An initial infection with dengue virus did not prime monkeys for an especially virulent infection of Zika virus, according to a new study. Nor did a bout with Zika make a follow-on dengue infection more dangerous.
As outbreaks on Pacific islands and in the Americas in recent years made Zika virus a pressing public health concern, the Zika virus’s close similarity to dengue presented the possibility that one infection may exacerbate the other.
Dengue virus infections are infamous for being bad the first time around. But following infection with one of the four variants (called serotypes) of dengue with an infection by a different serotype can amplify the already dangerous symptoms — high temperature, fatigue and pain — and make dengue fever even more life-threatening.
«When that second dengue virus occurs, antibodies kind of recognize it, but not in a way that allows them to take the virus out of the system and neutralize it like normal,» says Dawn Dudley, a scientist in the University of Wisconsin-Madison’s Department of Pathology and Laboratory Medicine and one of the authors of the new Zika study. «Instead, they have kind of a secondary effect, where by binding to the virus loosely they actually enhance the ability of the virus to get into other cells in the body and replicate more.»
Studies in tissue cultures and mice of back-to-back Zika and dengue infections suggested that the two members of the Flaviviruses — a genus that also includes West Nile virus and yellow fever virus — could interact to enhance each other. Data collected from human infections since the UW-Madison group began its work in 2017 appeared to contradict those tissue culture and mouse findings.
The study of 21 Wisconsin National Primate Research Center macaque monkeys, in which animals infected with one virus were challenged with another within nine to 12 months, supports the human epidemiological results.
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Materials provided by University of Wisconsin-Madison. Original written by Chris Barncard. Note: Content may be edited for style and length.