By Drs. David Niesel and Norbert Herzog, Medical Discovery News
Unless you are totally cut off from the news, you have heard about the Zika virus. Maybe more than you want because this is a scary virus, especially if you are pregnant. We have known about this virus for some time. It was first isolated in 1947 and has been pretty much of a scientific curiosity until recently. And then seemly we look up and there is a full-blown outbreak in Brazil that is marching steadily across South and Central America and the Caribbean. But also, it has breached American shores with infected individuals now reported in several American cities.
These Zika infections have originated from travelers to affected areas or those in close contact with those that have traveled in that region. Person to person spread has been shown after sexual contact and the virus can be found in infected individuals in semen, salvia and in urine.
The world is focused on this virus because of its devastating effects on the most helpless among us - babies. When a pregnant women becomes infected, there is a link between Zika infection and her baby being born with a small head and brain. This is called microcephaly. As you can imagine with an infection affecting the brain, microcephaly leads to developmental issues with the baby and many do not survive beyond adolescence.
While microcephaly is obvious at birth, this could be the "tip of the iceberg" in terms of the number of children with neurological problems that will be revealed as they grow older. Adults can be infected resulting in neurological consequences also. In infected adults, there is a 24 times higher chance of developing Guillain-Barre syndrome, which results the immune system attacking nerves. GBS can be mild for some, it can last for months and in ~5% of cases, GBS can lead to death.
Recent studies may have started to reveal how the Zika virus causes brain damage leading to the symptoms observed in babies and others. It has been shown that Zika interacts with neuroprogentior cells, which are immature cells on the path to becoming glia cells or neurons, two of the most important cells in the brain. In experiments, 90 percent of the neuroprogenitor cells became infected with the Zika virus and went on to produce more virus. Here is the punch line - this means that two of the major cell types in the brain are susceptible to Zika infection and those infected cells are eventually killed by the virus or slowed in growth significantly. This could be the "smoking gun" that explains how Zika can damage the brain.
Many adults who become infected with the Zika virus don't experience symptoms, and it's usually mild for those that do, such as joint pain, fatigue and low fever, which usually last two to seven days. However, women who are pregnant or want to become pregnant in the near future should avoid Zika-infected areas, and men who've traveled to Zika-infected area should refrain from unprotected sex. Currently, there are not any treatments or vaccines for Zika, so hang on, we are in for a bumpy ride this summer and beyond.
Medical Discovery News is hosted by professors Norbert Herzog at Quinnipiac University, and David Niesel of the University of Texas Medical Branch. Learn more at www.medicaldiscoverynews.com.