ZIKV Infection Research Articles

Importation of dengue, Zika and chikungunya infections in Europe: the current situation in Greece.

Although several arboviruses—such as dengue (DENV), Zika (ZIKV) and chikungunya (CHIKV) viruses—are not endemic in Europe, they have the potential to emerge following importation of the virus, taking advantage of the favourable climate and ecosystem. DENV, ZIKV and CHIKV are transmitted by Aedes species mosquitoes and are amongst the most common travel-associated arboviruses. Furthermore, they are linked to sporadic, local outbreaks, especially in the southern parts of Europe. In this review we present in brief the DENV, ZIKV and CHIKV cases imported to Greece during the last 6 years (2013–2018), and we describe the recent laboratory data obtained from the Hellenic Pasteur Institute and the National Reference Centre for Arboviruses. We report 21 imported cases of DENV, ZIKV and CHIKV infections in travellers arriving in Greece. The probable origins were south-eastern Asian (71%) and north-central American (29%) countries. Furthermore, we stress the importance of early and accurate diagnosis in spite of a plethora of diagnostic challenges that clinicians and virologists have to face. Altogether, with the authorities' awareness and the preventive measures to be applied, local transmission events can be successfully avoided, especially in summer when the temperature is favourable for mosquito-borne infections.

One-step RT-qPCR assay for ZIKV RNA detection in Aedes aegypti samples: a protocol to study infection and gene expression during ZIKV infection

BackgroundZika virus (ZIKV) is transmitted to humans during the bite of an infected mosquito. In a scenario of globalization and climate change, the frequency of outbreaks has and will increase in areas with competent vectors, revealing a need for continuous improvement of ZIKV detection tools in vector populations. A simple, rapid and sensitive assay for viral detection is quantitative reverse transcription polymerase chain reaction (qRT-PCR), yet oligos optimized for ZIKV detection in mammalian cells and samples have repeatedly shown high background when used on mosquito ribonucleic acid (RNA). In this paper, we present a one-step qRT-PCR protocol that allows for the detection of ZIKV in mosquitoes and for the evaluation of gene expression from the same mosquito sample and RNA. This assay is a less expensive qRT-PCR approach than that most frequently used in the literature and has a much lower background, allowing confident detection.MethodsOur new oligo design to detect ZIKV RNA included in silico analysis of both viral and mosquito (Ae. aegypti and Ae. albopictus) genomes, targeting sequences conserved between Asian and African ZIKV lineages, but not matching Aedes genomes. This assay will allow researchers to avoid nonspecific amplification in insect samples due to viral integration into the mosquito genome, a phenomenon known to happen in wild and colonized populations of mosquitoes. Standard curves constructed with in vitro transcribed ZIKV RNA were used to optimize the sensitivity, efficiency and reproducibility of the assay.ResultsFinally, the assay was used with success to detect both ZIKV RNA in infected mosquitoes and to detect expression of the Defensin A gene, an antimicrobial peptide (AMP) involved in Aedes aegypti immune response to virus infection.ConclusionsThe experimental approach to detect ZIKV RNA in Aedes aegypti presented here has demonstrated to be specific, sensitive and reliable, and additionally it allows for the analysis of mosquito gene expression during ZIKV infection.

Experience in diagnosing congenital Zika syndrome in Brazilian children born to asymptomatic mothers

IntroductionTypical symptoms of primary Zika virus infection are not specific and share similarities with other arbovirus infections such as dengue fever and chikungunya. As acute infection can be asymptomatic in up to 73% of cases, infants with microcephaly represent a diagnostic challenge for pediatricians. We describe the frequency of congenital Zika syndrome (CZS) in Brazilian children born to asymptomatic pregnant mothers and its differential diagnosis. MethodsThis longitudinal, observational study was conducted on children with suspected CZS whose mothers did not report rash during pregnancy, referred to the reference hospital in a metropolitan area of ​ Rio de Janeiro, Brazil. The diagnosis of suspected CZS was based on Brazilian Ministry of Health protocol. ResultsForty-three (17%) of 246 referred children were born to mothers without rash history during pregnancy. Thirteen (30%) of 43 children met the Brazilian Ministry of Health criteria for CZS, all with microcephaly (two post-natal). The other children included 11 cases with post-natal microcephaly due to hypoxic-ischemic encephalopathy (6), non-progressive encephalopathy of unknown etiology (2), microcephaly under investigation (2) and congenital toxoplasmosis (1); 17 children were misdiagnosed with microcephaly and progressed with normal head circumference during the follow-up period; one child was included because of epidemiological link and one was loss to follow-up. All children who underwent laboratory investigation for ZIKV infection during neonatal period had negative RT-qPCR tests. ConclusionWe emphasize the increasing importance of CZS in differential diagnosis of microcephaly at birth or post-natal period. Detailed clinical investigation assisted by neuroimaging tests may clarify the diagnosis of CZS when laboratory tests are not available during the acute phase of the disease.

