CSIM 1.20 Herpes Virus 2 Flashcards
What is the prevalence of EBV at 40 years of age?
95%
lifelong latency
What are the symptoms of cytomegalovirus?
How is it transmitted and what is its prevalence?
Where can cytomegalovirus be found when reactivation has occurred?
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)
CMV risk groups? What does CMV cause in each?
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
How often is cytomegalovirus transmitted to the baby of a pregnant woman?
Maternal primary infection
• 40%
Maternal reactivation
• 5%
Describe why patients must be considered carefully before solid organ or stem cell transplants for cytomegalovirus
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
How is CMV diagnosed?
Most patients
• CMV IgM
• Confirmatory tests if positive
Immunocompromised
• Blood PCR for viral DNA
Congenital infection
• Urine PCR for viral DNA
What must be carried out is a patient is found to be CMV IgM positive? Why?
Confirmatory tests, as the test is not very specific and can cause false positives
What is histologically observed in tissue infected with CMV?
Owl’s eye inclusions
How is CMV treated?
IMMUNOCOMPETENT:
• No treatment required
HIGH RISK:
• Ganciclovir (works same away as aciclovir but for CMV)
• Valganciclovir (prodrug with higher bioavailability)
• Reduce immunosuppression if possible
Recall how aciclovir (and ganciclovir) are activated?
By viral enzymes, therefore has high specificity
What are the toxic effects of valganciclovir?
Myelosuppressive
Nephrotoxic
How is CMV prevented in the immunosuppressed?
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
Describe the CMV vaccine
There is no licensed vaccine
Which cells do the following viruses replicate in, and which cells are they latent in:
1) Cytomegalovirus?
2) Epstein barr virus?
For both:
• Replicate in wide range of cell types
• Latent in lymphocytes (only B lymphocytes for EBV)
What are the symptoms of primary EBV?
Young children
• Asymptomatic
Adolescents
• Infectious mononucleosis
> Sore throat and lymphadenopathy
How is primary EBV diagnosed?
- Monospot test
- Serology immunoglobulins
- Atypical T-cells in blood film
Describe the monospot test
Describe in which populations this test may have a low sensitivity and specificity
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
Describe which immunoglobulins are checked for in EBV serology and why?
Which patients does immunoglobulin serology work on?
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)
Describe EBV treatment
Upon reactivation of EBV, what are the symptoms and where is it found?
What cancers is EBV associated with?
No vaccine or antivirals used
Asymptomatic, EBV found in the urine
- Burkitt’s lymphoma
- Nasopharyngeal carcinoma
- Hodgkins lymphoma
- Post transplant lymphoproliferative disease (PTLD)
Describe post-transplant lymphoproliferative disease (PTLD). Which virus causes this?
How is it treated
- 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
How is human herpes virus 6 and 7 (HHV6 and HHV7) transmitted?
Contact with secretions (saliva, etc)
What are the symptoms and complications of HHV?
Symptoms (if not asymptomatic)
• Roseola infantum
Complications
• Encephalitis and Febrile convulsions (from fever)
What is HHV 8 associated with?
Kaposi’s sarcoma in HIV infected individuals and so is seen in areas prevalent in HIV.
