Viruses

Question 1

“PICORNAVIRUS overview
(the peak-orna animal nursery)”

Answer 1

Features: “* +ssRNA
- direct transl by host RNA Pol
- replicates in cytoplasm
*Naked
* Polyprotein product (cleaved w viral protease)”
Reservoir/Transmission: *Fecal oral route (except rhinovirus)
Diseases: “A: Hep A
B: Enterovirus (Birds) = Coxsackie A/B, Poliovirus, Echovirus
C: Rhinoviruses (Common Cold)
PERCH”
Diagnosis:
Treatment:
Vaccines:

RNA Viruses (+) sense

Question 2

Enterovirus

Answer 2

Features: Poliovirus, Coxsackie A & B, Echovirus (3 most common causes of aspetic meningitis)
Reservoir/Transmission: Birds
Diseases: * #1 cause of aspetic meningitis (normal glucose, high protein CSF); mostly affects kids
Diagnosis:
Treatment:
Vaccines:

RNA Viruses (+) sense

Question 3

“Poliovirus
(flamingo breeding pool)”

Answer 3

Features: “Picornavirus Family (+ssRNA, Naked, Polyprotein product, Acid stable)
“
Reservoir/Transmission: * Fecal oral route
Diseases: “* Replicates in oropharynx (tonsils) & sm intestine (Peyer’s patches) –> bloodstream & CNS
Destroys anterior horn (LMN) of spinal cord
Symptoms: Malaise, HA, fever, nausea, weakness, hypotonia, flaccid paralysis, atrophy, faciculations, hyporeflexia, muscle atrophy”
Diagnosis: “CSF with pleocytosis (high WBC, slight increase in protein)
* Virus recovered from stool/throat”
Treatment:
Vaccines: “ Inactivated vaccine: (IgG response, no IgA); only form used in US
- Prevents vaccine-associated poliovirus
*Live attenuated oral:l (IgG & IgA response); provides herd immunity w person to person contact (used in developing countries)”

RNA Viruses (+) sense

Question 4

“Coxsackievirus
(coxsackie cockatoos)”

Answer 4

Features: “Picornavirus Family (+ssRNA, Naked, Polyprotein product, Acid stable)

• Infection common during summer/fall
  “
  Reservoir/Transmission: * Fecal oral route
  Diseases: “Coxsackie A:
  *Hand, foot & mouth disease: fever, red vasicular rash 1-2 days post-fever; poor appetite, malaise, sore throat –> meningitis, encephalitis, flaccid paralysis (lymphadenopathy ABSENT)
  
  • Herpangina: painful sores in mouth (1-2 days post fever)
    *Aspetic meningitis
• Acute hemorrhagic conjunctivitis

Coxsackie B:
*Devil’s Grip / Bornholm’s Disease / Pleruodynia: extreme sharp unilateral pain in lower chest with difficulty breathing
*Myocarditis –> Dilated cardiomyopathy (pericarditis w/ blue cells seen on biopsy of myocardium)
* Associated with hepatitis”
Diagnosis: *PCR
Treatment: * Supportive care
Vaccines:

RNA Viruses (+) sense

Question 5

“Rhinovirus
(rhino petting zoo)”

Answer 5

Features: “Picornavirus Family* (+ssRNA, Naked, Polyprotein product)

• Acid labile*
• Grows best at 33’C/cold
• MANY serotypes (no vaccine/tx)”
  Reservoir/Transmission: * Inhalation of resp droplets or fomites that attach to ICAM-1 to enter host cells
  Diseases: “* Upper resp tract infection (URI)
• # 1 cause of the common cold”Diagnosis:
  Treatment:
  Vaccines: No vaccine/tx due to MANY serotypes

RNA Viruses (+) sense

Question 6

“Hep A (HAV)
(hungry hungry hep A hippos)”

Answer 6

Features: “Picornavirus Family (+ssRNA, Naked, Polyprotein product, Acid stable)

Councilman bodies (eosinophilic apoptotic globules) on liver biopsy (also Yellow Fever)
“
Reservoir/Transmission: “ Fecal oral route: enters mouth & replicates in liver
* Contaminated shellfish in developed countries (produce too)
*Contaminated water in developing countries

• Incubation period = 15-50 days (avg 28); virus excretion can occur for up to 3 wks after symptom onset
• Risk factor: underlying liver disease”
  Diseases: “* Self-limiting illness that lasts ~1 mo
  *No chronic state
• General symptoms: fever, malaise, jaundice (except in children), anorexia, N/V, elevated LFTs
  *Adults are more likely to be symptomatic than kids
  Smokers develop aversion to smoking”
  Diagnosis: * Virus in blood/feces after 10-12 days
  Treatment:
  Vaccines: “ Inactivated vaccine (used in endemic areas, chronic liver pts, sexually active MSMs); can be used for PPX pre-exposure > 2 wk before
• Ig for ppx pre-exposure < 2 wk before”

RNA Viruses (+) sense

Question 7

Hep E (HEV)

Answer 7

Features: “* Acid stable
* Naked”
Reservoir/Transmission:
Diseases: “Fever, jaundice, elevated ALT/AST (all Hepatitis viruses)
* Self limiting
* No carrier state”
Diagnosis:
Treatment:
Vaccines:

RNA Viruses (+) sense

Question 8

“Norovirus
(cali sea cruise)”

Answer 8

Features:”* Calicivirus
+ssRNA
* Naked
Polyprotein product”
Reservoir/Transmission: “ Raw shellfish (fecal oral route)
* Cruises & daycare (contact, fomites)”
Diseases: “Presents 12-48 hr after exposure & resolves in 1-4 days (shed in stool 4 wk post-infection)
* Explosive, watery diarrhea, cramps, fever, chills
*Most common cause of viral gastroenteritis in all age groups worldwide”
Diagnosis: *PCR
Treatment:
Vaccines:

RNA Viruses (+) sense

Question 9

“FLAVIVIRUS
(flavor packed flavi)”

Answer 9

Features: “* +ssRNA
* Enveloped
* non-segmented RNA”
Reservoir/Transmission:
Diseases: West Nile, Dengue Fever, Yellow Fever, Hep C
Diagnosis:
Treatment:
Vaccines:

RNA Viruses (+) sense

Question 10

West Nile Virus

Answer 10

Features: “* +ssRNA
* Enveloped
* non-segmented RNA”
Reservoir/Transmission: “* birds (crows, blue jays; reservoir)
* Culex mosquitoes (vector)”
Diseases: “*West Nile fever (20%): HA, vomiting, confusion
* Neurologic disease (1%, especially if elderly)”
Diagnosis: *IgM in serum/CSF (detected 3-8 days after onset, persists 30-90 days)
Treatment: Supportive therapy
Vaccines:

RNA Viruses (+) sense

“FLAVIVIRUS
(flavor packed flavi)”

Question 11

Dengue Fever (Type 2)

