<prompt> Lymphocytosis with atypical lymphocytes are seen in infection with -HSVHBVEBVRSV  <response>: Ans. is c i.e., EBV o In IMN, there is predominantly lymphocytosis with a presence of 20 or more atypical lymphocytes, o These atypical lymphocytes are activated T-lymphocytes which have round or irregularly shaped nuclei, with abundant flowing cytoplasm that characteristically has a dark-staining periphery. o Burkitts lymphoma is caused by EBV. Epstein - Barr Virus EBV o Belongs to Herpes viruses family. o Infection is most common in early childhood, with a second peak during late adolescence. o Infectious mononucleosis IM is usually a disease of young adults. o EBV is transmitted by saliva oral secretions of an infected person. o Intimate oral contact, as in kissing is the predominant mode of transmission - causes kissing disease. o The virus enters the pharyngeal epithelial cells and B cells through CR 2or CD21 receptors, o Memory B Cells are the reservoir of FBI. Clinical Manifestations: o Most primary infections are asymptomatic o Causes an acute self-limited illness - Infectious mononucleosis Glandular fever o Incubation period - 4-8 weeks o Age groups - young adults o The most common symptom of IMN is sore throat o Most common sign is lymphadenopathy o Most common complication - meningitisencephalitis EBV associated malignancies Burkitts lyrijphoma Nasopharyngeal carcinoma Hodgkins disease mixed cellularity type Tonsillar Carcinoma T Cell lymphoma Thymoma Gastric carcinoma CNS lymphoma in AIDS and transplant recipient Angiocentric nasal NKT cell immunoproliferative lesions Leiomyosarcoma Angio-immunoblastic lymphadenopathy Other associated non-malignant conditions Oral hairy leukoplakia in AIDS patients Chronic fatigue syndrome X-linked lymphoproliferative syndrome Duncans disease 