Zika virus infection: an update

Since the ZIKV outbreak in Brazil in 2015, the scientific community has joined efforts to gather more information on the epidemiology, clinical features and pathogenicity of the virus. Here, we summarize the most important advances made recently and discuss promising, innovative approaches to understand and control ZIKV infection.     

Fetal loss in pregnant rhesus macaques infected with high-dose African-lineage Zika virus

Countermeasures against Zika virus (ZIKV), including vaccines, are frequently tested in nonhuman primates (NHP). Macaque models are important for understanding how ZIKV infections impact human pregnancy due to similarities in placental development. The lack of consistent adverse pregnancy outcomes in ZIKV-affected pregnancies poses a challenge in macaque studies where group sizes are often small (4–8 animals). Studies in small animal models suggest that African-lineage Zika viruses can cause more frequent and severe fetal outcomes. No adverse outcomes were observed in macaques exposed to 1x10⁴ PFU (low dose) of African-lineage ZIKV at gestational day (GD) 45. Here, we exposed eight pregnant rhesus macaques to 1x10⁸ PFU (high dose) of African-lineage ZIKV at GD 45 to test the hypothesis that adverse pregnancy outcomes are dose-dependent. Three of eight pregnancies ended prematurely with fetal death. ZIKV was detected in both fetal and placental tissues from all cases of early fetal loss. Further refinements of this exposure system (e.g., varying the dose and timing of infection) could lead to an even more consistent, unambiguous fetal loss phenotype for assessing ZIKV countermeasures in pregnancy. These data demonstrate that high-dose exposure to African-lineage ZIKV causes pregnancy loss in macaques and also suggest that ZIKV-induced first trimester pregnancy loss could be strain-specific.     

Zika病毒感染的实验室诊断

Zika病毒是一种新现虫媒黄病毒,近期在美洲暴发流行,并有向全球扩散的趋势,已成为国际关注的突发公共卫生事件。Zika病毒感染的临床诊断主要依据实验室检测结果。本文就Zika病毒的核酸检测、抗原和抗体检测、病毒分离鉴定等方面进行综述。     

三江地区妊娠妇女风疹病毒感染的血清学分析

目的调查2005年三江地区妊娠妇女风疹病毒感染情况。方法收集400例妊娠8～24周孕妇血清,采用酶联免疫吸附法（ELISA）检测风疹特异性IgM抗体,对IgM阳性患者进一步用PCR检测风疹病毒RNA,对该人群的风疹病毒感染率进行调查。结果检测400例孕妇风疹病毒IgM,阳性20例,阳性率为5．00％;检测IgM阳性者的风疹病毒RNA,结果阳性8例,占IgM阳性者的40．00％。结论用ELISA和PCR法进行妊娠早期风疹病毒感染的检测,对降低先天性风疹综合征患儿的出现具有重要意义。     

Management of infection by the Zika virus

A panel of national experts was convened by the Brazilian Infectious Diseases Society in order to organize the national recommendations for the management of zika virus infection. The focus of this document is the diagnosis, both clinical and laboratorial, and appropriate treatment of the diverse manifestations of this infection, ranging from acute mild disease to Guillain-Barré syndrome and also microcephaly and congenital malformations.     

Seroprevalence of Toxoplasma gondii infection and risk factors associated with seropositivity of pregnant women in Korea

A total of 351 serum samples was examined for anti-T. gondii antibody titers; the overall seroprevalence was 3.7%. The Sabin-Feldman dye test (DT), latex agglutination test (LAT), and IgG enzyme-linked immunosorbent assay (IgG ELISA) indicated seroprevalences of 3.7%, 3.4%, and 4.0%, respectively. Compared with the DT, the sensitivities of the LAT and IgG ELISA were 84.6% and 100.0%, respectively, and the specificities of the LAT and IgG ELISA were both 99.7%. An increase in T. gondii seroprevalence with increasing age was detected, but the difference was not significant. The overall seroprevalence of T. gondii-antibody titers in pregnant Korean women was relatively low compared to those of Europeans and Americans. A multivariate analysis of risk factors showed that T. gondii infection was positively correlated with eating raw meat, but was not associated with the consumption of unwashed vegetables, drinking untreated water, a history of raising a cat, or blood transfusion. The consumption of raw or undercooked meat may, therefore, be the main route of T. gondii infection in Korea.     

