Common Viral Pathogens Flashcards
How many herpes viruses infect humans?
8
What type of genome does that the herpes virus have?
Double-stranded DNA
Does herpes cause a latent or lytic infection?
Latent
What herpes viruses establish latency in sensory ganglia?
HSV-1, HSV-2, VZV
What herpes viruses establish latency in monocytes and lymphocytes?
CMV, HHV-6, and HHV-7
What herpes viruses establish latency in B cells?
EBV and KSHV
How does herpes enter the host cell?
Fusion of memebranes
What are immediate early (IE) genes?
Genes expressed prior to protein synthesis. Usually encode transcriptional activators.
What do E genes encode?
Proteins involved in DNA replication.
What do L genes encode?
Structural proteins
Herpes viruses are enveloped, for what membrane do they obtain their envelope.
Nucleus. It is also highly glycoprotein-rich.
Which herpes virus cause orofacial and ocular lesions?
HSV-1
What herpes virus causes most cases of genital lesions?
HSV-2, but 30% cause by HSV-1
How is HSV transmitted?
Direct contact
Define primary infection.
First infection. No serum antibodies. Most asymptomatic. If symptomatic usually more severe.
Define latency infection
Period of time where the virus is dormant or silent in the body
Which ganglion does orofacial herpes infect?
Trigeminal ganglion
What ganglion does genital herpes infect?
Sacral Ganglion
Define reactivation phase.
Emergence from latency. Most commonly asymptomatic. This is how someone can transmit the virus unknowingly
HSV-1 usually occurs during what time period?
Childhood
What are the symptoms of gingivostomatitis?
Ulcerations of the gums, lips and tongue. Swelling of the lips and drooling. Cervical node swelling.
What is the target structure of herpetic whitlow and what are the symptoms?
It is the inoculation of HSV from oral secretions onto the fingers through small cuts. Symptoms: erythema, sweeling and pustules.
What are the symptoms of gential herpes?
Mostly asymptomatic, but can cause painful vesicles and ulcers on genitals and perianal region and can last 10-14 days.
What is the leading cause of blindness in the US?
Herpes keratitis- caused by HSV in the cornea cause by HSV-1 (most commonly) and HSV-2.
What are some symptoms of encephalitis?
hemorrhagic, necrotizing encephalitis, and predilection for the temporal lobes of the brain. HSV-1 most common cause but HSV-2 more common in neonatal cases.
What is the most common cause of neonatal herpes?
HSV-2.
What are the three forms of neonatal herpes?
- Skin, eye, and mocous membrane
- CNS
- disseminating (most severe)
How bad is neonatal herpes?
Really fucking bad treat until proven otherwise.
What is the current treatment for herpes?
Nucleoside analog drugs (most commonly acyclovir)
HSV prophylaxis is used for what patient population?
Patients with frequent painful oral or genital outbreaks, patients that do not have a stable sexual partner, and patients with partners that do not have herpes.
What two clinical syndromes are caused by varicella zoster virus (VZV)?
Chickenpox (primary infection) and shingles (reactivation)
What is the incubation period for chickenpox?
10-21 days after exposure
What are the symptoms of chicken pox?
Fever, malaise, headache, and a cough (occasionally). Initial lesions might be flat and erythmatous and then develop into a dew drop shape. Then pustules, pop, and scab.
What are some complications of chickenpox in pregnant women?
Death, but before that varicella pneumonia.
Name six serious complications of chicken pox.
- Secondary infection (group A strep) or Cellulitis
- Pneumonia
- Necrotizing fascitits
- Encephalitis or Encephalomyelitis
- Hepatits
- Congenital varicella syndrome
What is used to treat high risk patients for varicella?
Intravenous acyclovir
Is the chickenpox vaccine a live attenuated vaccine?
Yes and you have to have 2-doses: one at 12-15 months and the booster at 4-6 Years
In what ganglia does VZV remain latent?
Cerebral or dorsal root ganglia.
VZV reactivation results in what disease?
Shingles in the distribution of the dermatome WILL NOT CROSS MIDLINE OF BODY!!!
What is the only Herpesvirus that does not exhibit asymptomatic viral shedding in normal hosts that experience reactivation.
VZV, it’s a SCREAMER
What is the treatment of shingles?
Within 48-72 Hours- Acyclovir
Pain control
What is the name of the shingles vaccine?
Zostavax
How is cytomegalovirus transmitted?
Contact with infected body fluids
What is the incubation period for CMV?
2 Weeks to 2 Months
Where does CMV go?
Everywhere
What are the two forms of primary infection of CMV?
- Mild febrile illness
2. Mononucleosis-like illness (fever, swollen nodes and mild hepatitis)
What are the symptoms of a CMV infection in an immunocompromised individual?
Pneumonia, colitis, hepatits, encephalitis, retinitis
What does reactivation of CMV look like in a normal patient?
Nothing it remains latent for life. in an immunocompromised individual it could produce the same symptoms as primary infection.
What are the symptoms of congenital CMV?
Low birth weight, microcephaly, hearing loss, mental impairment, hepatosplenomegaly, skin rash (blueberry muffin spots), jaundice, and chorioretinitis.
Can you distinguish between a primary and recurrent CMV infection?
Yes by the presence of IgM and IgG. IgM only = acute CMV disease. Both = recent CMV reactivation
What is the histological appearance of CMV?
Owl’s eye- dense, dark nuclear body surrounded by a halo
What is the treatment of CMV?
Normal- nothing
Immunocompromised- Antiviral ganciclovir.
No recommendation to treat infants.
True or False: There is no available vaccine for CMV
True. But you can give CMV-IG intravenously to immunocompromised patients monthly.
