Zika virus epidemic: an update

Infections in travellers returning to the UK: a retrospective analysis (2015-2020)

BACKGROUND

Every year, many thousands of travellers return to the United Kingdom (UK) from visits to other countries and some will become unwell due to infections acquired abroad. Many imported infections have similar clinical presentations, such as fever and myalgia, so diagnostic testing is an important tool to improve patient management and outcomes. The aim of this study was to examine the demographics, travel history, presenting symptoms and diagnostic outcomes of referrals to the UK's specialist diagnostic Rare & Imported Pathogens Laboratory (RIPL) for the period 2015-2020.

METHODS

Anonymised clinical and laboratory data was extracted from RIPL's Laboratory Information Management System (LIMS) and cleaned prior to descriptive analysis of the data. Travel history data was mapped to one of eight world regions, while symptom data was categorised into presenting syndromes. Diagnostic data was categorised as either positive, equivocal or negative.

RESULTS

During the period 2015-2020, RIPL received 73 951 samples from 53 432 patients suspected of having infections that are rare in the UK. The most common age group for unwell returning travellers was 30-39 years and the most commonly reported travel destination was Southern and SE Asia. Dengue virus was the most diagnosed infection overall, followed by chikungunya, Zika, leptospirosis and spotted fever group Rickettsia. Dengue virus was among the top three most frequent diagnoses for all world regions except Europe and represented 62.5% of all confirmed/probable diagnoses.

CONCLUSIONS

None of the top five infections diagnosed by RIPL in travellers are vaccine-preventable, therefore understanding traveller demographics, destination-specific risk factors and encouraging preventative behaviours is the best available strategy to reduce the number of returning travellers who become infected. Prompt referral of acute samples with a detailed travel history, including purpose of travel and activities undertaken as well as dates and destinations can be a valuable tool in designing public health interventions and diagnostic algorithms.

A deep neural network based context-aware smart epidemic surveillance in smart cities

Purpose

Epidemics not only affect the public health but also are a threat to a nation's growth and economy as well. Early prediction of epidemic can be beneficial to take preventive measures and to reduce the impact of epidemic in an area.

Design/methodology/approach

A deep neural network (DNN) based context aware smart epidemic system has been proposed to prevent and monitor epidemic spread in a geographical area. Various neural networks (NNs) have been used: LSTM, RNN, BPNN to detect the level of disease, direction of spread of disease in a geographical area and marking the high-risk areas. Multiple DNNs collect and process various data points and these DNNs are decided based on type of data points. Output of one DNN is used by another DNN to reach to final prediction.

Findings

The experimental evaluation of the proposed framework achieved the accuracy of 87% for the synthetic dataset generated for Zika epidemic in Brazil in 2016.

Originality/value

The proposed framework is designed in a way that every data point is carefully processed and contributes to the final decision. These multiple DNNs will act as a single DNN for the end user.

MASS SPECTROMETRY IN VIROLOGICAL SCIENCES

Virology, as a branch of the life sciences, discovered mass spectrometry (MS) to be the pivotal tool around two decades ago. The technique unveiled the complex network of interactions between the living world of pro- and eukaryotes and viruses, which delivered "a piece of bad news wrapped in protein" as defined by Peter Medawar, Nobel Prize Laureate, in 1960. However, MS is constantly evolving, and novel approaches allow for a better understanding of interactions in this micro- and nanoworld. Currently, we can investigate the interplay between the virus and the cell by analyzing proteomes, interactomes, virus-cell interactions, and search for the compounds that build viral structures. In addition, by using MS, it is possible to look at the cell from the broader perspective and determine the role of viral infection on the scale of the organism, for example, monitoring the crosstalk between infected tissues and the immune system. In such a way, MS became one of the major tools for the modern virology, allowing us to see the infection in the context of the whole cell or the organism. © 2019 John Wiley & Sons Ltd. Mass Spec Rev.

#JunkScience: Investigating pseudoscience disinformation in the Russian Internet Research Agency tweets

Recent research has identified anti-vaccination propaganda in the so-called Russian Troll Tweets strongly associated with the 2016 US Presidential election. This study builds on this: hypothesising that if vaccination content was found in the sample, the Russia Tweets would be likely to contain other science content, and perhaps, similar pseudo or anti-science messages. As well as vaccination, climate change, genetically modified organisms, Ebola, flat Earth beliefs (flat Earthism) and Zika were found in the Russia tweets. Genetically modified organisms and flat Earthism appear to have been camouflage content - tweeted at similar rates to other Twitter users - while climate change, Ebola, Zika and vaccination appear to have been emphasised beyond the background rate for strategic disinformation purposes.

Timing of gestational exposure to Zika virus is associated with postnatal growth restriction in a murine model

BACKGROUND

Vertical transmission of Zika virus leads to infection of neuroprogenitor cells and destruction of brain parenchyma. Recent evidence suggests that the timing of infection as well as host factors may affect vertical transmission. As a result, congenital Zika virus infection may only become clinically apparent in the postnatal period.

OBJECTIVE

We sought to develop an outbred mouse model of Zika virus vertical transmission to determine if the timing of gestational Zika virus exposure yields phenotypic differences at birth and through adolescence. We hypothesized that later gestational inoculations would only become apparent in adolescence.

STUDY DESIGN

To better recapitulate human exposures, timed pregnant Swiss-Webster dams (n = 15) were subcutaneously inoculated with 1 × 10⁴ plaque-forming units of first passage contemporary Zika virus HN16 strain or a mock injection on embryonic day 4, 8, or 12 with bioactive antiinterferon alpha receptor antibody administered in days preceding and proceeding inoculation. The antibody was given to prevent the robust type I interferon signaling cascade that make mice inherently resistant to Zika virus infection. At birth and adolescence (6 weeks of age) offspring were assessed for growth, brain weight, and biparietal head diameters, and Zika virus viral levels by reverse transcription-polymerase chain reaction or in situ hybridization.