HIV infection in pregnant women in Chelyabinsk

Data on HIV infection in pregnant women in Chelyabinsk are presented. Starting from 1999, a considerable rise in the number of HIV-infected persons was registered in this city. The social and epidemiological characteristics of HIV-infected pregnant women, as well as the main routes and factors of the infective agent transmission, are given. Relationship between the spread of HIV-infection and drug addiction is revealed. The occurrence of different opportunistic infections in HIV-infected pregnant women is determined.     

Prevalence of hepatitis B virus infection in pregnant women in the Montreal area.

From January 1982 to June 1984, 30,315 serum specimens from pregnant women at nine hospitals in the Montreal area were screened for hepatitis B surface antigen (HBsAg). Of the specimens 103, from 98 women, were positive, a prevalence rate of 3.4 per 1000. The ethnic origin of the 98 women and the number who were also positive for e antigen (HBeAg) were as follows: French-Canadian, 29 (3 HBeAg-positive); Asian, 28 (14); Haitian, 32 (0); other, 7 (0); and unknown, 2 (0). The prevalence rates of HBsAg positivity according to ethnic origin at one of the hospitals were 73.9 in Asians, 33.1 in Haitians, 0.9 in French Canadians and 8.0 in women of other extraction. If the prevalence rate found in this study is true for the 95 000 live births that occur yearly in the province of Quebec, there are an estimated 323 infants at risk for hepatitis B virus (HBV) infection each year in the province. Screening programs for detecting HBV carriage in pregnant women should be instituted, since recent studies have shown combined active-passive immunization to be effective in preventing perinatal transmission of HBV infection.     

Zika virus spreads through infection of lymph node-resident macrophages

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Identification of novel small-molecule inhibitors of Zika virus infection

The recent re-emergence of Zika virus (ZIKV), a member of the Flaviviridae family, has become a global emergency and a serious public health threat worldwide. ZIKV infection causes severe neuroimmunopathology and is particularly harmful to the developing fetuses of infected pregnant women causing various developmental abnormalities. Currently, there are no effective methods of preventing or treating ZIKV infection, and new treatment options are urgently needed. Therefore, we have used an in vitro plaque assay to screen a limited proprietary library of small organic compounds and identified highly bioactive leads, with the most active analogs showing activity in low picomolar range. Identified “hits” possess certain common structural features that can be used in the design of the next generation(s) of ZIKV inhibitors. Collectively, our findings suggest that identified compounds represent excellent template(s) for the development of inexpensive and orally available anti-Zika drugs.     

Yellow fever vaccine protects mice against Zika virus infection

Zika virus (ZIKV) emerged as an important infectious disease agent in Brazil in 2016. Infection usually leads to mild symptoms, but severe congenital neurological disorders and Guillain-Barré syndrome have been reported following ZIKV exposure. Creating an effective vaccine against ZIKV is a public health priority. We describe the protective effect of an already licensed attenuated yellow fever vaccine (YFV, 17DD) in type-I interferon receptor knockout mice (A129) and immunocompetent BALB/c and SV-129 (A129 background) mice infected with ZIKV. YFV vaccination provided protection against ZIKV, with decreased mortality in A129 mice, a reduction in the cerebral viral load in all mice, and weight loss prevention in BALB/c mice. The A129 mice that were challenged two and three weeks after the first dose of the vaccine were fully protected, whereas partial protection was observed five weeks after vaccination. In all cases, the YFV vaccine provoked a substantial decrease in the cerebral viral load. YFV immunization also prevented hippocampal synapse loss and microgliosis in ZIKV-infected mice. Our vaccine model is T cell-dependent, with AG129 mice being unable to tolerate immunization (vaccination is lethal in this mouse model), indicating the importance of IFN-γ in immunogenicity. To confirm the role of T cells, we immunized nude mice that we demonstrated to be very susceptible to infection. Immunization with YFV and challenge 7 days after booster did not protect nude mice in terms of weight loss and showed partial protection in the survival curve. When we evaluated the humoral response, the vaccine elicited significant antibody titers against ZIKV; however, it showed no neutralizing activity in vitro and in vivo. The data indicate that a cell-mediated response promotes protection against cerebral infection, which is crucial to vaccine protection, and it appears to not necessarily require a humoral response. This protective effect can also be attributed to innate factors, but more studies are needed to strengthen this hypothesis. Our findings open the way to using an available and inexpensive vaccine for large-scale immunization in the event of a ZIKV outbreak.     

