Virology

Question 1

What are the 6 DNA virus families?

Answer 1

Adenovirus
Hepadnavirus
Herpesvirus
Papovavirus
Parvovirus
Poxvirus

Question 2

What are the 3 arbovirus families?

Answer 2

Togavirus (Chikungunya)
Bunyavirus (Hanya)
Flavivirus (WNV, Zika, also HCV)

Question 3

Shell vial assay

Answer 3

Rapid (overnight) tissue culture assay

Use fluorescent antibody to identify viral cytopathic effect

Question 4

Direct fluorescence assay

Answer 4

Use fluorescent antibodies for viral antigens to directly observe viral effect.
Most appropriate for herpesviridae

Question 5

Adenovirus

Answer 5

Icosahedral, non-enveloped DNA virus.

40+ serovars, causes many infections including keratoconjunctivitis, gastroenteritis, pneumonia, hemorrhagic cystitis

Homogeneous smudgy intranuclear inclusions without halos

Question 6

Paramyxoviridae

Answer 6

Causes syncytia in infected tissue (usually pulmonary)

Measles: Pink intranuclear and intracytoplasmic inclusions
RSV: Pink intraCYTOplasmic inclusions only
Parainfluenza: No inclusions

Question 7

Hantavirus

Answer 7

Bunyavirus, contracted by inhalation of rodent feces (SW US)

Causes severe pulmonary edema, shock, coagulopathy, arrhythmia

Hematologic PENTAD: Hemoconcentration, neutrophilia, no toxic granulation, >10% immunoblasts, thrombocytopenia

Question 8

Hepatitis B serology (elements, order)

Answer 8

HBV DNA - Active viremia
HBcAg - Active viremia
HBcAb - Can be total or IgM (acute infection)
HBsAg - Active viremia
HBsAb - Immunity
HBeAg - Infectivity
HBeAb -

HBsAg&raquo_space; HbeAg&raquo_space; HBcAb&raquo_space; HBeAb&raquo_space; HBsAb

Question 9

Hepatitis B serology patterns

Answer 9

Naive: None
Acute infection: HBcAb IgM
Resolved infection: HBsAb, HBcAb IgG
Chronic active carrier: HBsAg, HBcAg, HBeAb NEGATIVE
Chronic inactive carrier: HBsAg, HBcAg, HBeAb POSITIVE

Question 10

COVID-19

Answer 10

Enveloped ssRNA virus

Causes lymphopenia (among other stuff…)

Question 11

HIV testing

Answer 11

Screen with PCR or EIA (include p24 to shorten window)

Confirm with western-blot (high specificity): Need p160/120 or p41+p24 bands.

Question 12

Needlestick transmission

Answer 12

HBV most transmissible

HCV most common in healthcare settings

Question 13

CMV

Answer 13

75% of general population seropositive

Question 14

RSV

Answer 14

Causes bronchiolitis in fall/winter months.

Diagnose with NAT or EIA.

No vaccine. Monoclonal antibody (palivizumab)

Question 15

Influenza

Answer 15

A (infects animals and humans), B (humans only)

Neuraminidase and hemagglutinin.
Genetic drift & shift.
Secondary bacterial pneumonias

Question 16

BK virus

Answer 16

Polyoma (papova) virus

Ubiquitous (90% seropositive by 10yo). Affects 5% of transplant kidneys.

Diagnose by urine PCR or cytology.

Question 17

HAART

Answer 17

Start if >100k/mL loads. Get genotyping to guide therapy.

Test again in 2-8 weeks, then 3-4 months.

Question 18

HCV

Answer 18

Flavivirus (RNA)

Genotype 1 (most common, longest treatment)
2, 3 also seen in US.
Genotypes 4-6 rare.

Question 19

WNV

Answer 19

Arboviral meningoencephalitis of summer/fall.

Transmitted by mosquitoes, but also transfusion/transplant and vertical.

Diagnose with serology or PCR>

Question 20

Flu treatments

Answer 20

Neuraminidase inhibitors (Oseltamivir, Zanamivir): For influenza A+B

Adamantine drugs: Influenza A only

**Start within 48hrs of symptom onset

Question 21

Blood screening for HBV

Answer 21

EIA for HBcAb (IgM or total)
EIA for HBsAg

May also include NAT for HBV DNA

Question 22

Rabies

Answer 22

Rhabdovirus. Spread by rodent bite. Tropism for neurons.

Diagnose by PCR, serology, postmortem histology.

Treatment: Rabies vaccine and rabies immune globulin