Now The Zika Virus Is Causing Unnerving Birth Defects
Zika Virus Birth Defects
The Zika virus continues to spread, reaching 52 countries so far, as new research establishes the link between the virus and the birth defect microcephaly.
The defect has led to sustained outbreaks in Brazil and French Polynesia, but other nations may soon join that list due to Zika’s presence across Europe, the Americas, the Caribbean and the Pacific. According to the World Health Organization (WHO), only two microcephaly pregnancies have been confirmed in women infected with Zika during travel while pregnant.
Researchers are still working to understand the cause of microcephaly while simultaneously trying to allocate the financial and medical resources for countries affected to respond accordingly to the Zika virus. This entails the detection, assistance and possibly prevention of affected pregnancies to avoid Zika virus birth defects.
Brazil has been in the midst of an “extraordinarily unusual” large outbreak since the virus arrived in the nation last year, likely causing the 641 confirmed cases of microcephaly. Another 4,222 cases are being looked into, and there have been 139 infant deaths or miscarriages due to microcephaly complications.
Before Zika, only two infections, rubella and cytomegalovirus, were known to cause microcephaly. Director of the U.S. Centers for Disease Control and Prevention (CDC) Dr. Thomas Frieden said of the virus: “In more than 50 years, no other pathogenic cause of severe fetal malformation has been identified—and as far as I know, never before has there been the possibility that you could be bitten by a mosquito, and end up with an infant with a devastating birth defect.”
U.S. officials are seeking to understand the Zika virus birth defects on the brains of infant children, as they anticipate continued cases in the country beyond the single affected birth, two miscarriages and two elective abortions so far. The current rate of microcephaly in the US is about six cases in every 10,000 births.
“Microcephaly is just a very crude estimate of the size of the head,” obstetrician and co-leader of the birth defects group of the CDC’s Zika Virus Response Team Dr. Denis Jamieson told National Geographic, “but really what we are seeing is a pattern of severe brain abnormalities—destruction of brain tissue, and then basically the skull collapses.”
Microcephaly, Jamieson suggests, might be thought of as a collection of defects. Although we’ve yet to label Zika as the cause of such Zika virus birth defects, the connection between microcephaly and the virus is growing stronger, as evidenced by the recent discovery of Zika in the brain tissue of microcephalic infants.
Microcephaly is also characterized by a lack of brain development, or “fetal brain disruption sequence,” otherwise seen in rare cases of pregnant mothers who have contracted other viruses or enduring traumatic injury.
Due to the CDC’s concerns that Zika may spread due to women travelling while pregnant or contracting it from a sexual partner, Zika has been made a “nationally notifiable” disease, meaning physicians are required to report diagnoses to state health department, who then report to the CDC. They’ve also set up a birth registry to collect and organize information from health departments to find clues as to the causes and spread of Zika and microcephaly.
Two recent scientific papers shed light on how Zika causes brain damage and affects pregnancies. One examination of pregnant women in Rio de Janeiro found serious problems in the fetal development in 29% of pregnancies of women who had experienced Zika symptoms and allowed prenatal imaging. The women were infected during different periods of their pregnancy, and the six live births from these women so far exhibit a range of birth defects extending beyond microcephaly, including brain tissue calcification, eye disorders, clubfoot and more.
Another group of researchers published their findings on a study wherein they infected human cells with Zika virus in a lab setting. The virus showed an apparent preference for developing within and destroying cells similar to those that form the cortex of the brain during fetal development, infecting up to 90% of them and destroying another third. The cells didn’t seem to mount an immune response to the virus.
CDC researches have mathematically determined that the risk of Zika infection in pregnancy is highest during the first and early second trimesters, which can hopefully help states prepare for the extensive public services necessary to treat and assist microcephalic infants and their families.
Public health is largely variable between states and nations, which could mean some areas affected by Zika will be ill-prepared to support affected children and families. The costs of long term treatment and research of early- and late-onset symptoms could be disastrous, even in the U.S.
“If we find Zika-associated microcephaly becomes a big problem in the United States,” said Dr. Edward R.B. McCabe, executive vice president and chief medical officer at the March of Dimes, “this is going to be a huge blow to the public health system.”