听
Microcephaly 鈥� babies born with brain damage and abnormally small heads 鈥� has jumped 20-fold in Brazil since the Zika virus arrived there. We don鈥檛 yet know how this condition will affect the lives of these babies, but early case studies suggest they could have serious brain damage.
Microcephaly is a poorly understood congenital condition in which babies are born with an unusually small head. It is associated with a range of causes, including having a malnourished mother or a genetic condition like Down鈥檚 syndrome. Some children born with the condition aren鈥檛 neurologically impaired, while others can have severe brain damage.
Advertisement
Since October, babies with microcephaly have been born in Brazil, and it is strongly suspected that Zika infections during pregnancy are to blame. But what isn鈥檛 yet known is how it will affect the children鈥檚 development.
鈥淭hey may not be able to recognise their parents or perceive pain, and will need constant attention because they wouldn鈥檛 be able to indicate when they need food or drink,鈥� says Geoff Woods, a clinical geneticist at the University of Cambridge, who has seen brain scans and from Brazil.
Limited life expectancy
Based on the scans, it appears that the brain stem and the cerebellum are the regions most affected. These oversee many functions that don鈥檛 require active thought, such as swallowing, controlling body temperature and blood pressure, says Woods. Impairment of these regions means that the babies are prone to choking and fits. 鈥淲e expect it to be a disease with a very limited life expectancy,鈥� he says.
The babies are also likely to be intellectually impaired, says Yanick Crow of the Imagine Institute in Paris, France, who has examined three brain scans sent from Brazil. Crow says these Zika-linked cases are similar to , a rare condition caused by an immune over-reaction to viral DNA in the brain.
鈥淭he majority of children with Aicardi-Goutieres syndrome have no useful hand, locomotion or verbal function and are severely intellectually affected, and I would fear the same here,鈥� he says.
But it isn鈥檛 yet certain that Zika is to blame for Brazil鈥檚 rise in microcephaly. 鈥淎 causal relationship between Zika virus infection and birth malformations has not been established, but is strongly suspected,鈥� Margaret Chan, director-general of the World Health Organization, said last week. 鈥淭he possible links, only recently suspected, have rapidly changed the risk profile of Zika, from mild threat to one of alarming proportions.鈥�
Supporting the link, Zika has been found in the tissues of , and unpublished research suggests the virus may attack the developing forebrain.
