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166 Cards in this Set

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How do you diagnose infection with HSV?
- Viral culture for skin / genitalia
- CSF PCR for herpes encephalitis
- Tzanck test (genital herpes) - a smear of an opened skin vesicle to detect multinucleated giant cells (picture)
- Infected cells also have intranuclear Cowdry A inclusions

- Viral culture for skin / genitalia
- CSF PCR for herpes encephalitis
- Tzanck test (genital herpes) - a smear of an opened skin vesicle to detect multinucleated giant cells (picture)
- Infected cells also have intranuclear Cowdry A inclusions

What does this image show? Sign of?
What does this image show? Sign of?
Positive Tzanck smear in genital herpes (HSV-2)
Positive Tzanck smear in genital herpes (HSV-2)
What are the types of RNA viruses?
- Reovirus
- Picornavirus
- Hepevirus
- Calicivirus
- Flavivirus
- Togavirus
- Retrovirus
- Coronavirus
- Orthomyxovirus
- Paramyxovirus
- Rhabdovirus
- Filovirus
- Arenavirus
- Bunyavirus
- Delta virus
- Reovirus
- Picornavirus
- Hepevirus
- Calicivirus
- Flavivirus
- Togavirus
- Retrovirus
- Coronavirus
- Orthomyxovirus
- Paramyxovirus
- Rhabdovirus
- Filovirus
- Arenavirus
- Bunyavirus
- Delta virus
Which RNA viruses are enveloped?
*Enveloped

- Reovirus
- Picornavirus
- Hepevirus
- Calicivirus
* Flavivirus
* Togavirus
* Retrovirus
* Coronavirus
* Orthomyxovirus
* Paramyxovirus
* Rhabdovirus
* Filovirus
* Arenavirus
* Bunyavirus
* Delta virus

*Enveloped

- Reovirus
- Picornavirus
- Hepevirus
- Calicivirus
* Flavivirus
* Togavirus
* Retrovirus
* Coronavirus
* Orthomyxovirus
* Paramyxovirus
* Rhabdovirus
* Filovirus
* Arenavirus
* Bunyavirus
* Delta virus

Which RNA viruses are not enveloped?
* Not enveloped

* Reovirus
* Picornavirus
* Hepevirus
* Calicivirus
- Flavivirus
- Togavirus
- Retrovirus
- Coronavirus
- Orthomyxovirus
- Paramyxovirus
- Rhabdovirus
- Filovirus
- Arenavirus
- Bunyavirus
- Delta virus
* Not enveloped

