سليمة Flashcards
Properties of herpesviruses
Enveloped double stranded DNA viruses.4 isomers
Three subfamilies of herpesviruses :
Alphaherpesviruses –[ HSV-1, HSV-2, VZV]
Betaherpesviruses –[ CMV, HHV-6, HHV-7]
Gammaherpesviruses –[ EBV, HHV-8
The genome of … share 50 - 70% homology.
They also share several … with each other. There is
also antigenic cross-reaction with …
HSV-1 and HSV-2
cross-reactive epitopes
VZV
HSV By far the most common form of infection results from a …
or adult from a person shedding the virus.
kiss given to a
child
HSV
There are 2 peaks of incidence, the first at …
and the second in
the .., when sexual activity commences.
0 - 5 years
late teens
Generally, … causes infection above the belt and …. below the
belt. In fact
HSV-1
HSV-2
Latency, following …… the virus enters ….. at the site of inoculation, travels up the axon and establishes a…..
supplying that area of skin
Genital area - … .
Oro-facial …..
The viral genome persists in the nucleus of the neuron.
Infection is life lo
primary infection,
sensory nerve
endings
latent infection in the ganglion
sacral ganglia
trigeminal ganglion
Clinical conditions
HSV
Acute Gingivostomatitis
Herpes Labialis (cold sore)recurrence
Ocular Herpes
Genital herpes
Skin infections
eczema herpeticum,Herpetic whitlow
Meningitis
8. Encephalitis
9. Neonatal herpes
… is the commonest manifestation of
primary herpetic infection.
Acute gingivostomatitis
Complications of Genital herpes
Transmission to newborn infant
Aseptic meningitis
Visceral herpes
Encephalitis
.. is most common cause
HSV-1
Laboratory Diagnosis hsv
1. Cytopathology
• …… from skin scrapings
Multinucleated giant cells
Immunofluorescence of skin scrappings - can
distinguish between ….
HSV and VZV
….are among the easiest viruses to cultivate
HSV-1 and HSV-2
Management hsv
… – this the drug of choice for most situations at present, it …..
Acyclovir
inhibits viral DNA synthesi
Varicella- Zoster Virus[VZV]
…. serotype only,
One antigenic
Varicella is one of the classic diseases of …..
childhood
Pathogenesis of Varicella- Zoster Virus[VZV]
The virus is thought to gain entry via the respiratory tract and
spreads shortly after to the lymphoid system.
After an incubation period of 14 days, the virus arrives at its main
target organ, the skin.
Following the primary infection, the virus remains latent in the
cerebral or posterior root ganglia. In 10 - 20% of individuals, a single
recurrent infection occurs after several decades.
The virus reactivates in the ganglion and tracks down the sensory
nerve to the area of the skin innervated by the nerve, producing a
varicella form rash in the distribution of a dermatome
The main target organ of VZV
Skin
Primary infection of vzv results in …
Presents …..
varicella (chickenpox)
fever, lymphadadenopathy. a widespread vesicular rash
Herpes Zoster (Shingles)
majority of patients are …
There is a characteristic…
more
than 50 years of ag
eruption of vesicles in the dermatome
which is often accompanied by intensive pain which may last for
months (postherpetic neuralgia
In the first 20 weeks of Pregnancy up to 3% chance of
transmission to the fetus, recognised …
congenital varicella
syndrome;
1. Scarring of skin
2. Hypoplasia of limbs
3. CNS and eye defects
4. Death in infancy normal
week before, to a week after delivery – …….
Neonatal varicella may vary from a mild disease to a fatal
disseminated infection
severe and even fatal
disease in the neonate
VZIG can be given within …of
contact
ten days
There are two vaccines against VZV: one designed to prevent varicella,
called …, and the other designed to prevent zoster, called ….
Both contain ..
Varivax
Zostavax
live, attenuated VZV.
The zoster vaccine is effective in
preventing the symptoms of zoster, but does not ….
eradicate the latent
state of VZV
The varicella vaccine is recommended for ,
whereas the zoster vaccine is recommended for
children
people older than 60
years and who have had varicell
Most individuals are infected by human cytomegalovirus (HCMV) in
the first few years of life and by adulthood 70-90% of people have…
IgG antibodies
CMV rarely causes disease in healthy people, particularly when
infection occurs…
in childhood.
When primary infection occurs in adulthood, patients may develop .. ..
associated with,
an infectious mononucleosis-like illness
fever, sore throat and lymphadenopathy.
There are two clinical situations where infection with CMV may cause
serious disease.
(…
A) Congenital infection
(B) Immunosuppressed individuals
…is the commonest viral cause of congenital abnormalities
Most infected babies appear normal at birth. However, affected
infants may later develop …
Rarely a …neonate may occur
(Cytomegalic inclusion disease).
CMV
deafness or mental retardation.
severe generalized infection
.. ..may develop life
threatening disease following either primary infection with HCMV or
reactivation.
Transplant patients and patients with AIDS,
Epstein-Barr Virus[EBV] Following primary infection, the virus
persists in a latent form in the ….
B lymphocytes of the host by
binding to C3d[ CR2 , CD21
Clinical Syndromes associated with EBV infection:
1) Infectious Mononucleosis
2) Burkitt’s lymphoma
3) Nasopharyngeal carcinoma
4) Lymphoproliferative disease and lymphoma in the
immunosuppressed patients
5) lymphoproliferative syndrome
6) Oral leukoplakia in AIDS patients
7) Chronic interstitial pneumonitis in AIDS patients
8) Hodgkin’s disease
Infectious Mononucleosis [I.M]
Signs and symptoms
Illness results from primary infection with EBV. A clinically apparent
illness usually only develops when primary infection occurs in
adolescence or adulthood.
Fever, generalized lymphadenopathy, sore throat, malaise, tiredness,
splenomegaly, hepatomegaly, and atypical lymphocytosis in the
peripheral blood. The disease is self-limiting
Laboratory Diagnosis of Infectious Mononucleosis[I.M]
- Abnormal liver function tests
- Heterophile antibody - Paul-Bunnell test (Monospot):
Screening test for acute IM; 70-80% of patients with acute IM develop
IgM antibodies that agglutinate sheep red blood cells. - Leukocytosis
- Lymphocytosis
- Presence of Atypical lymphocytes are enlarged lymphocytes that
have abundant cytoplasm, vacuoles, and indentations of the cell
membrane. - Antibody to the viral capsid and nuclear antigens
A. Viral capsid antigen IgM [VCA IgM]: only present during
acute phase
B. IgG to EBV nuclear antigens (EBNA): detectable late in
convalescence
(> 6 months’ post infection)
Diseases which have been found to be associated with HHV6 infection include:
1)Roseola Infantum
2)Infectious mononucleosis-like illness
3)Interstitial pneumonitis
4) Encephalitis
Human herpes virus 8 (HHV8, KSHV)
Initially found in biopsy specimens of …in AIDS
patients
Like EBV, …are primary target, but also infects other cell
types
Kaposi’s sarcoma
B cells
Human herpes virus 8 (HHV8, KSHV) Characteristic … associated with AIDS
It does not appear to be pathogenic in healthy individuals, but it is
thought to play a role in the ….
opportunistic infection
malignant process of all forms of
Kaposi sarcoma in AIDS patients
