Early dengue virus infection could ‘defuse’ zika virus

From Science Daily
May 17, 2019

“We now know for sure that Zika virus infection during pregnancy can affect the unborn fetus in such a way that the child develops microcephaly and other severe symptoms,” explains Prof Felix Drexler, a virologist at the Charité who has been developing diagnostic tests for Zika and other viruses at the DZIF. Just a few years ago, pictures of affected new-borns were cause for worldwide dismay and perplexity. “However, what we did not understand then was that high incidence of microcephaly seemed to occur particularly in northeastern Brazil,” says Drexler. Why are expecting mothers in these regions at a higher risk of developing a severe Zika-associated disease than in other regions? The scientists consequently began to search for cofactors that have an influence on whether a Zika infection during pregnancy will develop fatal consequences or not.

A suspected cofactor

Dengue viruses, which are widespread in Latin America and cause dengue fever, were suspected cofactors. Initially, the scientists suspected that the antibodies humans produce against the dengue virus contribute to the fetal damage caused in later Zika infection. It has been known for a long time that these antibodies can enhance subsequent dengue infections under certain conditions.

However, in the case of Zika, the opposite seems to be the case. “Surprisingly, our study has shown that a previous dengue infection can protect against Zika-associated damage,” emphasizes Drexler.

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