Foto: Sumaia Villela/Agência Brasil

With information from Flávia Albuquerque, from Agência Brasil

A serological test capable of identifying Zika virus contamination even after dengue infection began to be marketed in the country. The kits are aimed primarily at women of childbearing age and for epidemiological studies aimed at determining people who have already been exposed to the virus. This was one of the main demands after the Zika epidemic in Brazil between 2015 and 2016.

The test is the result of research initiated two years ago by a group of researchers from the Institute of Biomedical Sciences of the University of São Paulo. The study was supported by the São Paulo State Research Support Foundation and had a patent application licensed by AdvaGen Biotec and recently approved by the National Health Surveillance Agency for commercial use. The product has been tested on about 3,200 women in Brazil.

The test detects the presence of a specific Zika virus antibody  produced by the organism after 15 to 20 days after the individual becomes infected. However, as the Zika and Dengue viruses are very similar, commercially available tests eventually confuse them with false positive or negative, making it difficult or impossible to accurately diagnose dengue endemic areas. The test has 95% specificity for Zika, while others on the market have up to 75%.

“This antibody gives protection for life and it is very difficult to find a protein that is specific for Zika . But we found a protein site, which we call Delta NS1, that doesn’t cross-react with dengue, ”explained one of the researchers, virology expert Edison Luiz Durigon.

According to the researcher, the kit will facilitate the monitoring of pregnant women who will be tested every three months to prevent microcephaly in babies. If the woman is infected only in the final period of pregnancy, the baby is at risk of developing neurological problems.

“If the pregnant woman has Zika the test will accuse. And then the medical conduct changes, with the possibility of accompanying this child so that she is led to a normal pattern in childhood and adolescence, ”he said.

The test is based on the Elisa method and will also be useful for studying the prevalence of the virus because most infected people have no symptoms, so the woman can have the virus unknowingly and pass on to the fetus. Thus, some children may be born without microcephaly, but may have invisible brain damage at first, and may develop severe cognitive problems.

“The exam must be done in the laboratory and is ready in three and a half hours. It is a test that any clinical laboratory is equipped to do. This was our care, ”said the expert.