Usmle Step 1 Review - Viruses

Front 1

DNA Viruses:

Major cause of epidemic conjunctivitis (pink eye)

Back 1

Adenovirus

[Various subtypes are also associated with pharyngitis and gastroenteritis]

Front 2

DNA Viruses:

Major cause of retinitis, leading to blindness in an immunocompromised patient

Back 2

Cytomegalovirus (CMV)

[Can cause life-threatening interstitial pneumonia in such patients and heterophil-negative infectious mononucleosis in immunocompromised individuals]

Front 3

DNA Viruses:

Most common viral cause of congenital abnormalities in the United States

Back 3

Cytomegalovirus (CMV)

[Infected cells display characteristic "owl eye" intranuclear viral inclusions]

Front 4

DNA Viruses:

Infection results in the production of heterophil antibodies

Back 4

Epstein-Barr Virus (EBV)

[Viral infection results in the polyclonal activation of B cells with the production of antibodies to sheep RBCs (heterophil antibodies) that can be detected with the monospot test]

Front 5

DNA Viruses:

Major cause of infectious mononucleosis

Back 5

Epstein-Barr Virus (EBV)

[Characterized by weeks of fever, malaise, and lymphadenopathy, the peripheral blood contains an abundance of atypical lymphs, which are T cells that recognize EBV-infected cells]

Front 6

DNA Viruses:

Infection is associated with Burkitt's lymphoma and nasopharyngeal carcinoma

Back 6

Epstein-Barr virus (EBV)

[Burkitt's lymphoma is more commonly associated with EBV in Africa; nasopharyngeal carcinoma is more common in patients from Asia]

Front 7

DNA Viruses:

This virus encodes an RNA-dependent DNA polymerase (reverse transcriptase)

Back 7

Hepatitis B Virus (HBV)

[The virus produces its DNA genome through a single mRNA transcript, requiring the presence of a reverse transcriptase]

Front 8

DNA Viruses:

Appear in the serum as Dane particles and as large amounts of filaments of excess surface antigen

Back 8

Hepatitis B Virus (HBV)

[The surface antigen (HBsAg) is produced by recombinant DNA technology and is given as a vaccine]

Front 9

DNA Viruses:

A major cause of hepatocellular carcinoma worldwide

Back 9

Hepatitis B Virus (HBV)

[Although less likely to progress to either cirrhosis or carcinoma than is HCV, the worldwide prevalence especially in Africa makes HBV the leading cause]

Front 10

DNA Viruses:

Major cause of sexually transmitted and vertically transmitted hepatitis

Back 10

Hepatitis B Virus (HBV)

[Histologically, infected cells appear as ground glass hepatocytes because of the presence of excess surface antigen within the cytoplasm]

Front 11

DNA Viruses:

Infection with this virus is a leading cause of corneal blindness in the United States

Back 11

Herpes simplex virus-1 (HSV-1)

[Keratoconjunctivitis results in dendritic ulcers that can be visualized with fluorescein staining]

Front 12

DNA Viruses:

Infection results in Cowdry Type A intranuclear inclusions and multinucleated giant cells

Back 12

Herpes simplex virus-1 (HSV-1)

[One of the most common human viral infections, the virus enters broken skin and remains latent in the trigeminal ganglion, with spontaneous reactivation triggered by axonal injury, stress, or UV light]

Front 13

DNA Viruses:

Leading cause of sporadic encephalitis in the United States

Back 13

Herpes simplex virus-1 (HSV-1)

[Commonly affects the temporal lobe]

Front 14

DNA Viruses:

Most common cause of vesiculo-ulcerative lesions on the penis or vagina

Back 14

Herpes simplex virus-2 (HSV-2)

[Reactivation of the virus is common because the virus remains latent in the lumbar and sacral ganglia; detected using the Tzanck test]

Front 15

DNA Viruses:

Infection causes Roseola infantum or Sixth disease

Back 15

Herpes Virus 6

[A common, mild, childhood disease characterized by high fever and a skin rash]

Front 16

DNA Viruses:

Causes cranberry-pigmented lesions on AIDS patients

Back 16

Herpes Virus 8

[Kaposi sarcoma is a tumor of blood vessels characterized by a disarray of vascular channels filled with RBCs]

Front 17

DNA Viruses:

Infection is linked to premalignant lesions on the vulva, cervix, penis, and anus

Back 17

Human papilloma virus (HPV)

