Question

Diagnostic Virology Case Study #3

Patient A

A 17 yr old female is brought to the office for evaluation of a sore throat and fever. Her symptoms started about 1 week ago and have been worsening. She has been extremely fatigued and has spent most of the last 3 days in bed. She denies any ill contacts. She has no significant medical history, takes no medications, and has no allergies. On examination of her pharynx shows her tonsils to be markedly enlarged, almost touching in the midline. They are erythematous and covered with white exudates. She has prominent cervical adenopathy, which is mildly tender. A cardiovascular examination is normal, and her abdomen is soft, nontender, without organomegaly. A rapid streptococcal antigen test is negative. Depite the use of amoxicillin to combat streptococcal infection the patient is not getting better and now complains of a red rash (likely an allergic response) from head to toe.

1. What specific viruses may be involved in this infection?

2. What specific tests can be performed to help confirm a diagnosis (think serology and another type of specimen).

3. If you were to culture this patient for a virus what types of cells would you need to use to assure it will grow.

4. How was this viral infection likely acquired?

5. What are the basic characteristics of this virus? (example: DNA or RNA, single or double stranded, enveloped or naked, helical or icosahedral)

  

Answer 1

ANSWER 1) EPSTEIN BAR VIRUS

ANSWER 2)

• Monospot test (heterophil test). This quick screening test detects a type of antibody (heterophil antibody) that forms during certain infections. A sample of blood is placed on a microscope slide and mixed with other substances. If heterophil antibodies are present, the blood clumps (agglutinates). This result usually indicates a mono infection. Monospot testing can usually detect antibodies 2 to 9 weeks after a person is infected. It typically is not used to diagnose mono that started more than 6 months earlier.
• EBV antibody test. For this test, a sample of blood is mixed with a substance that attaches to antibodies against EBV. A series of tests can detect different types of antibodies to help determine whether you were infected recently or sometime in the past.Specific serology  – Antibodies against the lytic antigens, viral capsid antigen (VCA) and early antigen (EA) can be demonstrated from as early as the third week of infection. Antibodies against the latent antigen

ANSWER 3)

In primary infection, EBV replicates in oropharyngeal epithelial cells and establishes Latency III, II, and I infections in B-lymphocytes. EBV latent infection of B-lymphocytes is necessary for virus persistence, subsequent replication in epithelial cells, and release of infectious virus into saliva. Epstein-Barr virus can be cultured in lyphoblastoid cell lines. The virus can infect B-cells and epithelial cells. Thus B cell and epithelial cell of saliva could assure it presence

ANSWER 4)

The disease is mononucleosis. Infectious mononucleosis (mono) is often called the kissing disease. The virus that causes mono is transmitted through saliva, so you can get it through kissing, but you can also be exposed through a cough or sneeze, or by sharing a glass or food utensils with someone who has mono.

ANSWER 5)

Epstein-Barr virus belongs to genus lymphocryptovirus of the subfamily Gammaherpesvirinae in the Herpesviridae family. It consists of a double-stranded 172 Kb DNA genome, enclosed within an icosahedral capsid, surrounded by a phospholipid rich envelope.