members cannot easily be extrapolated to ZIKV. Thus, structure-function studies of ZIKV proteins are urgently needed to facilitate the development of effective preventative and therapeutic agents. Like other flaviviruses, ZIKV expresses an NS2B-NS3 protease, which consists of the NS2B cofactor and the NS3 protease domain and is essential for cleavage of the ZIKV polyprotein precursor and generation of fully functional viral proteins. Here, we report the enzymatic characterization of ZIKV protease, and we identify structural scaffolds for allosteric small-molecule inhibitors of this protease. Molecular modeling of the protease-inhibitor complexes suggests that these compounds bind to the druggable cavity in the NS2B-NS3 protease interface and affect productive interactions of the protease domain with its cofactor. The most potent compound demonstrated efficient inhibition of ZIKV propagation in vitro in human fetal neural progenitor cells and in vivo in SJL mice. The inhibitory scaffolds could be further developed into valuable research reagents and, ultimately, provide a roadmap for the selection of efficient inhibitors of ZIKV infection.

Summary CD8 + T cells may play a dual role in protection against and pathogenesis of flaviviruses, including Zika virus (ZIKV). We evaluated the CD8 + T cell response in ZIKV-infected LysMCre + IFNAR fl/fl C57BL/6 (H-2 b ) mice lacking the type I interferon receptor in a subset of myeloid cells. In total, 26 and 15 CD8 + T cell-reactive peptides for ZIKV African (MR766) and Asian (FSS13025) lineage strains, respectively, were identified and validated. CD8 + T cells from infected mice were polyfunctional and mediated cytotoxicity. Adoptive transfer of ZIKV-immune CD8 + T cells reduced viral burdens, whereas their depletion led to higher tissue burdens, and CD8 −/− mice displayed higher mortality with ZIKV infection. Collectively, these results demonstrate that CD8 + T cells protect against ZIKV infection. Further, this study provides a T cell competent mouse model for investigating ZIKV-specific T cell responses.

Zika virus (ZIVK) represents a new threat to global health, with particular relevance to neuroscientists, due to associated newborn and adult neurological disease. Consequences of vertical infection include microcephaly with brain and eye anomalies, and consequences of adult infection include Guillain-Barré syndrome (GBS) and meningoencephalitis. Recent data suggest specific vulnerability of neural progenitors to infection, leading to cell death and brain calcification, reminiscent of other viral syndromes. Prevailing models suggest entry into neuronal stem cells through transmembrane receptors, hijacking cellular signaling to interfere with neurogenesis and cell survival. Mechanisms of adult neurological disease are unknown, but recent evidence suggests propensity for infection of adult neural stem cells. Efforts focused on mechanisms of pathogenesis, vulnerabilities, and treatments are urgently needed.

Summary Case reports of Zika virus (ZIKV) sexual transmission and genital persistence are mounting. Venereal transmission and genital persistence threaten public health within and beyond the range of ZIKV's mosquito vectors. In this study, we administered ZIKV into the vaginas of AG129 mice and LysMCre + IFNAR fl/fl C57BL/6 mice after hormonal treatments. Mice infected during estrus-like phase were resistant to vaginal infection. In contrast, when infected during diestrus-like phase, AG129 mice succumbed to infection, whereas LysMCre + IFNAR fl/fl mice experienced transient illness. Patency of transgenital transmission (TGT) in diestrus-like mice was demonstrated by detection of viremia and ZIKV replication in spleen and brain, and viral RNA persisted in vaginal washes as late as 10 days post-infection. In these lethal and sublethal mouse models, this study indicates that intravaginal deposition of ZIKV can cause TGT, hormonal changes in the female reproductive tract (FRT) influence transmission, and ZIKV replication persists in the FRT for several days.

Infection with one of the four dengue virus serotypes (DENV1-4) presumably leads to lifelong immunity against the infecting serotype but not against heterotypic reinfection, resulting in a greater risk of developing Dengue Hemorrhagic Fever/Dengue Shock Syndrome (DHF/DSS) during secondary infection. Both antibodies and T cell responses have been implicated in DHF/DSS pathogenesis. According to the T cell-based hypothesis termed “original antigenic sin,” secondary DENV infection is dominated by non-protective, cross-reactive T cells that elicit an aberrant immune response. The goal of our study was to compare the roles of serotype-specific and cross-reactive T cells in protection vs. pathogenesis during DENV infection in vivo. Specifically, we utilized IFN-α/βR−/− HLA*B0702 transgenic mice in the context of peptide vaccination with relevant human CD8 T cell epitopes. IFN-α/βR−/− HLA*B0702 transgenic mice were immunized with DENV serotype 2 (DENV2)-specific epitopes or variants found in any of the other three serotypes (DENV1, DENV3 or DENV4), followed by challenge with DENV. Although cross-reactive T cell responses were lower than responses elicited by serotype-specific T cells, immunization with either serotype-specific or variant peptide epitopes enhanced viral clearance, demonstrating that both serotype-specific and cross-reactive T cells can contribute to protection in vivo against DENV infection., Highlights • Serotype-cross-reactive CD8 T cells elicit a polyfunctional immune response similar to the response elicited by serotype-specific CD8 T cells. • Serotype cross-reactive CD8 T cells play a role in protection against DENV infection in a HLA-B*0702 Transgenic IFN-α/βR−/− mouse model. There are four major subtypes (serotypes) of the mosquito-borne Dengue virus. Infection with a first serotype is generally asymptomatic, but secondary infection with a different serotype is capable of causing severe disease. T cells previously exposed to a first serotype and which produce an immune response to a second serotype are said to be cross-reactive. Using a mouse model engineered with human T cell features, we characterized the cross-reactive T cell response to live dengue virus serotypes and viral protein fragments. Our results suggested cross-reactive T cells contribute to control of and protection against infection by a second dengue serotype, rather than leading to more severe disease.

