Zika virus
hijacks cells to spread all over the body, crippling the immune system in a way that similar mosquito-borne disease do not.
That is according to a new study, which has mapped Zika's alarming patterns of behavior inside human hosts.
Even in the deadly Dengue virus, scientists normally see infected cells paralyzed in the bloodstream.
But researchers at
Florida
State University have found that Zika-infected cells retain their ability to move, allowing the virus to travel throughout the body and to inhibit the biological mechanisms of these cells that protect the immune system.
The team hopes the discovery could lead to more measures being developed to protect people from the deadly and destructive virus.
Dr Hengli Tang, a professor of biological sciences at FSU, and his postdoctoral researcher Jianshe Lang decided to compare Zika virus and Dengue virus.
Dengue is mosquito-borne, like Zika, which causes dengue fever and is characterized by a skin rash and flu-like symptoms including high fever, headache and vomiting.
According to the World Health Organization, the virus can sometimes bring on a life-threatening condition known as severe dengue.
Zika is caused by the same mosquito responsible for transmitting Dengue and West Nile virus. Those who
contract the disease experience fever, skin rashes, headache, and muscle or joint pain.
A report by the CDC in January stated that one in 10 pregnant women with confirmed Zika infections had a fetus or baby with birth defects.
The study looked at one million births in 15 US jurisdictions in 2016 to find birth defects possibly associated with Zika.
About half of those babies were born with brain abnormalities in addition to small head size, known as microcephaly.
Dr Tang and
researchers at Johns Hopkins University were the first to link Zika to microcephaly, where the brain is not properly developed leading to poor motor function, poor speech, and seizures.
In addition to the viruses being spread the same way and sharing similar symptoms, both have genetic material organized in the same way.
'We were really looking at one specific aspect,' Tang said.
'Does Zika virus get to more sites because of the ability to disseminate through the body better than Dengue?'
The team found that Zika is able to spread the virus throughout the body where Dengue and other viruses are stopped because of white blood cell called macrophages.
Macrophages detect and destroy bacteria and other harmful organisms including cellular debris and cancer cells.
Usually the cells detect foreign viruses in the bloodstream and attack it. This is the case with Dengue virus, but Zika is able to bypass this protection system.
The team grew macrophages from stem cells and then exposed them to either Zika virus or Dengue virus.
When infected with Dengue, the macrophages froze to fight the virus. But with Zika, the cells were able to move.
'They're hitching a ride on macrophages to other parts of the body,' Tang said.
'Now the question is, with the increased ability to spread throughout the body, does Zika virus also use these infected macrophages to cross the placenta barrier, the blood-brain barrier and the testicular barrier?'