According to a Johns Hopkins team of researchers, early exposure to the Zika virus could result in miscarriage, while exposure at a later date could lead to the fetus developing thinner brain tissue and neurological problems associated with the virus. By injecting mice with the pathogen, the researchers observed Zika was able to cross the placenta and penetrate the fetus.
Researchers say the placenta, which acts as a barrier that protects the fetus before delivery, is actually a multilayered defense system. Unfortunately, none of the discrete layers of tissue is able to keep the Zika virus from infecting the developing fetus, should the mother be exposed to the pathogen at any given time during the pregnancy. At the same time, it seemed that the virus was also preventing antiviral proteins from protecting the fetus.
Details of the study were published in the February 21st issue of the journal Nature Communications. The findings, say the researchers, put them closer to developing an antidote or a form of treatment for infected hosts, as there is currently no way of combating the disease. Last year, World Health Organization officials deemed the illness a public health emergency.
Now, Sabra Klein, study’s co-author and a microbiologist and immunologist at the Johns Hopkins Bloomberg School of Public Health, says her team is focused on finding ways of protecting the fetus from the Zika virus. She said that trials conducted on mice showed the fetuses were actually mounting some kind of defense against the pathogen but were falling short, especially if the mother was exposed to the virus at an early stage in the pregnancy, more specifically, during the equivalent of the first trimester in humans.
To be sure the Zika attacks the same areas as it does in humans, the researchers injected the virus straight into the pregnant mice’s reproductive tract. The procedure was done during the equivalent of the first trimester in humans. It was discovered that Zika exposure at such an early stage in the pregnancy resulted in miscarriages. However, fetuses exposed to the pathogen later in the pregnancy were able to survive but were born with neurological and physiological symptoms associated with the disease. Hence, the scientists concluded fetuses are less vulnerable to Zika later in the pregnancy and are making this the building block for future research.
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