Screening and exclusion of Zika virus infection in travellers by an NS1-based ELISA and qRT-PCR

ObjectivesZika virus (ZIKV) infection during pregnancy may cause neurological abnormalities in the foetus, and therefore fast and accurate laboratory assays are critical for rapid diagnosis. ELISA based on ZIKV NS1 protein has been developed and shown to be sensitive and highly specific; however, its negative and positive predictive values have not been tested. In this study we evaluated the ability of the NS1-based ELISA to exclude ZIKV infection and serve as a first-line screening tool for travellers. MethodsWe tested samples obtained during the peak of ZIKV infection from 1188 symptomatic and asymptomatic Israeli travellers using NS1-based IgG and IgM ELISA, real-time RT-PCR analysis and ZIKV neutralization. The Kaplan–Maier method was used to evaluate the duration of ZIKV RNA in whole blood and urine samples. ResultsNS1-based ELISA identified 20 true-positive, five false-positive and four false-negative cases, resulting in sensitivity and specificity of 83.3% (95%CI: 62–94%) and 97.5% (95%CI: 94–99%) respectively, and positive and negative predictive values of 80% (95%CI: 59–92%) and 98% (95%CI: 95–99%) respectively. Based on 14 RT-PCR-positive cases, median time to detect ZIKV RNA in whole blood was 17.5 days (range 5–58 days) and in urine 10 days (range 5–26 days). ConclusionsThe NS1-based ELISA and RT-PCR in whole blood are highly reliable for identification of ZIKV-negative and -positive cases, respectively. Combination of both assays minimizes the risk of false-negative results, and thus allows the exclusion of ZIKV infection in travellers returning from ZIKV-endemic countries, including those who are pregnant or wish for preconception screening.

Zika virus infection studies with CD34+ hematopoietic and megakaryocyte-erythroid progenitors, red blood cells and platelets.

To date, several cases of transfusion-transmitted ZIKV infections have been confirmed. Multiple studies detected prolonged occurrence of ZIKV viral RNA in whole blood as compared to plasma samples indicating potential ZIKV interaction with hematopoietic cells. Also, infection of cells from the granulocyte/macrophage lineage has been demonstrated. Patients may develop severe thrombocytopenia, microcytic anemia, and a fatal course of disease occurred in a patient with sickle cell anemia suggesting additional interference of ZIKV with erythroid and megakaryocytic cells. Therefore, we analyzed whether ZIKV propagates in or compartmentalizes with hematopoietic progenitor, erythroid, and megakaryocytic cells. ZIKV RNA replication, protein translation and infectious particle formation in hematopoietic cell lines as well as primary CD34+ HSPCs and ex vivo differentiated erythroid and megakaryocytic cells was monitored using qRT-PCR, FACS, immunofluorescence analysis and infectivity assays. Distribution of ZIKV RNA and infectious particles in spiked red blood cell (RBC) units or platelet concentrates (PCs) was evaluated. While subsets of K562 and KU812Ep6EPO cells supported ZIKV propagation, primary CD34+ HSPCs, MEP cells, RBCs, and platelets were non-permissive for ZIKV infection. In spiking studies, ZIKV RNA was detectable for 7 days in all fractions of RBC units and PCs, however, ZIKV infectious particles were not associated with erythrocytes or platelets. Viral particles from plasma or contaminating leukocytes, rather than purified CD34+ HSPCs or the cellular component of RBC units or PCs, present the greatest risk for transfusion-transmitted ZIKV infections.

