MICRO CH24: DNA viruses

• What do viruses infect?

• Are viruses living?

  • Why?

• How are viruses measured?

• ALL living cells

• NO

• requires host to survive

• electron microscope

• What is the capsid?

• What is capsid made of?

• function of the capsid?

  • what exactly determines the “shape”?

• What is inside the capsid?

• What is the optional covering EXTERNAL to capsid?

• protective protein coat

• capsomeres (specific protein subunits)

• determines shape = which is how virus is identified

• arrangement of capsomeres

• central core (DNA)

• envelope

5 steps of viral multiplication?

• absorption

• penetration/uncoating

• duplication/replication

• assembly

• release

• 2 ways virions are released from the cell:

  • ____ = cause immediate cell lysis 

  • ____= viral spikes penetrate host cell → virion buds from host cell

• naked virion

• enveloped virion

Differences between lytic and lysogeny? 

• ___ = virus DNA integrates with host cell DNA > remains dormant there for however long

• ___ = virus immediately replicates within host cell > lysis > virus particles released 

lysogeny, lytic

4 combinations of nucleic acids seen in viruses?

• double-stranded DNA (dsDNA)

• single-stranded DNA (ssDNA)

• double-stranded RNA (dsRNA)

• single-stranded RNA (ssRNA).

• are viral infections general or specific?

• persistent infections: infections last years or lifetime

  • is this associated with lytic or lysogenic cycles?

• 2 types of persistent infection?

• ___: virus detectable in tissue samples + slow multiplication rate

• ____: not detectable + virus remains dormant + can re-activate which causes recurrent infxns

• limited to SPECIFIC host/cell type

• lysogenic

• chronic infection

• latent infection

• Can viruses create oncogenic cells (forms tumor)?

• What does “teratogenic” mean?

• YES

• virus cross placenta = cause birth defects + possible stillbirth

• What do poxviruses produce?

  • does this cause scarring?

• is this largest or smallest complexity relative to other viruses?

• Why is smallpox not a current problem in the world?

• What is another name for smallpox?

• Is smallpox the only TRUE pox virus?

• pox (eruptive skin pustules)

• YES

• largest

• first ever disease to be eliminated by vaccines

• variola

• yes

• Difference between variola major and minor:

  • Variola major = more or less virulent?

    • SX?

  • Variola minor = more or less virulent?

• Of the other mammalian poxviruses, which are humans susceptible to?

• more

• fever, shock, toxemia, intravascular coagulation

• less

• monkeypox and cowpox

• How many human herpesviruses (HHV) are there?

• What behavior is common for HHV?

• 8

• latency + recurrent infection

what disease do each of these cause….

• HHV1 = ___

• HHV2 = ___

• HHV3 = ___

• HHV4 = ___

• HHV5 = ___

• HHV6 = ___

• HHV7 = ____

• HHV 8 = ___

• herpes simplex virus 1

• herpes simplex virus 2

• varicella zoster virus

• epstien barr virus

• cytomegalovirus

• herpesvirus 6 (roseola)

• herpes virus 7 (roseola)

• herpes virus 8 (karposi sarcoma)

• affects kids in early childhood

• SX: cold sores around mouth/lips

herpes simplex virus 1 (caused by HHV1)

• SX: lesions in genitalia

herpes simplex virus 2 (caused by HHV2)

• transmission of HSV: ____ exposure to secretions from ___ lesions 

• Where does the virus multiply?

  • Where does it move?

• Difference between location of multiplication:

  • HSV1 enters ___ cranial nerve

  • HSV2 enters ___ cranial nerve

• direct

• active

• sensory neurons

• ganglia

• 5th

• lumbo-sacral

• Where are locations of infection most commonly seen in HSV1?

• Where are locations of infections most commonly seen in HSV2?

• Can you have infections of HSV1&2 in alternative locations?

