HHV 4(EBV)
Epstein-Barr VirusEpstein-Barr virus (EBV) (HHV-5) infects oropharyngeal B-cell lymphocytes; latency is established locally
and in lymphatic tissue throughout the body. Primary infection mainly occurs when asymptomatic persons
shedding EBV in saliva have intimate contact with previously uninfected persons. Most often, infection is
asymptomatic and transpires in children and adolescents; antibodies to EBV are present in 95% of adults
worldwide. EBV is the most common cause of infectious mononucleosis, characterized by an exudative
pharyngitis, fever, and lymphadenopathy (mostly cervical).
Splenomegaly is present in approximately 50%
of patients. Other, less frequent findings include jaundice, hepatomegaly, and an erythema multiforme–likerash. In most cases, disease spontaneously resolve within 2 to 3 weeks; however, subsequent asthenia
may persist for variable periods. EBV is associated with the development of certain malignancies in
immunosuppressed and immunocompetent hosts
Diagnosis can be confirmed by the presence of EBV heterophile (Monospot) antibodies or by the detection
of EBV-specific antibodies, particularly IgM, to the EBV viral capsid antigen. With mononucleosis, a
lymphocytosis typically exists, classically consisting of atypical lymphocytes. Thrombocytopenia, elevated
hepatocellular enzymes, lactate dehydrogenase, and bilirubin are other commonly found laboratory
abnormalities.
Acyclovir and other antiviral agents have not proven beneficial in the treatment of infectious mononucleosis
or EBV malignancies. Glucocorticoids should be reserved for complications of EBV, such as a compromised
airway or autoimmune hemolytic anemia but in general are not recommended for the treatment of
mononucleosis.
Malignancies associated with EBV:
1-NASOPHARYNGEAL CARCINOMA.
2-BURKITT LYMPHOMA.
3-CNS lymphoma (in patients with AIDS).
4-POSTTRANSPLANT LYMPHOPROLIFERATIVE DISORDERS.
5-HAIRY LEUKOPLAKIA
6-Hodgkin lymphoma.
Differential diagnosis of mononucleosis like syndrome:
1-CMV.2-HIV.
3-HHV-6
4-Herpes simplex virus type 1&2.
5-Group A beta hemolytic streptococcus pyogenes.
6-toxoplasma gondii.
7-Hodgkin and non HODGKIN LYMPHOMA.
8-Rubella.
9-TB adenitis.10-hepatitis A and B VIRUS.
Human Cytomegalovirus
Most cases of cytomegalovirus (CMV) infection (HHV-5) are asymptomatic, and the virus remains latent
afterward. Serologic evidence of CMV is present in 60% to 100% of adults worldwide. CMV may spread by
close contact through saliva, blood transfusion, organ transplantation, and breastfeeding. Disease
acquisition can also occur through congenital or sexual transmission.
Symptomatic primary infection usually
manifests as a mononucleosis-like syndrome. Compared with patients who have EBV mononucleosis,patients are usually older and have pharyngitis less often. Fever alone may predominate, making CMV a
consideration in persons with fever of unknown origin. The lung, liver, heart, and hematologic and central
nervous systems may be involved during primary infection. Latent CMV frequently reactivates in
immunocompromised patients. Manifestations of secondary infection include fever, retinitis, pneumonitis,
hepatitis, esophagitis, gastritis, colitis, and meningoencephalitis.
Diagnosis relies on isolation of the virus from body fluids, such as urine; detection of CMV pp65 antigen in
leukocytes; cytopathic demonstration of “owl's eye” intracellular inclusions; PCR; and serologic assays.
Antiviral treatment is typically indicated in cases of disease reactivation in immunocompromised patients and occasionally in immunocompetent hosts with severe disease,Ganciclovir and valganciclovir are first line agents and can be used as prophylaxis in certain transplant patients.Fascarnet and cidofovir are second line agents.