Dengue virus (DENV) is a globally important mosquito-borne virus that causes a spectrum of diseases ranging from dengue fever (DF) to dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS), affecting 3.6 billion people in 128 countries [1,2(•)]. There is an urgent need for a drug or vaccine against DENV, yet none are presently available. In fact, results from recent Phase IIb and III trials of an attenuated tetrameric vaccine revealed that the vaccine provided limited protection against DENV serotype 2 in DENV-immune people, and no protection against any serotype in naïve individuals [3-5], highlighting the difficulties associated with dengue vaccine development. A challenge in the development of a DENV vaccine is that a vaccine must protect against all four DENV serotypes, which co-circulate in endemic areas. Further complicating DENV vaccine development is that the correlates of protection are not fully defined, mechanisms regulating the generation of protective antibody and T cell responses against all four DENV serotypes are as yet to be deciphered, and the adaptive immune response may actually contribute to severe disease. Recent studies using the only available animal model of DHF/DSS in mice lacking one or more components of the interferon (IFN) system have begun to provide crucial insights into the protective versus pathogenic nature of both antibody and T cell responses to DENV. Herein, we highlight key studies using the IFN receptor-deficient mouse models toward understanding the contribution of antibodies and T cells in impacting the outcome of DENV infection.

We have reported the synthesis of mesoporous titania with crystalline walls using hexadecyltrimethylammonium bromide (CTAB), a typical cationic surfactant, as a template and titanium sulfoxide as a reactant in aqueous solution (Shibata et al., 2005 [1] ). In this study, the removal method of CTAB from the mesopores without calcination or collapsing the ordered porous structure is described. First, CTAB molecules in the pore were replaced by acetic acid molecules under moderate reaction conditions. FT-IR spectra confirmed the removal of CTAB and adsorption of acetic acid. Removal of the adsorbed acetic acid was then performed by addition of carbonate ions that desorbed the acetate ions on the surface of the mesoporous titania. Mesoporous titania after removal of CTAB by the present method was found to have a more uniform pore structure compared with that after removal of CTAB by calcination treatment.

To develop improved nutrient management options for rainfed rice farmers in Nepal, we conducted two surveys and a field experiment on-farm during 2009 and 2010 in the Mid-hills, Lamjung district, and in the Inner Terai, Chitwan district. The objectives were to (i) initially distinguish together with farmers different recommendation domains for rainfed rice within the landscape, (ii) document farmers’ respective management practices, and (iii) test existing fertilizer options in these different recommendation domains with farmers’ participation. Based on the surveys and structured group discussions, four major field categories were distinguished: fields on upper or lower terraces and fields far from or close to the house. These categories did not define clearly different soils, but the trend was that soils close to the house were the most fertile and fields far from the house were the least fertile. Almost all farmers applied less fertilizer in fertile fields. Organic fertilizer was preferably applied in fields close to the house and to non-rice crops in the dry season, whereas inorganic fertilizer was preferably applied to rice and in lower fields and fields far from the house. Upper fields received little inorganic fertilizer in the Mid-hills but normal rates in the Inner Terai. No clear preference for fertilizer use in drought-prone versus wetter fields was found. In the Mid-hills, across both experimental seasons and all fertilizer treatments, rice yields were highest near the house (4.38 t ha−1), similar in lower fields and far from the house (3.86 and 3.35 t ha−1, respectively), and lowest in upper fields (2.78 t ha−1). A medium fertilizer rate tested (60–30–20 N–P2O5–K2O kg ha−1) increased average yields by 1 t ha−1 compared with the control (no fertilizer applied), and by 0.5 t ha−1 compared with the farmers’ practice. Yield gains and agronomic efficiency of N were similar in both seasons, and the highest values for both indicators were found for fields near the house, whereas the lowest values for both characteristics were found in upper terrace fields. We conclude that grain yields can be substantially increased with applications of medium fertilizer rates, and that inorganic fertilizer use is most profitable in fields near the house, followed by lower terrace fields and fields far from the house. The application of organic and little inorganic fertilizer seems to be the best option in drought-prone upper fields.