Answer 11

Features: “* +ssRNA
* Enveloped
* non-segmented RNA”
Reservoir/Transmission: “*Aedes mosquitoes (vector), blood transfusion, organ transplant
*Enhancing Ab: Ab to one serotype increase efficiency of infection by another”
Diseases: “Dengue / Bone-break fever (infects bone marrow)
* Dengue Fever: (3-7 days post bite) Faint macular rash that is diffuse/blanches (50%), fever, myalgias, arthralgias, headaches, retro-orbital pain, elevated AST, thrombocytopenia, hemorrhage
Dengue Hemorrhagic Fever: Shock, OD, bleeding, marked thrombocytopenia, fever 2-7d, increased vascular permeability
* Dengue Shock Syndrome
* 4 different serotypes”
Diagnosis: “ Serology
PCR”
Treatment: “ Supportive therapy
*No antiviral therapy”
Vaccines: *Vaccine exists but NOT used in travelers

RNA Viruses (+) sense

“FLAVIVIRUS
(flavor packed flavi)”

Question 12

Yellow Fever

Answer 12

Features: “* Flavirvirus
* Councilman bodies (eosinophilic apoptotic globules) on liver biopsy (also HAV)”
Reservoir/Transmission: “*Aedes mosquitoes (Africa)
Haemagogus mosquito (S America)”
Diseases: “ Jaundice, backache, bloody stool/vomiting (black)
*Asymptomatic –> febrile –> hemorrhagic fever with jaundice, renal failure, hemorrhage
Fever, malaise, diffuse pain, nausea/vomiting, dizzy, irritable –> remits 2d –> OD on d3”
Diagnosis:
Treatment:
Vaccines: “No anti-infective therapy for travelers
* Live attenuated vaccine (IM): > 9 mo living in/traveling to high risk area (Africa, South America)”

RNA Viruses (+) sense

“FLAVIVIRUS
(flavor packed flavi)”

Question 13

Chikungunya

Answer 13

Features:Alphavirus
Reservoir/Transmission: “ Aedes mosquito
Outbreaks during rainy seasons”
Diseases: “ High fevers, severe polyarthralgias 2-5d after (bilateral, symmetric), macular/maculopapular rash, HA, myalgias, GI symptoms
* Lab abnormalities: lymphopenia, thrombocytopenia, transaminitis, AKI”
Diagnosis:
Treatment:
Vaccines:

RNA Viruses (+) sense

“FLAVIVIRUS
(flavor packed flavi)”

Question 14

Zika virus

Answer 14

Features: * Flavivirus
Reservoir/Transmission: “* Aedes mosquito
Only vector-born infection that is transmitted sexually (transfusion & transplant too)
* Year round transmission in tropical/subtropical regions”
Diseases: “ Febrile illness: fever (3-5d), conjunctivitis, maculopopular rash, polyarthralgia (2-5d after fever), HA (1 wk) –> persistent arthritis & arthralgia following acute illness
* Complications: resp failure, meningoencephalitis, acute hepatitis, renal failure, CV decompensation
*Post-infection GBS
In utero: microcephaly, developmental problems, abortion, opthalmologic problems”
Diagnosis: “ Serology
*Viral culture “
Treatment: * supportive therapy
Vaccines:

RNA Viruses (+) sense

“FLAVIVIRUS
(flavor packed flavi)”

Question 15

“Hep C (HCV)
(the hep sea)”

Answer 15

Features: “Flavivirus family (+ssRNA, enveloped, non-segmented RNA)

• Antigenic variation due to lack of 3-5’ proofreading exonuclease activity in virion encoded RNA Pol”
  Reservoir/Transmission: “* Blood transfusion (also in placental, sex, breast milk)
  Sharing needles”
  Diseases: “Cryoglobulins: serum proteins containing IgM that precipitate in cool temp
• Acute hepatitis: jaundice, enlarged liver, elevated liver enzymes; viral RNA in serum for < 6 mo
  *Chronic hepatitis: viral RNA persists in serum > 6 mo; liver biopsy shows lymphocytes in portal tract (60-80% of infections become chronic)
• Increased risk of hepatocellular carcinoma & cirrhosis”
  Diagnosis: Acute infection characterized by rise & fall in ALT by 6 mo
  Treatment: “ Protease/pol inhibitors (new)
• IFN-a / Ribarvirin (older treatments)
  *Genotype testing should be done
  “
  Vaccines: * No vaccine due to antigenic variation of envelope proteins

RNA Viruses (+) sense

“FLAVIVIRUS
(flavor packed flavi)”

Question 16

“TOGAVIRUS
(toga-toga-togavirus)”

Answer 16

Features: “* +ssRNA
* Enveloped
* Polyprotein product”
Reservoir/Transmission:
Diseases: mainly rubella
Diagnosis:
Treatment:
Vaccines:

RNA Viruses (+) sense

Question 17

“Rubella
(German Measles)”

Answer 17

Features: “* +ssRNA
* Enveloped
* Polyprotein product”
Reservoir/Transmission: “* Resp transmission (replicates in nasopharynx & regional LNs)
* Pts w/o vaccinations (immigrants, anti-vaxers)
* Incubation period = 14-21 days”
Diseases: “Childhood Exanthem = Third Disease: Mild, usually subclinical
*Postaricular/occipital lymphadenopathy
*Maculopapular rash beginning on face (14-17 days post-exposure) + spreads down (lasts ~3 days)
* Low grade fever
*Conjunctivitis & palatal enanthem (petechia on hard palate), encephalitis, thrombocytopenia

Congenital Rubella: infection during 1/2 trimesters (later infection results in less anomalies)
*Transient symptoms: lymphadenopathy, hepatosplenomegaly, poor growth, bone marrow involvement, microcephaly, jaundice, purpuritic blueberry muffin rash (due to dermal erythropoiesis; also seen w congenital CMV)
*Permanent findings: heart (PDA, pulm arterial/valve stenosis), eye (retinopathy, cataracts, microphthalmia), brain, auditory symptoms (bilateral deafness)
* Triad: Cataracts, sensory neural deafness, PDA (I heart ruby earrings)

Adults:
* Arthritis & arthralgia (also have lymphadenopathy & fever, like children do)”
Diagnosis:
Treatment:
Vaccines: *MMR vaccine: (live attenuated) Should NOT be given to pregnant women, immunocompromised (HIV pts if CD4 < 200)

RNA Viruses (+) sense

“TOGAVIRUS
(toga-toga-togavirus)”

Question 18

Eastern Equine Encephalitis

Answer 18

Features: “* +ssRNA
* Enveloped
* Polyprotein product”
Reservoir/Transmission: “*Insect
* N America & Caribbean
*Peak incidence Aug-Sept
Hardwood swamp areass”
Diseases: “ Encephalitis in 4-5% infections
*Highest mortality rate (50%)”
Diagnosis:
Treatment:
Vaccines:

RNA Viruses (+) sense

“TOGAVIRUS
(toga-toga-togavirus)”

