The Zika virus is transmitted through mosquito bites and can be passed from mother to fetus during pregnancy, potentially causing microcephaly in infants. Microcephaly results in an abnormally small head size and can lead to seizures, developmental delays, intellectual disability, and problems with movement and balance. While most infected individuals have no symptoms or only mild symptoms, the virus poses serious risks during pregnancy due to its ability to cross the placenta and impact fetal brain development.