Final answer:
Rubella, also known as German Measles, is caused by the Rubella virus, a distinct agent separate from other diseases such as measles caused by the MeV.
Step-by-step explanation:
The agent responsible for causing Rubella, also known as German Measles, is the Rubella virus. It is a contagious viral infection marked by a rash that can resemble the symptoms of measles, although they are caused by different viruses. The Rubella virus is an enveloped RNA virus found in the respiratory tract, which can be transmitted via aerosolized droplets from coughing or sneezing. It is important to distinguish this from other diseases such as rubeola (measles), which is caused by the measles virus (MeV), or conditions caused by Streptococcus pyogenes, Influenza virus, or Hepatitis B virus, all of which are not related to Rubella. Vaccination is the best prevention strategy for Rubella.