1. Epstein-Barr Virus (EBV) Erika Guevara, Elly Nagata and Bin Yang

2. Case Study 17-year-old high school student 17-year-old high school student No prior major illnesses No prior major illnesses Low grade fever Low grade fever Malaise- several days Malaise- several days Sore throat Sore throat Swollen cervical lymph nodes Swollen cervical lymph nodes Increasing fatigue Increasing fatigue Discomfort in left upper quadrant of abdomen Discomfort in left upper quadrant of abdomen Sore throat, lymphadenopathy and fever resolve over next two weeks Sore throat, lymphadenopathy and fever resolve over next two weeks Full energy level does not return for another six weeks Full energy level does not return for another six weeks

3. Herpesviruses Linear genome Linear genome dsDNA with nicks or gaps dsDNA with nicks or gaps Enveloped Enveloped Icosahedral capsid Icosahedral capsid Infect humans Infect humans Remain latent within host Remain latent within host cell after primary infection cell after primary infection and may become activated and may become activated

4. EBV vs. Cytomegalovirus (CMV) CMV Infection Human herpesvirus type 5 Human herpesvirus type 5 Severe systemic disease can develop in infants Severe systemic disease can develop in infants Negative heterophile antibody test and serology Negative heterophile antibody test and serology EBV Infection Human herpesvirus type 4 Human herpesvirus type 4 Usually asymptomatic in infants Usually asymptomatic in infants Severe pharyngitis Severe pharyngitis

5. Tests Performed: CBC count CBC count Liver function test Liver function test Heterophile antibody test Heterophile antibody test - differential absorption - heterophile antibody titers - monospot EBV serology EBV serology Imaging Studies Imaging Studies

6. CBC count 40%-70% of patients have leukocytosis with a WBC count of 10,000-20,000 cells/mL. 10% of patients will have a WBC count greater than 25,000 cells/mL by the second week. 40%-70% of patients have leukocytosis with a WBC count of 10,000-20,000 cells/mL. 10% of patients will have a WBC count greater than 25,000 cells/mL by the second week. 80-90% of patients have lymphocytosis with more than 50% lymphocytes. 20-40% of the lymphocytes are atypical. The illness typically lasts for 2-6 weeks. 80-90% of patients have lymphocytosis with more than 50% lymphocytes. 20-40% of the lymphocytes are atypical. The illness typically lasts for 2-6 weeks. The atypical lymphocytes appear larger, have a lower nuclear-to-cytoplasmic ratio, and have a nucleus that is less dense than that of normal lymphocytes. The atypical lymphocytes appear larger, have a lower nuclear-to-cytoplasmic ratio, and have a nucleus that is less dense than that of normal lymphocytes.

7. Liver function test 80-100% patients have elevated liver function test results. 80-100% patients have elevated liver function test results. Alkaline phosphatase, aspartate aminotransferase (AST), and bilirubin levels peak 5-14 days after onset, and gama- glutamyltransferase (GGT) levels peak at 1-3 weeks after onset. Alkaline phosphatase, aspartate aminotransferase (AST), and bilirubin levels peak 5-14 days after onset, and gama- glutamyltransferase (GGT) levels peak at 1-3 weeks after onset. Lactic acid dehydrogenase (LDH) levels are increased in approximately 95% of patients. Lactic acid dehydrogenase (LDH) levels are increased in approximately 95% of patients. Most liver function test results return to normal within 3 months. Most liver function test results return to normal within 3 months.

8. Differential absorption test Bovine RBCs absorb infectious mononucleosis heterophile antibodies, but Guinea pig kidney cells do not. Bovine RBCs absorb infectious mononucleosis heterophile antibodies, but Guinea pig kidney cells do not. Serum from a patient with infectious mononucleosis agglutinates sheep RBCs after absorption with guinea pig cells, but no agglutination occurs after absorption with bovine RBCs. Serum from a patient with infectious mononucleosis agglutinates sheep RBCs after absorption with guinea pig cells, but no agglutination occurs after absorption with bovine RBCs.

