DNA viruses Flashcards
DNA virus - diagram
DNA virus –> 1. complex nucleocapsid 2. icosahedral nucleocapsid
1. DNA virus –> complex nucleocapsid –> envelop –> DS linear –> poxvirade –> a. smallpox b. molloscum contagiosum c. cowpox
2. DNA virus –> icosahedral nucleocapsid –> a. enveloped
b. non envelop
A. DNA virus –> icosahedral nucleocapsid –> enveloped:
- DS circular –> HEPADNAVIRIDAE (HBV)
- DS linear –> HERPESVIRIDAE (HSV1, HSV2, CMV, EBV, HHV6-8, VZV)
B. DNA virus –> icosahedral nucleocapsid –> nonenveloped:
- DS linear –> Adenoviridae
- DS circular –> Papovaviridae (Papillomavirus, Polyomavirus)
- SS linear –> Parvoviridae (B19)
icosahedral nucleocapsid nonenveloped virus
- DS lineae –> Adenoviridae
- DS circular –> Papovaviridae (Papillomavirus, Polyomavirus)
- SS linear –> Parvoviridae (B19)
Adenovirus - characteristics
icosahedral nucleocapsid nonenveloped DS linear DNA virus
Adenovirus - causes
- febrile pharyngitis (sore throat)
- Acute hemorrhagic cystitis
- Pneumonia
- Conjunctivitis (“pink eye”)
icosahedral nucleocapsid nonenveloped DS circular DNA - viruses?
Papovaviridae (Papillomavirus, Polyomavirus)
Papillomavirus - characteristics / aka
icosahedral nucleocapsid nonenveloped DS circular DNA –> papovaviridae
HPV
which is the MC STD
HPV
Papillomavirus (HPV) causes
- warts (serotypes 1,2, 6, 11) (condylomata acuminata on genitalis -6, 11)
- Cervical intraepithelial neoplasia (most commonly 16, 18)
- Cervical cancer (most commonly 16, 18)
- penile/anal cacrinoma (most commonly 16, 18)
- head and neck cancer (mc 16)
Polyomavirus - characteristics
icosahedral nucleocapsid nonenveloped DS circular DNA –> papovaviridae –> 1. JC virus 2. BK virus
Polyomavirus - viruses?
- JC virus
2. BK virus
JC virus - characteristics
icosahedral nucleocapsid nonenveloped DS circular DNA –> papovaviridae –> polyomavirus
Polyomavirus - clinical presentation
BK virus –> transplant patinets, commonly targets kidney
JC virus –> Progressive multifocal leukoencephalopathy in HIV patients
largest DNA virus
poxvirus
smallest DNA virus
Parvovirus
Parvovirus - characteristics
DNA virus –> icosahedral nucleocapsid –> nonenveloped –> SS and linear –> B19
Parvovirus - virus
B19
B19 virus causes
- aplastic crisis in sickle cell disease, thalassemia β, hereditary spherocytosis,
- slapped cheeks (erythema inectiosum or fifth disease)
- during pregnancy RBCs destruction –> fetal death (1st trimester), hydrops fetalis (2nd trimester), not significant in 3rs trimester
- RBCs destruction also leads to Rheumatoid arthritis - like symptoms and pure RBC aplasia
B19 virus - transmission
- respiratory aerosol
2. transplacental
BK19 in pregnancy
fetal death (1st trimester), hydrops fetalis (2nd trimester), not significant in 3rs trimester
BK19 in adults
RBCs destruction also leads to Rheumatoid arthritis - like symptoms and pure RBC aplasia
poxvirus - characteristics and viruses
DNA virus –> complex nucleocapsid –> envelop –> DS linear –> poxvirade –> a. smallpox b. molloscum contagiosum c. cowpox
poxvirus - viruses?
a. smallpox b. molloscum contagiosum c. cowpox
smallpox - causes today
smallpox eradicated by use of live attenuated vaccine
eradication was achieved by world-wide use of the live attenuated vaccine
Acute disseminated (postinfectious) encephalomyelitis is usually caused by (and examples)
- After infection (mesles, VZV)
2. Certain vaccinations (rabies, smallpox)
cowpox causes
milkmaid blisters
Moloscum contagiosum - presentation
flesh colored papule with central umblication
Herpesvirusus - characteristics and viruses
DNA virus –> icosahedral nucleocapsid –> enveloped –>
DS linear –> HERPESVIRIDAE (HSV1, HSV2, CMV, EBV, HHV6-8, VZV)
HHV-8 causes …/ seen in
Kaposi sarcoma
seen in HIV/AIDS and transplant patients
kaposi sarcoma - area
MC in skin, but also month, GI tract and respiratory tract
kaposi sarcoma - definition and appearance
endothelial malignancy
Dark/violaceous plaques or nodules representing vascular proliferations
HHV-8 - transmission
sexual contact
HHV-6 causes
Roseola infantum (exanthem subitum) (6th disease)
HHV-7 causes
Roseola infantum (exanthem subitum) (6th disease) (LESS COMMONLY)
Roseola infantum is AKA
(exanthem subitum) (6th disease)
Roseola infantum (exanthem subitum) (6th disease) - presentation
high fevers for several days that can seizures, followed by a diffuse macular rash
HHV-6 -transmission
HHV-7 -transmission
both saliva
causes of Roseola infantum (exanthem subitum) (6th disease) and their transmission
- HHV-6
- HHV-7 (less commonly)
both saliva
CMV is also called
HHV-5
CMV (HHV-5) - trasmission
- congenitally
- transfusion
- sexual contact
- saliva
- urine
- transplant
CMV (HHV-5) causes
- mononucleosis with (-) Monospot in immunocompoment)
- congenital infection
- in immunocompromised patients (pneumonia, retinitis, hepatitis, encephalitis, neuropathy) –> esp pneumonia in transplant
CMV (HHV-5) retinitis?
