Abstract
Epstein-Barr Virus (EBV) and Cytomegalovirus (CMV) are herpesviruses that cause different clinical syndromes depending on the host's immune status. EBV is known for causing infectious mononucleosis (IMN), which presents with fever, pharyngitis, cervical lymphadenopathy, and atypical lymphocytes. CMV can also cause a mononucleosis syndrome with similar symptoms but is less frequently reported. Comparative studies on IMN and CMV mononucleosis from India are rare. This study aimed to elucidate the clinical characteristics of IMN and CMV mononucleosis in a South Indian tertiary care center, emphasizing the differences in their presentations. A retrospective analysis using Electronic Medical Records (EMR) from a tertiary care hospital at Thiruvananthapuram, Kerala, was conducted, including patients diagnosed with IMN or CMV mononucleosis based on clinical and serological tests during 2017 to 2023. Immunocompromised patients were excluded. The study compared demographic, clinical, and laboratory characteristics between the two groups. Out of 136 IMN cases and 17 CMV mononucleosis cases, the CMV group had a significantly higher median age (34.0 years) compared to the IMN group (20.0 years). The CMV group experienced a longer duration of fever (median 14.0 days) compared to the IMN group (5.0 days). Sore throat, cervical lymphadenopathy, and tonsil enlargement were significantly less common in CMV cases. The study concludes that CMV mononucleosis is more likely in older adults with prolonged fever and an absence of sore throat, tonsillitis, or cervical lymphadenopathy.