[Viral oncoprotein E6 binds to p53 and viral oncoprotein E7 binds to Rb, stimulating infected cells to undergo uncontrolled growth]

Front 18

DNA Viruses:

Infection of keratinized tissue results in the formation of warts on the hands and feet

Back 18

Human papilloma virus (HPV)

[Typically caused by infection with HPV 1-4, with the development of warts on the hands (Verruca Palmaris) and feet [Verruca Plantaris)]

Front 19

DNA Viruses:

Infection causes cauliflower-like lesions on the external genitals or perianal areas

Back 19

Human Papilloma Virus (HPV)

[Condyloma acuminatum is microscopically characterized by the presence of vacuolated infected cells, termed koilocytes]

Front 20

DNA Viruses:

Reactivation of latent viral infection in immunocompromised patients can result in Progressive multifocal leukoencephalopathy (PML)

Back 20

JC Virus

[This polyomavirus causes foci of demyelination surrounded by oligodendrocytes with viral inclusions]

Front 21

DNA Viruses:

This contagious virus causes benign epithelial tumors that appear as pearly, umbilicated nodules with a central caseous plug

Back 21

Molluscum contagiosum

[These lesions caused by the pox virus occur as clusters on the trunk, genitalia, and extremities; it is transmitted by towels, barbers, swimming pools, and sexual activity]

Front 22

DNA Viruses:

Causes aplastic crisis in patients with sickle cell anemia, thalassemias, and acquired hemolytic anemias

Back 22

Parvovirus B19

[Virion replicates best in rapidly dividing erythroblasts, resulting in cell lysis]

Front 23

DNA Viruses:

Infection of a child results in a "slapped cheek" appearance

Back 23

Parvovirus B19

[This single-stranded DNA virus causes Erythema infectiosum or Fifth disease]

Front 24

DNA Viruses:

The only DNA virus that replicates solely in the cytoplasm and that carries its own DNA-dependent polymerases

Back 24

Poxvirus

[The largest of all viruses, it appears brick-shaped by electron microscopy, and causes characteristic Guarnieri inclusion bodies when replicating in cells]

Front 25

DNA Viruses:

Found as a contaminant in preparations of polio vaccines produced in monkey cell culture

Back 25

SV40

[This polyoma virus is typically a simian virus, which can cause tumors in mice, although no pathogenic effects have been reported in humans]

Front 26

DNA Viruses:

Causes chickenpox upon initial infection, and shingles upon reactivation

Back 26

Varicella-zoster virus (VZV)

[The only herpes virus with a live attenuated vaccine; reactivation most commonly occurs along the dermatomal distribution of the ophthalmic division of the trigeminal nerve]

Front 27

DNA Viruses:

Infection results in the successive appearance of macules, papules, vesicles, and crusts all seen simultaneously

Back 27

Varicella-zoster virus (VZV)

[Severe infection can result in pneumonia with multinucleated giant cells]

Front 28

DNA Viruses:

Associated with Reye syndrome when the accompanying fever is treated with aspirin

Back 28

Varicella-zoster virus (VZV)

[Reye syndrome is an acute encephalopathy associated with fatty infiltration of the liver, which is often fatal]

Front 29

RNA Viruses:

Group of Togaviruses transmitted by mosquitoes leading to encephalitis

Back 29

Alphavirus

[This genus includes Eastern equine encephalitis virus (EEE), Western equine encephalitis virus (WEE), and Venezuelan equine encephalitis (VEE)]

Front 30

RNA Viruses:

A grouping of viruses that are transmitted by mosquitoes and ticks

Back 30

Arboviruses

[The group contains members of the Flavavirus family, Togavirus family, and Bunyavirus family]

Front 31

RNA Viruses:

Only bunyavirus member causing diseases endemic to the United States

Back 31

California encephalitis virus
(including La Crosse virus)

[Results in a mild encephalitis, sometimes only meningitis]

Front 32

RNA Viruses:

Causes pleurodynia (Bornholm disease)

Back 32

Coxsackie B virus

[Sudden onset of stabbing chest pain with waxing and waning symptoms]

Front 33

RNA Viruses:

Most common cause of viral myocarditis

Back 33

Coxsackie B Virus

[Usually self-limiting, but may cause fatal arrhythmias or lead to dilated cardiomyopathy]

Front 34

RNA Viruses:

Causes herpangina

Back 34

Coxsakievirus

[Discrete vesicles on the throat and tongue with pain and difficulty swallowing]

Front 35

RNA Viruses:

Infection may result in destruction of the pancreas with resultant insulin-dependent diabetes mellitus

Back 35

Coxsackieviruses B3 and B4

[May be due to molecular mimicry owing to shared antigens between virus and pancreatic beta cells]

Front 36

RNA Viruses:

Causes a severe hemorrhagic fever with outbreaks in Zaire and Sudan

Back 36

Ebola virus

[Another filovirus family member, Marburg virus, has been associated with infection of laboratory personnel working with monkey tissue]

Front 37

RNA Viruses:

Infection leads to severe hemorrhage and renal failure

Back 37

Hantavirus

[A member of the Bunyavirus family with three segments of RNA]

Front 38

RNA Viruses:

Infection is associated with ingestion of raw shellfish from fecally contaminated water

Back 38

Hepatitis A virus (HAV)

[The virus is transmitted via the fecal/oral route and causes an acute hepatitis with no chronic carrier state]

Front 39

RNA Viruses:

Major cause of post-transfusion hepatitis

Back 39

Hepatitis C virus (HCV)

[This Flavavirus often results initially in subclinical infection although it is a major cause of chronic hepatitis and cirrhosis in the United States; it is the hepatitis virus most likely to result in hepatocellular carcinoma]

Front 40

RNA Viruses:

Replication-deficient virus, requiring the presence of hepatitis B virus for productive infection

Back 40

Hepatitis D virus (HDV)

[The HDV viral particle, known as the Dane particle, requires packaging into hepatitis B surface antigen to be infectious]

Front 41

RNA Viruses:

Infection is associated with a high mortality rate in infected pregnant women

Back 41

Hepatitis E virus (HEV)

[This Calcivirus is transmitted by the fecal/oral route, as with hepatitis A, and is most prevalent in developing nations]

Front 42

RNA Viruses:

Infection leads to destruction of T cells, with the development of life-threatening opportutnistic infections

Back 42

Human immunodeficiency virus (HIV)

[Opportunistic infections include CMV infection, Kaposi sarcoma, Pneumocystis carinii, Toxoplasma gondii, and Mycobacterium avium-intracellulare]

Front 43

RNA Viruses:

Virus binds to CD4+ cells via viral glycorotein gp120

Back 43

Human immunodeficiency virus (HIV)

[Entry of virus requires the presence of chemokine receptors CCR5 on monocyte/macrophages or CXCR4 on T lymphocytes]

Front 44

RNA Viruses:

Retrovirus that causes oncogenic transformation of CD4+ T cells

Back 44

Human T-cell lymphotropic virus-1 (HTLV-1)

[This virus, related to HIV, is endemic to Japan and the Caribbean basin, and also causes Tropical spastic paraparesis]

Front 45

RNA Viruses:

Treatment with salicylates for this viral cause of respiratory symptoms may result in Reye syndrome in children

Back 45

Influenza virus (Orthomyxovirus)

[In children, this virus can also cause croup, otitis media, muscle aches, and a high fever; influenza and retroviruses are the only RNA viruses to replicate in the nucleus]

Front 46

RNA Viruses:

Changes in the viral surface proteins resulting from point mutations; reassortment of genome segments result in epidemics and pandemics

Back 46

Influenza virus (orthomyxovirus)

[Point mutations in viral hemagglutinin (HA) or neuraminidase (NA) result in antigen drift, whereas reassortment of genes results in antigenic shifts]

Front 47

RNA Viruses:

Major viral cause of pneumonia, and infection typically predisposes to secondary bacterial pneumonia

Back 47

Influenza virus (orthomyyxovirus)

[Decrease in respiratory mucosal viscosity by viral neuraminidase and destruction of the respiratory epithelium lower the resistance to bacterial superinfection by Staphylococcus spp., Streptococcus spp., and Haemophilus spp. infection]

Front 48

RNA Viruses:

Infection has been associated with subacute sclerosing panencephalitis (SSPE)

Back 48

Measles virus

[Caused by a defective virus encoding a defective M protein]

Front 49

RNA Viruses:

Infection leads to an immune-mediated maculopapular rash on the head, trunk, and limbs

Back 49

Measles virus

[The presence of Koplik spots, small bluish-white ulcerations on the oral mucosa, are pathognomonic]

Front 50

RNA Viruses:

Giant-cell pneumonia and encephalomyelitis are potential complications

Back 50

Measles virus

[Vaccination for this previously common viral infection is included in the MMR vaccine, along with mumps and rubella]

Front 51

RNA Viruses:

Infection can result in orchitis, which can lead to sterility

Back 51

Mumps virus

[Orchitis complicates parotidits in 20% of infected males]

Front 52

RNA Viruses:

Infection results in swelling of one or both parotids

Back 52

Mumps virus

[May result in aseptic meningitis and pancreatitis]

Front 53

RNA Viruses:

Major agent of epidemic gastroenteritis in adults

Back 53

Norwalk agent

[Outbreaks of this Calcivirus are common in institutional settings and on cruise ships]

Front 54

RNA Viruses:

Leading cause of croup

Back 54

Parainfluenza virus

[Also known as laryngotracheobronchitis, obstruction of the larynx results in a characteristic seal-bark cough]

Front 55

RNA Viruses:

Infection leads to the destruction of the cells of the anterior horn of the spinal cord

Back 55

Poliovirus

[Viral infection with this picornavirus can lead to denervation atrophy of innervated muscles with flaccid paralysis]

Front 56

RNA Viruses:

Infection is associated with an aversion to water, foaming at the mouth, and choking (hydrophobia)

Back 56

Rabies virus

["Bullet-shaped" virion can be seen by electron microscopy; causes intracellular viral inclusions in infected cells known as Negri bodies]

Front 57

RNA Viruses:

Only virus for which postexposure vaccination is indicated

Back 57

Rabies virus

[Long incubation period allows for the development of a protective immune response, without which CNS symptoms lead invariably to death]

Front 58

RNA Viruses:

Infection is associated with symptoms of sympathetic over-reactivity (i.e.salivation)

Back 58

Rabies virus

[Virus binds to the nicotinic acetylcholine receptor]

Front 59

RNA Viruses:

Most important cause of lower respiratory tract infection in infants

Back 59

Respiratory syncytial virus (RSV)

[Virally infected cells often form multinucleated syncytia]

Front 60

RNA Viruses:

Virion contains two identical strands of positive RNA (diploid-like genome)

Back 60

Retrovirus

[The virion also carries and RNA-dependent RNA polymerase, a reverse transcriptase, and an integrase for integration into the host cell genome]

Front 61

RNA Viruses:

Major cause of upper respiratory tract infections in humans

Back 61

Rhinovirus

[This picornavirus binds and enters epithelial cells via attachment to ICAM-1 and replicates best at 33⁰C, explaining its predilection for the mucosa of the nasopharynx]

Front 62

RNA Viruses:

Major cause of diarrhea (gastroenteritis) in young children

Back 62

Rotavirus

[This reovirus contains 10-12 segments of dsRNA within two concentric capsids]

Front 63

RNA Viruses:

Teratogenic virus leading to congenital defects of the heart, brain, and eye

Back 63

Rubella virus

[A member of the TORCH group of infectious agents that are capable of crossing the placenta and infecting the developing fetus]

Front 64

RNA Viruses:

This cause of mosquito-borne encephalitis can also be transmitted via blood transfusions and organ transplants, and causes life-threatening symptoms in elderly and immunosuppressed patients

Back 64

West Nile Virus

[Although first reported in Africa in the 1930's, the appearance of the Flavivirus family was first reported in the United States in 1999; recent years have seen large outbreaks with thousands of cases and nearly 200 deaths]

Front 65

RNA Viruses:

Arbovirus that causes severe hepatitis with jaundice and severe gastrointestinal hemorrhage with black vomit

Back 65

Yellow fever virus

[Infection by this Flavivirus, transmitted by the Aedes mosquito, can be prevented using a vaccine developed from the 17D strain]

Front 66

Disease:

A unique class of infectious agents that can result in Spongiform encephalitis

Back 66

Prions

[Composed only of proteinaceous material, it is highly resistant to most forms of sterilization and can be transmitted iatrogenically (e.g. surgical instruments, cadaveric material), or from consuming contaminated meats]

Front 67

Disease:

Opportunistic infections common in AIDS patients:

✦ Bacterial?

✦ Fungal?

✦ Protozoal?

✦ Viral?

Back 67

✦ Bacterial: Mycobacterium avium-intracellulare

✦ Fungal: Pneumocystis carinii

✦ Protozoal: Toxoplasma gondii & Cryptosporidium parvum

✦ Viral: Cytomegalovirus (CMV) & Kaposi sarcoma virus

Front 68

Disease:

Major sexually transmitted diseases in the United States:

✦ Bacterial?

✦ Protozoal?

✦ Viral?

