The emergence of Zika virus in Brazil: investigating viral features and host responses to design preventive strategies.

Zika virus is an arbovirus that belongs to the Flaviviridae family and was initially isolated from rhesus monkeys in Uganda in 1947. The most common reported symptoms are rash, fever, arthralgia, and conjunctivitis. The majority of the patients experiences only a mild and transitory disease, but severe neurologic complications have been described. The virus, previously described in Africa and oher parts of the world, has recently emerged in Brazil. It is thus a good example of how viruses can emerge around the world and start transmission cycles in novel environments. Zika virus is predominantly transmitted by Aedes species mosquitoes such as Ae. aegypti. Brazil is a large (8.5 million km2), predominantly tropical area. There are five geographical regions (North, Northeast, Center-West, Southeast and South) and five climate zones: Equatorial, Temperate, Central Brazil Tropical, Eastern Northeast Tropical and Equatorial Zone Tropical. Such characteristics favor the proliferation of Ae. aegypti mosquitoes that are dispersed around all the 27 Brazilian Federative Units in more than 3,587 cities. Besides dengue viruses, other arboviruses are now circulating in Brazil. In 2014, a total of 41 chikungunya importations and 27 autochthonous cases were detected in northeast Brazil. More recently, 34 cases of ZIKV infection have been confirmed by the Brazilian Ministry of Health. The confirmed cases occurred in eight of the 27 Brazilian states and are distributed in the Northeast, North and Southeast regions of the country, suggesting that the infection is widespread. The source of these outbreaks and the potential for virus establishment in Brazil is still not known. Arboviruses such as Zika have the potential to initiate large scale epidemics, and these infections can be extremely debilitating in absence of any specific treatments or vaccine. Thus, this newly emerged arbovirus represents a serious social and economic threat, especially because of the excessive demand on health services by the poor population. Zika virus symptoms are related to already circulating human arboviruses such as dengue and chikungunya. Thus diagnosis of Zika virus infection on the basis of clinical syndromes is not reliable and needs to be confirmed by laboratory diagnosis. Indeed, misinterpretation may have consequences for treatment but also the general understanding of pathogens local populations are at risk from. Current Zika virus diagnosis is based on molecular techniques only accessible to a few highly specialized laboratories. This project proposes to better understand the spread and epidemiology of Zika virus infection by understanding individual cases and analyse full virus genomes to put them into a global context. It will also aim to develop more easily accessible diagnostic tools that can be used in wider settings thus supporting the local health systems. At this point, it is also crucial to investigate the underlying biological processes involved in Zika virus pathogenesis and how the virus interacts with host responses, which could lead towards more effective treatment of confirmed cases. Moreover this project aims to develop tools to understand and manipulate the viral genome (called "reverse genetics") with view of better understanding viral genes, replication etc. These tools can also form the backbone of future vaccines. The strength of this project is the coming together of experts from different research areas to study the questions outlined above with the aim of significantly improving our understanding of Zika virus biology, impact on public health and study this emerging virus. This is highly relevant to Brazil, but also other regions and countries affected by this virus.

The mosquito-borne flavivirus Zika has recently emerged in Brazil, where large potential vector populations (Aedes aegypti mosquitoes) exist. This virus had been detected in Africa and other tropical regions of the world, but was imported into Brazil in all likelihood in the recent past. Symptoms can be similar to dengue virus or the also recently emerged chikungunya virus, thus complicating diagnosis, treatment and intervention strategies. Indeed, very little is known about the biology and molecular biology of Zika virus, but diagnosis currently also requires specialist set ups. Thus, the potential impact of this pathogen needs to be assessed and public health preparedness improved. This project brings together experts from various fields to work on the following aims that impact on our understanding of Zika virus: (i) monitor Zika virus circulation in selected areas (including virus isolation and genetic characterisation) and develop improved diagnostic methods to identify Zika virus; (ii) use patient material for immunological studies on Zika virus infection (cytokines and antibody responses, gene expression) and set up a mouse model to assess intervention strategies and study pathogenesis further; (iii) develop an infectious clone of Zika virus for reverse genetics studies of the virus and vaccine design (including tools to produce virus-like particles); (iv) study viral antagonism of host responses at cellular level. As arbovirus infections are on the rise, there is an urgent need to share knowledge and improve the capacity response of research centers. Effective collaborative projects and networks can lead to effective ways to disease control, and this network on Zika virus can in the long term also help other countries affected by this virus.

Zika virus is a newly emerged flavivirus in Brazil which is transmitted by aedine mosquitoes. Given the geography and socio-economics of Brazil, the risks associated with this novel human pathogenic may be considerable. This adds to the presence of human pathogenic mosquito-borne viruses which already have considerable public health impact; in particular dengue virus or the recently emerged chikungunya virus which can present similar disease symptoms and thus complicate diagnosis, treatment and preventive efforts. With regards to Zika virus, recent studies have focused on monitoring the virus and data about the current impact in Brazil have now confirmed its presence in parts of Brazil. It may spread further as vector mosquitoes are widely distributed across the Brazilian territory. It is important to develop measures to distinguish Zika infections from other circulating arboviruses and obtain correct public health data. There is still a lack of reliable methods for the early and accurate diagnosis of Zika virus infection. Currently Zika virus diagnosis is based on virus genome detection by either PCR or quantitative Real Time PCR (qRT-PCR); however, these methodologies demand specialized laboratories and well trained people which leaves only a few laboratories in Brazil able to diagnose this infection. At the host level, Zika virus immunopathogenesis is a largely unknown process as there are no data about cytokine and chemokine responses that are participating in host responses, and how the immune system contributes to the disease process. Based on this, a better understanding of virus biology can provide new therapeutic targets and more efficient ways to control the disease spreading in Brazil and other countries. Moreover we aim to develop a reverse genetics system and virus-host interaction studies that will allow better understanding and manipulation of the virus with the aim to vaccine development.
This consortium brings together experts from Fiocruz and the MRC-University of Glasgow Centre for Virus Research. Both partners include scientific groups with considerable expertise in key areas of the project. As consequence, the Fiocruz - MRC-University of Glasgow Centre for Virus Research integration will further enable Zika virus investigations by a team of multidisciplinary researchers and active exchanges of research that will enhance the capacity of the partner in Brazil to deal with this infection and thus enhance the local capabilities to deal with Zika virus and set up an efficient research programme. Indeed, the integration of scientific groups with expertise in molecular virology, immunology, genetics and vaccine development as brought together in this project will lead to strong interactions and a consortium capable of (i) improving viral diagnostics in a manner that is supportive of public health efforts in Brazil, (ii) understand ZIKV outbreaks in Brazil, (iii) contribute to future measures in treatment and prevention of ZIKV infections, and (iv) enhance the research capabilities and scientific impact of the Brazilian research partner, Fiocruz. The exchange of skills and expertise at the heart of our proposal, makes this a dynamic and timely combination of projects, which is likely to be relevant beyond the duration of this interaction. This collaboration will set the pace for future projects in this area. Our results will impact on policy (prevention, treatment, diagnostics) as well as point towards preventive measures.