Question 19

Western Equine Encephalitis

Answer 19

Features: “* +ssRNA
* Enveloped
* Polyprotein product”
Reservoir/Transmission: “* Culex mosquito
N & S America”
Diseases: “Encephalities is RARE
*Lower fatality rate 3-7%”
Diagnosis:
Treatment:
Vaccines:

RNA Viruses (+) sense

“TOGAVIRUS
(toga-toga-togavirus)”

Question 20

“CORONAVIRUS
(kingdom of SARS)”

Answer 20

Features: “* +ssRNA
Enveloped
* Helical capsule”
Reservoir/Transmission:
Diseases: “Common cold (2nd most common cause behind rhinovirus)
*Acute bronchitis that can progress to ARDS (diagnosed with antibody/PCR)
* MERS (middle east resp syndrome)
* SARS (severe acute resp syndrome)”
Diagnosis:
Treatment:
Vaccines:

RNA Viruses (+) sense

Question 21

“Retrovirus/HIV
(one cane to rule them all)”

Answer 21

Features: “* +ssRNA (uses RT to convert into DNA that is then incorporated into host DNA)
*Enveloped
Diploid nature (2 RNA strands per virion)”
Reservoir/Transmission: “ Transmitted via bodily fluids (blood, breast milk, vaginal fluids, semen)

*Infects macrophages (early stage) then CD4+ T helper cells (late stage)
* Binds to CD4+ via CCR5 (early stage) or CXCR4 (late stage) for entry into cells
- Homo CCR5 del –> resistance
- Hetero CCR5 del –> slow prog
* Env genes:
- gp120: outer glycoprotein
- gp41: transmembrane protein, mediates viral-cell fusion & syncytia formation
* Pol gene: RT, integrase, Asp protease
*Gag gene:
- p24: capsule protein
- p17: matrix protein
* Reg proteins: required for viral replication
- Rev gene: regulates viral RNA transport of unspliced viral transcripts out of nucleus
- Tat gene: reg protein that transcriptionally activates other viral genes
*Nef: cytoplasmic accessory protein that enhances viral rep by down-reg CD4/MHC-1 expression”
Diseases: “Stage 1 = Prodrome/Primary/Acute Infection:
*Flu/mono-like symptoms (fever, cervical lymphadenopathy)
* Lasts several weeks
* Wide dissemination to lymphoid organs

Stage 2 = Clinical Latency: CD4+ count < 500
*Replicates in lymph nodes
* Mild symptoms (mucocutaneous, resp tract infections)
* Lasts up to 10 yrs

Stage 3 = Advanced Symptoms appear: CD4+ count < 350
* chronic diarrhea, recurrent/severe bacterial infections

Stage 4 = AIDS: CD4+ count < 200 OR > 200 + AIDS-defining illness (PCP/Pneumocystitis pneumonia or Candida esophagitis)
* Diffuse large B cell lymphoma: AIDS-defining illness directly caused by HIV”
Diagnosis: “*ELISA: screen for ab
- HIV-1/2 Ag/Ab: detects viral p24 ag capsid protein & IgG ab to HIV-1/2
Western Blot: confirm positive screening result (no longer recommended by CDC)
* PCR: measure CD4 count
* Neonates: test for HIV RNA/DNA nucleic acid antigen test (anti-gp120 ab can cross placenta)”
Treatment: “ NRTI: nucleotide analog that becomes incorporated & inhibits elongation; backbone of ART
- Ziduvedine: safe to use in pregnancy
* NNRTI: non-nucleotide RT inhibitor that inhibits without incorporation
*Genotype testing for best therapy
* Most important in those with CD4 count < 350, high viral load or pregnant
*Protease inhibitor
* Maraviroc: CCR5 inhibitor that prevents entry into CD4 cell”
Vaccines:

RNA Viruses (+) sense

Question 22

“Orthomyxovirus (Influenza)
(night shift at the orthodontist)”

Answer 22

Features: “* -ssRNA (carries own RNA pol to form +ssRNA)
Enveloped
* 8 segments (BOAR)
Replicates in nucleus”
Reservoir/Transmission: “ Resp droplet transmission

• HA: surface gp that binds sialic acid in upper resp tract cells; H1-3 ag most common & determine cell tropism (what virus binds to); anti-HA ab protect from future infection w same strain
• NA: Cleaves sialic acid from HA releasing new virions from host cell
  *M2 protein: Creates proper pH for viral uncoating

*Incubation period = 1-4 days (viral shedding for 3-7 days)”
Diseases: “Influenza A, B, C (3 strains)
*A –> epidemics/pandemics (drift + shift)
* B –> endemics (drift only)
* Antigenic Drift: pt mutations in viral genome cause changes in HA or NA molecules –> need for new annual vaccine & epidemics
* Antigenic Shift: reassortment btw shared RNA segments of diff species due to segmented genome –> pandemics

• Abrupt onset of fever, chills, rigors, headache, myalgia –> resp symptoms (soar throat, nasal congestion, runny nose, cough)
• As systemic illness diminishes, resp symptoms/cough remain for wks

Complications:
Secondary Bacterial Pneumonia (caused by S aureus, H influenzae, or S pneumoniae); OM, sinusitis, rarely bacterial tracheitis
* GBS: ascending paralysis, high protein/low WBC in CSF
Exacerbation of underlying illness (CF, asthma, chronic bronchitis especially), sepsis, myocarditis, febrile seizures, encephalitis/encephalopathy, transverse myelitis
* Myositis: tender leg muscles & elevated serum Cr kinase (esp with influenza B)
*Reye Syndrome: hepatic & CNS complication in children associated with salicylate/aspirin use”
Diagnosis: “ RT-PCR (gold standard)
* Specimen: NP swab/aspirate (highest yield in first few days of illness during peak viral shedding)
* Rapid antigen test (30-60 min, less sensitive)”
Treatment: “ High risk: pregnant, high BMI, care facility resident
*Amantadine/Rimantadine: inhibit M2 preventing viral uncoating
- Used to treat strain A
- No longer recommended due to resistance
- Used to treat Parkinson’s disease (raises DA)
Oseltamivir/Zanamivir/Peramivir: Sialic acid analogs that inhibit NA preventing virion release (must be given early before release)
- Used to treat strains A & B”
Vaccines: “ Killed inj vaccine: trivalent (2A + 1B), quadvalent (2A + 2B)
- Annually after 6 mo old
- 2 doses if < 8 yo for first dose
*Quad + adjuvant/high dose: > 65 yo
* Live intranasal vaccine: 2-49 yo”

RNA Viruses (-) sense

Question 23

“PARAMYXOVIRUS
(paranormal mixer)”

Answer 23

Features:
Reservoir/Transmission:
Diseases: Rubeola/Measles, RSV, Mumps, Parainfluenza virus/Croup
Diagnosis:
Treatment:
Vaccines:

RNA Viruses (-) sense

Question 24

Rubeola/Measles (FIRST disease)

Answer 24

Features:”* -ssRNA
* Enveloped”
Reservoir/Transmission: “* Resp transmission (replicates in nasopharynx)
*Common in unimmunized/travelers

