And how exactly does Zika affect developing babies?
This is a two-week old baby girl born with microcephaly asleep in a Brazilian hospital.
Zika is a virus originally from the Zika forests in Uganda. It is sweeping across the Western Hemisphere, and is especially prevalent in Brazil though a few recent cases have been reported in Florida. According to the New York Times, “About four in five victims have no symptoms, and those who do usually recover within a week.” The reported symptoms are those of a normal viral infection, including fever, headaches, and joint pain. Generally, the virus is transmitted by mosquitos, but there have also been cases in which the virus was transmitted sexually. According to the New York Times, all such cases involved a man transmitting the virus to a woman. Scientists think that the male prostate or testes somehow protect the virus from the immune system, since viral RNA can be found in semen up to two months after initial infection. Currently, there are no accurate tests to discover if someone has been infected with Zika.
The most publicized aspect of this virus is the damage it inflicts upon in-utero babies. Babies born to mothers who were infected with Zika duri[crossword]ng pregnancy are often born with microcephaly, which means that the infants have unusually small heads. Technically, the link between Zika and microcephaly is only theoretical, and has not been proven, but the number of Brazilian babies born with this birth defect has increased twenty-fold since the disease first appeared in Brazil. Microcephaly can range from just a physical birth defect with no complications to a severe condition involving a malformed brain and constant seizures. In severe forms of Zika, babies may be born with an extremely small smooth brain that does not contain normal characteristic ridges. Evidence indicates that Zika infection at any time during pregnancy can cause birth defects.
The manner in which the virus actually degrades the developing brains of babies is still being studied. It appears that the virus attacks feidal radial glial cells, progenitor cells (stem-cells) of the central nervous system. Typically, these cells provide structure for the growing nerves and later diversify into multiple different forms of neurons. Currently, there is no treatment available for babies born with microcephaly. Interestingly, the Zika virus has only been linked to microcephaly as recently as October of 2015, even though Zika existed for years in Africa and Asia.
This is an X-ray comparing a normal baby head (on the left) with that of a baby of a mother infected with Zika (right). Note the smaller head size and the drastically decreased number of brain ridges.
As there is no treatment available in the immediate future, doctors recommend wearing skin-covering clothing and using insect repellant to minimize mosquito bites while traveling in contaminated areas. In addition, pregnant women are advised not to travel in infected regions. In South American countries like Colombia, Ecuador, and El Salvador, government officials recommend their female citizens to delay pregnancy plans. Although research is being conducted and more information is known, the Zika virus does not look like it will be going away anytime soon.
Information is courtesy of Donald G. McNeil Jr., Catherine Saint Louis, and Nicholas St. Fleur from the New York Times; the CDC; and Zara Husaini from FitPregnancy.
Pictures are courtesy of Stat, Pulse Headlines, and Vox