Clinical aspects of Zika virus

Identification of a small compound that specifically inhibits Zika virus in vitro and in vivo by targeting the NS2B-NS3 protease

Zika virus (ZIKV) has rapid become a global threat, but no ZIKV-specific vaccines or drugs are currently available. In this study, inhibitors of ZIKV NS2B-NS3 protease were screened from a library containing 4,452 compound fragments. One of the compounds, 6-bromo-1,2-naphthalenedione, exhibited high specific inhibition against ZIKV NS2B-NS3 protease, but had no inhibitory effects against other viral proteases. A microscale thermophoresis (MST) assay confirmed that the compound bound to ZIKV NS2B-NS3 protein with a binding constant (Kd) of 12.26 μM. Indirect immunofluorescence assays, Western blots, and plaque assays indicated that the compound inhibited virus replication in cells. Virus titer was reduced by more than 75% when the compound was present at 1 μM. A time-of-addition assay showed that inhibition occurred at the virus replication stage, but not at the adsorption or invasion stages. The half cytotoxicity concentration (CC50) of the compound on HeLa, Vero, and BHK-21 cells were 445.44 μM, 123.87 μM, and 123.64 μM, respectively. In vivo tests using infected AG129 mice demonstrated that treatment with the compound reduced mortality by up to 60%. Mice treated with the compound showed a reduction in histopathological lesions in brain, testis, and ovary. Viral RNA, IL-1β, and IL-6 mRNA levels decreased significantly in these tissues. In summary, this study has identified a small compound with high and specific inhibitory effects on ZIKV. The compound can be used as a therapeutic agent and is also an ideal starting point for drug optimization.

Zika Virus Pathogenesis: A Battle for Immune Evasion

Zika virus (ZIKV) infection and its associated congenital and other neurological disorders, particularly microcephaly and other fetal developmental abnormalities, constitute a World Health Organization (WHO) Zika Virus Research Agenda within the WHO’s R&D Blueprint for Action to Prevent Epidemics, and continue to be a Public Health Emergency of International Concern (PHEIC) today. ZIKV pathogenicity is initiated by viral infection and propagation across multiple placental and fetal tissue barriers, and is critically strengthened by subverting host immunity. ZIKV immune evasion involves viral non-structural proteins, genomic and non-coding RNA and microRNA (miRNA) to modulate interferon (IFN) signaling and production, interfering with intracellular signal pathways and autophagy, and promoting cellular environment changes together with secretion of cellular components to escape innate and adaptive immunity and further infect privileged immune organs/tissues such as the placenta and eyes. This review includes a description of recent advances in the understanding of the mechanisms underlying ZIKV immune modulation and evasion that strongly condition viral pathogenesis, which would certainly contribute to the development of anti-ZIKV strategies, drugs, and vaccines.

Going Viral 2019: Zika, Chikungunya, and Dengue

Chikungunya and Zika virus infections are emerging diseases in the Americas, and dengue continues to be the most prevalent arthropod-borne virus in the world. These arbovirus diseases may spread by endemic transmission or as travel-related infections and have rapidly expanded their geographic distribution secondary to vector spread. All 3 share a similar clinical picture that includes a maculopapular rash. Zika is characterized by pruritic rash, low-grade fever, and arthralgia. Congenital nervous system malformations are a growing public-health concern. Chikungunya distinctive dermatologic manifestations include facial melanosis and bullous eruption. Dengue bleeding complications may be life-threatening and require inpatient management.

Establishment of a comprehensive and high throughput serological algorithm for Zika virus diagnostic testing

The previous serological algorithm for Zika virus (ZIKV) comprised screening by anti-ZIKV IgM capture ELISA (MAC-ELISA) for samples collected within 3 months postexposure or onset (MPEO). Samples positive by MAC-ELISA and samples collected beyond 3 MPEO were tested by the confirmatory plaque reduction neutralization test (PRNT), which proved laborious and time-consuming during the 2015 outbreak. Thus, we evaluated several ZIKV ELISAs to establish an anti-IgM and anti-IgG combination for use as a screening tool for all samples prior to PRNT confirmation. The MAC-ELISA or InBios-M in combination with the Euroimmun-G demonstrated sensitivities of 99.1% and 97.2%, respectively, and nonflavivirus specificity of 96.0%. Their cross-reactivities were 71.4% and 50.0%, respectively, for sera positive for Dengue virus antibodies. Due to near-perfect interrater agreement with PRNT and excellent detection of samples collected beyond 3 MPEO, these combinations were recommended as a screening protocol in a new high-throughput algorithm with special considerations for ZIKV diagnostics.

Zika clinical updates: implications for pediatrics

PURPOSE OF REVIEW

Zika virus (ZIKV), a mosquito-borne flavivirus, has gained recognition over the past few years as an important new cause of congenital infection. As a result, it is critical that pediatricians understand its epidemiology, clinical presentation, clinical sequelae, and management.

RECENT FINDINGS

The recent ZIKV epidemiology, clinical presentation of acute infection in children and complications, perinatal infection, and congenital infection will be summarized in this ZIKV review. This will be followed by a brief summary on ZIKV diagnosis, management, treatment, and prevention.

SUMMARY

The field of clinical research in ZIKV has rapidly evolved over recent months. It is critical that pediatricians continue to stay up-to-date with the continuously evolving understanding of the clinical aspects of ZIKV to ensure optimal identification and management of affected infants and children. Given the recent changes in Centers for Disease Control and Prevention guidelines to limit screening of asymptomatic pregnant women in the United States with possible ZIKV exposure, comprehensive ZIKV clinical knowledge becomes even more crucial.