*VF: HA + Fusion Protein: cause fusion of respiratory lymphocytes –> Warthin-Finkeldey giant cells (multinucleated giant cells w eosinophilic inclusion bodies)

*Incubation period = 10-12 days”
Diseases: “Primary viremia (2-3 days) w secondary viremia (5-7 days) w spread
* Early symptoms: Fever > 104 for 4 days, Cough, Coryza (runny nose), Conjunctivits
* THEN maculopapular rash begins on face & spreads down (confluent rash 3-5 days post-infection)
* Koplik spots (before rash): blue spots on buccal mucosa w surrounding erethyma
* Other symptoms: Photophobia, myalgia, sore throat, ““miserable””, fever
* Lymphadenitis w Warthin-Finkeldey giant cells

Complications:
* Secondary bacterial infections, OM, croup, diarrhea
*Giant cell/measles pneumonia (immunosuppressed)
* Subacute Sclerosing Pan Encephalitis (SSPE): rare degenerative CNS disease w behavioral/intellectual deterioration & seizures (occurs 7-10 yrs after esp in infants), anti-measles ab in CSF, no Tx
Myocarditis
* Thrombocytopenic purpura”
Diagnosis:
Treatment: “ Vitamin A reduces morbidity & mortality of measles
“
Vaccines: * MMR Vaccine: live attenuated vaccine (contraindicated in pregnancy); lifelong immunity

RNA Viruses (-) sense

“PARAMYXOVIRUS
(paranormal mixer)”

Question 25

Mumps

Answer 25

Features: “* -ssRNA
* Enveloped”
Reservoir/Transmission: “* Resp transmission
* Replicates in parotid glands
*Incubation period = 14-18 days

*VF: Fusion protein, HA, NA”
Diseases: “Replicates in parotid gland, testes, CNS, pancreas –> Viremia 12-25 days post-exposure
*Parotitis: inflammation of parotid glands
*Unilateral Orchitis: testicular atrophy & sterility can occur
* Meningitis (virus replicates in CNS)
* Pancreatitis”
Diagnosis:
Treatment:
Vaccines: * MMR Vaccine: live attenuated vaccine (contraindicated in pregnancy); lifelong immunity

RNA Viruses (-) sense

“PARAMYXOVIRUS
(paranormal mixer)”

Question 26

Respiratory Syncytial Virus (RSV)

Answer 26

Features: “* -ssRNA
* Enveloped”
Reservoir/Transmission: “* Fusion protein
* G protein: allows for attachment to resp endothelium

Humans are the ONLY source, can live on surfaces
* Occurs in annual epidemics during winter/early spring
* Incubation period = 2-8 days (viral shedding for 3-4 wks)”
Diseases: “ Common in infants < 6 mo
* Infants: #1 cause of pneuomnia & bronchiolitis in infants (lower resp infection)
infiltrates seen on CXR
* Adults: severe lower resp infection esp in immunocompromised”
Diagnosis: “ PCR (most sensitive)
Antigen detection assay
* DFA/culture (rare)”
Treatment: “ Ribavirin: Not commonly used in kids/pregnant women; used in adults only
* Palivizumab: monoclonal ab against fusion protein; used for prevention of RSV in premature infants”
Vaccines:

RNA Viruses (-) sense

“PARAMYXOVIRUS
(paranormal mixer)”

Question 27

Parainfluenza Virus/Croup

Answer 27

Features: “* -ssRNA
* Enveloped”
Reservoir/Transmission: * Fusion protein, HA, NA
Diseases: “* Bronchiolitis & pneumonia in children < 1 yr (HPIV-3)
* Croup/Laryngotracheobronchitis in 1-5 yo (HPIV1/2): inspiratory stridor & seal-bark cough
* Refractory pneumonia in HSCT pts w 40% mortality
* Bronchiolitis obliterans in lung transplant pts”
Diagnosis: “*CXR: Steeple-sign (narrow trachae & subglottic region) indicates croup
* Direct fluorescent ab, PCR or viral culture
* Lung biopsy in immunocompromised or HSCT pts”
Treatment: * Ribavirin: inhaled with IVIG for severe pneumonia
Vaccines:

RNA Viruses (-) sense

“PARAMYXOVIRUS
(paranormal mixer)”

Question 28

Human Metapneumovirus

Answer 28

Features:
Reservoir/Transmission:
Diseases:
Diagnosis:
Treatment:
Vaccines:

RNA Viruses (-) sense

Question 29

“Rhabdovirus
(rabid wrecking yard)”

Answer 29

Features: “* -ssRNA
* Enveloped
* Helical capsid
* Bullet shaped
* Negri bodies “
Reservoir/Transmission: “*Carriers: bats (US), foxes, skunks, rodents, dogs (developing countries)
* Transmitted via aerosol or bite

• Binds nicotinic Ach receptors on post-synaptic motor end plate –> binds NCAMs entering neurons
  *Replicates in motor neurons/striated muscle cells
• Retrograde movement along peripheral nerves to DRG”
  Diseases: “Rabies
• Incubation period = weeks to months (depends on bite location)
• Non-specific flu-like symptoms (malaise, headache, nausea, vomiting) –> Fever, encephalitis, foamy mouth (enters salivary glands) –> Acute neurologic syndrome including hydrophobia (fear of water), aerophobia (fear of breeze), photophobia
• Pharyngeal muscle spasms–> dysphagia
• Eosinophilic Negri bodies in cytoplasm of hippocampal pyramidal cells & cerebellar Purkinje cells (do not confuse w cowdry bodies which are nuclear inclusions w herpesvirus)”
  Diagnosis:
  Treatment: “* NOT effective once symptoms appear
  Wound cleaning”
  Vaccines: “ Passive immunization post-exposure with preformed Abs
• Killed vaccine (active immunization)”

RNA Viruses (-) sense

Human Metapneumovirus

Question 30

“Filovirus
(soccer field’o virus)”

Answer 30

Features: “* -ssRNA
* Enveloped
* Helical capsid”
Reservoir/Transmission: “* Monkey/bat
* spread via bodily fluids (puts healthcare workers at risk)
*Travel to Africa”
Diseases: “Marburg & Ebola (can result in DIC)
*Hemorrhagic fever & petechial rash
* Hemorrhagic/hypovolemic shock –> End organ failure –> death”
Diagnosis: * RT-PCR of blood/bodily fluids within 48 hr symptom onset
Treatment:
Vaccines:

RNA Viruses (-) sense

Human Metapneumovirus

Question 31

Hantavirus (Sin nombre)

Answer 31

Features: “* -ssRNA
* Enveloped (obtained from golgi bodis of host cells)
* 3 circular segments (BOAR)”
Reservoir/Transmission: “* Reservoir = deer mouse (arbovirus exception = robovirus - rodents)
* Transmitted via rodent urine/feces”
Diseases: “*Pulmonary capillary leak (radiographically similar to ARDS) –> hypotension, pre-renal azotemia & pulmonary edema
*Cardiopulmonary syndrome (HCPS)
* Hemorrhagic fever with renal syndrome (HFRS)”
Diagnosis:
Treatment:
Vaccines:

RNA Viruses (-) sense

“BUNYAVIRUS
(paul bunyavirus)”

Question 32

California Encephalitis & Rift Valley Fever

Answer 32

Features: “* -ssRNA
* Enveloped (obtained from golgi bodis of host cells)
* 3 circular segments (BOAR)”
Reservoir/Transmission: * spread via Aedes mosquitoes (arbovirus)
Diseases: “* Seizures
* Encephalitis (all arboviruses cause encephalitis)”
Diagnosis:
Treatment:
Vaccines:

RNA Viruses (-) sense

“BUNYAVIRUS
(paul bunyavirus)”

Question 33

“Arenavirus
(welcome to the arenavirus)”

Answer 33

Features: “* -ssRNA
*Ambisense (both +/- RNA)
Enveloped
* Helical capsid
* 2 circular segments (BOAR)
* Grainy appearance w electron microscopy (host cell ribosomes)”
Reservoir/Transmission: * transmitted by rodents
Diseases: “ Lymphocytic Choriomeningitis Virus (LCV): fever & meningoencephalitis
* Lassa Fever: Hemorrhagic fever & encephalitis (West Africa)”
Diagnosis:
Treatment: * Inactivated by heat and irradiation
Vaccines:

RNA Viruses (-) sense

Question 34

Rotavirus

Answer 34

Features: “* dsRNA (replicates in cytoplasm)
* Naked
* 11 segments (BOAR)
* Infection common in winter”
Reservoir/Transmission: “Entry through mouth, fecal oral
* NSP4: enterotoxin that causes symptoms by increasing Cl- permeability –> Na & H2O leak out
* Children @ risk”
Diseases: “ #1 cause of severe diarrhea in young children
*Watery diarrhea within 48 hrs infection that lasts 3-8 days (attacks villous cells of sm intestine)
Complications: dehydration, electrolyte imbalance, metabolic acidosis”
Diagnosis: * Wheel-shaped
Treatment:
Vaccines: “ Live attenuated oral vaccine: first dose should be given when < 3 mo old due to side effect of intussesception (telescoping of bowel)
- 2, 4, 6 mo”

RNA Viruses (-) sense

“REOVIRUS
(a race on the rio)”

Question 35

Colorado Tick Virus (Coltivirus)

Answer 35

Features: “* dsRNA (replicates in cytoplasm)
* Naked
* 11 segments (BOAR)
* Infection common in winter”
Reservoir/Transmission:
Diseases: * Myalgia, fever, vomiting
Diagnosis:
Treatment:
Vaccines:

RNA Viruses (-) sense

“REOVIRUS
(a race on the rio)”

Question 36

“HSV-1 & HSV-2
(Hermes, the god of herpes)”

Answer 36

Features: “Herpes Virus Family
* dsDNA, linear
*Enveloped
*Cowdry bodies: Intranuclear eosinophilic inclusion bodies (also in CMV/VZV)
* Tzank smear w multinucleated giant cells (same as VZV)”
Reservoir/Transmission:
Diseases: “Above the waist (1) symptoms vs below the waist (2)
Herpetic whitlow: painful hand vesicle/wart; common in dentists

Genital Herpes:
* Most with HIV-2 have not been diagnosed with genital herpes, but shed virus in genital tract
HSV-1 increasing in first episodes of anogenital herpes (MSM, young women)
Cervicitis: discharge, intermenstrual bleeding
HIV –> Reactivation of HSV: esophagitis, recurrent mucocutaneous & genital ulcers”
Diagnosis: “ PCR (gold standard)
* Cell culture has low sensitivity that declines as healing occurs
* Cowdry intranuclear inclusion bodies”
Treatment: “*First episode: Acyclovir, Famcyclovir, or Valacyclovir (10 day course, extend if healing incomplete)
*Recurrent: Higher doses of above antivirals for shorter courses
* Suppressive therapy: reduces frequency of recurrence”
Vaccines:

DNA Viruses

Question 37

HSV-2

Answer 37

Features: “Herpes Virus Family
* dsDNA, linear
Enveloped
Cowdry bodies: Intranuclear eosinophilic inclusion bodies (also in CMV/VZV)
* Tzank smear w multinucleated giant cells (same as VZV)”
Reservoir/Transmission: * Lies dormant in sacral ganglia
Diseases: “ Aseptic meningitis in adolescents/adults
* Painful inguinal lymphadeopathy
Vesicular genital lesions”
Diagnosis: * Tzank smear w multinucleated giant cells (old test, now use PCR)
Treatment: “ NO cure
* Prevent with acyclovir or valcyclovir”
* “First episode: Acyclovir, Famcyclovir, or Valacyclovir (10 day course, extend if healing incomplete)
*Recurrent: Higher doses of above antivirals for shorter courses
* Suppressive therapy: reduces frequency of recurrence”
Vaccines:

DNA Viruses

Question 38

HSV-1

Answer 38

Features: “Herpes Virus Family
* dsDNA, linear
Enveloped
Cowdry bodies: Intranuclear eosinophilic inclusion bodies (also in CMV/VZV)
* Tzank smear w multinucleated giant cells (same as VZV)”
Reservoir/Transmission: “ Vertical transmission (TORCHES)
Latent in trigeminal ganglia & reactivated by stress/immunosuppression”
Diseases: “First sign is gingivostomatitis (inflammed lips/tongue)
* Rash: dew drops on rose petal appearancen on upper body
Erythema multiform: target-shaped rash w pink-red ring around pale center that appears 1-2 wk post-infection
* Serpiginous/dendritic corneal ulcers seen on slit lamp exam of Keratoconjunctivitis (red eyes)
*Temporal lobe encephalitis (#1 cause of sporadic encephalitis in US) –> hemorrhage/necrosis of tissue –> personality changes, hallucinations
* Esophagitis with volcano-like ulcers (immunocompromised)
* Herpes labialis (cold sores) result from reactivation of virus from stress”
Diagnosis: “ PCR (gold standard)
* Cell culture has low sensitivity that declines as healing occurs
* Cowdry intranuclear inclusion bodies”
Treatment:
“First episode: Acyclovir, Famcyclovir, or Valacyclovir (10 day course, extend if healing incomplete)
*Recurrent: Higher doses of above antivirals for shorter courses
* Suppressive therapy: reduces frequency of recurrence”
Vaccines:

DNA Viruses

Question 39

“EBV
(ye olde epstein bar)”

Answer 39

Features: “* dsDNA (linear)
* Enveloped
Atypical CTLs (Downey type II): basophilic, vacuolated cytoplasm & lobulated nucleus
* Reed-Sternberg Cells: Hodgkin’s lymphoma; binucleate w prominent nucleoli (owl eyes)”
Reservoir/Transmission: “ Mainly saliva transmission
* Virus envelope gp binds CD21 to infect B cells (CD21 is a receptor & binds gp350) –> spread to lymphoid system
* Latent in B cells (episome)
*Incubation period = 30-50 days
* More common in adults/adolescents in developed countries & in kids in developing countries

