Viruses

Structure of viruses

A nucleic acid that is surrounded by a capsid.

• some have envelopes = fragile

• viruses without envelopes = last longer

Genetics of viruses

DNA: more stable, last longer

RNA: mutates faster, harder to prevent

single stranded viruses = mutate faster

Structure of HSV

Genetics: DNA, double stranded

• enveloped

Structure of Influenza

Genetics: RNA, single-stranded

• enveloped

Structure of HIV

Genetics: RNA, single-stranded

• enveloped

Structure of Hep A

Genetics: RNA, single-stranded

• non-enveloped

Structure of Hep B

Genetic: DNA =, partially double-stranded

• enveloped

Structure of Hep C

Genetics: RNA, single-stranded

• enveloped

Treatment of Viral Infections Fact

Many viral infections resolve with supportive care

• resistance can happen

• ADRs may outweigh benefits in mild illness

HSV: HSV-1, HSV-2

oral + genital herpes

S/S:

• sores

• itching

• tingling

• neuropathic pain

Transmission:

• contact

Treatment:

• gabapentin for pain

HSV: VZV

chicken pox/ shingles

S/S:

• vesicular rash

• fever

• unilateral rash (cyclosporin = bilateral)

Transmission:

• chicken pox: contact + air

• shingles: contact

Treatment:

• prevented by vaccine

• give gabapentin for nerve pain

HSV: EBV

Mono

S/S:

• big spleen

• sore throat

• lymphadenopathy

*affects B cells

*do NOT give amoxicillin

Influenza Characteristics

has protein spikes on envelope:

• hemagglutinin - viral entry

• neuraminidase - viral release

S/S:

• fever = systemic

• headache

• sore throat

• fatigue

*often results in secondary bacterial infection

Transmission:

• airborne

• contact

HIV Characteristics

Effects CD4 cells + T cells

2 enzymes:

• reverse transcriptase - turns RNA to DNA

• integrase - inserts DNA to host

S/S:

• lymphadenopathy

• rash

• fever

Transmission

• blood

• breastmilk

• sex

Treatment:

• ART Therapy

Hep A Characteristics

Only non-enveloped virus

Transmission:

• fecal-oral

Treatment

• no treatment

Hep B Characteristics

Unique reverse transcriptase step

Transmission:

• blood

• sex

Treatment:

• no treatment

Hep C Characteristics

Often asymptomatic; frequently becomes chronic

Transmission

• blood

Treatment:

• DAA (direct-acting antiviral)