Common Viral Pathogens I Flashcards
Herpes Simplex Type I (HSV1)
Type
dsDNA
Herpes Simplex Type II (HSV2)
Type
dsDNA
Varicella Zoster Virus (VZV)
Type
dsDNA
Cytomegalovirus (CMV)
Type
dsDNA
HSV1
Cells targeted for primary infection and latency
Primary- mucosal epithelium
Latency- Neuron
HSV2
Cells targeted
Primary- mucosal epithelium
Latency- Neuron
VZV
Cells Targeted
Primary- mucosal epithelium
Latency- Neuron
CMV
Cells targetted
Primary- Epithelia, monocytes and lymphocytes
Latency- Monocytes and lymphocytes
HSV1
Transmission and incubation period
Close contact, 2-12 days
HSV2
Transmission and incubation
Close contact usually sexually, 2-12 days
CMV
Transmission and incubation
Contact, blood transfusion, transplantation, congenital, 2 weeks to 2 months
VZV
Transmission and incubation
Contact or respiratory (droplet), 10-21 days
HSV1
Disease entity and clinical presentation
Orofacial (And some) genital lesions
Encephalitis
Herpes whitlow and keratitis
Neonatal herpes
HSV2
Disease Entitity and clinical presentation
Same as HSV1, but predominately genital lesions with some orofacial lesions
CMV
Disease Entity and clinical presentation
Infectious mononucleosis-like,
In immunocompromised- retinitis, penumonia, colitis
Congential CMV in newborns
VZV
Disease entity and clinical presentation
Chickenpox for varicella and shingles for zoster
Shingles is super painful and confined to infected dermatomes
HSV1
DIagnosis
Clinically, viral culture, direct fluorescent Ab staining og lesions, PCR of lesions
HSV2
Diagnosis
Clinically, viral culture, direct fluorescent Ab staining og lesions, PCR of lesions
VZV
Diagnosis
Both clinically
but also
Fluorescent antibody, PCR and Culutre
CMV
Diagnosis
Culture, PCR, antibody stain, serology, histology
HSV1
Treatment
Nucleoside analog (acyclovir)
HSV2
Treatment
Nucleoside analog (acyclovir)
VZV
Treatment
Acyclovir to shorten course of chickenpox
CMV
Treatment
No indicated treatment, but ganciclovir for immunocompormised patients
HSV1
Prophylaxis including vaccines
Oral antiviral suppressive therapy
HSV2
Prophylaxis including vaccines
Oral antiviral suppressive therapy
VZV
Prophylaxis including vaccines
Live attenuated VZV vaccine for chicken pox
Shingles vaccine for 50 years and older
CMV
Prophylaxis including vaccines
No vaccine, but CMV-IG can be given to immunocompromised patients for high risk patients
Describe the virion structure and replication cycle of herpesvirus
Icosahedral capsid, surroudnmed by a glycoprotein rich envelope
Entry- envelope fusion mediated by targeted receptors
Replication- Immediate-early (IE) genes encode for transcription activators, E proteins code for proteins involved in DNA replication, L genes are viral structures
Assembly- In the nucleus, self assembly, budding through the nucleus and getting their glycoprotein from the golgi
Exit/Egress- lysis or exocytosis
Complicaytions of chickenpox
Secondary infection/cellulitis, pneumonia, necrotizing faciitis, encephalitis, hepatitis and congenital VZV
Who we do and do not give the varicella and shingles vaccine to
Contraindicated in immunocompromised patients
What is the importance of T cell mediated immunity to the VZV infection
Its what essentially prevents shingles in people, as is why we see singles happen often in older people
Explain the consequences of maternal herpesvirus infection during pregnancy including the risk of the infant developing neonatal HSV, or congenital VZV and CMV syndromes
Neonatal HSV- mostly caused by HSV2, high morbidity and mortality. 3 forms, SEM, CNS, or disseminated
Congenital VZV- first 8-20 weeks of pregnancy, with fetus exhibiting multiple tissue/organ abnormalities
Congenital CMV- more often in primary infection, 3-5% chance baby will be born with CMV (leads to complications such as low BW, microcephaly, hearing loss, mental impairment)
Know and be able to recognize how CMV can be diagnosed histologically in infected tissues
Owl’s eye appearance , a dense dark nuclear body surrounded by a halo, representing intranuclear unclusions
How do you interpret serology (IgM and IgG tests) in the diagnosis of CMV
+igm - igg, acute CMV
-igm -igg, no infection
-igm +igg, previous infection in life
+igm +igg, reactivation of CMV recently
Herpes Whitlow
Infection of the fingers through oral or GU contact, can lead to painful pustules
Herpes Keratitis
HSV infects cornea of the eye, from primary infection or reactivation, leading to dendritic scarring that can result in blinding