Zika virus (ZIKV) targets neural progenitor cells in the brain, attenuates cell proliferation, and leads to cell death. Here, we describe a role for the ZIKV protease NS2B-NS3 heterodimer in mediating neurotoxicity through cleavage of a host protein required for neurogenesis. Similar to ZIKV infection, NS2B-NS3 expression led to cytokinesis defects and cell death in a protease activity-dependent fashion. Among binding partners, NS2B-NS3 cleaved Septin-2, a cytoskeletal factor involved in cytokinesis. Cleavage of Septin-2 occurred at residue 306 and forced expression of a non-cleavable Septin-2 restored cytokinesis, suggesting a direct mechanism of ZIKV-induced neural toxicity. Video Abstract: Mechanisms by which Zika virus leads to microcephaly are poorly understood. Here, Li et al. demonstrate the Zika protease, required for viral replication, associates with host proteins and cleaves Septin-2, a protein required for neural cell division.

An influenza pandemic poses a serious threat to humans and animals. Conventional treatments against influenza include two classes of pathogen-targeting antivirals: M2 ion channel blockers (such as amantadine) and neuraminidase inhibitors (such as oseltamivir). Examination of the mechanism of influenza viral infection has shown that endosomal acidification plays a major role in facilitating the fusion between viral and endosomal membranes. This pathway has led to investigations on vacuolar ATPase (v-ATPase) activity, whose role as a regulating factor on influenza virus replication has been verified in extensive genome-wide screenings. Blocking v-ATPase activity thus presents the opportunity to interfere with influenza viral infection by preventing the pH-dependent membrane fusion between endosomes and virions. This study aims to apply diphyllin, a natural compound shown to be as a novel v-ATPase inhibitor, as a potential antiviral for various influenza virus strains using cell-based assays. The results show that diphyllin alters cellular susceptibility to influenza viruses through the inhibition of endosomal acidification, thus interfering with downstream virus replication, including that of known drug-resistant strains. In addition, combinatorial treatment of the host-targeting diphyllin with pathogen-targeting therapeutics (oseltamivir and amantadine) demonstrates enhanced antiviral effects and cell protection in vitro.

The aim of the present study was to evaluate the ability of the iminosugar drug UV-4 to provide in vivo protection from lethal dengue virus (DENV) challenge. This study utilized a well-described model of dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS)-like lethal disease in AG129 mice lacking the type I and II interferon receptors. Herein, we present UV-4 as a potent iminosugar for controlling DENV infection and disease in this mouse model. Specifically, administration of UV-4 reduced mortality, as well as viremia and viral RNA in key tissues, and cytokine storm. In addition, UV-4 treatment can be delayed, and it does not alter the anti-DENV antibody response. These results have set the foundation for development of UV-4 as a DENV-specific antiviral in phase I human clinical trials.

Posttranslational modification of proteins by lysine acetylation regulates many biological processes ranging from signal transduction to chromatin compaction. Here we identify the acetyl-transferases CBP/p300, Tip60 and PCAF as new substrates for the ubiquitin E3 ligases SIAH1 and SIAH2. While CBP/p300 can undergo ubiquitin/proteasome-dependent degradation by SIAH1 and SIAH2, the two other acetyl-transferases are exclusively degraded by SIAH2. Accordingly, SIAH-deficient cells show enhanced protein acetylation, thus revealing SIAH proteins as indirect regulators of the cellular acetylation status. Functional experiments show that Tip60/PCAF-mediated acetylation of the tumor suppressor p53 is antagonized by the p53 target gene SIAH2 which mediates ubiquitin/proteasome-mediated degradation of both acetyl-transferases and consequently diminishes p53 acetylation and transcriptional activity. The p53 kinase HIPK2 mediates hierarchical phosphorylation of SIAH2 at 5 sites, which further boosts its activity as a ubiquitin E3 ligase for several substrates and therefore dampens the late p53 response. © 2012 Elsevier B.V., German Research Foundation; International Graduate Program PROMISE; MICINN (SAF2010-17122), Consejería Salud Junta de Andalucía (PI-0650-2010)

Antibody (Ab)-dependent enhancement can exacerbate dengue virus (DENV) infection due to cross-reactive Abs from an initial DENV infection, facilitating replication of a second DENV. Zika virus (ZIKV) emerged in DENV-endemic areas, raising questions about whether existing immunity could affect these related flaviviruses. We show that mice born with circulating maternal Abs against ZIKV develop severe disease upon DENV infection. Compared with pups of naive mothers, those born to ZIKV-immune mice lacking type I interferon receptor in myeloid cells (LysMCre+Ifnar1fl/fl) exhibit heightened disease and viremia upon DENV infection. Passive transfer of IgG isolated from mice born to ZIKV-immune mothers resulted in increased viremia in naive recipient mice. Treatment with Abs blocking inflammatory cytokine tumor necrosis factor linked to DENV disease or Abs blocking DENV entry improved survival of DENV-infected mice born to ZIKV-immune mothers. Thus, the maternal Ab response to ZIKV infection or vaccination might predispose to severe dengue disease in infants.