Common Viral Pathogens I Flashcards
Herpes simplex Type 1: type, cells targeted for infection, transmission and incubation period
- dsDNA
- mucosal epithelium
- close contact with person shedding virus
- 2-12 days (average 4)
Herpes simplex Type 1: Disease entities and their clinical presentations and Diagnosis and key diagnostic tests
- Orofacial lesions and genital lesions (only sometimes), encephalitis, herpes whitlow, herpes keratitis, neonatal herpes
- Viral culture of lesion, direct IF stain of lesions, PCR of lesions
Herpes simplex Type 1: Treatment and prophylaxis
- Acyclovir (oral or IV)
- oral antiviral suppressive therapy
Herpes simplex Type 2: type, cells targeted for infection, transmission and incubation period
- dsDNA
- mucosal epithelium
- close contact (usually sexual)
- 2-12 days (average 4)
Herpes simplex Type 2: Disease entities and their clinical presentations and Diagnosis and key diagnostic tests
- Genital lesions and orofacial lesions (sometimes), encephalitis, herpes whitlow, herpes keratitis, neonatal herpes
- Viral culture of lesion, direct IF stain of lesions, PCR of lesions
Herpes simplex Type 2: Treatment and prophylaxis
- Acyclovir
- oral antiviral suppressive therapy
Varicella zoster: type, cells targeted for infection, transmission and incubation period
- dsDNA
- mucosal epithelium
- contact or respiratory
- 10-12 days
Varicella zoster: Disease entities and their clinical presentations and Diagnosis and key diagnostic tests
-chickenpox, shingles
-Differentiate between HSV and VZV:
Direct fluorescent antibody, HSV and VZV PCR, viral culture (VZV grows slowly)
Varicella zoster: Treatment and prophylaxis
- Chickenpox is self-limited, but acyclovir therapy can shorten the course (if given 48-72 hours after onset)
- Live attenuated varicella zoster virus vaccine: 2 dose series (1st dose: 12-15 months, booster: 4-6 years). Contraindicated in immune-compromised patients. Shingles live attenuated vaccine (Zostavax) approved for ppl˃50yo, 1 dose, boosts immune response to VZV, reduces risk by 70%.
Cytomegalovirus: type, cells targeted for infection, transmission and incubation period
- dsDNA
- epithelia, monocytes, lymphocytes, other
- contact, blood, transfusion, transplantation, congenital
- 2 weeks - 2 months
Cytomegalovirus: Disease entities and their clinical presentations and Diagnosis and key diagnostic tests
- Infectious mono-like syndrome, in immunocompromised patients: retinitis, pneumonia, colitis, in newborns: congenital CMV
- Serology, viral culture, PCR, antigen test, histology “owls eye”
Cytomegalovirus: Treatment and prophylaxis
- Only in immunocompromised pts: antiviral, Ganciclovir + CMV-IG (immunoglobin with CMV antibodies)
- No vaccine, CMV-IG given 1/month to immunocompromised pts to prevent CMV
Primary infection:
the first infection EVER with a virus. Your body does not have any serum antibody present when symptoms arise. If patient is symptomatic, the primary disease is likely to be the most severe than any reactivation/other exposures because body will have some immunological memory.
Latency:
period of time where the virus is dormant or silent in the body. In HSV, after primary infection, the virus travels along nerve axon to nerve cell body in sensory ganglion (typically trigeminal nerve for orofacial and sacral nerve for genital). Virus genome enters the nucleus of neuron and will persist indefinitely in latency. During latency, lab tests will not detect any active virus in the body (ie: everything will be negative)
Reactivation:
virus emerges from latent state and begins to replicate again. Travels from infected ganglion or neuronal body down the axons to cause “recurrence” of disease supplied by the nerve. Reactivation triggered by: stress, sunlight, illness, menstruation or immunosuppression. With HSV, reactivations can be asymptomatic, but virus is still being shed and is transmissible (major way in which genital herpes is spread unknowingly). If lesions develop, the outbreaks are milder than the primary infection presentation
