Infectious mononucleosis can be caused by either cytomegalovirus (CMV) or Epstein-Barr virus (EBV). Both of these viruses belong to the Herpesviridae family. The classical virus that causes mono and a positive monospot test is the Epstein-Barr virus. Both are very common viruses that usually just cause a cold. In some people, usually teens and young adults, they can cause "mono." The form caused by the EBV is by far the most common.
What is the causative agent that caused you to ask this question
The causative agent of the symptoms of tetanus is Clostridium tetani.
The causative organism is a herpesvirus known as Epstein-Barr virus.
The causative agent of syphilis is the bacterial spirochete called Treponema pallidum.
The genus of the causative agent of malaria is Plasmodium. It belongs to the group of protozoa.
The causative agent for Hepatitis B is Hepatitis B virus.
Rhinoviru
Rabies virus is the causative agent for rabies.
HIV is the causative agent for AIDS. It attacks the T Cells of the body.
The polio virus.
Fungus
Mycobacterium tuberculosis, the causative agent of TB