Upgrade to remove ads
Terms in this set (68)
DNA replication factor, transcription factor, also binds to and prevents pRB and p53 from functioning.
What causes progressive multifocal leukoencephalopathy?
After initial infection (tonsils or GI tract?), remains 'latent' or under immunological control in GI or kidneys where it can continue to reproduce and shed virions into urine. JC virus moves to the nervous system. In immunocompromised individuals (primarily HIV/AIDS patients, also transplant patients) ~5% patients get PML.
very mild! Then moves to kidneys. Remains for life, either 'latent', or present at a low level - likely kept under control immunologically. Serious disease only seen in immunocompromised people - kidney transplant patients! Nephritis, 1-10% suffer nephropathy and loose their transplants.
Herpes Virus structure
nucleocapsid, tegument(between membrane and nucleocapsid, full of viral enzymes and proteins), genome, membrane, and glycoprotein complex I and III(attachment sites) - there are NOT resistant to drying.
What is the importance of the glycoprotein complexes of the herpes virus?
allow virus particle to attach to target proteins on the host cells and allow virus to fuse and enter the host cell
What surrounds the DNA in a herpes virus?
The icosahedral capsid
What are the 3 classes of herpes viruses?
alpha,beta, and gamma
Herpes genome structure
linear but can circularize.
How does the Herpes Virus infect?
Following an initial infection (primary), the virus establishes itself in a non-infectious form in neural or lymphoid tissues(latent), and can reactivate to give a secondary (recurrent) infection
Most individuals are infected with five of the eight human herpesviruses. - Most are seropositive by age 5 or 6.
When does the Herpes virus usually cause issues?
In the secondary or recurring infection
How does Herpes replication occur?
During the lytic phase of infection (both in initial infection and during reactivation) virus will attach to susceptible cells, membranes fuse (via glycoprotein spikes) with cellular membrane, nucleocapsid released into cell with some tegument, nucleocapsid will dock with the nuclear pore, and viral DNA and some tegument 'injected' into the cell nucleus, and viral replication cycle starts.
Where does the herpes virus replicate?
In the host cell nucleus
What are the 3 rounds of transcription?
- Immediate Early (tegument), Early (DNA replication proteins), and Late phase
What causes the lytic phase?
When the virus particles bud out of the cell membrane and cause holes, when there are too many holes it will causes lysis even though the holes can reseal.
What are the advantages to being a large virus?
They encode their own DNA machinery and have their own DNA polymerases and helicases, etc. This allows us to develop drugs against these viruses.
virus shed by close contact individuals, enters through micro abrasions, and will replicate in the local skin and local neurons.
What does the Trigeminal ganglia innervate?
The face and skull
What happens when the Herpes Simplex Virus reaches the Trigeminal Ganglia?
The replication stops and there will be no lytic infection.
a "cold sore" - a cold/flu may reactivate the virus due to a suppressed immune system.
Where does a reactivated herpes infection usually show up?
In the same place it last occurred.
Herpes Simplex Virus Type 1 - they are full of infectious virus. If you touch a blister, the fluid can be transferred. Once place is to the eye.
Who usually transfers HSV1?
parents and grandparents
HSV-1 Induced keratitis
The cornea can become opaque due to large dendritic structures (protein deposits caused by immune cells killing infected cells). - can cause corneal blindness
HSV-1: common on Large guys, sumo wrestlers - causes pink abrasions on their body, arms legs - will cause microabrasions (skin areas that have been abraded can get infected with the virus)
Encephalitis due to HSV1
This is uncommon because it rarely cross the blood brain barrier, this usually only occurs in the elderly and immunocomprimised
HSV1 v. HSV2
HSV1 is generally above the waist while HSV2 is below the waist (sacral)
Neonatal HSV infection
Contracted during passage through the genital canal, Contracted postnatally from individuals shedding virus, Disseminated HSV infection to major organs and CNS, Progression of infection to CNS results in death, mental retardation or neurologic disability even with treatment. 80% mortality in the absence of antiviral therapy, even with antiviral therapy there is a 50% mortality.
What do Anti-HSV drugs target?
The DNA polymerase
A very specific HSN anti-viral drug. It is specific because it requires activation, therefore producing less toxicity and less side effects.
This is essentially acyclovir with a valine in replace of a hydrogen - This drug is more available and gets in the bloodstream and into the cells more rapidly. Once in cells, valine cleaves off, Hydrogen goes on and becomes acyclovir.
