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MOD Exam 3 > Viral Infectious Diseases > Flashcards

Viral Infectious Diseases Flashcards

(34 cards)

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1
Q

What are the most clinically significant DNA viruses in the US and environs?

  • Mnemonic: HHAPPPy
A 
– Herpesvirus
– Hepadnavirus
– Adenovirus
– Poxvirus
– Parvovirus
– Papovavirus
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2
Q

ORTHOMYXO VIRUS

Influenza type A: human and animal strain

Influenza type B: human only strain

Influenza type C: human only strain

  • Morphology?
  • Virulence factors?
  • Clinical?
  • Miscellaneous?
A

• Morphology:

  1. Negative (-) single-stranded RNA
  2. Segmented (7-8)
  3. Lipid containing envelope
  4. Helical symmetry
  5. Replicates in the nucleus! (Retroviruses are the only other type of RNA viruses that replicate in the nucleus)

• Virulence factors:
1. HEMAGGLUTININ (HA) GLYCOPROTEIN:
binds to red blood cells. Also binds to cells of the upper respiratory tract. The HA is then cleaved into two pieces (HA1 and HA2) by host cell proteases, which allows HA to activate fusion. The viral RNA is then dumped into these cells.

  1. NEURAMINIDASE (NA) GLYCOPROTEIN:
    breaks down neuraminic acid, an important component of mucin

• Clinical:

  • The FLU: Fever, runny nose, cough, myalgias arthralgias, etc.
  • Complications:
    1. Secondary bacterial pneumonias in the elderly
  1. REYES SYNDROME in children who use aspirin; get liver and brain disease
  2. Increased mortality in the elderly and in those with underlying pulmonary and cardiac disease.

• Miscellaneous:
1. Antigenic drift: small mutations, resulting in minor changes in the antigenicity of HA or NA. This results in EPIDEMICS of the common flu.

  1. Antigenic shift (only occurs with Influenza type A): reassortment. Major changes of the HA or NA (including acquisition of animal HA or NA), This results in devastating influenza PANDEMICS
  2. Avian influenza viruses such as H5N1 and H7N9 pose great risk for human pandemics.
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3
Q

PARAMYXO VIRUS: Parainfluenza

  • Morphology?
  • Virulence factors?
  • Clinical?
A

• Morphology:

  1. Negative (-) single-stranded RNA
  2. Unsegmented
  3. Lipid containing envelope
  4. Helical symmetry
  5. Replicates in the cytoplasm

• Virulence factors:

  1. Glycoproteins with combined HA and NA activity
  2. F-protein **(fusion protein): Results in multinucleated giant cells (called syncytial cells)

• Clinical:

  1. Upper respiratory tract infection in adults: bronchitis, pharyngitis, rhinitis
  2. Viral pneumonia in children, elderly and immunocompromised
  3. CROUP: Children develop a barking cough due to infection and swelling (narrowing) of the larynx
  4. Bronchiolitis in children
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4
Q

PARAMYXO VIRUS: Respiratory syncytial virus

  • Morphology?
  • Virulence factors?
  • Clinical?
  • Miscellaneous?
A

• Morphology:

  1. Negative (-) single-stranded RNA
  2. Unsegmented
  3. Lipid containing envelope
  4. Helical symmetry
  5. Replicates in the cytoplasm

• Virulence factors:

  1. F-protein **
  2. NO HA nor NA glycoproteins

• Clinical:
1. MOST COMMON CAUSE OF PNEUMONIA IN INFANTS LESS THAN 6 MONTHS OF AGE

  1. Acute otitis media occurs in up to 33% of children with RSV illness
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5
Q

PARAMYXO VIRUS: Metapneumovirus

  • Morphology?
  • Virulence factors?
  • Clinical?
  • Miscellaneous?
A

• Morphology:

  1. Negative (-) single-stranded RNA
  2. Unsegmented
  3. Lipid containing envelope
  4. Helical symmetry
  5. Replicates in the cytoplasm

• Virulence factors:
- Integrin alpha-V-beta receptor allows infection of respiratory tract epithelial cells.

• Clinical:
- Upper and lower respiratory tract infections in young children and older adults

• Miscellaneous:
- Diagnose with RT-PCR of respiratory samples.

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6
Q

PARAMYXO VIRUS: Mumps

  • Morphology?
  • Virulence factors?
  • Clinical?
  • Treatment and prevention?
  • Miscellaneous?
A

• Morphology:

  1. Negative (-) single-stranded RNA
  2. Unsegmented
  3. Lipid containing envelope
  4. Helical symmetry
  5. Replicates in the cytoplasm

• Virulence factors:

  1. Glycoproteins with combined HA and NA activity
  2. F-protein **
• Clinical: 
Mumps ** 
1. Parotid gland swelling (painful) 
2. Testicular inflammation (very painful) 
3. Meningitis 
4. Encephalitis

• Treatment and prevention:

  • Prevention: MMR vaccine:
    1. Measles
    2. Mumps (live attenuated)
    3. Rubella

• Miscellaneous:
- Only one antigenic type. Therefore, the virus is protective.