Embryotoxic impact of Zika virus in a rhesus macaque in vitro implantation model†.

Zika virus (ZIKV) infection is associated with adverse pregnancy outcomes in humans, and infection in the first trimester can lead to miscarriage and stillbirth. Vertical and sexual transmissions of ZIKV have been demonstrated, yet the impact of infection during the initial stages of pregnancy remains unexplored. Here we defined the impact of ZIKV on early embryonic and placental development with a rhesus macaque model. During in vitro fertilization (IVF), macaque gametes were inoculated with a physiologically relevant dose of 5.48log10 plaque-forming units (PFU) of Zika virus/H.sapiens-tc/PUR/2015/PRVABC59_v3c2. Exposure at fertilization did not alter blastocyst formation rates compared to controls. To determine the impact of ZIKV exposure at implantation, hatched blastocysts were incubated with 3.26log10, 4.26log10, or 5.26log10 PFU, or not exposed to ZIKV, followed by extended embryo culture for 10days. ZIKV exposure negatively impacted attachment, growth, and survival in comparison to controls, with exposure to 5.26log10 PFU ZIKV resulting in embryonic degeneration by day 2. Embryonic secretion of pregnancy hormones was lower in ZIKV-exposed embryos. Increasing levels of infectious virus were detected in the culture media post-exposure, suggesting that the trophectoderm is susceptible to productive ZIKV infection. These results demonstrate that ZIKV exposure severely impacts the zona-free blastocyst, whereas exposure at the time of fertilization does not hinder blastocyst formation. Overall, early stages of pregnancy may be profoundly sensitive to infection and pregnancy loss, and the negative impact of ZIKV infection on pregnancy outcomes may be underestimated.

Risk of Zika virus-associated birth defects in congenital confirmed cases in the Brazilian Amazon.

ABSTRACTObjective.To establish the risk of microcephaly in neonates born to women infected with ZIKV during pregnancy.Methods.A cohort of laboratory-confirmed ZIKV cases of congenital infections (109 mothers infected during pregnancy and 101 newborns) among 308 suspect cases was followed in Belem, Pará, Brazil, from October 2015 to December 2017.Results.A microcephaly risk of 1.98% (95% CI 0.54-6.93%) was found, or 2 cases among the 101 neonates infected with ZIKV during pregnancy. 72% of the pregnant women had ZIKV infection confirmed by RT-qPCR during gestation.Conclusions.Results showed a low incidence of ZIKV-associated birth defects, stillbirth, and miscarriage, which contrasts with previous studies in other Brazilian regions. Previous exposure to yellow fever vaccine and/or multiserotype DENV infection could be implicated in the protection from ZIKV congenital infection.

The role of maternal malnutrition on Zika virus congenital effects

The congenital Zika syndrome is a set of birth disabilities caused by Zika virus infection during gestation. However, not all infected mothers transmit the virus to their babies. Does any environmental factor increase susceptibility? Here we explore whether protein deficiency in the maternal diet enhances the detrimental effects of ZIKV infection in early development. - submission by Jimena Barbeito-Andrés, Patricia Pestana Garcez

Congenital Zika syndrome: association between the gestational trimester of maternal infection, severity of brain computed tomography findings and microcephaly at birth.

ABSTRACTThis study analyzed possible associations between the trimester of maternal Zika virus infection (ZIKV) in pregnancy, severity of brain computed tomography (CT) findings and the presence of microcephaly at birth in children with Congenital Zika Syndrome (CZS). It was an analytical study in a cohort of children with CZS. Symptoms of maternal infection were dichotomized into the 1st trimester of pregnancy and other trimesters. Head circumference (HC) at birth was used to calculate the z-score. Mild microcephaly was defined as HC between 2 and ≥3 standard deviations (SD) below the mean for each gestational age and sex, and severe microcephaly when HC <3 SD below average. Brain CT images were evaluated by two radiologists and classified, according to the severity, into mild, moderate and severe. Fisher’s exact, Mann-Whitney and Kruskal-Wallis tests were used to verify the associations between variables. In 108 children, maternal infection in the 1st trimester of pregnancy was associated with more severe brain CT abnormalities (p=0.038), greater severity of microcephaly at birth (p=0.013) and lower HC z-scores at birth (p=0.021). The severity of brain CT lesions was also associated with lower HC z-scores at birth (p<0.001). Maternal ZIKV infection during the first trimester of pregnancy proved to be an important risk factor for a more severe spectrum of CZS, as it is associated with more severe brain CT abnormalities and, consequently, with lower HC z-scores at birth.