* Reovirus
* Picornavirus
* Hepevirus
* Calicivirus
- Flavivirus
- Togavirus
- Retrovirus
- Coronavirus
- Orthomyxovirus
- Paramyxovirus
- Rhabdovirus
- Filovirus
- Arenavirus
- Bunyavirus
- Delta virus
Which RNA viruses are DS?
DS = *
* Reovirus - linear (10-12 segments)
- Picornavirus
- Hepevirus
- Calicivirus
- Flavivirus
- Togavirus
- Retrovirus
- Coronavirus
- Orthomyxovirus
- Paramyxovirus
- Rhabdovirus
- Filovirus
- Arenavirus
- Bunyavirus
- Delta virus
DS = *
* Reovirus - linear (10-12 segments)
- Picornavirus
- Hepevirus
- Calicivirus
- Flavivirus
- Togavirus
- Retrovirus
- Coronavirus
- Orthomyxovirus
- Paramyxovirus
- Rhabdovirus
- Filovirus
- Arenavirus
- Bunyavirus
- Delta virus
Which viruses are (+) linear ssRNA?
+ssRNA = *
- Reovirus
* Picornavirus
* Hepevirus
* Calicivirus
* Flavivirus
* Togavirus
* Retrovirus
* Coronavirus
- Orthomyxovirus
- Paramyxovirus
- Rhabdovirus
- Filovirus
- Arenavirus
- Bunyavirus
- Delta virus
+ssRNA = *
- Reovirus
* Picornavirus
* Hepevirus
* Calicivirus
* Flavivirus
* Togavirus
* Retrovirus
* Coronavirus
- Orthomyxovirus
- Paramyxovirus
- Rhabdovirus
- Filovirus
- Arenavirus
- Bunyavirus
- Delta virus
Which viruses are (-) linear ssRNA?
(-) ssRNA, linear = *
- Reovirus
- Picornavirus
- Hepevirus
- Calicivirus
- Flavivirus
- Togavirus
- Retrovirus
- Coronavirus
* Orthomyxovirus
* Paramyxovirus
* Rhabdovirus
* Filovirus
- Arenavirus
- Bunyavirus
- Delta virus
(-) ssRNA, linear = *
- Reovirus
- Picornavirus
- Hepevirus
- Calicivirus
- Flavivirus
- Togavirus
- Retrovirus
- Coronavirus
* Orthomyxovirus
* Paramyxovirus
* Rhabdovirus
* Filovirus
- Arenavirus
- Bunyavirus
- Delta virus
Which viruses are (-) circular ssRNA?
(-) ssRNA, circular
- Reovirus
- Picornavirus
- Hepevirus
- Calicivirus
- Flavivirus
- Togavirus
- Retrovirus
- Coronavirus
- Orthomyxovirus
- Paramyxovirus
- Rhabdovirus
- Filovirus
* Arenavirus
* Bunyavirus
* Delta virus
(-) ssRNA, circular
- Reovirus
- Picornavirus
- Hepevirus
- Calicivirus
- Flavivirus
- Togavirus
- Retrovirus
- Coronavirus
- Orthomyxovirus
- Paramyxovirus
- Rhabdovirus
- Filovirus
* Arenavirus
* Bunyavirus
* Delta virus
Which RNA viruses are icosahedral?
* Reovirus
* Picornavirus
* Hepevirus
* Calicivirus
* Flavivirus
* Togavirus
* Retrovirus
- Coronavirus
- Orthomyxovirus
- Paramyxovirus
- Rhabdovirus
- Filovirus
- Arenavirus
- Bunyavirus
- Delta virus
* Reovirus
* Picornavirus
* Hepevirus
* Calicivirus
* Flavivirus
* Togavirus
* Retrovirus
- Coronavirus
- Orthomyxovirus
- Paramyxovirus
- Rhabdovirus
- Filovirus
- Arenavirus
- Bunyavirus
- Delta virus
Which RNA viruses are helical?
- Reovirus
- Picornavirus
- Hepevirus
- Calicivirus
- Flavivirus
- Togavirus
- Retrovirus
* Coronavirus
* Orthomyxovirus
* Paramyxovirus
* Rhabdovirus
* Filovirus
* Arenavirus
* Bunyavirus
* Delta virus
- Reovirus
- Picornavirus
- Hepevirus
- Calicivirus
- Flavivirus
- Togavirus
- Retrovirus
* Coronavirus
* Orthomyxovirus
* Paramyxovirus
* Rhabdovirus
* Filovirus
* Arenavirus
* Bunyavirus
* Delta virus
What are the types of Reoviruses?
- Coltivirus
- Rotavirus
What is the #1 cause of fatal diarrhea in children?
Rotavirus (Reovirus - no envelope, DS linear, icosahedral (double))
What is the medical importance of the Coltivirus?
- Causes Colorado Tick Fever
- Type of arbovirus - transmitted by arthropods (ticks)
- Reovirus - no envelope, DS linear (10-12 segments), icosahedral (double)
What is the medical importance of the Rotavirus?
- #1 cause of fatal diarrhea in children
- Reovirus - no envelope, DS linear (10-12 segments), icosahedral (double)
What are the types of Picornaviruses?
PERCH:
- Poliovirus
- Echovirus
- Rhinovirus
- Coxsackievirus
- HAV
What is the medical importance of the Poliovirus?
Causes Polio
- Salk (killed / injected) and Sabin (live attenuated / oral) vaccines
- Picornavirus (no envelope, SS (+) linear, icosahedral)
What is the medical importance of the Echovirus?
Causes aseptic meningitis
- Picornavirus (no envelope, SS (+) linear, icosahedral)
What is the medical importance of Rhinovirus?
"Common cold"
- Picornavirus (no envelope, SS (+) linear, icosahedral)
What is the medical importance of the Coxsackievirus?
- Aseptic meningitis
- Herpangina (mouth blisters, fever)
- Hand, foot, and mouth disease
- Myocarditis and pericarditis

- Picornavirus (no envelope, SS (+) linear, icosahedral)
What is the medical importance of the HAV?
Causes Acute Viral Hepatitis
- Picornavirus (no envelope, SS (+) linear, icosahedral)
What is the medical importance of the Hepevirus family?
- Hepatitis E Virus (HEV)
- No envelope, SS (+) linear, icosahedral
What is the medical importance of the Calicivirus family?
Norovirus - viral gastroenteritis
- No envelope, SS (+) linear, icosahedral
What are the types of Flaviviruses?
- HCV
- Yellow Fever
- Dengue Fever
- St. Louis Encephalitis
- West Nile Virus
What are the characteristics of Flaviviruses?
- Envelope
- SS (+) linear
- Icosahedral
- Envelope
- SS (+) linear
- Icosahedral
What is the medical importance of Togaviruses? Characteristics?
- Rubella
- Eastern equine encephalitis
- Western equine encephalitis

- Envelope, SS(+) linear, Icosahedral
- Rubella
- Eastern equine encephalitis
- Western equine encephalitis