9. Heterophile antibody titers The titer of heterophile antibody is determined with tube dilution. A titer of 1:40 after absorption with guinea pig cells is considered positive for acute infectious mononucleosis. The titer of heterophile antibody is determined with tube dilution. A titer of 1:40 after absorption with guinea pig cells is considered positive for acute infectious mononucleosis. 60-90% of patients have test results that are positive for heterophile antibodies in the second or third weeks. Then it begins to decline until less than 1:40 within 2-3 months. 60-90% of patients have test results that are positive for heterophile antibodies in the second or third weeks. Then it begins to decline until less than 1:40 within 2-3 months. As many as 20% of patients still have positive titer resutls within 1-2 years. 75% of patients have positive horse RBC agglutinin findings at 1 year. As many as 20% of patients still have positive titer resutls within 1-2 years. 75% of patients have positive horse RBC agglutinin findings at 1 year. 10-30% of children younger than 2 years and 50-75% of children aged 2-4 years develop heterophile antibodies with primary EBV infection. 10-30% of children younger than 2 years and 50-75% of children aged 2-4 years develop heterophile antibodies with primary EBV infection.

10. EBV serology Antibodies to EBV antigens include antibodies to viral capsid antigen (VCA), early antigens (EAs), and EBNA. Antibodies to EBV antigens include antibodies to viral capsid antigen (VCA), early antigens (EAs), and EBNA. They are measured with enzyme immunoassays, indirect immunofluorescence assays, and immunoblot assays. They are measured with enzyme immunoassays, indirect immunofluorescence assays, and immunoblot assays. Antibody to the restricted component of early antigens (EA/R) is measurable in children younger than 4 years with primary EBV infection or in patients with nonsymptomatic infection. Antibody to the restricted component of early antigens (EA/R) is measurable in children younger than 4 years with primary EBV infection or in patients with nonsymptomatic infection. 80% of the patients with infectious mononucleosis have antibodies to the diffuse-staining component of EA (EA/D). 80% of the patients with infectious mononucleosis have antibodies to the diffuse-staining component of EA (EA/D). Patients who are immunocompromised and have persistent or reactivated EBV infections often have high levels of antibodies to EA/D or EA/R. Patients who are immunocompromised and have persistent or reactivated EBV infections often have high levels of antibodies to EA/D or EA/R.

11. EBV serology In patients with a more prolonged symptomatic illness, EA/D may become umeasurable, and EA/R results may become positive. In patients with a more prolonged symptomatic illness, EA/D may become umeasurable, and EA/R results may become positive. The antibody pattern in 3-12 months includes positive findings for VCA-IgG and EBNA antibodies, negative VCA-IgM antibodies, and positive EA antibodies. The antibody pattern in 3-12 months includes positive findings for VCA-IgG and EBNA antibodies, negative VCA-IgM antibodies, and positive EA antibodies. After 12 months, EA antibodies are not present. After 12 months, EA antibodies are not present.

12. EBV serology Kit Components Peptide-coated paddles, IgM Enzyme conjugate, IgG Enzyme conjugate, Substrate 1, Substrate 2, Substrate mixing vial, Wetting agent /wash solution, Stop solution, Paddle storage bag. Positive and negative controls available separatly. Indirect immunofluorescence assay designed for qualitative and/or semi- quantitative detection of IgM antibodies to Epstein-Barr Virus viral capsid antigen (EBV-VCA) in human serum.

13. Monospot Slide tests use either horse RBCs or bovine RBCs. Slide tests use either horse RBCs or bovine RBCs. Bovine RBCs are specific for acute infectious mononucleosis heterophile antibodies, while horse RBCs are more sensitive. Bovine RBCs are specific for acute infectious mononucleosis heterophile antibodies, while horse RBCs are more sensitive. Low sensitivity (63%-84%), with a negative predictive value of more than 10%. Low sensitivity (63%-84%), with a negative predictive value of more than 10%. Rarely yield false-positive results in patients. Rarely yield false-positive results in patients.

