Scientists delve into differences between Zika virus and dengue virus

July 6, 2018

A New Study Examines Cellular and Molecular Differences Between Dengue and Zika

More than two years after reports of steep rise in Zika rates appeared around the world. University researchers are a little closer to finding answers.

In an article published today in the journal Stem Cell Reports biological science professor Hengli Tang and his postdoctoral researcher Jianshe Lang delve deeply into the differences. between the Zika virus and the Dengue virus.

On the surface, these viruses are very similar -; they are both delivered by mosquitoes and their genetic material is organized in the same way. Yet, Zika is much more effective in penetrating the body's natural barriers to infection and leaves behind a trail of devastating effects on infected fetuses.

"We were really looking at a specific aspect," Tang said. "Does the Zika virus reach more sites because of its ability to spread through the body than dengue?"

Tang and Lang found that Zika had a unique ability to carry the virus throughout the body. All of this has to do with a type of immune cell called macrophage.

These immune system warriors essentially engulf any kind of foreign substance -; cell debris, cancer cells, microbes -; that do not make the appropriate proteins compatible with healthy body cells. Macrophages usually float in the bloodstream and when a virus invades, they flock to the site of the disease to fight it.

This is what happens when Dengue enters the body. However, this is not what happens when Zika enters the body, the researchers found.

Researchers developed macrophages from stem cells in Tang's laboratory. They then exposed these cells to Zika virus or Dengue virus. The macrophages were then subjected to a test measuring the mobility of the infected cells.

In the dengue experiment, macrophages were essentially immobilized because they remained at one point to fight the infection. However, those infected with Zika virus have retained their ability to migrate on glass slides.

It may be for this reason that the Zika virus is so effective, Tang said. In mammals, macrophages loaded with Zika would have continued to float in the bloodstream.

"They hitchhike macrophages to other parts of the body," Tang said.

It seems that the Zika virus is actively suppressing the ability of the macrophage to perform its usual tasks in the fight against diseases.

"Now the question is whether the Zika virus uses these infected macrophages to cross the body – the placental barrier, the blood-brain barrier, and the testicular barrier?" Tang said. "If you understand how they cross these barriers, then you can develop more effective countermeasures to protect people."

Although Zika was discovered in 1947, little was known about how the virus works. By the end of 2015. Researchers and health professionals have been eager to learn as much as possible about the virus, but many questions remain about how the virus actually works. Tang and his colleagues at Johns Hopkins University were the first group of researchers to officially link Zika to microcephaly, a brain abnormality that occurs in developing fetuses.