乙肝孕妇宫内感染监测与HBVM评估

目的监测孕妇产前感染HBV与宫内感染情况,评估乙肝孕妇血清中乙肝血清标志物（HBVM）对宫内感染HBV的风险大小,指导育龄妇女早期预防宫内感染。方法采用ELISA法检测孕妇血清乙肝标志物（HBVM）6项,即HBsAg、HBsAb、HBeAg、HBeAb、HBcAb与Pre-S1;筛选乙肝携带者采用实时荧光定量PCR法进行HBV DNA检测;应用ELISA法对新生儿24h内（免疫接种前）外周血HBsAg、Pre-S1和、HBeAg进行检测。结果1002例孕妇中乙肝感染率为10．6％,106例乙肝孕妇宫内感染34例,宫内感染率为32％。HBeAg（＋）者宫内感染风险率最高为77％,HBV DNA（＋）与Pre-S1（＋）次之。HBV DNA（-）宫内感染风险率最低为2％,HBeAg（-）与Pre-S1（-）次之。结论乙肝孕妇宫内感染率较高;HBeAg（＋）孕妇宫内感染HBV风险最高,可作为育龄妇女采取措施积极预防宫内感染的指标。HBV DNA（-）宫内感染率最低,可作为育龄妇女宫内安全的评估指标。Pre-S1是宫内感染的有利补充指标。     

Zika virus infection activates sting-dependent antiviral autophagy in the Drosophila brain

Viral infection of neurons is pathogenic, yet the factors that govern innate control of neurons remain incompletely understood. Using a Drosophila model we have defined the essential role that inflammatory-dependent Sting activation plays in inducing antiviral macroautophagy/autophagy to restrict Zika infection in the fly brain. Our discovery that Sting is an essential mediator of innate defenses in Drosophila provides further support for an ancient and conserved pathway that likely evolved to target intracellular pathogens for autophagic destruction.     

Toxoplasma gondii infection in pregnant women in China

Toxoplasmosis, caused by the protozoan parasite Toxoplasma gondii, is one of the most common parasitic infections in humans. Primary infection in pregnant women can be transmitted to the fetus leading to miscarriage or congenital toxoplasmosis. Carefully designed nationwide seroprevalence surveys and case-control studies of risk factors conducted primarily in Europe and America, have shaped our view of the global status of maternal and congenital infection, directing approaches to disease prevention. However, despite encompassing 1 in 5 of the world's population, information is limited on the status of toxoplasmosis in China, partly due to the linguistic inaccessibility of the Chinese literature to the global scientific community. By selection and analysis of studies and data, reported within the last 2 decades in China, this review summarizes and renders accessible a large body of Chinese and other literature and aims to estimate the seroprevalence in Chinese pregnant women. It also reviews the prevalence trends, risk factors, and clinical manifestations. The key findings are (1) the majority of studies show that the overall seroprevalence in Chinese pregnant women is less than 10%, considerably lower than a recently published global analysis; and (2) the few available appropriate studies on maternal acute infection suggested an incidence of 0·3% which is broadly comparable to studies from other countries.     

Zika virus infection of the placenta alters extracellular matrix proteome

Journal of Molecular Histology - Zika virus (ZIKV) infection has been associated with fetal abnormalities by compromising placental integrity, but the mechanisms by which this occurs are unknown....     

Optimization of 1,3-disubstituted urea-based inhibitors of Zika virus infection

Zika virus (ZIKV) has become a public health concern worldwide due to its association with congenital abnormalities and neurological diseases. To date, no effective vaccines or antiviral drugs have been approved for the treatment of ZIKV infection, and new inexpensive therapeutic options are urgently needed. In this study, we have used an in vitro plaque assay to assess an antiviral activity of the second generation of anti-ZIKV compounds, based on 1,3-disubstituted (thio)urea scaffold. Several compounds in the library were found to possess excellent activity against Zika virus with IC₅₀ values <200 pM. The most active analog, A5 exhibited an exceptional IC₅₀ = 85.1 ± 1.7 pM. Further analysis delineated structural requirements necessary for potent antiviral effects of this class of compounds. Collectively, our findings suggest that 1,3-disubstituted (thio)urea derivatives are excellent preclinical candidates for the development of anti-ZIKV therapeutics.