Zika virus infection
Zika virus infection is a zoonosis which is associated with congenital birth defects, most famously microcephaly.
Zika was once isolated to Africa and Asia, however, it spread to the Americas in the last decade 1. There were thousands of cases confirmed in the Americas in 2018 2.
In up to 80% adult cases Zika disease is asymptomatic.
When symptoms are present in adults, they are usually mild, with a similar presentation to dengue, including fever, malaise, joint pain and rash. Acute conjunctivitis and even rarely Guillain-Barré syndrome have been described.
Following vertical transmission to the fetus, the disease may be associated with congenital birth defects including microcephaly (and micrencephaly (small brain)).
Zika is a single RNA stranded Flavivirus usually transmitted by a mosquito vector, for example Aedes aegypti. Although both vertical and sexual virus transmission are seen 3.
Radiographic features of congenital Zika viral infection has been reported on ultrasound, CT and MRI, and most result from a negative effect on brain development.
Congenital Zika has been shown to cause various brain abnormalities affecting both grey and white matter and ventricular size 4,5. Intracranial calcifications resulting from congenital Zika virus infections are typically more florid than caused by the TORCH infections and also characteristically at the grey-white matter interface, which is unusual for other congenital viral diseases.
Arthrogryposis is a commonly seen extracranial sequela.