Back 68

✦ Bacterial: Chlamydia trachomatis & Neisseria gonorrhoeae

✦ Protozoal: Trichomonas vaginalis

✦ Viral: Herpes simplex virus-2 (HSV-2), Human Immunodeficiency virus (HIV) & Human papilloma virus (HPV)

Front 69

Disease:

Major causes of meningitis:

✦ Newborns?

✦ Children?

✦ Young adults?

✦ Elderly (>60 years)?

✦ AIDS patients?

Back 69

✦ Newborns: Streptococcus agalactiae & Escherichia coli

✦ Children: Haemophilus influenzae

✦ Young adults: Neisseria meningitidis

✦ Elderly: Streptococcus pneumonia

✦ AIDS patients: Cryptococcus neoformans

Front 70

Disease:

Major cause of pneumonia:

✦ Neonates?

✦ Children (6 weeks-18 years)?

✦ Adults?

✦ Elderly (60 years)?

✦ Alcoholics & IV drug users?

✦ Post-viral?

✦ Cystic fibrosis patients?

Back 70

✦ Neonates: Streptococcus agalactiae & Escherichia coli

✦ Children: Respiratory syncytial virus (RSV) & Streptococcus pneumoniae (<4 years)

✦ Adults: Mycoplasma pneumonia

✦ Elderly: Streptococcus pneumoniae

✦ Alcoholics & IV drug users: Klebsiella pneumonia

✦ Post-viral: Haemophilus influenza

✦ Cystic fibrosis patients: Pseudomonas aeruginosa

Front 71

Disease:

Common nosocomial infections associated with:

✦ Newborns?

✦ Urinary catheterizations?

✦ Renal dialysis units?

✦ Respiratory therapy equipment?

✦ Water aerosols?

Back 71

✦ Newborns: Respiratory syncytial virus (RSV) & Cytomegalovirus (CMV)

✦ Urinary catheterizations: Escherichia coli & Proteus spp.

✦ Renal dialysis units: Hepatitis B virus (HBV)

✦ Respiratory therapy equipment: Pseudomonas aeruginosa

✦ Water aerosols: Legionella pneumophila

Front 72

Disease:

Major causes of endocarditis:

✦ Subacute endocarditis?

✦ Acute endocarditis?

✦ IV drug users?

✦ Patients with prosthetic valves?

Back 72

✦ Subacute endocarditis: Streptococcus viridans

✦ Acute endocarditis: Staphylococcus aureus

✦ IV drug users: Staphylococcus aureus

✦ Patients with prosthetic valves: Staphylococcus epidermidis

Front 73

Disease:

Major causes of osteomyelitis:

✦ General population?

✦ Sexually active?

✦ Drug users?

✦ Sickle cell anemia patients?

Back 73

✦ General population: Staphylococcus aureus

✦ Sexually active: Neisseria meningitidis

✦ Drug users: Pseudomonas aeruginosa

✦ Sickle cell anemia patients: Salmonella spp.

Front 74

Disease:

Organisms causing a watery diarrhea

Back 74

Cryptosporidium parvum
Escherichia coli
Vibrio cholerae
Giardia lamblia
Norwalk Agent
Rotavirus

Front 75

Disease:

Major causes of urinary tract infections

Back 75

Escherichia coli (most common)
Enterococcus faecalis
Klebsiella pneumonia
Proteus mirabilis
Proteus vulgaris
Pseudomonas aeruginosa
Serratia marcescens
Staphylococcus saprophyticus

Front 76

Disease:

Organisms causing a bloody diarrhea (dysentery)

Back 76

Campylobacter jejuni
Escherichia coli (enteroinvasive and enterohemorrhagic)
Salmonella spp.
Shigella dysenteriae
Entamoeba histolytica

Front 77

Disease:

Major causes of food poisoning

Back 77

Bacillus cereus
Clostridium perfringens
Staphylococcus aureus
Vibrio parahaemolyticus

Front 78

Disease:

Major cause of transplacental neonatal infections

Back 78

Toxoplasma gondii
Treponema pallidum
Rubella virus
Cytomegalovirus (CMV)
Herpes simplex virus (HSV)
Human immunodeficiency virus (HIV)

[Collectively known as the TORCH group, many of these infections can lead to congenital defects if acquired in utero]

Front 79

Disease:

Major causes of transcervical neonatal infections (acquired by vaginal delivery)

Back 79

Candida albicans
Escherichia coli
Listeria monocytogenes
Streptococcus agalactiae