- Envelope, SS(+) linear, Icosahedral
What is the medical importance of Retroviruses? Types? Characteristics?
- Have reverse transcriptase
- HIV: AIDS (complex and conical)
- HTLV: T-Cell Leukemia (icosahedral)
- Enveloped, SS (+) Linear
- Have reverse transcriptase
- HIV: AIDS (complex and conical)
- HTLV: T-Cell Leukemia (icosahedral)
- Enveloped, SS (+) Linear
What is the medical importance of Coronaviruses? Characteristics?
- Common cold
- SARS
- Envelope, SS (+) linear, Helical
- Common cold
- SARS
- Envelope, SS (+) linear, Helical
What is the medical importance of Orthomyxoviruses? Characteristics?
Influenza Virus
- Envelope
- SS (-) Linear (8 segments)
- Helical
Influenza Virus
- Envelope
- SS (-) Linear (8 segments)
- Helical
What is the medical importance of Paramyxoviruses? Characteristics?
PaRaMyxovirus:
- Parainfluenza = Croup
- RSV = bronchiolitis in babies, rx = ribavirin
- Measles
- Mumps

- Envelope, SS (-) linear (non-segmented), helical
PaRaMyxovirus:
- Parainfluenza = Croup
- RSV = bronchiolitis in babies, rx = ribavirin
- Measles
- Mumps

- Envelope, SS (-) linear (non-segmented), helical
What does RSV cause? Treatment? Characteristics?
- Causes bronchiolitis in babies
- Treat with Ribavirin

- Paramyxovirus: enveloped, SS (-) linear (non-segmented), helical
- Causes bronchiolitis in babies
- Treat with Ribavirin

- Paramyxovirus: enveloped, SS (-) linear (non-segmented), helical
What is the medical importance of Rhabdoviruses? Characteristics?
Rabies
- Envelope
- SS (-) linear
- Helical
Rabies
- Envelope
- SS (-) linear
- Helical
What is the medical importance of Filoviruses? Characteristics?
Ebola / Marburg hemorrhagic fever (often fatal)
- Envelope
- SS (-) linear
- Helical
Ebola / Marburg hemorrhagic fever (often fatal)
- Envelope
- SS (-) linear
- Helical
What is the medical importance of Arenaviruses? Characteristics?
- LCMV: Lymphocytic Choriomeningitis Virus
- Lassa Fever Encephalitis (spread by mice)

- Enveloped, SS (-) Circular (2 segments), Helical
- LCMV: Lymphocytic Choriomeningitis Virus
- Lassa Fever Encephalitis (spread by mice)

- Enveloped, SS (-) Circular (2 segments), Helical
What is the medical importance of Bunyaviruses? Characteristics?
- California encephalitis
- Sandfly / Rift Valley fevers
- Crimean-Congo hemorrhagic fever
- Hantavirus - hemorrhagic fever, pneumonia

- Enveloped, SS (-) circular (3 segments), helical
- California encephalitis
- Sandfly / Rift Valley fevers
- Crimean-Congo hemorrhagic fever
- Hantavirus - hemorrhagic fever, pneumonia

- Enveloped, SS (-) circular (3 segments), helical
What is the medical importance of Delta Virus? Characteristics?
- HDV: defective virus that requires HBV co-infection

- Enveloped, SS (-) circular, uncertain capsid symmetry
- HDV: defective virus that requires HBV co-infection

- Enveloped, SS (-) circular, uncertain capsid symmetry
What are the negative stranded viruses? What do they require?
Always Bring Polymerase Or Fail Replication
- Arenaviruses
- Bunyaviruses
- Paramyxoviruses
- Orthomyxoviruses
- Filoviruses
- Rhabdoviruses