Simian Immunodeficiency Virus Infection of Rhesus Macaques Results in Delayed Zika Virus Clearance.

Flaviviruses are controlled by adaptive immune responses but are exquisitely sensitive to interferon-stimulated genes (ISGs). How coinfections, particularly simian immunodeficiency viruses (SIVs), that induce robust ISG signatures influence flavivirus clearance and pathogenesis is unclear. Here, we studied how Zika virus (ZIKV) infection is modulated in SIV-infected nonhuman primates. We measured ZIKV replication, cellular ZIKV RNA levels, and immune responses in non-SIV-infected and SIV-infected rhesus macaques (RMs), which we infected with ZIKV. Coinfected animals had a 1- to 2-day delay in peak ZIKV viremia, which was 30% of that in non-SIV-infected animals. However, ZIKV viremia was significantly prolonged in SIV-positive (SIV+) RMs. ISG levels at the time of ZIKV infection were predictive for lower ZIKV viremia in the SIV+ RMs, while prolonged ZIKV viremia was associated with muted and delayed adaptive responses in SIV+ RMs.IMPORTANCE Immunocompromised individuals often become symptomatic with infections which are normally fairly asymptomatic in healthy individuals. The particular mechanisms that underlie susceptibility to coinfections in human immunodeficiency virus (HIV)-infected individuals are multifaceted. ZIKV and other flaviviruses are sensitive to neutralizing antibodies, whose production can be limited in HIV-infected individuals but are also sensitive to type I interferons, which are expressed at high levels in HIV-infected individuals. Data in this study highlight how individual components of the innate and adaptive immune responses which become perturbed in HIV-infected individuals influence ZIKV infection.

Maternal vaccination and protective immunity against Zika virus vertical transmission

An important goal of the Zika virus (ZIKV) vaccine is to prevent a congenital syndrome in fetuses of pregnant women, but studies directly evaluating maternal vaccination for ZIKV are lacking. Here we report maternal vaccination using a live-attenuated ZIKV vaccine (3ʹUTR-∆10-LAV) in a pregnant mouse model. Maternal immunization with 3ʹUTR-∆10-LAV does not cause any adverse effects on pregnancy, fetal development, or offspring behavior. One maternal immunization fully protects dams against ZIKV infection and in utero transmission. Although neutralizing antibody alone is sufficient to prevent in utero transmission, a higher neutralizing titer is required to protect pregnant mice against in utero transmission than that required to protect non-pregnant mice against viral infection. The immunized dams transfer maternal antibodies to pups, which protect neonates against ZIKV infection. Notably, pregnancy weakens maternal T cell response to 3ʹUTR-∆10-LAV vaccination. Our results suggest that, besides vaccinating non-pregnant individuals, 3ʹUTR-∆10-LAV may also be considered for maternal vaccination.

Study protocol for the multicentre cohorts of Zika virus infection in pregnant women, infants, and acute clinical cases in Latin America and the Caribbean: the ZIKAlliance consortium

