Zika virus disease (ZVD) has, quite rightly, been making headlines around the world. ZVD is carried by the same type of mosquito, Aedes aegypti, as other insect-vector diseases, including dengue and chikungunya. In healthy individuals the disease presents a lower risk than other diseases. It is asymptomatic with 80 percent of patients (this means those infected do not know they have an infection); and in the remaining 20 percent of cases the disease is manifest as a mild rash.
However, over 4,000 babies in Brazil have reportedly been born with severe birth defects, including microcephaly (small head), and the reason is theorized to be connected to the Zika virus. For this reason, on February 1, 2016, the World Health Organization (WHO) declared a Public Health Emergency of International Concern. To add to the risk to pregnant women, a case in Dallas of possible sexual transmission of the virus worried health officials (although this incident has yet to be replicated.)
Evidence for the microcephaly connection has been presented to the medical journal Lancet Infectious Diseases (see: “Detection and sequencing of Zika virus from amniotic fluid of fetuses with microcephaly in Brazil: a case study.”) Here the Zika virus has been found in the amniotic fluid from two women. Both women showed Zika-like symptoms during their pregnancies. Tests were made after ultrasound scans indicated that the developing foetuses, carried by the women, had microcephaly.
One of the researchers involved — Dr Ana de Filippis, from the Oswaldo Cruz Institute in Rio de Janeiro, Brazil — told BBC Science: “This study reports details of the Zika virus being identified directly in the amniotic fluid of a woman during her pregnancy, suggesting the virus could cross the placental barrier and potentially infect the fetus.”
However, WHO has urged caution in relation to the findings. The United Nations health body stated that more evidence is needed before a definitive link between the virus and the issue affecting pregnant women and their babies in Brazil can be made.
