Study shows Zika and dengue viruses infect differently

A new study reveals that Zika and dengue viruses, which are closely related, have very different ways of infecting people. Researchers from La Jolla Institute for Immunology and UC San Diego found that Zika uses stealth to evade the immune system, while dengue launches a strong immune response. Zika virus sneaks into dendritic cells and blocks them from warning nearby T cells about the infection. This means that the immune system is not alerted to the threat. In contrast, dengue virus causes dendritic cells to release inflammatory signals that overwhelm the immune system, allowing the virus to spread. Understanding how these viruses operate is crucial for developing effective vaccines. The researchers aim to create vaccines that stimulate the appropriate T cell responses to fight both Zika and dengue viruses. They highlight the importance of knowing how these viruses trick the immune system to design better vaccine strategies. The team discovered that Zika virus suppresses a key molecule in dendritic cells, which prevents a proper immune response. This finding explains why people might respond more weakly to Zika compared to dengue. The research also sheds light on how Zika can infect unborn babies by evading the immune defenses in the placenta. Currently, there are no effective vaccines for either virus. The researchers emphasize the urgency of finding solutions, as dengue cases have surged recently, with millions infected in 2024. Many mosquito-borne viruses have pandemic potential, which raises the need for research into vaccines and treatments. The scientists are working on a "pan-flavivirus" vaccine that could protect against multiple related viruses. They are also exploring ways to develop antiviral therapies that could counteract Zika's suppression of the immune response.