BackgroundThe European Commission (EC) Horizon 2020 (H2020)-funded ZIKAlliance Consortium designed a multicentre study including pregnant women (PW), children (CH) and natural history (NH) cohorts. Clinical sites were selected over a wide geographic range within Latin America and the Caribbean, taking into account the dynamic course of the ZIKV epidemic.MethodsRecruitment to the PW cohort will take place in antenatal care clinics. PW will be enrolled regardless of symptoms and followed over the course of pregnancy, approximately every 4 weeks. PW will be revisited at delivery (or after miscarriage/abortion) to assess birth outcomes, including microcephaly and other congenital abnormalities according to the evolving definition of congenital Zika syndrome (CZS).After birth, children will be followed for 2 years in the CH cohort. Follow-up visits are scheduled at ages 1–3, 4–6, 12, and 24 months to assess neurocognitive and developmental milestones. In addition, a NH cohort for the characterization of symptomatic rash/fever illness was designed, including follow-up to capture persisting health problems.Blood, urine, and other biological materials will be collected, and tested for ZIKV and other relevant arboviral diseases (dengue, chikungunya, yellow fever) using RT-PCR or serological methods. A virtual, decentralized biobank will be created. Reciprocal clinical monitoring has been established between partner sites.Substudies of ZIKV seroprevalence, transmission clustering, disabilities and health economics, viral kinetics, the potential role of antibody enhancement, and co-infections will be linked to the cohort studies.DiscussionResults of these large cohort studies will provide better risk estimates for birth defects and other developmental abnormalities associated with ZIKV infection including possible co-factors for the variability of risk estimates between other countries and regions. Additional outcomes include incidence and transmission estimates of ZIKV during and after pregnancy, characterization of short and long-term clinical course following infection and viral kinetics of ZIKV.Study registrationsclinicaltrials.gov NCT03188731 (PW cohort), June 15, 2017; clinicaltrials.gov NCT03393286 (CH cohort), January 8, 2018; clinicaltrials.gov NCT03204409 (NH cohort), July 2, 2017.

In silico drug repurposing for the identification of potential candidate molecules against arboviruses infection

Arboviral diseases caused by dengue (DENV), Zika (ZIKV) and chikungunya (CHIKV) viruses represent a major public health problem worldwide, especially in tropical areas where millions of infections occur every year. The aim of this research was to identify candidate molecules for the treatment of these diseases among the drugs currently available in the market, through in silico screening and subsequent in vitro evaluation with cell culture models of DENV and ZIKV infections. Numerous pharmaceutical compounds from antibiotics to chemotherapeutic agents presented high in silico binding affinity for the viral proteins, including ergotamine, antrafenine, natamycin, pranlukast, nilotinib, itraconazole, conivaptan and novobiocin. These five last compounds were tested in vitro, being pranlukast the one that exhibited the best antiviral activity. Further in vitro assays for this compound showed a significant inhibitory effect on DENV and ZIKV infection of human monocytic cells and human hepatocytes (Huh-7 cells) with potential abrogation of virus entry. Finally, intrinsic fluorescence analyses suggest that pranlukast may have some level of interaction with three viral proteins of DENV: envelope, capsid, and NS1. Due to its promising results, suitable accessibility in the market and reduced restrictions compared to other pharmaceuticals; the anti-asthmatic pranlukast is proposed as a drug candidate against DENV, ZIKV, and CHIKV, supporting further in vitro and in vivo assessment of the potential of this and other lead compounds that exhibited good affinity scores in silico as therapeutic agents or scaffolds for the development of new drugs against arboviral diseases.

846. Postnatally Acquired Zika Virus (ZIKV) Infection in Infants and Young Children in Guatemala: Serologic and Neurodevelopmental (ND) Evaluation

BackgroundDiagnosing ZIKV infection in children in dengue (DENV) endemic regions is challenging. The kinetics and effects of maternal Ab on infant infection responses remain unknown, as do the ND effects of ZIKV acquired in early life.MethodsThis is a population-based prospective cohort study in infant–mother pairs and children <5 years in a rural DENV endemic area of Guatemala evaluating the incidence and ND outcomes of postnatally cquired ZIKV infection. Subjects were followed 1 year for symptoms of flavivirus-like illness (FLI), serologic and virologic evidence of ZIKV or DENV infection and ND outcomes. ZIKV and DENV neutralizing antibodies (NAb) were measured at enrollment and longitudinally. Subjects were classified as ZIKV- or DENV-infected based on NAb. Specimens from acute illnesses were tested for viral RNA by rRT-PCR. ND was assessed at enrollment and longitudinally using an adapted Mullen Scales of Early Learning (MSEL).ResultsIn total, 1,371 subjects (374 children 1–5 years, 500 infants, 497 mothers) were enrolled from June 2017 to July 2018. Among 1,335 evaluable subjects, 7.6% (101) had serologic evidence of recent ZIKV infection (NAb >500 or >100 and DENV-neg); 13.2% (176) were DENV-pos only; 44.8% (598) were ZIKV-neg (NAb15 −<100) or low (<500) ZIKV and DENV NAb, suggesting prior flavivirus infection or cross-reactivity (Figures 1 and 2). ZIKV infection alone was more prevalent in children 1–5 years, while infants’ serologic pattern was similar to that of their mothers. One child ZIKV seroconverted. In 391 FLI episodes (67 children 1–5 years and 215 infants with fever, rash, myalgia, and conjunctivitis; 109 mothers with fever, myalgia, and joint pain), acute DENV infections, but not ZIKV, were identified by rRT-PCR. MSEL scores were similar to US norms in infants <12 m (composite mean 94.8, SD 11.9), but lower in children 1–5 years in all domains (mean 75.1, SD 17.4, P < 0.0001) (Figure 3).ConclusionSerologic evidence of recent ZIKV infection, but no acute ZIKV, was documented in young children in Guatemala. Infant seroreactivity derives from prior maternal infection and DENV cross-reactivity. Observed substantial differences in ND scores between infants and children 1–5 years challenge the ability to isolate the potential effects of ZIKV infection in early life. NIAID Contract HHSN272201300015I Task Order HHSN27200013. FMM and EJA Co-PIs. DisclosuresFlor M. Munoz, MD, Biocryst: Grant/Research Support; CDC: Research Grant; Moderna: Other Financial or Material Support, Safety Monitoring Board Member/Chair; NIH: Research Grant; Novavax: Research Grant; UP to Date: Author and Editor: Royalties, Other Financial or Material Support.