Compromised hosts include:
*X-linked lymphoproliferative syndrome: genetic inability to mount normal immune response to EBV
*Infection associated Hemophagocytic Syndrome: CTL/NK cells inability to regulate EBV proliferation; hypercytokinemia
*Post transplant Lymphoproliferative Disorder: risk due to immunosuppression highest in first year after
*HIV infection –> Primary CNS Lymphoma: Lethargy, confusion, seizures, constitutional symptoms (dx: imaging, EBV PCR on CSF if possible)”
Diseases: “Heterophile-positive Mononucleosis (agglutinates with non-human RBCs)
* 3-5 days of headache, malaise & fatigue; fevers (high as 40’C & last 7-14 days)
* Generalized lymphadeopathy, fever, splenomegaly (T cell proliferation), pharyngitis (sore throat) & tonsilar exudate, periorbital edema
*Confused w Strep (which is more common in kids); when given amox/ampicillin for suspected strep –> maculopapular rash

Complications:
* Neuro: meningitis, encephalitis, optic neuritis, cranial nerve palsy, myelitis, psychosis
* Heme: hemolytic anemia, thrombocytopenia, aplastic anemia, leukopenia

Associated Conditions:
* Lymphocytic Interstitial Pneumonitis: pulmonary condition that causes chronic wheezing (very rare)
*Non-Hodgkin’s Lymphoma: VERY common
*Oral Hairy Leukoplakia: seen in HIV pts; non-cancerous lesion usually on lateral tongue similar to candida/oral thrush (But CANNOT be scraped off)
* Leiomyosarcoma: soft tissue tumors that can occur anywhere in body (common in those with AIDS)
*Hodgkin’s Lymphoma: Mediastinal mass/non-tender lymphadenopathy
- Reed-Sternberg cell: binucleate B cells w nucleoli (owl eyes)
- mixed cellularity & lymphocyte depleted subtypes
*Endemic/African Burkitt Lymphoma: large jaw lesion & swelling (non-endemic/sporadic form presents w abd mass)
Nasopharyngeal Carcinoma: Asian ancestry”
Diagnosis: “ Heterophile Ab: IgM Abs produced by B cells that are reactive against sheep, horse RBCs & do NOT react with specific EBV proteins (non-specific)
- Monospot test POSITIVE
* EBV Viral Capsid Antigen:
- IgM peaks 2-6 wks, decline 2-3 mo
- IgG Ab perists for life
* Early Antigens (EA): IgG Ab that appears while symptomatic & indicates ACUTE infection
*EBV Nuclear Antigen (EBNA): Abs that indicate LATENT infection (maintains virus in episome)
“
Treatment: *Supportive care, avoid contact sports (risk of splenic rupture)
Vaccines:

DNA Viruses

Question 40

“CMV
(cyto mega-lo virus)”

Answer 40

Features: “* dsDNA
* Owl’s eye inclusion bodies
Icosahedral shape”
Reservoir/Transmission: “ Binds cellular integrans (heparan sulfate)
*Transmitted via sexual contact, organ transplant, vertically (placenta, TORCHES)
- Primary infection to upper resp & GI tract mucosal surfaces
- Spread during acute phase & in asymptomatic hosts for mo-yrs
* Latent in bone marrow stem cells (B/T lymphocytes & macrophages)
- Blocks MHC-I express –> inhibits CTLs
- Reactivated with immunosuppression

• OI: HIV w CD4 < 50 –> reactivation”
  Diseases: “Congenital: Greatest risk during 1st trimester
• # 1 cause of congenital infection (1-2% infected at birth, 10% infected during birth)*MR DICS - Microcephaly, Retardation, Deaf, Intracranial calcifications, Seizures
  *Other symptoms: Jaundice, hepatosplenomegaly, ventriculomegaly (head CT), anemia, pneumonitis
• Hydrops fetalis: heart failure –> edema –> spont abortion
• Blueberry muffin rash: thrombocytopenia, petechial rash (similar to rubella)

Immunocompetent hosts: Mononucleosis w sore throat, lymphadenopathy, fatigue (mono spot test = neg, differs from EBV mono)

Immunocompromised hosts: Organ transplant & AIDS pt (CD4 count < 50)
* Interstitial pneumonia: HSCT complication within first 120 days; rapid onset resp symptoms that last < 2 wk, fever, non-productive cough, dyspnea that can progress to hypoxia
*Retinitis: full thickness necrotizing infection that has pizza pie appearance & cotton wool spots on fundoscopy (retinal lesions with intraretinal hemorrhages)
* Esophagitis: Singular/deep linear ulcers (differs from HSV which has multiple shallow ones)
Colitis w ulcerated walls (diarrhea, abdominal pain, fever)
* CNS manifestations: dementia, ventriculoencephalitis, radiculopathy”
Diagnosis: “Buffy Coat Culture: Tests transplant pts for lg cells w prominent owl’s eye inclusions
*Fundoscopy (retinitis)
* Endoscopy with biopsy: (esophagitis & colitis) large cells w intracellular & intracytoplasmic inclusions

Congenital
* Viral isolation from urine/saliva sample during first 3 wk of life
* PCR on serum, urine or CSF”
Treatment: “* Ganciclovir (IV): Nucleoside analog that inhibits viral DNA Pol; initial phosphorylation step catalyzed by viral enzyme & final steps by host enzymes; half-life > 24 hr; myelosuppression
*Valganciclovir (PO): Pro-drug of ganciclovir (same MOA & spectrum) but allows for oral dosing; myelosuppression
*Foscarnit in those with resistance to ganciclovir due to mutated UL97 gene (phosphotransferase) & UL54 (viral DNA Pol)

*Prevent interstitial pneumonia in HSCT pts using antivirals 90-120 days post-transplant
*No PPX for HIV pts

Congenital
* Ganciclovir or oral valganciclovir”
Vaccines:

DNA Viruses

Question 41

“Varicella Zoster Virus (VZV)
(varicella zeus-ter virus)”

Answer 41

Features: “Herpes Virus Family (all enveloped)

• Multinucleated giant cells on Tzank smear (same as HSV)+C32”
  Reservoir/Transmission: “* Resp droplet transmission
• Latent in DRG
  
  • Primary = sensory ganglia (4-6 days disseminates to other organs/here)
  • Secondary = viral infection of skin
    *Incubation period = 10-21 days”
    Diseases: “VZV/Chickenpox:
• Vesicular dew drops on rose rash (HSV); chickenpox (superficial, mostly on trunk); lesions in different stages of healing (smallpox = same stage)
• Fever, headache
  *Pneumina & encephalitis in adults/immunocompromised

Congenital Varicella Syndrome: Infection during 1/2 trimester
*Limb hypoplasia
*Cutaneous scarring in dermatomal pattern
* Blindness