RESULTS

Pups of Zika virus-infected dams infected at embryonic days 4 and 8 but not 12 were growth restricted (P < .003). Brain weights were significantly smaller at birth (P = .01) for embryonic day 8 Zika virus-exposed offspring. At 6 weeks of age, biparietal diameters were smaller for all Zika virus-exposed males and females (P < .05), with embryonic day 8-exposed males smallest by biparietal diameter and growth-restriction measurements (weight >2 SD, P = .0007). All pups and adolescent mice were assessed for Zika virus infection by reverse transcription-polymerase chain reaction. Analysis of all underweight pups reveled 1 to be positive for neuronal Zika virus infection by in situ hybridization, while a second moribund animal was diffusely positive at 8 days of age by Zika virus infectivity throughout the brain, kidneys, and intestine.

CONCLUSION

These findings demonstrate that postnatal effects of infection occurring at single time points continue to be detrimental to offspring in the postnatal period in a subset of littermates and subject to a window of gestational susceptibility coinciding with placentation. This model recapitulates frequently encountered clinical scenarios in nonendemic regions, including the majority of the United States, where travel-related exposure occurs in short and well-defined windows of gestation. Our low rate of infection and relatively rare evidence of congenital Zika syndrome parallels human population-based data.

A conceptual model for optimizing vaccine coverage to reduce vector-borne infections in the presence of antibody-dependent enhancement

Background

Many vector-borne diseases co-circulate, as the viruses from the same family are also transmitted by the same vector species. For example, Zika and dengue viruses belong to the same Flavivirus family and are primarily transmitted by a common mosquito species Aedes aegypti. Zika outbreaks have also commonly occurred in dengue-endemic areas, and co-circulation and co-infection of both viruses have been reported. As recent immunological cross-reactivity studies have confirmed that convalescent plasma following dengue infection can enhance Zika infection, and as global efforts of developing dengue and Zika vaccines are intensified, it is important to examine whether and how vaccination against one disease in a large population may affect infection dynamics of another disease due to antibody-dependent enhancement.

Methods

Through a conceptual co-infection dynamics model parametrized by reported dengue and Zika epidemic and immunological cross-reactivity characteristics, we evaluate impact of a hypothetical dengue vaccination program on Zika infection dynamics in a single season when only one particular dengue serotype is involved.

Results

We show that an appropriately designed and optimized dengue vaccination program can not only help control the dengue spread but also, counter-intuitively, reduce Zika infections. We identify optimal dengue vaccination coverages for controlling dengue and simultaneously reducing Zika infections, as well as the critical coverages exceeding which dengue vaccination will increase Zika infections.

Conclusion

This study based on a conceptual model shows the promise of an integrative vector-borne disease control strategy involving optimal vaccination programs, in regions where different viruses or different serotypes of the same virus co-circulate, and convalescent plasma following infection from one virus (serotype) can enhance infection against another virus (serotype). The conceptual model provides a first step towards well-designed regional and global vector-borne disease immunization programs.

Zika virus, vaccines, and antiviral strategies

INTRODUCTION

Zika virus (ZIKV) recently emerged as a global public health emergency of international concern. ZIKV is responsible for severe neurological complications in adults and infection during pregnancy and can lead to congenital Zika syndrome. There is no licensed vaccine or drug to prevent or treat ZIKV infection. Areas covered: The aim of this article is to provide an overview and update of the progress of research on anti-ZIKV vaccine and medications until the end of 2017, with a special emphasis on drugs that can be used during pregnancy. Expert commentary: Development of new vaccines and drugs is challenging and several points particular to ZIKV infections augment this difficulty: (1) Cross-reactions between ZIKV and other flaviviruses, the impact of ZIKV vaccination on subsequent flavivirus infections, and vice-versa, is unknown, (2) Drugs against ZIKV should be safe in pregnant women, and (3) Evaluation of the efficacy of vaccine and drugs against ZIKV in clinical trials phase II-IV will be complicated due to the decline of ZIKV circulation.

Protein Interactions during the Flavivirus and Hepacivirus Life Cycle

Protein-protein interactions govern biological functions in cells, in the extracellular milieu, and at the border between cells and extracellular space. Viruses are small intracellular parasites and thus rely on protein interactions to produce progeny inside host cells and to spread from cell to cell. Usage of host proteins by viruses can have severe consequences e.g. apoptosis, metabolic disequilibria, or altered cell proliferation and mobility. Understanding protein interactions during virus infection can thus educate us on viral infection and pathogenesis mechanisms. Moreover, it has led to important clinical translations, including the development of new therapeutic and vaccination strategies. Here, we will discuss protein interactions of members of the Flaviviridae family, which are small enveloped RNA viruses. Dengue virus, Zika virus and hepatitis C virus belong to the most prominent human pathogenic Flaviviridae With a genome of roughly ten kilobases encoding only ten viral proteins, Flaviviridae display intricate mechanisms to engage the host cell machinery for their purpose. In this review, we will highlight how dengue virus, hepatitis C virus, Japanese encephalitis virus, tick-borne encephalitis virus, West Nile virus, yellow fever virus, and Zika virus proteins engage host proteins and how this knowledge helps elucidate Flaviviridae infection. We will specifically address the protein composition of the virus particle as well as the protein interactions during virus entry, replication, particle assembly, and release from the host cell. Finally, we will give a perspective on future challenges in Flaviviridae interaction proteomics and why we believe these challenges should be met.