2805. Kinetics of Anti-Zika Virus (ZIKV) Antibodies after Acute Infection in Pregnant Women

BackgroundThe kinetics and specificity of anti-ZIKV antibodies after acute ZIKV infection is not well known, especially in areas where different flaviviruses circulate. The objective of this study was to describe the kinetics of anti-ZIKV antibodies in pregnant women in whom an acute ZIKV infection was identified during pregnancy.MethodsWithin a cohort of pregnant women living in Guadeloupe and exposed to ZIKV during the 2016 zika outbreak, we identified 65 women who presented with an acute, symptomatic PCR-confirmed ZIKV infection at various times of their pregnancy, with a known date of first Zika symptom. Anti-ZIKV neutralizing antibodies (using a Virus Neutralisation Test (VNT)) and anti-ZIKV NS1 antibodies (using IgM and IgG ELISA Euroimmun® kits) were searched for on frozen serum samples obtained from blood drawn at the time of delivery in all women and at various times between acute infection and delivery in 23 women.ResultsPatients’ mean age was 30 years and ZIKV infection had occurred during the first, second, and third trimester of pregnancy in 14 (21%), 35 (54%), and 16 (25%) women, respectively. ZIKV serology on delivery samples was positive in 65/65 (100%; one-sided 97.5% CI: 94.4%–100%) women by both VNT and IgG ELISA assays and in 5/65 (8%) women by IgM ELISA assay. In these 5 cases, median time between first symptom and sampling date was 36 days. Results of ELISA assays on the intermediate samples were as follows: IgG antibodies were negative in all 5 samples that had been drawn within 7 days of first symptom and positive in the 18 samples that had been drawn afterwards; IgM antibodies were positive in 10 of the 19 samples that had been drawn within 3 months of first symptom and negative in 2 of the 4 samples that had been drawn afterwards.ConclusionAfter acute ZIKV infection, IgG antibodies developed and remained detectable until delivery by a commercially available ELISA assay in all women tested. These antibodies were specific of ZIKV, with concomitantly positive VNT results. From these findings, the absence of ZIKV antibodies at delivery would strongly indicate the absence of infection during pregnancy.Disclosures All authors: No reported disclosures.

