Important properties
1. Adenovirus
a. Structure and genome
i. Naked, nonenveloped
ii. Icosahedral
iii. Double stranded linear DNA
iv. Only viruses with a fiber protruding from each of 12
vertices of capsid
v. Fiber is the organ of attachment; functions as
hemagglutinin
b. Replication and pathogenesis
i. Replicate in host cell nucleus
ii. DNA-dependent host RNA polymerase is used
iii. Infects
1. GI tract
2. Respiratory tract
3. Conjunctiva
iv. Latent infections in adenoids and tonsillar tissue
c. Clinical significance
i. Transmit via aerosol droplets, fecal oral route and direct
contact
ii. Cause
1. Pharyngitis
2. Common cold
3. Pneumonia
4. Hemorrhagic cystitis
d. Tumorigenesis and prevention
i. Certain serotypes induce sarcomas in rodents, not
humans
2. Papillomavirus
a. Structure and genome
i. Nonenveloped icosahedral
ii. Double-stranded, circular supercoiled DNA
b. Pathogenesis and tumorigenesis
i. Hallmark of HPV presence of vacuolated squamous
epithelial cells; koilocytes
ii. HPV is highly oncogenic; E6 and 7 cause p53 and RB
mutation respectively
iii. Overexpression seen in malignancy
, c. Clinical significance
i. Skin to skin genical contact
ii. Cause skin and plantar warts types 1-4
iii. Genital warts types 6-11
iv. 16 and 18 cause cervix and penis carcinoma
d. Prevention
i. 2 vaccines
1. Gardasil (6, 11, 16, 18)
2. Cervarix (16, 18)
3. Parvovirus
a. Structure and genome
i. Smallest of these viruses
ii. Nonenveloped
iii. Icosahedral capsid
iv. Only DNA virus with single-stranded DNA genome
b. Replication
i. No polymerase is present
ii. Only replicate when host cell is dividing in the S phase
iii. Single stranded DNA with hairpin loops at both ends
c. Clinical significance
i. Parvovirus b19 transmitted by respiratory droplets or
vertically
ii. Requires dividing cells so preferentially infects
erythroblasts in bone marrow
iii. Leads to aplasic anemia
iv. In children, bright red rash “erythema infectiosum”
(slapped cheek syndrome) is seen.
d. Fetal infection:
i. If non immune woman is infected in second trimester
virus crosses placenta fatal anemia and congestive
heart failure fatal condition is called “hydrops fetalis”
Transmission and pathogenesis
1. Adenovirus
a. Transmission
i. Several routes;
1. aerosol droplets,
2. fecal-oral route,
3. direct inoculation of conjunctivas
ii. Fecal-oral route is most common.
1. Adenovirus
a. Structure and genome
i. Naked, nonenveloped
ii. Icosahedral
iii. Double stranded linear DNA
iv. Only viruses with a fiber protruding from each of 12
vertices of capsid
v. Fiber is the organ of attachment; functions as
hemagglutinin
b. Replication and pathogenesis
i. Replicate in host cell nucleus
ii. DNA-dependent host RNA polymerase is used
iii. Infects
1. GI tract
2. Respiratory tract
3. Conjunctiva
iv. Latent infections in adenoids and tonsillar tissue
c. Clinical significance
i. Transmit via aerosol droplets, fecal oral route and direct
contact
ii. Cause
1. Pharyngitis
2. Common cold
3. Pneumonia
4. Hemorrhagic cystitis
d. Tumorigenesis and prevention
i. Certain serotypes induce sarcomas in rodents, not
humans
2. Papillomavirus
a. Structure and genome
i. Nonenveloped icosahedral
ii. Double-stranded, circular supercoiled DNA
b. Pathogenesis and tumorigenesis
i. Hallmark of HPV presence of vacuolated squamous
epithelial cells; koilocytes
ii. HPV is highly oncogenic; E6 and 7 cause p53 and RB
mutation respectively
iii. Overexpression seen in malignancy
, c. Clinical significance
i. Skin to skin genical contact
ii. Cause skin and plantar warts types 1-4
iii. Genital warts types 6-11
iv. 16 and 18 cause cervix and penis carcinoma
d. Prevention
i. 2 vaccines
1. Gardasil (6, 11, 16, 18)
2. Cervarix (16, 18)
3. Parvovirus
a. Structure and genome
i. Smallest of these viruses
ii. Nonenveloped
iii. Icosahedral capsid
iv. Only DNA virus with single-stranded DNA genome
b. Replication
i. No polymerase is present
ii. Only replicate when host cell is dividing in the S phase
iii. Single stranded DNA with hairpin loops at both ends
c. Clinical significance
i. Parvovirus b19 transmitted by respiratory droplets or
vertically
ii. Requires dividing cells so preferentially infects
erythroblasts in bone marrow
iii. Leads to aplasic anemia
iv. In children, bright red rash “erythema infectiosum”
(slapped cheek syndrome) is seen.
d. Fetal infection:
i. If non immune woman is infected in second trimester
virus crosses placenta fatal anemia and congestive
heart failure fatal condition is called “hydrops fetalis”
Transmission and pathogenesis
1. Adenovirus
a. Transmission
i. Several routes;
1. aerosol droplets,
2. fecal-oral route,
3. direct inoculation of conjunctivas
ii. Fecal-oral route is most common.