AIDS retinitis –> hemorrhage, cotton-wool exudates, vision loss
CMV (HHV-5) latent in
mononuclear cels
CMV (HHV-5) - histology
characteristic “owl eye” inclusions
EBV is AKA / transmission
HHV-4
resp secretions, saliva
EBV (HHV-4) causes
- Mononucleosis
- endemic Burkit lymphoma
- Hodgkin lymphoma
- nasopharyngeal carcinoma
- primary CNS lymphoma in immunocompromised patients)
- Hairy leukoplakia (HIV+, organ transplant recipients)
Hairy leukoplakia is occurs in
HIV+, organ transplant recipients
mononucleosis - clinical presentation
- fever
- hepatosplenomegaly
- pharyngitis
- lymphadenopathy (esp posterior cervical nodes)
mononucleosis is also called (why)
kissing disease since commonly seen in teens, young adults
mononucleosis - EBV infects ..
B cellS through CD21
mononucleosis - detection (and mechanism)
- Monospot test: heterophile antibodies detected by agglutination of sheep or horse RBCs
- Atypical lymphocytes seen on peripheral smear (reactive cytotoxic T cells, not infected B cells)
VZV - transmission / aka
respiratory secretions
HHV-3
VZV causes
- chickenbox
- shingles
- encephalitis
- pneumonia
- Acute disseminated (postinfectious) encephalomyelitis (after)
VZV - Latent in
dorsal root ganglia or tringeminal ganglion
MC complication of shingles
post-herpetic neuralgia
HSV-1 causes
- oral lesions (gingivostomatitis, herpes labialis)
- keratinoconjuctivitis
- temporal lobe encephalitis
- genital lesions (rare) (herpes genitalis)
- herpes whitlow
- Kluver-Bucy
HSV-1 - temporal lobe encephalitis (characteristics, presentations)
- MCC of sporadic encephalitis
- can present with altered mental status, seizures, and/or aphasia
HSV-1 - temporal lobe encephalitis - presentation
- altered mental status
- seizures
- aphasia
HSV-1 - transmission
- respiratory secretions
2. saliva
HSV-2 - transmission
- sexual contact
2. perinatally
HSV-2 causes
- Herpes genitalis
- neonatal herpes
- oral lesion (rare)
- herpes whitlow
MCC of sporadic encephalitis
HSV-1
HSV identification - process
- viral culture for skin/genitalia
- CSF pcr for herpes encephalitis
- Tzanck test - a smear of an opened skin vesicle to detect multinucleated giant cells commonly seen in HSV1, 2 and VZV infection
- Intranuclear inclisions also seen with HSV-1, HSV-2, VZV
Viral vaccines - categories and viruses
A. Live attenuated vaccines (1. smallpox 2. yellow fever 3. rotavirus 4. VZV 5. Sabin polio 6. Influenza (intransal) 7. Measles 8. Mumps 9. Rubella)
B. Killed (1. Rabies 2. Influenza (injected) 3. Salk Polio 4. HAV)
C. Subunit (1. HBV (antigen=HBsAg) 2. HPV (types 6, 11, 16, 18))
Hepadinavirus - characteristics
DNA virus –> icosahedral nucleocapsid –> enveloped:
- DS circular –> HEPADNAVIRIDAE (HBV)
Hepadinavirus (HBV) - structure
enveloped
icosahedral nucleocapsid
PARTIALLY DS AND CIRCULAR
HAS REVERSE TRANSCRIPTASE
slapped cheeks is also called
erythema inectiosum or fifth disease
6th disease?
5th disease?
6- Roseola infantum (exanthem subitum)
5- slapped cheeks (erythema inectiosum)
HSV-1 - temporal lobe encephalitis - presentation
- altered mental status
- seizures
- aphasia
HSV-2, VZV, CMV: area of latent state
HSV-2 –> sacral ganglia
VZV –> latent dorsal root or trigeminal ganglia
CMV –> mononuclear cells
CMV EBV receptors
CMV –> integrins (heparan sulfate)
EBV –> CD21
HIV receptors
- CD4
- CXCR4
- CCR5
Rabies receptor
Nicotinic AChR
Rhinovirus receptor
ICAM-1