Must transcribe (-) strand to (+)
- Virion brings its own RNA-dependent RNA polymerase
What are the segmented viruses? How many segments?
All are RNA viruses: BOAR
- Bunyaviruses: 3 segments
- Orthomyxoviruses (influenza): 8 segments
- Arenaviruses: 2 segments
- Reoviruses: 10-12 segments
What are the Picornaviruses?
PERCH on a "Peak" (PICO)
- Poliovirus
- Echovirus
- Rhinovirus
- Coxsackievirus
- HAV
What is unique about Picornaviruses?
- Small RNA virus
- RNA is translated into 1 large polypeptide that is cleaved by proteases into functional viral proteins
- Can cause aseptic (viral) meningitis (except Rhinovirus and HAV)
- All are enteroviruses (fecal-oral spread) except rhinovirus
What are the characteristics of Rhinovirus? What does it cause?
Picornavirus - non-enveloped RNA virus
- Cause of common cold
- > 100 serologic types
- Acid labile (destroyed by stomach acid) therefore does not infect the GI tract (unlike other picornaviruses)
What family of virus is Yellow Fever Virus? How is it transmitted? Symptoms?
Flavivirus (also an arbovirus - transmitted by Aedes mosquitos)
- Virus has a monkey or human reservoir
- Symptoms: high fever, black vomitus, and jaundice
Which virus causes high fever, black vomitus, and jaundice?
Yellow Fever Virus (type of flavivirus)
What is the most important global cause of infantile gastroenteritis? Characteristics?
Rotavirus = Right Out The Anus
- Type of Reovirus
- Segmented dsRNA virus
- Major cause of acute diarrhea in US during winter, especially at day-care centers, kindergartens
Rotavirus = Right Out The Anus
- Type of Reovirus
- Segmented dsRNA virus
- Major cause of acute diarrhea in US during winter, especially at day-care centers, kindergartens
What is the mechanism of action of Rotavirus? Implications?
- Villous destruction with atrophy leads to decreased absorption of Na+ and loss of K+
- Major cause of acute diarrhea in Us during winter, especially in day-care centers and kindergartens
- CDC recommends routine vaccination of all infants
- Villous destruction with atrophy leads to decreased absorption of Na+ and loss of K+
- Major cause of acute diarrhea in Us during winter, especially in day-care centers and kindergartens
- CDC recommends routine vaccination of all infants
What type of virus is Influenza Virus? Characteristics?
Orthomyxovirus
- Enveloped
- (-) ssRNA w/ 8-segment genome
- Rapid genetic gchanges
What antigens are on influenza viruses? Actions?
- Hemagglutinin - promotes viral entry
- Neuraminidase - promotes progeny virion release
Which protein on influenza virus promotes viral entry?
Hemagglutinin
Which protein on influenza virus promotes progeny virion release?
Neuraminidase
Patients infected with the influenza virus are at risk for what?
Fatal bacterial superinfection
What are the types and characteristics of the influenza vaccines?
- Reformulated vaccine ("the flu shot" contains the viral strains most likely to appear during the flu season
- Killed viral vaccine (injected) most commonly used
- Live attenuated (temperature sensitive) vaccine that replicates in the nose but not in the lung is administered intranasally
What are the types of genetic changes to the influenza vaccine? Which is more serious?
- Genetic shift / antigenic shift
- Genetic drift

Sudden Shift is more deadly than graDual Drift
What does genetic SHIFT of influenza viruses cause?
Pandemics
- Reassortment of viral genome
- Segments undergo high-frequency recombination, such as when human flu A virus combines with swine flu A virus
What does genetic DRIFT of influenza viruses cause?
Epidemics
- Minor (antigenic drift) changes are based on random mutation
What kind of virus is Rubella? What disease does it cause?
Togavirus
- Causes rubella, aka German (3-day) Measles
- Fever, postauricular and other lymphadenopathy, arthralgias and fine rash
- Mild disease in children, but severe congenitally
Togavirus
- Causes rubella, aka German (3-day) Measles
- Fever, postauricular and other lymphadenopathy, arthralgias and fine rash
- Mild disease in children, but severe congenitally
What are the impacts of Rubella (togavirus) if acquired congenitally?
Serious congenital disease (a ToRCHeS infection):
- Blueberry muffin appearance indicates extramedullary hematopoiesis
Serious congenital disease (a ToRCHeS infection):
- Blueberry muffin appearance indicates extramedullary hematopoiesis
What are the types of Paramyxoviruses?
- Parainfluenzae
- Mumps
- Measles
- RSV
Which virus causes croup - seal-like barking cough?
Parainfluenza (type of paramyxovirus)
Which virus causes respiratory tract infections (bronchiolitis, pnuemonia) in infants?
RSV (type of paramyxovirus)
What are the characteristics of all paramyxoviruses?
- Contain surface F (fusion) proteins
- F protein causes respiratory epithelial cells to fuse and form multinucleated cells
Which drug can prevent pneumonia caused by RSV infection in premature infants? Mechanism?
Palivizumab - monoclonal antibody against F protein
Which virus causes Koplik spots (left) and a descending maculopapular rash (right)
Which virus causes Koplik spots (left) and a descending maculopapular rash (right)
Measles virus (a paramyxovirus)
Measles virus (a paramyxovirus)
What are the characteristic symptoms of Measles infection?
- Koplik spots - bright red spots with blue-white center on buccal mucosa that precedes measles rash by 1-2 days (left)
- Descending maculopapular, erythematous rash that includes limbs (right)

3 "C's" of measles:
- Cough
- Coryza (inflammat...
- Koplik spots - bright red spots with blue-white center on buccal mucosa that precedes measles rash by 1-2 days (left)
- Descending maculopapular, erythematous rash that includes limbs (right)

