Oral Viruses- Herpes Lecture 6 (Test 1) Flashcards
(43 cards)
What are Human Herpesvirus (HHV) 1-8 ?
A large group of fragile enveloped viruses which remain LATENT in the individual throughout life and cause oral diseases.
How are Human Herpesvirus (HHV) 1-8 spread?
exception?
Spread thru mucosal-mucosal contact → viremina. Exception: VZV: spread thru resp. droplets
Exception: Varicella/Zoster is spread via resp. droplet to lung muscosa
The latent period in the HHV can be interrupted and cause what?
Interrupted form variable periods of replication of transmissible virus & accompanying host tissue damage.
Herpes viruses infections are extremely _______?
-Common
Where does the HHV virus remain latent?
Remain latent in neurons, macrophages, lymphocytes
Who does HHV affect?
Viruses usually cause benign diseases in children, but can also cause morbidity and mortality, especially in immunosuppressed individuals.
What can lessen the viral shedding and recurrence of HHV symptoms?
The large herpesvirus genomes encode multiple targets for ANTIVIRAL THERAPY but cant cure latent infection
What are some characteristics of HHV ?
- genome?
- where do they replicate?
- infect what?
- Tx?
1) Enveloped (fragile)
2) Large dsDNA genome
3) Replicate & assemble in nucleus
4) initial mucsoal epi infection
5) All infections LIFE LONG (LATENCY)
6) Multiple relapses common
7) Treated with ACYCLOVIR (Antivirals)
What the common name for HHV-5?
-Where is it latent?
-important Disease?
% infected?
Cytomegalovirus (CMV)
Latent in Lymph/Mono
Important disease: Congenital infections
50%
Which HHV (s) do we all have present in our saliva?
common name ?
latent in?
important disease?
% infected?
HHV 6 (no common name)
-Latent in Mono/Macrophages
Disease: Roseola Infantum
-100%
& HHV 7 (no common name )
-Latent in T cells
Disease: Roseola Infantum
-100%
Note: 25% of ER visits due to HIGH FEVER
(4-6 months of age)
HHV 1 ? common name ? latent in? important disease? % infected?
- Herpes simplex Virus 1
- Latent in Neuron
- Disease: Cold sore, oral ulcers
- 67%
HHV 2 ? common name ? latent in? important disease? % infected?
- Herpes simplex Virus 2
- Latent in Neuron
- Disease: Genital herpes
- 15%
HHV 3 ? common name ? latent in? important disease? % infected?
- Varicella-Zoster Virus
- Latent in Neuron
- Disease: Chickenpox, Shingles
- 100%
HHV 4 ? common name ? latent in? important disease? % infected?
Epstein-Barr Virus -Latent in B-cells Disease: Infectious mono & Burkitt's lymphoma (Sub. Sahara Africa) -75%
HHV 8 ? common name ? latent in? important disease? % infected?
- Kaposi Sarcoma Virus
- Latent in Lymphocytes
- Disease: Kaposi sarcoma
- 10%
Viruses can infect many cell types but the initial cell infected is?
- The Mucosal epithelium
- It results in the release of many viral particles that SPREAD VIA the BLOOD (VIREMIA) to other cells and organs.
Note: If pregnant viremia can be dangerous
Once the virus is in the blood what happens?
1) The entire immune system is altered with Th, Tc and B cells all specifically cloning.
2) T cells & NK cells will kill infected cells (viral factories)
3) B cells will produce Ab to neutralize any free viral particles (stops spread)
4) Viruses can become latent (as plasmid or integrated into the host DNA) in neurons or lymphocytes
5) Viruses will “hide” from immune system and become reactivated and continue to infect nearby cells
6) Memory T & B cells will respond to keep from spreading but local pathology (e.g, cold sore) is caused by the viral damage and Tc cells damage.
What is a unique characteristic for Herpesviruses?
The nucleocapsid “docks” w/ the nuclear membrane & delivers the genome into the nucleus, where the genome is transcribed and replicated. Viruses are ASSEMBLED in the NUCLEUS, **ACQUIRE their envelope (and SPIKES) BEFORE they reach the CYTOPLASMIC OUTER MEMBRANE
In both HSV-1 & VSV the primary infection usually occurs when?
- In childhood or adolescence, followed by establishment of life-long latent infection in CEREBRAL or SPINAL GANGLIA
- Later reactivation causes recurrent herpes simplex (cold sore) or zoster (shingles)
Recurrences are common for _______ but less common for this herpesvirus.
Common for HSV-1 less common for VZV
Note: Immune suppression allows these recurrences to become more frequent and severe
HSV-1
- frequency?
- disease acquired?
- transmission?
- latency?
- 60-80% in US infected w/ HSV-1 before adulthood
-Most common cause of viral encephalis in USA - HSV-1 keratitis is the leading infectious cause of blindness in USA
- MOST often occurs via Oral-oral contact AS A CHILD
-Can be spread or any combo of oral and/or genital contact at ANY AGE - Remain latent in “trigeminal ganglia”
-VACCINES NEEDED
-First 5 yrs of life primary lip lesion -85% asymptomatic
(if present lesion persists 2-3 wks w/ viremia)
-Primary & Secondary lesions–> Gingivostomatis & Herpes labialis MOST COMMON
-T-cell immunity destorys infected epi cells & lesion heals
HSV-2?
- frequency?
- disease acquired?
- transmission?
- 20- 25% in US infected w/ HSV-2 before adulthood
-Herpes genitalis is a sexually transmitted infection caused by HSV-2
-Sexually spread or any combo of oral and/or genital contact at ANY AGE - Remain latent in “SACRAL ganglia”
Note: Herpes genitalis infection INCREASES the risk of acquiring HIV during intercourse by 2-4 fold.
-VACCINES NEEDED
VZV ?
- Primary and Secondary infections?
- Transmission?
- Causes Chickenpox in primary infection (as a child) and Shingles in the secondary reactivation infections (adult)
- Only HHV spread via resp. droplets, DOES NOT REQUIRE intimate mucosal to mucosal contact
- VACCINE AVAILABLE :)
What does the VZV infect?
1) The lung mucosal epi followed by the lymph nodes
2) Enters the blood where it infects the skin epi cells
