A group of Chinese researchers has found that viruses are using a technique strikingly similar to the Trojan Horse—unknown until now—to infiltrate and spread within the body.
At different stages of evolution, viruses have developed diverse strategies to spread and survive. How efficiently a virus moves from one cell to another plays a major role in how severe an infection becomes. The two main ways viruses spread are cell-free diffusion—virus particles are released into the space outside cells and go on to infect new ones—and direct cell-to-cell spread, which helps viruses evade the host’s immune system.
Now, a new and more dangerous viral path has been discovered. Researchers found that a newly identified cellular structure called migrasomes forms specifically during cell movement and that the vesicular stomatitis virus can package its genetic material and proteins inside these migrasomes. In effect, viral cargo is cleverly hidden and discreetly loaded in structures linked to cell migration. These virus-like packages, named migrions, are made not only of viral components but also of the host cell’s own material.
When viruses spread using migrions instead of individual virus particles, they grow much faster in newly infected cells. This happens because migrions deliver multiple copies of the viral genetic material at once, allowing replication to begin immediately and in parallel. Therefore, they are far more infectious than free virus particles. When viruses enter the body hidden inside migrions, the disease becomes significantly more severe. Experimental mice developed serious infections in the lungs and brain, often leading to encephalitis and death.
Although Odysseus devised the idea of the Trojan Horse outside the gates of Troy, it was the city’s residents who unwittingly carried the enemy inside. Similarly, viruses appear to be exploiting the body’s migratory machinery to move efficiently, infect cells and survive.