Zika Cartoon (IMAGE) University of California - San Diego Caption In a 3-D brain model, Zika virus activates immune receptor TLR3, which in turn inhibits brain cell development and survival, causing the organoids to shrink -- an effect reminiscent of microcephaly. Credit UC San Diego Health Usage Restrictions Use credit as indicated License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.