The news about the Zika virus has accelerated this week. A newborn in the Houston area tested positive for Zika-related microcephaly. Doctors are also trying to figure out how an elderly Utah man was infected without transmission through sex or mosquito bites. These developments come as a new study from UT Southwestern Medical Center finds that Zika can infect brain cells and hide itself from the immune system.
Dr. John Schoggins co-authored the study and explained its findings.
Interview Highlights: John Schoggins...
... on the type of brain cell Zika infects:
"Brain progenitor cells are the cells in the brain that can eventually give rise to different type of cells including adult neurons. When the virus infects these brain cells, we found that there are a certain number of cells that die from the infection - they literally round up and die. And then there is a number of cells that survive the infection, but they continue to make more virus for long periods of time, which we found to be quite interesting. We can actually detect virus being made for many weeks after the initial infection."
... on how Zika might infect the placenta and cause birth defects in newborns: "There is a relatively brand new study that came out this week showing that there are certain cell types in the placenta that the virus is able to infect directly, and what we think is happening is that it crosses those cells through the placenta and then it gain access to the fetus."
... on how Zika evades the immune system:
"We looked for hallmarks of the immune response in these neural progenitors. This would be induction of molecules that would cause sort of alarm to the immune system, and we don't see those things being produced. However, if you stimulate the cells with other types of things that would normally activate the immune system, they appear to be capable of being activated but the virus just doesn't do it."
... on the Zika case out of Utah:
"What we do know is that the person who was infected had really high levels of virus in their blood, and so its formally possible that this was a simple needle stick, maybe there was some sort of accidental needle stick if the caregiver was doing some sort of treatment.
We know that the virus has been detected in saliva and urine and other bodily fluids, so if there was a very high level of the virus in these fluids, then there could have been some sort of transmission to a mucus membrane or cut in the persons hands. There are definitely ways to think about how this could have happened that aren't too surprising."
Dr. John Schoggins is a professor of microbiology with UT Southwestern Medical Center
