EBV is associated with (a) infectious mononucleosis, (b) EBV-induced tumors, and (c) EBV infection in immunocompro-mised host.
This is a clinical syndrome that represents the immunopatho-genic response of the host to infection with EBV. It is the classic syndrome associated with primary EBV infection in adolescents and young adults. EBV is the causative agent in approximately 90% of cases of acute infectious mononucleo-sis. Cytomegalovirus (CMV) is most commonly associated with EBV-negative cases of infectious mononucleosis.
The condition is most often asymptomatic in children younger than 4 years. In symptomatic cases in adolescents and in adults, the condition is characterized by high fever, sore throat, headache, myalgia, nausea, and abdominal pain. The condition is associated with pharyngitis, generalized lymph-adenopathy, hepatosplenomegaly, and fatigue. The symptoms are usually present for 2–3 weeks. But fatigue, which is the major complaint, continues to persist.
Epstein–Barr virus infection rarely causes death in immu-nocompromised patients but may cause neurological complications (meningoencephalitis, Guillain–Barre syndrome, etc.), upper airways obstruction, or splenic rupture.
Epstein–Barr virus infection is associated with a number of tumors. Endemic Burkitt’s lymphoma caused by EBV is a poorly differentiated monoclonal B cell lymphoma of the jaw. It is the most common tumor of childhood in Africa associated with both EBV and falciparum malaria. Plasmodium falciparum malaria causes stimulation andproliferation of polyclonal B cells in the presence of EBV infection. The malaria parasite also alters response of T lym-phocytes to EBV, apparently contributing to pathogenesis of the tumor.
Epstein–Barr virus infection in immunocompromised host
The virus causes most severe diseases in patients who are immunocompromised. In these patients, the EBV causes several syndromes and proliferation disorders including Duncan syndrome, ataxia telangectasia, Wiskott–Aldrich syndrome, and common variable immunodeficiency.