Herpes Zoster/Shingles:
* Reactivated with stress, aging, immunosuppression
*Same dew drop on rose appearance with dermatomal distribution (commonly lumbar & thoracic; disseminated if it crosses midline)
*Opthalmicus: vision loss if trigeminal nerve VI affected
* Post-herpetic neuralgia: pain after rash subsides
* Ramsey Hunt Syndrome?”
Diagnosis: *VZV: Tzank smear shows multinucleated giant cells (old test, now use PCR)
Treatment: “Shingles:
*Famciclovir: shingles tx

VZV:
* Acyclovir: kids > 12 yo, adults, immunocompromised
Valcyclovir”
Vaccines: “Shingles (Shingrex): killed vaccine for > 50 yo (2 doses); shingles & PHN

• Varicella (Varivax): Live attenuated vaccine for kids > 12 mo
• MMRV: 1-12 yo”

DNA Viruses

Question 42

“HHV-6 (Roseola)
(a roseola by any other name would smell as sweet)”

Answer 42

Features: “Herpes Virus Family
* dsDNA”
Reservoir/Transmission: “* Infects CD4 T cells
* Remains latent in lymphocytes/monocytes”
Diseases: “Roseola / Sixth Disease / Exanthum Subitum: 6-19 mo, usually self-limiting
* High fever (> 104) for 4 days w abrupt onset –> Febrile seizures (bulging fontanelle)
* After fever resolves, diffuse lacy rash that SPARES face (measles = fever DURING rash)
*Cervical & occipital lymphadenopathy
*GI or resp symptoms, inflammed tympanic membrane
* Latent in WBCs & reactivation can occur –> rejection of transplants”
Diagnosis:
Treatment: Cooling/fluids
Vaccines:

DNA Viruses

Question 43

“HHV-8 (Kaposi’s Sarcoma)
(ring around a ka-posi)”

Answer 43

Features: “Herpes Virus Family
* dsDNA”
Reservoir/Transmission: “* Higher incidence in Russian men & African populations
*Associated w AIDS & immunosuppression (ART will alleviate lesions)”
Diseases: “Kaposi’s Sarcoma:
* Most common cancer seen in AIDS pts
* initial cutaneous disease (violaceous lesions on nose, extremities & mucous surfaces)
- Most often on hard palate (arched ceiling of mouth) & GI tract
- Inactivates Rb –> Dysregulation of VEGF –> Angiogenesis –> lesions
* Lymphocytic infilitrate (Bacillary angiomatosis = neutrophilic bc bacteria)

Primary Effusion Lymphoma: infection of B cells; type of B cell lymphoma (aka body cavity based lymphoma)”
Diagnosis:
Treatment: “*ART & chemo alleviate lesions
* IFN-a: Kaposi sarcoma tx”
Vaccines:

DNA Viruses

Question 44

“Polyomavirus JC & BK
(et tu, BK?)”

Answer 44

Features: “* circular dsDNA
Naked”
Reservoir/Transmission: “ Ubiquitous in immunocompetent
* Affects HIV pts w CD4 < 200 & immunocompromised

*Resp transmission during childhood
*seed kidney –> clinically latent infection”
Diseases: “JC Virus (John-Cunningham):
* Mostly immunocompromised
*Progressive Multifocal Leukoencephalopathy (PML): demyelinating disease that kills oligodendrocytes (lethal, death within months) –> Non-enhancing multifocal brain lesions in white matter (toxoplasma causes ring-enhancing lesions)
- Normal ICP
- Increased risk w natalizumab/rituximab (tx of MS)

BK Virus:
* Nephropathy, esp in kidney/bone marrow transplant pts
* Hemorrhagic cytitis –> Hematuria
* Ureteral stenosis”
Diagnosis:
Treatment:
Vaccines:

DNA Viruses

Question 45

“Papillomavirus (HPV)
(pilloma bugs)”

Answer 45

Features: “* dsDNA
* Naked
circular genome
* > 100 types (most important are 6, 11, 16, 18, 31, 33)
* Predilection for stratified squamous epithelium”
Reservoir/Transmission: “Infects mucosal epithelium

• Virus encodes proteins that target regulators of cell cycle G1 to S phase –> uncontrolled cell growth
  
  • E6 inhibits p53
  • E7 inhibits Rb (tumor suppressor gene)

Immunosuppression & HIV are risk factors”
Diseases: “Most common STD
* AIDS-definining illness: invasive cervical, anal or penile cancer
*Clinical Manifestations: anogenital warts, recurrent resp papillomatosis (RRP), cervical cancer precursors (cervical intraepithelial neoplasia), cancer (cervical, anal, vaginal, vulvar, penile, head, neck)

HPV 1, 4
* Verruca Vulgans: cutaneous common wart on hands/feet that is soft, flesh-colored, cauliflower-like papule; infection of keratinocytes
- Transmitted via contact

HPV 6, 11:
* Recurrent resp papillomatosis: tumors present on kids airway (vocal cords)
- Acquired during vaginal birth (NOT sexually transmitted)
* Condyloma acuminata: Angiogenital warts & koilocytes
- Sexually transmitted

HPV 16, 18 + 31, 33
* Oncogenic or high risk infection are responsible for cervical, penile, vulvar, vaginal & oropharyngeal cancers + precancers
* Cervical Intraepithelial Neoplasia (CIN): dysplastic pre-cancerous lesion of cervix that commonly manifests following loss of p53/Rb after infectio
* Anogenital cancer of skin, anus, cervix
- Squamous cell carcinoma = most common cervical cancer
- Sexually transmitted”
Diagnosis: “* Pap smear: cervical cancer screening; sample cervical cells from transformation zone where outer squamous cells meet inner columnar cells
*Koilocytes: Large, dense, wrinkled nucleus w perinuclear halos”
Treatment: Cutaneous warts: salicylic acid/liquid nitrogen
Vaccines: “ Gardasil Vaccine: inactivated subunit that treats HIV 6, 11, 16, 18 to prevent STDs by targetting capsid proteins (9-45 yo)
- HPV L1: capsid protein; Ag used
- 11-12 yo: 2 doses (6-12 mo)
- 15+ yo: 3 doses”

DNA Viruses

Question 46

“Parvovirus B19
(bombs away)”

Answer 46

Features: “* ssDNA
* Smallest DNA virus
* Naked”
Reservoir/Transmission: “* Resp, blood products & vertical transmission (TORCHES)

• Preferentially infects erythroid progenitors (requires P blood group antigen receptor/globoside to enter cell)”
  Diseases: “Fifth Disease / Erythema infectiosum / Slapped Cheek Fever:
• Fever for 1 wk (clears BEFORE rash begins)
• Slapped cheek rash: red lacy rash that starts on face & moves down; can relapse with sunlight, stress, exercise but does NOT indicate relapse of infection
  *IgM appears in serum
• Aplastic anemia w SCD: depletion of bone marrow causes adipocytes to pack into cob webs; normally transient condition

Adults: Polyarthropathy syndrome
* Papular-purpuric gloves & socks syndrome (adults/adolescents, painful, resolves in 1-3 wks)
* Hydrops fetalis: if infected during 1/2 trimester; edema & death”
Diagnosis:
Treatment: * Immunocompromised: IVIG & RBC transfusion
Vaccines:

DNA Viruses

Question 47

“Adenovirus
(a den-o-lions)”

Answer 47

Features: “* Naked
dsDNA
* 54 serotypes”
Reservoir/Transmission: “ Risk factors: military recruits, children, public swimming pools, organ transplant
* Fecal-oral, contact (fomites) AND resp transmission
* Enters/lysis mucosal cells by binding w hemagglutinin”
Diseases: “* #1 cause of infection in adenoids & tonsils (tonsilitis)
*Resp infections: OM, pharyngitis, exudative tonsilitis, cervical adenopathy, croup, bronchitis, pertussis-like syndrome, bronchiolitis, pneumonia (+/- pleural effusions) and necrotizing pneumonia w resp failure
* Pharyngoconjunctival Fever: Keratoconjunctivitis, gastroenteritis, acute hemorrhagic cystitis (hematuria), acute myocarditis
* Organ transplant –> reactivation”
Diagnosis: “
* Histopathology (tissue)
* Culture
*PCR (used for organ transplant)
* Liver biopsy: necrosis, intracellular inclusion bodies”
Treatment: *Self limiting
Vaccines: * Live attenuated vaccine for military recruits only

DNA Viruses

Question 48

“Poxvirus
(pox in a box)”

Answer 48

Features: “*Linear dsDNA (largest DNA virus)
* contains DNA-dep RNA Pol (replicates in cytoplasm)
* Makes its own envelope
* Dumbbell shaped core (only DNA virus W/O icosahedral symmetry)
*Guarnieri bodies (type B1): intracytoplasmic inclusion bodies that are sites of replication”
Reservoir/Transmission: * Sexual transmission in adults
Diseases: “Molluscum Contagiosum: Causes flesh colored, dome shaped, umbilicated (dimple center) skin lesions (similar to snail shell)
* Most common in children, present on trunk (not palms/soles)
* Adults: ususally a single lesion
- Diffuse infection suggests HIV infection
*Sexually transmitted

Smallpox / Variolla: Raised blisters on skin/mucosal surfaces that are all of the same stage & deep; mostly affect face/palms (chickenpox is of various stages & superficial)

Cowpox: Transmitted by contact with infected cow uterus; led to eradication of smallpox”
Diagnosis:
Treatment:
Vaccines: “* Smallpox has been eradicated
* Vaccinia: Live attenuated vaccine “

DNA Viruses

Question 49

“Hep B
(Hep B love)”

Answer 49

Features: “Hepdnavirus Family

• Partially ds circular DNA
• Enveloped
• Uses RT (does not integrate into host DNA/not a retrovirus like HIV)
• Replicates both in nucleus & cytoplasm; viral DNA Pol completes partial dsDNA upon entry into nucleus; HOST RNA Pol transcribes mRNA from dsDNA”
  Reservoir/Transmission: “* Transmitted via sex & blood products: HBsAg-positive fluids from person with acute or chronic infection
• Transmitted during delivery (too large to cross placenta, TORCHES)
• Humans are the ONLY host”
  Diseases: “* Causes chronic hepatitis, cirrhosis & hepatocellular carcinoma
• Similar to serum sickness (fever, rash, arthralgias)
  
  • Purpuric rash with non-blanching dark macules
• Polyarthritis nodosa: systemic vasculitis that affects sm/med vessels –> small aneurysms w beads on string appearance –> HTN & decreased GFR (renal dysfunction)
  *Membranous glomerulonephritis: thickened glomerular membrane –> Membranous proliferative glomerulonephritis: deposits in mesangium

Perinatal Transmission:
* Newborns infected have a 90% chance of developing chronic infection (older pts are less likely)
* Mother who is HBsAg (chronic infection) AND HBeAg (highly infectious) positive is MORE likely to infect NB than if just HBsAg positive”
Diagnosis: “LFTs:
*Alcoholic hepatitis: AST > ALT
* Viral hepatitis: ALT > AST
* Neonatal hepatitis: Normal ALT in early infection

Biomarkers:
* HbsAg: first marker of infection (surface ag); required for HDV infection
* HbeAg: high levels indicate highly infectious
- BOTH in early symptomatic ifection
* Anti-HBc: positive during window period; indicates recovery
* Anti-HBe: present during low infectivity
* Anti-HBs: indicates recovery; checked with vaccination to ensure immunity from vaccine”
Treatment: “* Acute cases are self-limiting/supportive care

• Chronic cases/pregnant women should receive tx:
  
  • Lamivudine, IFN-a (Hep C tx), NRTIs (HIV tx)
  • does NOT eradicate disease, prevents replication
• Newborns: anti-Hep B Ig & Hep B vaccine (active & passive immunity)
  “
  Vaccines: “*Recombinant HBsAg: lasts 20 yrs, 3 doses, booster not routinely recommended; used in:
  
  • ALL infants
  • High risk: MSM, many partners, IVDU”

DNA Viruses

Question 50

Hep D

Answer 50

Features: “Deltavirus Family

• Circular -ssRNA virus
• Enveloped (received from HBsAg)”
  Reservoir/Transmission:
  Diseases: “* Requires HBsAg from Hep B to be infectious
• Coinfection with simultaneous transmission of Hep B & D
• Superinfection with Hep D transmission AFTER Hep B –> worse outcome
• Similar presentation to Hep B”
  Diagnosis:
  Treatment:
  Vaccines:

DNA Viruses

Question 51

Multisystem Inflammatory Syndrome (MIS-C)

Answer 51

Features: * Complication with COVID-19 infection
Reservoir/Transmission:
Diseases: “* Diagnosis: < 21 yo with fever inflammation, multisystem organ involvement (CV, renal, heme, GI, neuro, derm)
- AND no alternative dx
- AND recent SARS-CoV-2 infection
*Fever > 38’C for > 24 hr
* Elevated CRP, ESR, fibrinogen, procalcitonin, d-dimer, ferritin, LDH, IL6, neutrophils; low lymphocytes/albumin
*Skin manifestations”
Diagnosis:
Treatment:
Vaccines:

DNA Viruses

Question 52

Kawasaki Disease

Answer 52

Features: < 5 yo, highest rates in Asian ancestry
Reservoir/Transmission:
Diseases: “Febrile exanthematous multisystem med vessel vasculitis
* STARTS w fever & irritabillity
* Rash: fiery red, confined to groin, demarcated stocking/glove distribution of erythema, digital cyanosis/gangrene
*Dx with 5 days of fever + 4/5 of the following: bilateral bulbar conjunctival injection w/o exudate, erythematous mouth/pharynx w strawberry tongue & cracked red lips, polymorphous generalized erythematous rash (NOT vesicular), changes in peripheral extremities, later periungal desquamation, acute unilateral cervical lymphadenitis
*CV consequences including aneurysm”
Diagnosis:
Treatment: * high doseIVIG + oral aspirin
Vaccines:

DNA Viruses