3 "C's" of measles:
- Cough
- Coryza (inflammation of nose)
- Conjunctivitis
What are the possible sequelae of Measles infection?
- SSPE: Subacute Sclerosing Panencephalitis (occurs years later)
- Encephalitis (1:2000)
- Giant cell pneumonia (rarely, in immunosuppressed)
What can be used to prevent severe exfoliative dermatitis in malnourished children with Measles?
Vitamin A
Which virus causes Parotitis (picture), Orchitis (inflammation of testes), and aseptic Meningitis?
Which virus causes Parotitis (picture), Orchitis (inflammation of testes), and aseptic Meningitis?
Mumps virus (a type of paramyxovirus)
Mumps virus (a type of paramyxovirus)
What are the symptoms of Mumps?
Mumps makes your parotid glands and testes as big as POM-poms
- Parotitis (picture)
- Orchitis (inflammation of testes)
- Aseptic Meningitis

- Can cause sterility (especially after puberty)
Mumps makes your parotid glands and testes as big as POM-poms
- Parotitis (picture)
- Orchitis (inflammation of testes)
- Aseptic Meningitis

- Can cause sterility (especially after puberty)
Which virus is bullet-shaped?
Which virus is bullet-shaped?
Rabies virus
Rabies virus
What cells are affected by the Rabies virus?
Rabies virus characteristically infects Purkinje cells of the cerebellum and neurons in the hippocampus
- Cytoplasmic inclusions = Negri body (arrows)
Rabies virus characteristically infects Purkinje cells of the cerebellum and neurons in the hippocampus
- Cytoplasmic inclusions = Negri body (arrows)
What are the symptoms of Rabies Virus?
- Long incubation period (weeks to months) before onset of symptoms
- Progression of disease: fever, malaise → agitation, photophobia, hydrophobia → paralysis, coma → death
From which animals is it more common to acquire Rabies virus?
Bat, raccoon, and skunk bites more common than dog bites in US
What is the pathophysiology of Rabies virus?
Virus travels to the CNS (Purkinje cells of cerebellum and hippocampal neurons) by migrating in a retrograde fashion up nerve axons
How should you treat a patient you think may be exposed to Rabies virus?
- Wound cleansing
- Vaccination +/- rabies immune globulin
What are the types of Hepatitis viruses? Virus family? DNA/RNA?
- HAV: RNA picornavirus
- HBV: DNA hepadnavirus
- HCV: RNA flavivirus
- HDV: RNA delta virus
- HEV: RNA hepevirus
How are the Hepatitis viruses transmitted?
- HAV: fecal-oral
- HBV: parenteral, sexual, maternal-fetal
- HCV: primarily blood (IVDU, post-transfusion)
- HDV: parenteral, sexual, maternal-fetal
- HEV: fecal-oral, especially with waterborne epidemics

* HAV and HEV: the vowels hit your bowels
What are the signs and symptoms of ALL hepatitis viruses?
- Episodes of fever
- Jaundice
- ↑ ALT and AST
Which Hepatitis viruses require a carrier?
HBV, HCV, HDV
What is the relative incubation time for the Hepatitis viruses?
- HAV: short (weeks)
- HBV: long (months)
- HCV: long
- HDV: superinfection (HDV after HBV) is short
- HDV: co-infection (HDV with HBV) is long
- HEV: short
Which Hepatitis viruses have risk for progressing to hepatocellular carcinoma? How?
- HBV (integrates into host genome, acts as oncogene
- HCV (from chronic inflammation)
- HDV
What are the characteristics of HAV?
- RNA picornavirus
- Fecal-oral transmission
- No carrier
- Short incubation time (weeks)
- No risk for HCC
- Usually "A"symptomatic, "A"cute, "A"lone (no carrier)
What are the characteristics of HBV?
- DNA hepadnavirus
- Parenteral, sexual, or maternal-fetal transmission
- Carrier
- Long incubation time (months)
- Risk for HCC (integrates into host genome and acts as oncogene)

