More on the latest news regarding Zika virus research in pregnant women and their growing fetuses is included in this article.
Earlier this year, a link between Zika virus infection and microcephaly was confirmed, making the possibility of contracting the infection during pregnancy all the more threatening. Researchers have been working towards a means to block Zika infection in developing brains of infants infected with Zika congenitally. More on the latest news regarding infection with the Zika virus is included below.
Scientists have been racing to understand all there is to know about the Zika virus and how it effects developing fetuses. Recently, the Centers for Disease Control and Prevention (CDC) released a study examining the prevalence of Zika-related complications in fetuses and infants congenitally infected with the virus.
The research, which was published in the Journal of American Medical Association, found that approximately 6% (26) of the 442 women infected with Zika virus during pregnancy either gave birth to infants or had fetuses that developed birth defects. Furthermore, the study found that a staggering 9% of women who experienced Zika-related symptoms in their first trimester of pregnancy had infants or fetuses with birth defects, while women who were infected with Zika virus in the second and third trimesters did not.
In a case report recently published in the New England Journal of Medicine, researchers discussed a case study of a woman who visited Colombia. The authors wrote, “at 9 weeks’ gestation, she had a self-limited maculopapular, nonconfluent rash for 3 days that affected her trunk, arms, and legs; she had no fever or other concurrent symptoms.” The woman tested negative for Dengue, Chikungunya, parvovirus B19, sexually transmitted diseases, cytomegalovirus, and varicella—zoster virus, but both blood samples and amniotic fluid tested positive for Zika virus.
According to the authors, the woman’s blood test results tested positive six times for the duration of 89 days. After 12 and 15 weeks of pregnancy, scans showed that the fetus’s brain had no abnormalities. Nonetheless, at weeks 20, 24 and 29 of pregnancy, neurosonography “revealed bilateral mild ventriculomegaly and a shortened corpus callosum,” while “the posterior fossa was normal.” Furthermore, “the brain parenchyma had calcifications and severe atrophy.” The doctors reported that MRI scans showed similar results. At 37 weeks of pregnancy, the woman delivered her baby, during which time Reverse transcription polymerase chain reaction assays came back negative for “maternal serum, urine, amniotic fluid, placenta, membranes, and umbilical cord,” while “neonatal serum, urine, and cerebrospinal fluid” came back positive. MRI scans later confirmed microcephaly in the infant.
In a press release, the CDC confirmed that the Zika virus was found to replicate in placentas and brains of fetuses. According to the CDC, this may explain why the virus can cause such harmful complications in brains of developing fetuses.
In their study, tissue samples from 52 patients who were suspected of Zika virus infection were tested. In addition, 8 brain tissue samples were collected from infants who died as a result of congenital infection. Additionally, 44 placenta tissue samples were also tested. Of these, 22 belonged to women who experienced “adverse pregnancy or birth outcomes.”
This study, which was published in Emerging Infectious Disease Journal, is the first to display that the RNA of the Zika virus replicated “in brain tissues of infants with microcephaly who later died and in placentas of women who suffered pregnancy losses.” Moreover, levels of Zika virus RNA were found to be 1000 times higher in infants’ brain tissues than in placenta samples collected for this study.
Furthermore, the RNA remained in the brains of the fetuses and in the placentas for more than 7 months after the pregnant women were initially infected with Zika virus. In addition, the researchers also discovered that the virus was able to infect and thrive in Hofbauer cells in the placenta, which may be the manner by which Zika virus is able to travel from the mother into the fetus and infect the brain cells.
The results of a recent study published in JAMA Ophthalmology showed that optical coherence tomography can be used to efficiently assess ocular damage associated with congenital Zika virus infections. The researchers were able to predict severe damage to the retina of the babies in the study by only observing the fundus of the babies.
Read Part One of this article.