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1 July 2016

The lessons we're learning from Zika

More than a year after its outbreak, Zika virus infections are still an unresolved threat in many countries – especially in Brazil, where pregnant women remain at high risk, warns science leader and TWAS Fellow Hernán Chaimovich.

The outbreak of Zika virus infections that began early last year in Brazil shows how fragile our world is. Since May 2015, when it was first identified, and through April 2016, Zika has caused almost 7,000 cases of microcephaly and central nervous system damage in Brazil alone.


Hernán Chaimovich, president of Brazil's elite National Council for Scientific and Technological Development (CNPq), Brazil, sees a link between Zika, Chikungunya and dengue fever. All have posed high-profile viral threats in the past year. All, he says, have spread more easily due to growing populations, more crowded cities and the ease of intercontinental travel.

In an email interview, Chaimovich warned that no breakthrough in Zika control appears imminent. "It is not realistic to expect a vaccine soon," he said. "Even if a vaccine were available other approaches, such as vector-control measures and efforts to reduce human exposure to vectors, need to be explored."

Such was the situation at the end of April. Today there are several studies of effective vaccines in animal models that will certainly lead to human trials in the next months.

As of 25 May 2016, transmission of Zika virus has affected 60 countries and territories (46 countries are experiencing a first outbreak since 2015), showing that much still needs to be done to contain, and hopefully avoid, future infectious outbreaks. This event also suggests that promoting prevention by informing people of the nature and evolution of disease is becoming mandatory.

Chaimovich has been awarded a TWAS Medal and has also received the Brazilian Order for Scientific Merit. He was elected a TWAS Fellow in 2000. In an interview with TWAS staff writer Cristina Serra, he offered his view and expertise on measures that should be taken to avoid similar health crises in the future.

In recent years the world has witnessed epidemics caused by viruses that have become very virulent. Zika is the latest. From what we see, after the peak has been reached, how might it evolve?

So far, there is not enough information to predict whether the Zika outbreak is going to be more devastating than previous infections. However, modelling predicts it will be a major problem in the next years in several regions of the world and may subside to come back later. By previous experiences with other virulent pathogens, the most likely scenario is that Zika-mediated diseases will be less severe, but we cannot rely on that.

Significant new scientific advances will be necessary to understand the disease and to develop the necessary tools to protect the population. Damage caused by congenital Zika transmission may have severe consequences in the future in Brazil and it may become an excruciating burden if it gets worse. Zika-associated neurological diseases have also to be considered.

Why is the world experiencing these bursts – Zika, Ebola and dengue in recent months? What might cause the explosive dissemination of a virus: climate change, populations moving from one country to another, sanitary conditions, or other factors?

There are several elements implicated in the new epidemic outbreaks of severe viral diseases. The enormous increase in mobility worldwide created new possibilities of faster dissemination. Additionally, the density of the human population also increased, with consequences in disease transmission. Several other unproved factors may participate, such as mutations in the pathogens (although nothing on this line has been reported so far in the Zika outbreak); co-infections that may alter disease susceptibility or disease manifestations.

Not to be neglected are also environmental changes, global warming mainly, in diseases transmitted by insect vectors. Possibilities are a legion and the immediate task of the scientific community is sorting out which of those are more relevant to the current epidemic.

A major criticism regarding Ebola's spread was the lack of coordination among world health organizations, national and local health agencies. Have these lessons shaped the response to Zika? If so, in what way?

International response to the Zika outbreak has been certainly faster and more coordinated than in previous major viral outbreaks. The recognition of a public health emergency of national concern issued by the Brazilian authorities was followed without delay by the recognition of international concern by the World Health Organization. Efforts from major US agencies, including both the Centers for Disease Control and Prevention (CDC) and the National Institutes of Health (NIH), were very fast and advanced through close dialog with Brazilian scientists and public health authorities. Although there is room for improvement, we must acknowledge the improvement in relation to previous experiences.

Reports say that trials for Zika virus vaccine are months away. Is there no way to speed up this process? What makes it so difficult to develop a vaccine? Is it worth it to invest money in such a vaccine, rather than using money to set up prevention initiatives or, at least, more urgent "buffering" measures?

No infectious disease has been controlled without a vaccine. Vaccine development against Zika is mandatory in the global effort against this pathogen. However, vaccine development is not a fast endeavour. In the case of Zika-caused disease, there was extremely scarce information on the virus, pathogenesis and characteristics of the host immune response. Essentially no information on adequate animal models to the preclinical tests of a vaccine. All these aspects represent important hurdles in development.

Is Zika more likely to hit people from disadvantaged social classes or is the infection likely to have an impact everywhere?

Aedes aegypti, the vector (mosquito) implicated in Zika virus transmission, is highly urbanized and affects people from several economic conditions. However is undeniable that the highest burden is on the disadvantaged social classes, as conditions for transmission involve sanitary aspects.

In times of uncertainty, rumours tend to spread rapidly, sometimes inducing panic. Months ago, scientists thought that the larvicide pyriproxyfen used to control the mosquito could be associated with microcephaly in newborns. Now it turns out that it's the virus itself that causes havoc. How important was – and is – communication in the fight against Zika or other infectious diseases? What approach to communication are you seeing in Brazil and elsewhere in Latin America?

An appropriate communication strategy ought to be a major pillar of a programme for the control of any health condition. Besides the regular media, social networks have a major impact on fast dissemination of information, be it scientifically based or not. Brazilian scientists and scientific institutions are aware of this need and are playing an active role in informing the press and directly disseminating information.

To keep these insects at bay, scientists are pursuing the GMO option. What's your opinion about genetically modified mosquitoes? Can they cause unanticipated negative consequences?

Genetically modified mosquitoes should be considered within the range of tools used to combat insect-transmitted diseases. However, there is not enough information if their use against Zika will be effective. Due caution is always necessary upon introducing GM organisms in the environment.

What role has the CNPq taken in managing this health emergency in Brazil? Is the Brazilian National Council a sort of "scientific lighthouse" where other institutes ask for advice, guidelines and other help?

CNPq, an institution of the Ministry of Science Technology and Innovation, has participated from the very start in the formulation of policy for coordinating and increasing the science component of the Zika health emergency. In addition, CNPq has historically participated in partnership with other ministries, including the Brazilian Health Ministry, in building the scientific capacity that permits today the formation of several research networks that have Zika as the focus.

Cristina Serra

Hernán Chaimovich: Biodata

Hernán Chaimovich, a full professor of biochemistry at the Institute of Chemistry, São Paulo, Brazil, is the president of the National Council for Scientific and Technological Development (CNPq), Brazil.

Elected to TWAS in 2000, Chaimovich served as the co-chair of the Inter-American Network of Academies of Science (IANAS) from 2004-2010 and as vice president of the Brazilian Academy of Sciences from 2007-2015.

Born in Chile, Chaimovich holds a PhD in biological sciences from University of São Paulo, and post-doctorates from the University of California and Harvard University. His scientific interests focus on experimental and theoretical analysis of specific ion effects on shape transitions of surfactant aggregates.

He is the recipient of a TWAS Medal (2007) and of the Brazilian Order for Scientific Merit.

 

 

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