- DNA polymerase has both DNA- and RNA-dependent activities; upon entry into nucleus the polymerase functions to complete the partial dsDNA
- The host RNA polymerase transcribes mRNA from viral DNA to make proteins
- DNA polymerase then reverse transcribes viral RNA to DNA which helps form new viral particles
What are the characteristics of HCV?
- RNA flavivirus
- Primarily transmitted via blood (IVDU, post-transfusion)
- Carrier
- Long incubation time
- Risk of HCC (from chronic inflammation)
- "C"hronic, "C"irrhosis, "C"arcinoma, "C"arrier
What are the characteristics of HDV?
- RNA delta virus
- Parenteral, sexual, or maternal-fetal transmission
- Carrier
- Superinfection (HDV after HBV) has short incubation time
- Co-infection (HDV with HBV) has long incubation time
- Risk for HCC
- "D"efective virus "d"ependent on HBV superinfection → ↓ prognosis
What are the characteristics of HEV?
- RNA hepevirus
- Fecal-oral transmission, especially with waterborne epidemics
- No carrier
- Short incubation time
- No risk for HCC
- High mortality in pregnant women
- "E"nteric, "E"xpectant mothers, "E"pidemic
What does it mean if your patient has anti-HAV (IgM)?
Best test to detect active Hepatitis A infection
What does it mean if your patient has anti-HAV (IgG)?
Indicates prior HAV infection and/or prior vaccination; protects against re-infection
What does it mean if your patient has HBsAg?
Indicates hepatitis B infection (antigen found on surface of HBV)
What does it mean if your patient has anti-HBs?
Indicates immunity to Hepatitis B (antibody to HBsAg)
What does it mean if your patient has anti-HBc (IgM)?
Acute / recent infection with HCV (antibody to HBcAg)
What does it mean if your patient has anti-HBc (IgG)?
Prior exposure to HCV or chronic infection
What does it mean if your patient has HBeAg?
Active viral replication and therefore high transmissibility
What does it mean if your patient has anti-HBe?
Low transmissibility
What is the best serologic marker to detect active Hepatitis A infection?
Anti-HAV (IgM)
What is the serologic marker that indicates prior HAV infection and/or prior vaccination?
Anti-HAV (IgG)
Which serologic marker protects against reinfection of HAV?
Anti-HAV IgG
Which serologic marker indicates hepatitis B infection?
HBsAg
Which serologic marker indicates immunity to Hepatitis B infection?
Anti-HBs
Which serologic marker is associated with the core of HBV?
HBcAg
Which serologic marker indicates acute / recent infection with HBV?
Anti-HBc IgM
Which serologic marker indicates prior exposure or chronic infection with HBV?
Anti-HBc IgG
Which serologic marker is positive during the window period of HBV infection?
- Anti-HBc (IgG and IgM)
- Anti-HBe
Which serologic marker indicates active viral replication and high transmissibility of HBV?
HBeAg
Which serologic marker indicates low transmissibility of HBV?
Anti-HBe
When is the ratio of ALT > AST?
Viral hepatitis
When is the ratio of AST > ALT?
Alcoholic hepatitis
Which serologic markers are present during Acute HBV? What do these markers mean?
- HBsAg: hepatitis B infection
- HBeAg: high transmissibility and active viral replication
- Anti-HBc IgM: acute / recent HBV infection
- HBsAg: hepatitis B infection
- HBeAg: high transmissibility and active viral replication
- Anti-HBc IgM: acute / recent HBV infection
Which serologic markers are present during the window period of HBV infection? What do these markers mean?
- Anti-HBe: low transmissibility
- Anti-HBc IgM: acute / recent HBV infection
- Anti-HBe: low transmissibility
- Anti-HBc IgM: acute / recent HBV infection
Which serologic markers are present during Chronic HBV (high infectivity)? What do these markers mean?
