The ninth edition of FIOTEC-FIOCRUZ Connection, the institutional journal of FIOTEC, features news stories on the efforts by the Oswaldo Cruz Foundation (FIOCRUZ) in prevention and the fight against arbovirus infections in Brazil. Luciano Moreira, a researcher at the René Rachou Institute (FIOCRUZ-Minas Gerais), explained the methodology of a project that releases Aedes aegypti mosquitoes with the Wolbachia bacteria in Greater Metropolitan Rio de Janeiro, with the aim of controlling the mosquito vector’s reproduction and decreasing its capacity to transmit the dengue virus.

On other pages of the same edition, Celina Turchi, named by Nature magazine to the list of the ten most important scientists in the world in 2016, described in detail the work done by the research groups she heads, definitively proving the link between the Zika virus and the alterations now known as congenital Zika syndrome.

The Carlos Chagas Institute (FIOCRUZ-Paraná) has presented a new tool that expands the capacity for differential diagnosis of arbovirus infections. The new equipment, with the capacity to process an average of 1,580 samples per hour, reduces from 50% to 9% the cases of cross-reactivity between dengue and Zika samples. In other words, the new technology allows scientists to say with almost absolute precision whether the individual was infected with the dengue virus or the Zika virus.

Claudia N. Duarte dos Santos, head of the Molecular Virology Laboratory at ICC/FIOCRUZ, explains how the new technique works and its immediate benefits:

What are the diseases caused by flaviviruses in Brazil, and why is it so difficult to obtain precise diagnoses?

We have several flaviviruses circulating in Brazil, but today the main ones are dengue, yellow fever, and more recently Zika. There are other flaviviruses, but they circulate less intensely, so their public health impact is smaller. It’s difficult to obtain a diagnosis because the initial clinical symptoms of these virus infections [dengue, yellow fever, and Zika] are very similar. They are phylogenetically close, belong to the same family, and share many proteins, which in the case of a serological diagnosis leads to a crossover of information. In other words, we end up with an ambiguous test response, which in many cases prevents us from determining which virus infected (or is currently infecting) the individual.

What are the main differences between the new diagnostic methodology and the one that was used previously?

The choice of the diagnostic format depends on the moment, the course of the disease in which the diagnosis is performed. For example, in the case of Zika, right after the onset of symptoms, the diagnostic technique of choice is the one that detects either the virus circulating in the individual’s body or the viral genome circulating in the body. This occurs up to five days after the onset of symptoms. After this phase, the diagnosis of choice, the format, is serological diagnosis, which detects the antibodies that the individual has produced to the infectious agent.

This diagnostic technique, which we now use here [at the Molecular Virology Laboratory], relies on a classic technique, well known and used for years, neutralization technique, which produces very precise results. However, this technique is very labor-intensive and requires a trained person and a special environment to perform, which explains the ten-day processing time. We thus combine this classic technique with an ultramodern, high-performance platform, capable not only of reducing the diagnostic turnaround time, but also of analyzing a large number of samples precisely, since the platform is automated. So that’s the first benefit. The second is its capacity to differentiate between Zika, dengue, and yellow fever infections much more precisely than the diagnostic kits now available on the market.

The methodology diagnoses Zika and dengue today. Is there any forecast on when this technology can be used to detect other diseases?

Another advantage to the new platform is its flexibility to include other viruses or pathogens. Today we can analyze other viruses like chikungunya or the Saint Louis encephalitis virus, as long as there’s a demand. This new technology allows us to customize the diagnosis of viral infections.

Do the projects you coordinate (with FIOTEC’s support) for the development of diagnostic kits for arboviruses circulating in Brazil bear any relationship to this new diagnostic methodology?

Yes. We have two projects that include this equipment, one funded by BNDES [the National Economic and Social Development Bank], in which the equipment is already functioning in our laboratory; and another project, supported and coordinated by FIOTEC, which is the donation of a second piece of equipment [Opereta] by an international philanthropical institution.

This equipment began to be used previously to screen a large number of antiviral compounds for their capacity to inhibit the replication of dengue, Zika, chikungunya, and finally yellow fever virus. We began using this equipment in our laboratory for this purpose. A group headed by Dr. Andrea Koishi realized the equipment’s true capacity and had the idea of combining the classic diagnostic technique, used until then, with the new technology. We now have this extremely powerful equipment for performing basic and applied research, and with very rapid results.

How do you see the contribution by the Carlos Chagas Institute to the efforts by FIOCRUZ in the fight against Zika, dengue, and yellow fever?

With the new equipment’s capacity to simultaneously process a large number samples, the idea is to perform diagnoses not only here from the South of Brazil, but also, when necessary, from other FIOCRUZ units that receive large numbers of samples but lack the capacity to deal with such a big workload. The idea is to form a network and use this equipment to support FIOCRUZ in its mission of furnishing diagnoses to more individuals as quickly as possible. This would allow making the decision for effective measures in dealing with future epidemics.

With the help of this new diagnostic technology, do you believe we are closer to understanding and better preventing Zika virus infection?

Our idea is not to conduct a study for prevention. We are actually conducting a diagnostic project. But I do believe that when we understand the proportion of individuals that are infected with the Zika virus but do not show clinical symptoms, and we identify them, we will be able to contribute with the prognosis in family planning for these individuals. In the sense of saying, “Look, you have antibodies to Zika, so you must have been infected,” which of course could contribute to a better understanding of the virus’ spread and other epidemiological aspects. But I wouldn’t go so far as to say that we would prevent the infection better. Prevention will come from the production of a vaccine or an antiviral treatment.

By improving diagnosis, we contribute to a better understanding of the extent of the infection, the number of asymptomatic patients, thus obtaining a broader understanding of the disease. In addition, since the platform is capable of differentiating between ZIKV and DENV infections, it allows better patient management (treatments/interventions).