Kay SI, Mittal J, Bandstra ES, Younis RT, Chapagain P, Jayaweera DT, Liu XZ. Zika Virus: An Emerging Global Health Threat

Zika virus (ZIKV) is an emerging healthcare threat. The presence of the mosquito Aedes species across South and Central America in combination with complementary climates have incited an epidemic of locally transmitted cases of ZIKV infection in Brazil. As one of the most significant current public health concerns in the Americas, ZIKV epidemic has been a cause of alarm due to its known and unknown complications. At this point, there has been a clear association between ZIKV infection and severe clinical manifestations in both adults and neonates, including but not limited to neurological deficits such as Guillain-Barré syndrome (GBS) and microcephaly, respectively. The gravity of the fetal anomalies linked to ZIKV vertical transmission from the mother has prompted a discussion on whether to include ZIKV as a formal member of the TORCH [Toxoplasma gondii, other, rubella virus, cytomegalovirus (CMV), and herpes] family of pathogens known to breach placental barriers and cause congenital disease in the fetus. The mechanisms of these complex phenotypes have yet to be fully described. As such, diagnostic tools are limited and no effective modalities are available to treat ZIKV. This article will review the recent advancements in understanding the pathogenesis of ZIKV infection as well as diagnostic tests available to detect the infection. Due to the increase in incidence of ZIKV infections, there is an immediate need to develop new diagnostic tools and novel preventive as well as therapeutic modalities based on understanding the molecular mechanisms underlying the disease.

Evaluation of 5 Commercially Available Zika Virus Immunoassays

Because of the global spread of Zika virus, accurate and high-throughput diagnostic immunoassays are needed. We compared the sensitivity and specificity of 5 commercially available Zika virus serologic assays to the recommended protocol of Zika virus IgM-capture ELISA and plaque-reduction neutralization tests. Most commercial immunoassays showed low sensitivity, which can be increased.

A unique case of human Zika virus infection in association with severe liver injury and coagulation disorders

Zika virus (ZIKV) has caused major concern globally due to its rapid dissemination and close association with microcephaly in children and Gullian-Barr syndrome in adults. In this study, we identified a patient returned from Cambodia who experienced high fever, chill and myalgia. Lab tests discovered sign of severe liver injury including significantly elevated serum transaminases’ level, decreased serum albumin level, and markedly increased levels of lactic dehydrogenase, alpha-hydroxybutyric dehydrogenase and creatine kinase in serum. Moreover, severe thrombocytopenia and altered blood levels of fibrinogen and fibrinogen degradation product were also observed, indicating the existence of clotting disorders. A ZIKV strain clustered into the Asian lineage was isolated from the patient’s serum. When inoculated into suckling mice, this virus significantly retarded mouse body-weight gain and caused 70% mortality. Our results demonstrate a close association between ZIKV and severe liver injury and coagulation disorders and suggest that clinicians should be aware of compatible symptoms in patients and manage them accordingly.

Neurological Presentation of Zika Virus Infection Beyond the Perinatal Period

PURPOSE OF REVIEW

Our purpose was to summarize the current knowledge about the neurological presentation of Zika virus infection after the perinatal period. Other Flaviviruses infections, such as West Nile virus (WNV) or Japanese encephalitis virus (JEV), can result in neuro-invasive disease such as myelitis, encephalitis, or meningitis. We aimed at describing the specificities of ZV neurological infection.

RECENT FINDINGS

The recent outbreaks demonstrated clearly the neurotropism of ZV. However, by contrast with other Flaviviruses, the most frequent neurological presentation of ZV infection beyond the perinatal period was Guillain-Barré syndrome, especially the demyelination form of GBS. Encephalitis and myelitis seem to occur less frequently after ZV infection than after WNV or JEV infection. The pathophysiology of neurological ZV infections is still poorly understood and no specific treatment is available. Moreover, no data is available about long-term persisting symptoms and possible impairment of patients after the acute clinical episode.

Chikungunya and Zika Virus Cases Detected against a Backdrop of Endemic Dengue Transmission in Vietnam

Between 2010 and 2014, four chikungunya and two Zika virus infections were identified among 8,105 febrile children in southern Vietnam. Zika viruses were linked to French Polynesian strains, chikungunya to Cambodian strains. Against a backdrop of endemic dengue transmission, chikungunya and Zika present an additional arboviral disease burden in Vietnam.

Zika Virus: Recent Advances towards the Development of Vaccines and Therapeutics

Zika is a rapidly emerging public health threat. Although clinical infection is frequently mild, significant neurological manifestations have been demonstrated in infants born to Zika virus (ZIKV) infected mothers. Due to the substantial ramifications of intrauterine infection, effective counter-measures are urgently needed. In order to develop effective anti-ZIKV vaccines and therapeutics, improved animal models and a better understanding of immunological correlates of protection against ZIKV are required. This review will summarize what is currently known about ZIKV, the clinical manifestations and epidemiology of Zika as well as, the development of animal models to study ZIKV infection, host immune responses against ZIKV, and the current state of development of vaccines and therapeutics against ZIKV.

Emerging arboviral human diseases in Southern Europe

Southern Europe is characterized by unique landscape and climate which attract tourists, but also arthropod vectors, some of them carrying pathogens. Among several arboviral diseases that emerged in the region during the last decade, West Nile fever accounted for high number of human cases and fatalities, while Crimean-Congo hemorrhagic fever expanded its geographic distribution, and is considered as a real threat for Europe. Viruses evolve rapidly and acquire mutations making themselves stronger and naive populations more vulnerable. In an effort to tackle efficiently the emerging arboviral diseases, preparedness and strategic surveillance are needed for the early detection of the pathogen and containment and mitigation of probable outbreaks. In this review, the main human arboviral diseases that emerged in Southern Europe are described.