Virophage

A virophage is a small virus that infects giant viruses, such as those belonging to the *Mimivirus* family. It is completely dependent on the host giant virus for replication and lacks the genes necessary for independent reproduction. Virophages were first discovered in 2008, providing a new dimension to the viral world and demonstrating a complex interplay of viral interactions, where one virus is a parasite of another. They offer insight into virus evolution and suggest possible roles in regulating viral infections and maintaining ecological balance in aquatic environments. The term virophage comes from the combination of "virus" and "-phage" meaning "eater".

Virophage meaning with examples

• In the initial experiments with *Acanthamoeba* and *Mimivirus*, it was observed that co-infection with the virophage, *Sputnik*, significantly reduced the replication of *Mimivirus*. This showed that virophages could act as biological controls for giant viruses, impacting their effects on host cells and influencing the broader microbial ecosystem.
• The discovery of *Sputnik* marked a critical turning point in understanding the complexity of viruses. Researchers are studying how virophages hijack giant virus machinery to replicate, revealing new insights into the co-evolution of these viruses and the ways in which virophages manipulate their giant virus hosts for survival.
• Analysis of metagenomic data from diverse environments continues to unveil new types of virophages and their corresponding giant virus hosts. Scientists are eager to understand the distribution of virophages to understand the implications for viral diversity and abundance.
• The presence of virophages such as *Zamilon* affects the replication cycles of giant viruses. These interactions impact the host cell by modulating the host cell’s response, illustrating a dynamic interplay of viral-viral interactions and ultimately determining the host cell's fate.