• lesions/cold sores around mouth

• lesions in genetalia

• yes (like eyes and throat)

has FATAL affect on neonates if baby is infected via vertical transmission… or infected mom touches infant

HSV1 and HSV 2

• note: HSV1 and 2 are recurrent infections

• What 4 things would be considered a stimuli for a recurrent infection?

• Fever

• UV radiation

• Stress

• Physical injury 

_____: virus penetrates a break in the skin to cause local infxn usually on 1 finger

• what virus causes this?

• SX?

• herpes whitlow

• HSV1 and HSV2

• PAINFUL itchiness

HHV3 causes what virus?

varicella zoster virus

• what disease does Varicella cause?

  • SX: skin lesion > progresses into itchy crusty fluid-filled red bump

  • who is this more common in?

• what disease does Zoster cause?

  • what is this a recurrent infection of?

  • is this painless or painful?

• which of the two are more common in older adults?

• both are recurrent infections occur along _____

• chickenpox

• pediatric patients

• shingles

• recurrent chickenpox

• PAINFUL

• shingles

• thoracic and trigeminal dermatones

• What is the vaccine for varicella?

  • what kind of vaccine is it?

  • can this cause an infection?

• What 2 vaccines for shingles?

  • age group is advised for these?

• varivax

• live attenuated

• yes

• shingrix and zostavax

• older people

are DNA viruses?

are RNA viruses

• NO (but viruses contain DNA)

• yes

• causes Infectious mononucleosis?

• acquisition?

• epstien barr virus (caused by HHV4)

• direct oral contact or with saliva

causes:

• Enlarged liver/spleen

• Micro-encaphaly (tiny head)

• Inflamed eyes 

cytomegalovirus (caused by HHV5)

• SX: faint rash on neck, trunk, or butt

roseola disease (caused by HHV6 and HHV7)

• what type of HHV is associated with Kaposi sarcoma?

HHV8

• What does HPV stand for?

• What does it cause?

• Common wart/seed wart

  • from HPV1 or 2?

  • where on body?

• Plantar wart

  • from HPV1 or 2?

  • where on body?

• Genital wart

  • where on body?

  • small warts can develop into bigger cauliflower shaped warts called ____

• Human papilloma virus 

• Causes papilloma (warts)

• HPV2

• hands

• HPV1

• soles of feet

• internal and external genetalia

• condylomata acuminata

____: cauliflower-like GENITAL warts 

• caused by?

• wart removal options:

  • Interferons

  • Laser off/cauterization

  • Freezing

  • Podophylin (drug)

• condylomata acuminata

• HPV

which HPV strains can cause cervical cancer? 

HPV 16 and HPV 18

what is the vaccine for HPV?

gardasil

what type of virus infects cats + dogs that can lead to fatal cardiac infections?

parvovirus

• what does erythrovirus (b19) cause?

• SX in children?

• erythema infectionsum (aka fifth disease)

• fever + slapped face fash

• can cross placenta

to help u remember:

• which HSV is “above hips”?

• which HSV is “below hips”?

• HSV1

• HSV2

most common STD?

genital warts from HPV

____: inflamed hepatocytes @ liver

• what effect can a hep infection have visible on the body and sclera?

• which hep viruses caused by RNA virus?

• which hep viruses caused by DNA virus?

• hepatitis

• jaundice

• A and C

• B

HEPATITIS A, B, OR 3… GO:

• called serum hepatitis bc it releases viral load into blood?

• has vaccine + what is it?

• has NO vaccine?

• caused by contaminated water/food (especially raw oyster/shellfish)

• called “infectious hepatitis”

• more likely to cause a chronic infection?

• the only vaccine newborns receive in hospital is for this hepatitis type

• more likely to cause an acute infection?

• transmitted by blood transfusions, sex, needles, infected mother?

• can cross placenta

• Chronic infections can have what effect on liver?

• B

• A; vaccine is Havrax

• C

• A

• A

• B and C

• B

• A

• B and C

• B and C

• cirrhosis and liver cancer

is roseola an enterovirus?

YES