14. Monospot test Qualitative or semi-quantitative differential slide agglutination test for detection of infectious mononucleosis heterophile antibodies in human serum or plasma. The test is based on fresh horse RBC. Kit Components Guinea Pig Antigen (Reagent I), Beef RBC Antigen (Reagent II), Horse RBC (Indicator cells), Positive control, Negative control, Glass Slide, Microcapillary Pipettes, Rubber Bulbs, Plastic Pipettes, Wooden Applicators

15. Imaging Studies Not for diagnosing acute infectious mononucleosis. Not for diagnosing acute infectious mononucleosis. Chest radiography can detect lymph node enlargement, but should prompt consideration of other diagnoses. Chest radiography can detect lymph node enlargement, but should prompt consideration of other diagnoses. Abdominal CT scanning can reveal splenic rupture. Abdominal CT scanning can reveal splenic rupture. Ultrasonography, radionuclide scanning or the spleen may assist diagnosis. Ultrasonography, radionuclide scanning or the spleen may assist diagnosis.

16. Diagnosis Symptoms and age of patient Symptoms and age of patient Increased percentage of atypical mononuclear cells Increased percentage of atypical mononuclear cells Positive reaction to “mono spot” test Positive reaction to “mono spot” test - Positive for heterophile antibodies Serology results: Serology results: -Positive EA, VCA-IgM, VCA-IgG, EBNA

17. Epstein-Barr Virus Also known as Human Herpesvirus 4 Also known as Human Herpesvirus 4 Infectious mononucleosis; hepatitis; retinitis; pneumonia; colitis; Burkitt’s lymphoma, certain B-cell tumors; nasopharyngeal carcinoma Infectious mononucleosis; hepatitis; retinitis; pneumonia; colitis; Burkitt’s lymphoma, certain B-cell tumors; nasopharyngeal carcinoma EBV remains dormant or latent throughout lifetime EBV remains dormant or latent throughout lifetime Affects 95% of the population Affects 95% of the population Only 5% of patients acquire EBV from someone who has an acute infection Only 5% of patients acquire EBV from someone who has an acute infection More transmission in areas of lower socioeconomic groups and crowded conditions More transmission in areas of lower socioeconomic groups and crowded conditions Patients that are immunocompromised (organ allograft recipients or HIV- infected) are at greater risk. Patients that are immunocompromised (organ allograft recipients or HIV- infected) are at greater risk. Infections do not occur in epidemics Infections do not occur in epidemics

18. Infectious Mononucleosis Transmission: Transmission: -Intimate contact of oral saliva; usually between an uninfected person and EBV-seropositive person who is shedding the virus asymptomatically -Transfusion of blood products Widespread; infection apparent chiefly in young adults Widespread; infection apparent chiefly in young adults

19. Symptoms: Fatigue- usually lasts 2-3 weeks. Fatigue- usually lasts 2-3 weeks. Splenomegaly- occurs in about 50% of cases in 2 nd -3 rd week and lasts 6-8 weeks. This can cause anemia = fatigue. Splenomegaly- occurs in about 50% of cases in 2 nd -3 rd week and lasts 6-8 weeks. This can cause anemia = fatigue. Fever- peaks in afternoon Fever- peaks in afternoon Pharyngitis- may be severe and painful Pharyngitis- may be severe and painful Lymphadenopathy- usually symmetric, involves group of nodes; may be the only manisfestation Lymphadenopathy- usually symmetric, involves group of nodes; may be the only manisfestation Cardiac, jaundice, periorbital edema, palatal enanthema, maculopapular eruptions, CNS problems (rare) Cardiac, jaundice, periorbital edema, palatal enanthema, maculopapular eruptions, CNS problems (rare) Complications: neurological, hematologic, splenic rupture, respiratory, and hepatic Complications: neurological, hematologic, splenic rupture, respiratory, and hepatic Incubation period is about 30-50 days Incubation period is about 30-50 days Asymptomatic in young children Asymptomatic in young children Not fatal Not fatal Palatal petechiae, erosions and a greyish exudate in a patient with infectious mononucleosis.

20. Treatment: No specific treatment No specific treatment Rest Rest No specific antiviral drug No specific antiviral drug Corticosteroids can be used for swelling of pharyngitis, airway obstruction, severe thrombocytopenia, and hemolytic anemia. Corticosteroids can be used for swelling of pharyngitis, airway obstruction, severe thrombocytopenia, and hemolytic anemia.

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