- HBsAg: hepatitis B infection
- HBeAg: high transmissibility and active viral replication
- Anti-HBc IgG: prior exposure or chronic infection
- HBsAg: hepatitis B infection
- HBeAg: high transmissibility and active viral replication
- Anti-HBc IgG: prior exposure or chronic infection
Which serologic markers are present during Chronic HBV (low infectivity)? What do these markers mean?
- HBsAg: hepatitis B infection
- Anti-HBe: low transmissibility
- Anti-HBc IgG: prior exposure or chronic infection
- HBsAg: hepatitis B infection
- Anti-HBe: low transmissibility
- Anti-HBc IgG: prior exposure or chronic infection
Which serologic markers are present during Recovery from HBV? What do these markers mean?
- Anti-HBs: immunity to HBV
- Anti-HBe: low transmissibility
- Anti-HBc IgG: prior exposure or chronic infection
- Anti-HBs: immunity to HBV
- Anti-HBe: low transmissibility
- Anti-HBc IgG: prior exposure or chronic infection
Which serologic markers are present if immunized to HBV? What do these markers mean?
Anti-HBs: indicates immunity to HBV
What kind of virus is HIV?
Retrovirus
- Enveloped
- SS (+) linear RNA
- Diploid genome: 2 molecules of RNA
- Complex and conical
What are the structural genes (proteins coded for) by HIV?
- env (gp120 and gp41)
- gag (p24)
- pol
- env (gp120 and gp41)
- gag (p24)
- pol
What does the "env" gene by HIV code for?
gp120 and gp41
- Formed from cleavage of gp160 to form envelope glycoproteins
- gp120: attachment to host CD4+ T cell
- gp41: fusion and entry
gp120 and gp41
- Formed from cleavage of gp160 to form envelope glycoproteins
- gp120: attachment to host CD4+ T cell
- gp41: fusion and entry
What does the "gag" gene by HIV code for?
p24
- Capsid protein
p24
- Capsid protein
What does the "pol" gene by HIV code for?
- Reverse transcriptase
- Aspartate protease
- Integrase
- Reverse transcriptase
- Aspartate protease
- Integrase
Which HIV gene/protein is responsible for attachment to host CD4+ T cell?
gp120 glycoprotein
- Formed from cleavage of gp160 which is encoded by "env" gene
- One of the "env"elope proteins
Which HIV gene/protein is responsible for fusion and entry?
gp41 glycoprotein
- Formed from cleavage of gp160 which is encoded by "env" gene
- One of the "env"elope proteins
Which HIV gene/protein is the capsid protein?
p24 protein
- "gag" gene
Which HIV gene encodes reverse transcriptase, aspartate protease, and integrase?
"pol" gene
What is the function of Reverse Transcriptase in HIV?
- Synthesizes dsDNA from RNA
- dsDNA then integrates into host genome
What does HIV bind on T cells?
- CCR5 co-receptor (early) OR CXCR4 co-receptor (late)
- CD4
What does HIV bind on macrophages?
- CCR5 co-receptor
- CD4
What can give someone immunity to HIV? How?
Homozygous CCR5 mutation (usually the virus will bind this co-receptor on T cells and macrophages)
What can give someone a slower course of HIV? How?
Heterozygous CCR5 mutation (usually the virus will bind this co-receptor on T cells and macrophages)
How do you make an initial diagnosis of HIV infection?
ELISA - sensitive, so it rules out (SNOUT) but has a high false-positive rate and low threshold
How do you make a confirmatory diagnosis of HIV infection?
Western Blot assay confirms positive ELISA results
- Specific so rules in (SPIN)
- High false-negative rate and high threshold
How can you determine the amount of HIV RNA in the plasma? Implications of this test?
HIV PCR / viral load test
- High viral load associated with poor prognosis
- Also can be used to monitor effects of drug therapy
How do you diagnose AIDS?
≤ 200 CD4+ cells / mm3
(normal 500-1500 cells/mm3)

