Trojan.Agent refers to a generic Trojan malware detection. It is used for detections that are either associated with no specific malware families or not enough information is available to pinpoint the malware family.
Trojan.Qhost is the generic detection for malware that modifies the system’s hosts file. You can find some information about this file and how it can be abused in our blog post, Hosts file hijacks.
Malwarebytes can remove Trojan.Qhost without further user interaction.
If you were using a custom hosts file before infection, you may have to re-create it or restore from your backup.