Which virus is implicated along with Epstein-Barr virus as a cause of infectious mononucleosis?

Cytomegalovirus (CMV) is the correct answer because it is a well-established agent that can cause infectious mononucleosis, often alongside Epstein-Barr virus (EBV). Infectious mononucleosis is characterized by symptoms such as fever, sore throat, and lymphadenopathy, which can arise due to either of these viruses. CMV, in particular, has a significant association with heterophile antibody production, leading to a clinical presentation similar to that of EBV.

While other viruses listed play roles in various illnesses, they are not primarily associated with infectious mononucleosis in the way that CMV is. For example, Coxsackie A and B viruses are associated with conditions such as hand-foot-and-mouth disease and viral myocarditis, respectively, rather than infectious mononucleosis. Hepatitis B virus primarily leads to liver inflammation and does not typically cause the classic symptoms of mononucleosis. Therefore, CMV’s relationship with EBV in causing infectious mononucleosis solidifies it as the correct choice.