OR

HIV positive with AIDS defining condition (eg, Pneumocystis pneumonia)

OR

CD4 percentage < 14%
What is the use of ELISA and Western Blot tests for HIV?
Looks for antibodies to viral proteins
- Both often falsely negative in the first 1-2 months of HIV infection
- Both often falsely positive initially in babies born to infected mothers (anti-gp120 crosses placenta)

- ELISA used first to rule out (sensitive)
- Western blot used second to rule in (specific)
What are the four stages of untreated HIV infection?
Four F's:
1. Flu-like (acute)
2. Feeling fine (latent)
3. Falling count
4. Final criss
What happens during the latent phase of HIV infection?
Virus replicates in the lymph nodes
What happens to the CD4+ T-cell count during an HIV infection?
Red line
- Primary infection: drops from normal to ~500 over ~1 month
- Latency: increases initially within a couple of months but eventually drops over a number of years
- Late in disease: count drops more significantly first to moderate immun...
Red line
- Primary infection: drops from normal to ~500 over ~1 month
- Latency: increases initially within a couple of months but eventually drops over a number of years
- Late in disease: count drops more significantly first to moderate immunocompromise (<400) and eventually into AIDS diagnosis (<200)
What happens to the HIV RNA copies / mL plasma during an HIV infection?
Blue line
- Primary infection: spikes within 2 months
- Drops back down during clinical latency
- Increases when latent period ends / immunocompromise
Blue line
- Primary infection: spikes within 2 months
- Drops back down during clinical latency
- Increases when latent period ends / immunocompromise
What pathogen(s) cause a systemic presentation in HIV-positive adults?
Histoplasma capsulatum
What pathogen(s) cause a dermatologic presentation in HIV-positive adults?
- Candida albicans
- EBV
- Bartonella henselae
What pathogen(s) cause a gastrointestinal presentation in HIV-positive adults?
Cryptosporidium species
What pathogen(s) cause a neurologic presentation in HIV-positive adults?
- Toxoplasma gondii
- HIV itself
- JC virus reactivation (cause of PML)
- Cryptococcus neoformans
- CMV
What pathogen(s) cause an oncologic presentation in HIV-positive adults?
- EBV
- HPV
- HHV-8
What pathogen(s) cause a respiratory presentation in HIV-positive adults?
- CMV
- Aspergillus fumigatus
- Pneumocystis jirovecii
- S. pneumoniae
- Mycobacterium avium-intracellulare (aka Mycobacterium Avium Complex - MAC)
Which pathogen causes low-grade fevers, cough, hepatosplenomegaly, and tongue ulcers in HIV-positive adults? Lab findings? Other?
Histoplasma capsulatum
- Oval yeast cells within macrophages
- CD4+ < 100 cells / mm3
- Usually H. capsulatum only causes pulmonary symptoms in immunocompetent hosts
Which pathogen causes fluffy white cottage-cheese lesions in HIV-positive adults? Lab findings? Other?
Candida albicans
- Pseudohyphae
- Commonly oral if CD4+ < 400 cells/mm3
- Esophageal if CD4+ < 100 cells/mm3
- C. albicans causes oral thrush and esophagitis
Which pathogen causes hairy leukoplakia in HIV-positive adults? Findings? Other?
Ebstein Barr Virus (EBV)
- Often on lateral tongue
Which pathogen causes superficial vascular proliferation in HIV-positive adults? Lab findings? Other?
Bartonella henselae
- Biopsy reveals neutrophilic inflammation
- B. henselae causes bacillary angiomatosis
Which pathogen causes chronic, watery diarrhea in HIV-positive adults? Lab findings? Other?
Cryptosporidium species
- Acid-fast cysts seen in stool
- Especially when CD4+ < 200 cells / mm3
Which pathogen causes abscesses in HIV-positive adults? Lab findings? Other?
Toxoplasma gondii
- Many ring-enhancing lesions on imaging
- CD4+ < 100 cells/mm3
Which pathogen causes dementia in HIV-positive adults? Other?
Directly associated with HIV
- Must differentiate from other causes
Which pathogen causes encephalopathy in HIV-positive adults? Lab findings? Other?
JC virus reactivation
- Cause of PML (progressive multifocal leukoencephalopathy)
- Due to reactivation of a latent virus
- Results in demyelination
- CD4+ < 200 cells/mm3
Which pathogen causes meningitis in HIV-positive adults? Lab findings? Other?
Cryptococcus neoformans
- India ink stain reveals yeast with narrow-based budding and large capsules
- CD4+ < 50 cells/mm3
Which pathogen causes retinitis in HIV-positive adults? Lab findings? Other?
Cytomegalovirus (CMV)
- Cotton-wool spots on fundoscopic exam
- May also occur with esophagitis
- CD4+ < 50 cells/mm3
Which pathogen causes non-Hodgkin Lymphoma (large cell type) in HIV-positive adults? Findings? Other?
May be associated with EBV
- Often on oropharynx (Waldeyer ring)
Which pathogen causes primary CNS lymphoma in HIV-positive adults? Findings? Other?
Often associated with EBV
- Focal or multiple
- Differentiate from toxoplasmosis
Which pathogen causes squamous cell carcinoma in HIV-positive adults? Findings? Other?
HPV
- Often in anus (men who have sex with men)
- Or in cervix
Which pathogen causes Superficial Neoplastic Proliferations of Vasculature in HIV-positive adults? Findings? Other?
HHV-8 (Kaposi Sarcoma)
- Do not confuse with Bacillary Angiomatosis caused by B. henselae
- Biopsy reveals lymphocytic inflammation
Which pathogen causes interstitial pneumonia in HIV-positive adults? Findings? Other?
Cytomegalovirus (CMV)
- Biopsy reveals cells with intranuclear (owl eye) inclusion bodies
Which pathogen causes pleuritic pain and hemoptysis in HIV-positive adults? Findings? Other?
Aspergillus fumigatus
- Invasive aspergillosis
- Infiltrates seen on imaging
Which pathogen causes pneumonia with a ground-glass appearance on imaging of lungs in HIV-positive adults? Lab findings? Other?
Pneumocystis jirovecii
- Especially with CD4+ < 200 cells/mm3
Which pathogens cause pneumonia in HIV-positive adults? Findings? Other?
- CMV: interstitial pneumonia, biopsy shows intranuclear (owl eye) inclusion bodies
- Pneumocystis jirovecii: pneumocystis pneumonia, ground glass appearance on imaging
- S. pneumoniae: generally with CD4+ >200 cells/mm3
Which pathogen causes tuberculosis like disease in HIV-positive adults? Lab findings? Other?
Mycobacterium avium-intracellulare (aka Mycobacterium Avium Complex (MAC))
- Especially with CD4+ < 50 cells/mm3
What are the types of prion diseases?
- Creutzfeldt-Jakob disease (sporadic form)
- Gerstmann-Sträussler-Scheinker syndrome (inherited form)
- Kuru (acquired form)
What is the cause of prion diseases?
Conversion of normal (predominantly α-helical) protein termed prion protein (PrP-c) to a β-pleated form (PrP-sc) which is transmissible
What accumulates in patients with prion diseases? Characteristics?
PrP-sc (β-pleated form of proteins)
- Resists protease degradation
- Facilitates conversion of still more PrP-c → PrP-sc
What are the results of accumulation of PrP-sc in patient with prion diseases?
- Spongiform encephalopathy
- Dementia
- Ataxia
- Death
Which form of prion disease is sporadic?
Creutzfeldt-Jakob disease (rapidly progressive dementia)
Which form of prion disease is inherited?
Gerstmann-Sträussler-Scheinker Syndrome
Which form of prion disease is acquired?
Kuru