2904. Protective Efficacy of Nucleic Acid Vaccines Against Transmission of Zika Virus During Pregnancy in Mice

BackgroundZika virus (ZIKV) caused an epidemic of microcephaly and congenital malformations in 2015–2016, prompting the development of ZIKV vaccines. Plasmid DNA and modified mRNA lipid nanoparticle-encapsulated (mRNA-LNP) vaccines were among the first to reach human clinical trials, where their evaluation is ongoing. Few studies have evaluated vaccine efficacy in the setting of infection during pregnancy, and there is an open question around antibody-dependent enhancement (ADE) of flaviviral disease due to cross-reactive fusion loop epitope (FLE) antibodies.MethodsFemale C57BL/6J mice and human STAT2 knock-in (hSTAT2-KI) mice were immunized with plasmid DNA (VRC5283) or mRNA-LNP (Moderna Inc.) vaccines encoding the ZIKV prM-E genes. Antibody responses were assayed, and immunized mice were mated and WT mice were transiently immunocompromised by administration of interferon blocking antibody, followed by ZIKV challenge. 1 week post-infection, ZIKV burden was measured via qRT-PCR. ZIKV-specific memory B cell (MBC), long-lived plasma cell (LLPC), and CD8+ T cell vaccine responses were also assayed.ResultsVRC5283 and mRNA-LNP vaccines were highly immunogenic, eliciting serum neutralizing EC50 responses >1:10,000, and markedly reduced placental ZIKV burden and fetal transmission. An improved mRNA-LNP construct with higher immunogenicity correlated with reduced placental viral burden. Significantly, an FLE-mutant mRNA-LNP vaccine yielded comparable EC50 responses without compromising vaccine efficacy; sera from these mice did not enhance dengue virus infection in vitro. Both VRC5283 and mRNA-LNP vaccines elicited MBC, LLPC, and CD8+ T cell responses, although MBC and LLPC responses were greater after mRNA-LNP immunization. Surprisingly, low-level ZIKV infection of the placenta and a minority of fetal heads were observed despite robust neutralizing antibody responses, which was not seen in the immunocompetent hSTAT2-KI model.ConclusionNucleic acid vaccines were highly immunogenic and protective against vertical ZIKV transmission during pregnancy in mice. These data support and inform the ongoing clinical development of these vaccines in humans.Disclosures All Authors: No reported Disclosures.

Surveillance for Zika in Mexico: naturally infected mosquitoes in urban and semi-urban areas

ABSTRACTZika cases have been reported in 29 out of the 32 states of Mexico. Information regarding which mosquito species might be driving Zika virus transmission/maintenance in nature must be regularly updated. From January 2017 to November 2018, mosquitoes were collected indoors and outdoors using the CDC backpack aspirator in urban and semi-urban areas with evidence of mosquito-borne disease transmission. 3873 mosquito pools were tested for Zika infection using the CDC Trioplex real-time RT-PCR. For each collected specie, maximum likelihood estimator of infection rate (MLE) was estimated. Results showed 492 mosquito pools positive for Zika virus RNA. The majority of the positive pools were Aedes (Stegomyia) aegypti (Linnaeus) (54.6%, MLE = 19) (males and females) and Culex (Culex) quinquefasciatus (Say) (19.5%, MLE = 16.8). For the first time, ZIKV infection was detected in Ae. (Georgecraigius) epactius (Dyar and Knab) (MLE = 17.1), Cx. (Melanoconion) erraticus (Dyar and Knab) (MLE = non-estimable), Culiseta (Culiseta) inornata (Williston) (MLE = non estimable), and Cs (Cs.) particeps (Adams) (MLE = 369.5). Other detected species were: Ae. (Stg.) albopictus (Skuse) (MLE = 90.5), Cx. (Cx.) coronator s.l. (Dyar and Knab) (MLE = 102.8) and Cx. (Cx.) tarsalis (Coquillett) (MLE = 117.2). However, our results do not allow for the incrimination of these species as vectors of ZIKV. Routine surveillance should start to consider other mosquito species across the taxonomic spectrum of the Culicidae.