What treats HSV encephalitis?
Ara A (Adenosine arabinoside )
What treats HSV keratitis?
Trifluridine and Iododeoxyuridine
neurotropic herpesvirus - causative agent of chickenpox (varicella) and shingles (zoster) - this is a systemic infection
How does Varicella infect?
- breath into lungs, replicates in lymph nodes/throat to lungs, begin to breath out virus (during incubation period, before pox show), eventually to internal organs, spread by T-cells, goes out to capillaries, to infections in the skin (pox) - about day 14
When is a person with Varicella infectious?
From onset to day 14.
Starts out as a flat red bump, then a blister, then a bigger blister, then an umbillicated lesion (blister with a dimple in the middle). Blisters are full of virus. - As the lesions dry they release virus into the air, can be breathed in. Two avenues for airborne virus!
HSV v VZV
VZV is systemic, HSV is localized
Where does Varicella establish a latency?
VZV infect the neurons and move up to dorsal root ganglia - one synapse away from spinal cord
What can causes a VZV reactivation?
old age, decreased immune system.
Herpes Zoster/Singles symptoms
runs around the chest/spine, these vesicles are full of infectious virus. Occasionally it can run around the cranial dermatome - severe reactivation - can also be a thoracic dermatome. This reactivation can cause blindness.
Varicella and pregnancy.
The virus can cross the placental barrier and infect the child in utero. Depending on trimester can have neurological problems or even limb atrophy, or can have chicken pox in utero and then have a more severe kind of shingles outbreak at earlier ages. These are rare
What drugs are used to treat VZV?
acyclovir and valacyclovir
yes, there is one for varicella and zoster.
Viruses which infect cells of the lympho-reticular system
T cells, B cells, monocyte/macrophages, dendritic cells.
Epstein-Barr Virus (EBV)
the primary cause of infectious mononucleosis
How is EBV spread?
Through close contact with saliva - the "kissing" disease
What does the Epstein-Barr Virus infect?
B-cells and will blunt the T-cell response, allowing the virus to become latent in B-cells (antibody producing cells)
What cells does EBV become latent in?
What can EBV cause? (rarely)
Burkitts lymphoma or Hodgkins disease
Where is Burkitt's Lymphoma found?
In endemic areas associated with malaria - common in kids and those immunocomprimised
Who is at risk for Nasopharyngeal Carcinoma?
Those with the genetics and those with poor diet. It is also mostly found in S. China and N. America. common with those who eat salty fish.
Oral Hairy Leukoplakia
AIDS-Related EBV Syndrome - EBV reactivation causes these lesions on the tongue, lips, gums - contain actively replication virus. Loss of taste as taste buds are destroyed. - found in the immunocomprimised
major cause of hearing loss and deafness - usually asymptomatic/mild symptoms -
How is Cytomegalovirus transferred?
Perinatal and venereal transmission - Spread by close contact. Present in virtually all human body fluids. Virus shed in saliva, tears, urine, semen and vaginal secretions
Who is at high risk for Cytomegalovirus?
embryos, neonates and immunocompromised individuals, including transplant recipients
What is the drug used to treat Cytomegalovirus?
What diseases can Gancyclovir treat?
Cytomegalovirus retinitis, esophagitis colitis and pneumonia
associated with roseola or exanthem subitum in children. - HHV6 can infect both T and B lymphocytes
causative agent of roseola and is most frequently recovered from individuals having bone marrow transplants. Both are associated with encephalitis
HHV6-A v. HHV6-B
A is more neuroinvasive
not associated with any diseases - The virus can infect T cells. - a concern in the context of organ transplant recipients and donors.
rash in children disappears in 2 days
Kaposi's Sarcoma / HHV8
a cancerous skin syndrome found in HIV/AIDS patients - member of the gamma herpesvirus family - most common neoplasm in homosexual and bisexual men. - also been associated with Castleman's Disease, primary effusion lymphoma, and body cavity lymphoma.
acyclovir and ganciclovir.
Who is at high risk for HHV8?
men and children
Types of Anti-viral agents:
Nucleotide analogs that target viral polymerases, those that inhibit proteases, retrovirus integration, M2/acidification & uncoating, or neuraminidase
What is the anti-viral to treat HPV?
There is NONE.
This set is often in folders with...
You might also like...
Herpes Viruses I & II
Other sets by this creator
Top 300 Drug Questions Part 1
Oral VEGF Inhibitors