Epidemiologists and other researchers are still learning about Zika and its effects on those infected, including pregnant women and their unborn children.
The Zika epidemic in Brazil has garnered worldwide attention due in large part to the rise in babies born in the South American nation with brain defects linked to the virus. However, epidemiologists and other researchers are still learning about Zika and its effects on those infected, including pregnant women and their unborn children.
In a case report published online in the journal PLOS Neglected Tropical Diseases, a team of researchers working at the frontlines of the epidemic document the case of a 20-year-old pregnant woman referred to their clinic following the outbreak of Zika in her home city of Salvador, Brazil. Zika, a mosquito-borne flavivirus, was first identified in Brazil in early 2015, and an increase in the number of newborns with microcephaly (incomplete brain development) was first observed in November of last year.
The authors report that the pregnant patient presented to their clinic with an uneventful course of pregnancy and normal ultrasound findings at the 14th gestational week. The patient reported no Zika symptoms and had received no diagnosis for Zika, dengue fever, or chikungunya.
Ultrasound examination of the patient’s fetus at the 18th gestational week, however, revealed intrauterine growth retardation. Further ultrasound examinations in the second and third trimesters revealed severe microcephaly as well as hydranencephaly, intracranial calcifications, destructive lesions of the posterior fossa, hydrothorax, ascites and subcutaneous edema. Due to fetal demise, the authors induced labor at the 32nd gestational week and obtained Zika virus real-time PCR amplification samples from the female fetus’ cerebral cortex, medulla oblongata, and cerebrospinal and amniotic fluid.
As the authors are still working to combat the Zika virus and its effects, they were unable to comment on their case report to Contagion® at press time. However, in their concluding remarks, they write that because the Zika virus is asymptomatic, “it is likely that exposures in pregnant women... often go unnoticed.” They believe that the explanation for fetal demise in their case is due to “asymptomatic exposure of the mother… likely in the first trimester, [causing] an intrauterine infection which in turn, resulted in hydranencephaly and hydrops fetalis in the fetus.”
The authors add that the finding of an association between Zika and hydrops fetalis suggests that the virus may cause damage to tissues in addition to the fetal central nervous system, writing that, “We cannot extrapolate from this single case the overall risk for developing hydrops fetalis and fetal demise among pregnant women exposed to the virus. The strain detected in this case… appears to be the same as the epidemic strain that has spread across the Americas and Caribbean. Given that large numbers of pregnant women in the region have been or will be exposed to this strain, systematic investigation of spontaneous abortions and stillbirths may be warranted to evaluate the risk that [Zika virus] infection imparts on these outcomes.”
Brian P. Dunleavy is a medical writer and editor based in New York. His work has appeared in numerous healthcare-related publications. He is the former editor of Infectious Disease Special Edition.