Impact of Organophosphate Pesticide Exposures on Zika Infection Health Outcomes

TPS 633: Health effects of pesticides, Johan Friso Foyer, Floor 1, August 27, 2019, 3:00 PM - 4:30 PM Zika infection during pregnancy is the first identified vector-borne human teratogen. Although causality was established, the rate of affected infants varies geographically, appearing to be higher in the rural areas than in urban settings. Environmental exposures, such as pesticides, may interact with Zika infection to result in different degrees of severity of disease or an increased risk to the infant. Pesticides and other environmental exposures are ubiquitous and some, such as organophosphate pesticides, are endocrine disruptors and have been associated with eliciting oxidative stress, as well as birth outcomes including miscarriages and developmental disabilities in children. The Zika in Infants and Pregnancy (ZIP) study, sponsored by NIH, is an observational cohort study that planned to recruit up to 10,000 pregnant women in 10 sites throughout South America, Central America, and Puerto Rico. Women are recruited on or before 18 weeks of gestation and followed monthly including clinical exams and specimen collection. Additionally, information is collected on health behaviors, home product use, household and occupational characteristics, as well as pesticide exposure laboratory analysis. The pesticide exposure analysis being presented is conducted by the NIEHS Children’s Health Exposure Analysis Resource (CHEAR) laboratory resources. This presentation will communicate the preliminary results of the urinary organophosphate metabolite analysis of over 2000 samples from about 1200 pregnant women in Puerto Rico, Nicaragua, Guatemala, and Brazil. This analysis will provide the first survey of pesticide exposures among pregnant women in several Latin American countries and will further the understanding of cause-effect relationships between pesticides and developmental defects. It is also a unique opportunity to understanding the potential interaction between ZIKV infection and pesticide exposure during pregnancy.

Antibodies to Zika virus, Campylobacter jejuni, gangliosides in Guillain Barre syndrome. A prospective single centre study from southern India

The objective was to study the presence of antibodies against Zika virus, Camplyobacter jejuni and gangliosides in patients with Guillain Barre syndrome. Ninety consecutive patients (age more than 12 years) with GBS admitted to a tertiary care centre in southern India were included in this study. Data on the clinical manifestations, Nerve conduction studies and response to therapy were collected. The following tests were done in stored serum samples - Anti-Zika virus (IgM) antibodies, Anti-Campylobacter jejuni (IgG) antibodies and Anti-ganglioside antibodies (IgG). Those samples which were positive to Anti Zika antibodies were tested for conventional PCR for Zika virus, IgM antibodies against Dengue and Japanese encephalitis. Of the 90 patients, 3 died and 8 had persistent weakness. AIDP was the most common type of GBS (56.7%). Anti-ganglioside antibodies were present in 62.2% with GT1b being most common. Anti-C.jejuni antibodies were present in 46.6%. Anti-Zika antibodies (IgM) were present in 14 patients (15.5%). Four of these patients also had anti-Dengue antibody (IgM) positivity. This is one of the largest study on GBS from India and the first one to report on the presence of Zika antibodies form this geographical area. Our study had high prevalence of anti C.jejuni and anti ganglioside antibodies. Evidence of recent ZIKV infection as evidenced by anti IgM antibodies was present in 14 patients with 4 of them tested positive for anti-Dengue IgM antibody. Whether this represents cross reaction with Dengue or prior/co- infection with Dengue could not be addressed in this study.

High specificity and sensitivity of Zika EDIII-based ELISA diagnosis highlighted by a large human reference panel.

BackgroundZika virus (ZIKV) and Dengue virus (DENV) are often co-endemic. The high protein-sequence homology of flaviviruses renders IgG induced by and directed against them highly cross-reactive against their antigen(s), as observed on a large set of sera, leading to poorly reliable sero-diagnosis.MethodsWe selected Domain III of the ZIKV Envelope (ZEDIII) sequence, which is virus specific. This recombinant domain was expressed and purified for the specific detection of ZEDIII-induced IgG by ELISA from ZIKV-RT-PCR-positive, ZIKV-IgM-positive, flavivirus-positive but ZIKV-negative, or flavivirus-negative sera. We also assessed the reactivity of ZEDIII-specific human antibodies against EDIII of DENV serotype 4 (D4EDIII) as a specific control. Sera from ZEDIII-immunized mice were also tested.ResultsCross-reactivity of IgG from 5,600 sera against total inactivated DENV or ZIKV was high (71.0% [69.1; 72.2]), whereas the specificity and sensitivity calculated using a representative cohort (242 sera) reached 90% [84.0; 95.8] and 92% [84.5; 99.5], respectively, using a ZEDIII-based ELISA. Moreover, purified human IgG against D2EDIII or D4EDIII did not bind to ZEDIII and we observed no D4EDIII reactivity with ZIKV-induced mouse polyclonal IgGs.ConclusionsWe developed a ZEDIII-based ELISA that can discriminate between past or current DENV and ZIKV infections, allowing the detection of a serological scar from other flaviviruses. This could be used to confirm exposure of pregnant women or to follow the spread of an endemic disease.