CSIM 1.20 Herpes Virus 2

Question 1

What is the prevalence of EBV at 40 years of age?

Answer 1

95%

lifelong latency

Question 2

What are the symptoms of cytomegalovirus?

How is it transmitted and what is its prevalence?

Where can cytomegalovirus be found when reactivation has occurred?

Answer 2

Primary infection:
• Asymptomatic, RARELY glandular fever
Reactivates intermittently though live
• Asymptomatic

Direct contact
• Saliva
• Sexual
Prevalence: 40% + 1% for every year of age

Found in:
• Urine
• Saliva
(why contact causes transmission)

Question 3

CMV risk groups? What does CMV cause in each?

Answer 3

PREGNANT
7% of babies will have:
• Growth retardation
• Encephalitis
• Hepatosplenomegaly (secondary viraemia sources)
• 20% mortality
Some who were asymptomatic will have developmental problems later

IMMUNOSUPPRESSED/COMPROMISED
CMV syndrome 
  •  Fever 
  •  Neutropenia 
  •  Organ inflammation

Question 4

How often is cytomegalovirus transmitted to the baby of a pregnant woman?

Answer 4

Maternal primary infection
• 40%

Maternal reactivation
• 5%

Question 5

Describe why patients must be considered carefully before solid organ or stem cell transplants for cytomegalovirus

Answer 5

Solid organ
• If the donor is CMV positive, and the recipient is CMV negative (D+R-), you may cause a primary infection in the recipient
• Recipients are immunosuppressed, a risk group for CMV.

HSCT
• If the donor is negative but the recipient is positive for CMV, the new bone marrow will contain no CMV-specific T cells to control the infection
• The transplanted immune system is therefore naive to the infection and will undergo a second, more aggressive primary infection

Question 6

How is CMV diagnosed?

Answer 6

Most patients
• CMV IgM
• Confirmatory tests if positive

Immunocompromised
• Blood PCR for viral DNA

Congenital infection
• Urine PCR for viral DNA

Question 7

What must be carried out is a patient is found to be CMV IgM positive? Why?

Answer 7

Confirmatory tests, as the test is not very specific and can cause false positives

Question 8

What is histologically observed in tissue infected with CMV?

Answer 8

Owl’s eye inclusions

Question 9

How is CMV treated?

Answer 9

IMMUNOCOMPETENT:
• No treatment required

HIGH RISK:
• Ganciclovir (works same away as aciclovir but for CMV)
• Valganciclovir (prodrug with higher bioavailability)
• Reduce immunosuppression if possible

Question 10

Recall how aciclovir (and ganciclovir) are activated?

Answer 10

By viral enzymes, therefore has high specificity

Question 11

What are the toxic effects of valganciclovir?

Answer 11

Myelosuppressive

Nephrotoxic

Question 12

How is CMV prevented in the immunosuppressed?

Answer 12

Prophylaxis
• Give oral valganciclovir for several months post transplant

Pre-emptive monitoring
• Monitor CMV in the blood routinely, and begin treatment as soon as it is detected

Question 13

Describe the CMV vaccine

Answer 13

There is no licensed vaccine

Question 14

Which cells do the following viruses replicate in, and which cells are they latent in:

1) Cytomegalovirus?
2) Epstein barr virus?

Answer 14

For both:
• Replicate in wide range of cell types
• Latent in lymphocytes (only B lymphocytes for EBV)

Question 15

What are the symptoms of primary EBV?

Answer 15

Young children
• Asymptomatic

Adolescents
• Infectious mononucleosis
> Sore throat and lymphadenopathy

Question 16

How is primary EBV diagnosed?

Answer 16

• Monospot test
  
  • Serology immunoglobulins
  • Atypical T-cells in blood film

Question 17

Describe the monospot test

Describe in which populations this test may have a low sensitivity and specificity

Answer 17

Detects heterophile antibodies
• These antibodies appear in acute primary EBV and cause clumping of hoarse red blood cells

Low sensitivity in young children
Low specificity in adults

Question 18

Describe which immunoglobulins are checked for in EBV serology and why?

Which patients does immunoglobulin serology work on?

Answer 18

EBV EBNA (Epson barr virus nuclear antigen)
• A form of IgG
• Only present after 8 weeks post-infection
• This is FOLLOWED by IgM and IgG tests if negative
EBV IgM and IgG is prone to false positives

ONLY immunocompetent patients (as this is needed for antibody production)

Question 19

Describe EBV treatment

Upon reactivation of EBV, what are the symptoms and where is it found?

What cancers is EBV associated with?

Answer 19

No vaccine or antivirals used

Asymptomatic, EBV found in the urine

• Burkitt’s lymphoma
• Nasopharyngeal carcinoma
• Hodgkins lymphoma
• Post transplant lymphoproliferative disease (PTLD)

Question 20

Describe post-transplant lymphoproliferative disease (PTLD). Which virus causes this?

How is it treated

Answer 20

• Occurs in reduced T cell immunity within a year of transplant when immunity is at its lowest, and after primary infection (from transplanted organ)
  
  • The reduced immunity allows the virus to proliferate aggressively driving B cells cells to proliferate and mutate

Caused by EBV

• Reduce immunosuppression
• Use anti B cell antibodies - Ritucimab
• Use chemotherapy

IMG 50

Question 21

How is human herpes virus 6 and 7 (HHV6 and HHV7) transmitted?

Answer 21

Contact with secretions (saliva, etc)

Question 22

What are the symptoms and complications of HHV?

Answer 22

Symptoms (if not asymptomatic)
• Roseola infantum

Complications
• Encephalitis and Febrile convulsions (from fever)

Question 23

What is HHV 8 associated with?

Answer 23

Kaposi’s sarcoma in HIV infected individuals and so is seen in areas prevalent in HIV.