Fenger Flashcards
What is a latent virus? Example?
- a virus that has been integrated into the host genome and can become reactivated at a later date.
- Herpesvirus family
What patient population can herpes be especially devastating for?
immunocompromised
-HIV, Cancer, Chemo, Transplant
What are in the alpha Herp family?
HSV, VZ
Type of genomic material for herp? Configuration?
- Double stranded DNA wound around protein core
- configured with 4 different arrangement of Ul and Us regions
Does the herpes family have a capsid or envelope?
Both. Icosohedral capsid made of capsomers. Envelope with glycoprotein spikes
Which type of HSV is tranmitted genitally mostly? How is the other type transmitted?
- HSV2
- HSV1 is transmitted orally generally
What are the primary diseases of Herpes? (Big notecard)
- Mouth(HSV-1): Gingivostomatitis-vesicular lesions all over oral cavity
- Eyes(mostly HSV-1): Dendritic Keratitis- infection of the cornea of the eye
- Skin(HSV-1): Gladiatorum- occurs in sweaty spots; Herptetic Whitlow- fingers/dentists; cold sores; herpeticum eczema
- CNS: Children(HSV2): infected birth canal from some skanky mom tranmits to neonate brain through blood. VIREMIA
Adults(HSV1): spreads in from olfactory nerve and infects temporal lobe. NEUROGENIC
Typical ways to acquire HSV 1 and 2?
HSV1- usually acquired as a child and inapparent for first 6-18 months. Check Ab for evidence infection has occurred at some point
HSV2- acquired after Jacobs balls dropped and he learned that his penis had a purpose other than making shadow monsters on the wall at night…AKA getting that poon tang and exchanging sexual fluids raw dawg style
Herpes Virus travels along ____1_____ to reach the _______2_______for HSV1 and _____3_____ for HSV2
- nerves
- Trigeminal Ganglia
- Sacral Ganglia
What factors can cause herpes reactivation despite AB presence and cell mediated immunity?
Host hormonal changes, chemotherapy, mal functionaing immune system, aging, UV light
Why dont lymphocytes and other immunity cells kill the latent virus?
- the latent virus is sequestered away from the immune system as it lays dormant in the ganglia.
- when it becomes reactivated it travels along the axon to the original site of infection where the immune system can now respond and cause symptoms.
How does occular herpes cause blindness?
Repeat occurrences can cause stromal scarring with every inflammatory healing process
What percent of adults have been infected and what fraction of them will have recurrent disease?
70-90 percent have been infected and 1/3 to 1/2 will have recurring disease
What cancer is HSV2 potentially linked with?
suspected to be indirectly linked to cervical cancer but potentiating the papilloma virus’ cancer causing ability.
What branch of adaptive immunity is important for resistance to HSV and which branch is important for recovery from infection?
- Ab is important in resistance
- Cellular immunity is important is recovery
Types of vaccines for Herpes
- Liv Attentuated: will induce a cell mediated and antibody response
- Killed: Will give just an Ab response
- Split Vaccine: a killed purified bundle of viral antigens (subunit vaccine)
HSV recurrence can initiate what 2 sequelae?
- Erythema multiforme: 75% of the time is due to HSV recurrence
- Idiopathic neuralgia: bells palsy, trigeminal neuralgia, epileppsy
Flashback: What Nerve is damaged in Bells Palsy?
Cranial Nerve 7. Thats the facial in case keegan forgot.
Tzanck Smear?
- Test for Herpes
- Scrape cells from the base of the lesion, stain and look for nuclear inclusions
What type of sample is best for HSV virus isolation in a cell culture
- fluid from the vesicle
When Jacob is making his OBGYN rotation he will likely at some point see a late term pregnant woman with a herpetic lesion her puss. What should jacob recommend?
Jacob should suggest the baby be delivered via C-section to avoid neonatal infection of fetus brain and visceral organs.
What anti viral drug class do the acyclovir family fall under?
nucleoside analogs
Acyclovir MoA and use?
-reduces the severity of recurring Herpes infection.
-inhibits viral DNA polymerase by blocking it progression on the DNA
administered as prodrug and activated by viral thymidine kinase and cellular kinase to become triphosphate.
Valacylovir advantages?
taken orally and absorbs better than acyclovir
How does foscarnet work>
inhibits viral DNA polymerase by binding to it
Two mechanisms mutants use for anti-viral resistance?
- alter DNA polymerase gene so protein can no longer bind (foscarnet)
- alter thymidine kinase gene so it no longer phosphorylates (acyclovir)
What agents inactivate infectious virus?
Chloroform, ether, glutaraldehyde, detergents
-All act to destroy virus envelope
What is the typical primary infection for Varicella?
Chicken pox
What type of DNA does VZ have?
Double stranded DNA
How do the lesion of VZ and small pox differ?
VZ- successive crops in specific area
SP- one crop of lesions in a specific area
What are common complications seen in adults and children with VZ infections?
Adults: pneumonitis causing x-ray calcified nodules in lung
Children: encephalitis (2X more in males); hemorrhagic varicella (bleeding vesicles)
What drug is reyes syndrome related to?
apirin
-dont give while VZ infected b/c of hepatic failure and encephalopathy
What is Shingles? How does it present? Where is it latent?
- Recurrent infection of VZ
- present as unilateral lesions following a dermatome
- lies latent in dorsal root ganglia: Thoracic > Ophthalmic > Lumbar > Cervical
How does VZ initiate primary infection?
Respiratory mucosa –> viremia –> skin (macular papular, non umbilicate vesicles
VZ incubation period?
2 weeks
When are most people first infected with VZ?
Children 6-8 yo
Causes of VZ reactivation?
X-rays, tumor in CNS, trauma, immunosuppression, reexposure to VZ
How are zoster lesions typically treated?
Zoster Ummine Globulin to help prevent comlications. Given IM 2-3 days within exposure. Ab neutralizes virus
Zoster Vaccine?
- licensed in 1995
- attenuated live virus given to kids twice at 12 months and against at 4-6 years
Varivax vs Proquad
Varivax- single antigen VZ vaccine
Proquad- vaccine for measles, mumps, rubella, and varicella
Zoster Vaccine for old people?
Zostavax- for those over 60 years old reduces likelihood of shingles by 50%
What is the treatment for immunocompromised patients with V or Z?
For adults adenine arabinoside along with oral acyclovir (valacyclovir?)
For Children IV acyclovir
Orthomyxoviridae are responsible for what type of virus?
Influenza Type A B and C
What are the possible hosts for the Influenza types?
A- humans, swine, avian, equine(or horses for keegan)
B- human
C- human
What is the genomic composition in orthomyxo?
- single stranded RNA with - polarity (complimentary to mRNA)
- must first convert to mRNA with + polarity to serve as messanger