Infectious mononucleosis is caused by the Epstein-Barr virus, and patients often exhibit a fever, ...

Infectious mononucleosis is caused by the Epstein-Barr virus, and patients often exhibit a fever, sore throat, swollen glands, and fatigue for several weeks. In some patients, the virus can reactivate later and cause physical symptoms once again.
 
  This is likely because
 
 
 A. they were misdiagnosed the first time, and only really were infected by the virus the second time they became sick.
  B. the virus was latent in these patients, and then switched to the active form and began making new virus particles
  C. the patients had the virus initially, and they became sick again at the time the virus became latent.
 
  D. the Epstein-Barr virus is an emerging virus so we do not know much about its infectious life cycle.