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7
Q

PARAMYXO VIRUS: Measles (rubeola)

  • Morphology?
  • Virulence factors?
  • Clinical?
  • Miscellaneous?
A

• Morphology:

  1. Negative (-) single-stranded RNA
  2. Unsegmented
  3. Lipid containing envelope
  4. Helical symmetry
  5. Replicates in the cytoplasm

• Virulence factors:

  1. HA, but no NA
  2. F-protein **

• Clinical:
Measles
1. PRODROME: high fever, hacking cough, and conjunctivitis

  1. KOPLIK’S spots: small red based blue-white centered lesions in the mouth
  2. RASH: from head, then to neck and torso, then to feet. As the rash spreads, it coalesces
  3. Complications:
    A. Pneumonia, eye damage, myocarditis and encephalitis
    B. 20% risk of fetal death if acquired by a pregnant woman early in her pregnancy
    C. SUBACUTE SCLEROSING PANENCEPHALITIS: slow form of encephalitis that occurs many years after a measles infection.

• Treatment and Prevention:

  • Prevention: MMR vaccine:
    1. Measles (live attenuated)
    2. Mumps
    3. Rubella

• Miscellaneous:
- Biopsy of rash or Koplik’s spots reveals multinucleated giant cells

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8
Q

Hepatitis A

  • Morphology?
  • Transmission?
  • Clinical?
  • Serology?
A

• Morphology:

  • Picorna viridae
    1. Positive (+) single stranded RNA
    2. No envelope (naked)
    3. Icosahedral capsid

• Transmission:
- Fecal-oral

• Clinical:
- ACUTE VIRAL HEPATITIS: fever, jaundice, and a painful enlarged liver
A. 1% develop fulminant hepatitis
B. Never becomes chronic

• Serology:

  1. Anti-HAV IgM = Active disease
  2. Anti-HAV IgG = Old; No active disease. Protective against repeated infection.
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9
Q

Hepatitis B:

  • Morphology?
  • Transmission?
  • Clinical?
  • Serology?
  • Miscellaneous?
A 
• Morphology: 
- Hepadna viridae 
1. Double-stranded circular DNA 
2. Envelope 
3. Icosahedral capsid 
4. DANE PARTICLE (intact virus) includes: 
  A. Envelope 
  B. Capsid associated proteins 
  C. Capsid 
  D. Core (DNA + protein enzymes) 
5. Hepatitis B SURFACE antigen (HBsAg) 
   A. Envelope 
   B. Capsid associated proteins 
6. Hepatitis B core antigen (HBcAg) 
    A. Double stranded DNA 
    B. DNA polymerase enzyme 
    C. Capsid 
 - Disassociation of the Dane particles leaves HBsAg and HBcAg 
7. Hepatitis B antigen (HBeAg): soluble component of the core, which is a marker for active disease

• Transmission:

  1. Blood transfusion
  2. Needle sticks
  3. Sexual
  4. Across the placenta

• Clinical:
1. ACUTE VIRAL HEPATITIS

  1. FULMINANT HEPATITIS: severe acute hepatitis with rapid destruction of the liver
  2. CHRONIC HEPATITIS (10%)
    A. Asymptomatic carrier
    B. Chronic persistent hepatitis
    C. Chronic active hepatitis
  3. Coinfection or superinfection with Hepatitis Delta virus (HDV)

Complications:

  1. Primary hepatocellular carcinoma
  2. Cirrhosis

• Serology:

  • HBsAg = Disease (Acute or chronic)
  • Anti-HBsAg = Immunity: provides protection against repeat infection
  • IgM anti-HBcAg = New infection
  • IgG anti-HBcAg= Old infection
  • HBeAg = High infectivity
  • Anti-HBeAg = Low infectivity

• Miscellaneous:
1. Only hepatitis B carries a DNA polymerase enzyme without the virion

  1. Liver injury occurs from a cell-mediated immune system attack on HBV
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10
Q

Hepatitis C:

  • Morphology?
  • Transmission?
  • Clinical?
  • Serology?
  • Miscellaneous?
A

• Morphology:

  1. Probably a Flavivirus
  2. Single-stranded RNA
  3. Enveloped icosahedral capsid

• Transmission:

  1. Blood transfusion
  2. Needle sticks
  3. Sexual
  4. Across the placenta
• Clinical: 
ACUTE VIRAL HEPATITIS 
- Up to 85% develop chronic hepatitis 
- 20% will develop cirrhosis 
- Increased risk of developing primary hepatocellular carcinoma

• Serology:
- Screening: anti-HCV antibodies

• Miscellaneous:

  1. HCV is leading cause for liver transplantation
  2. Genotype 1 most common in United States
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11
Q

Hepatitis D:

  • Morphology?
  • Transmission?
  • Clinical?
  • Serology?
A

• Morphology:
1. Incomplete RNA virus-only infective with the help of hepatitis B virus

  1. Helical nucleocapsid that requires the hepatitis B envelope (HBsAg) to be infectious

• Transmission:

  1. Blood transfusion
  2. Needle sticks
  3. Sexual
  4. Across the placenta

• Clinical:
1. COINFECTION: HBV and HDV are acquired at the same time, and cause an acute hepatitis. Anti-HBV antibodies help cure infection

  1. SUPERINFECTION: HDV infects a patient with chronic hepatitis B who can not manufacture Anti-HBsAg antibodies
  • Complications:
    A. Fulminant hepatitis
    B. Cirrhosis

• Serology:
- Serology is not very helpful, since detectable titers of IgM and IgG anti-HDV are present only fleetingly

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12
Q

Hepatitis E:

  • Morphology?
  • Transmission?
  • Clinical?
  • Serology?
  • Miscellaneous?
A

• Morphology:

  1. In family of Hepeviridae
  2. Single-stranded RNA
  3. No envelope (naked)

• Transmission:
- Fecal-oral

• Clinical:
- Hepatitis (like hepatitis A)

• Miscellaneous:
- Responsible for epidemics of hepatitis in Asia. Very rare in the United States.

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13
Q

Hepatitis G:

  • Morphology?
  • Transmission?
  • Clinical?
  • Serology?
  • Miscellaneous?
A

• Morphology:
- Flavivirus

• Transmission:

  1. Transfusion
  2. Needle sticks

• Clinical:
- It has not been conclusively shown to cause liver disease.

• Miscellaneous:
- Some studies have shown that co-infection with HGV might actually slow the progression of HIV disease!

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14
Q

Herpes simplex virus-1 (HSV-1)

  • Morphology?
  • Transmission?
  • Clinical?
  • Diagnostics?
A

• Morphology:

  1. Double-stranded linear DNA
  2. Enveloped
  3. Icosahedral symmetry

• Transmission:
1. Direct contact of mucous membranes
NOTE: viral shedding usually occurs in the presence of obvious herpetic lesions, but viral shedding can also occur when there are no visible lesions

  1. Sexually transmitted
  2. Herpes virus travels up sensory nerve fibers to the sensory nerve ganglia, where it replicates, then returns along the sensory nerve fibers to produce skin lesions.

• Clinical:
1. GINGIVOSTOMATITIS (COLD SORES): painful group of vesicles on the lips and mouth, which ulcerate, and heal usually without leaving a scar. Often accompanied by fever and “viral” symptoms

  1. REACTIVATION of gingivostomatitis occurs in immuno-compromised individuals or when individuals are “stressed out.” Similar eruptions of vesicles as with primary gingivostomatitis, but the vesicles are less painful and last for fewer days
  2. HERPETIC KERATITIS OF THE EYE: Recurrence is common. This is the most common cause of corneal blindness in the U.S.
  3. ENCEPHALITIS (#1 cause of viral encephalitis in the U.S.): infection (most cases are reactivation of latent HSV-1) of the brain results in cell death and brain tissue swelling, manifested as fever, headache, and neurologic abnormalities
  4. GENITAL HERPES: painful group of local vesicles on the cervix, or on the external genitalia of men and women. Often associated with fever and viral symptoms. These vesicles usually do not scar.
  5. REACTIVATION of genital herpes: similar eruption of vesicles, but less painful and vesicles last for fewer days
  6. NEONATAL HERPES: acquired during the passage of a fetus through an infected birth canal. The risk of transmission is highest when a primary genital infection is present during delivery (One of the TORCH*ES Organisms)
    A. Disseminated
    B. CNS
    C. Skin
    D. Eye
    • Note: HSV-1 and HSV-2 can interchangeably cause any of the above diseases
  7. HERPETIC WHITLOW
  8. Disseminated herpes infection of organs

• Diagnostics:

  1. Tzanck prep: reveals multinucleated giant cells and intranuclear inclusion bodies
  2. Viral culture
  3. Polymerase chain reaction
  4. Serology
  5. Direct Fluorescent Antibodies (DFA): Ulcer base scrapings can be tested with antibodies against HSV. The antibodies will latch onto HSV if present, and will fluoresce.
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15
Q

Herpes simplex virus-2 (HSV-2):

  • Morphology?
  • Transmission?
  • Clinical?
  • Diagnostics?
A

SAME AS HERPES 1 EXCEPT YOU CAN PREVENT THIS ONE WITH CONDOM USE

• Morphology:

  1. Double-stranded linear DNA
  2. Enveloped
  3. Icosahedral symmetry

• Transmission:
1. Direct contact of mucous membranes
NOTE: viral shedding usually occurs in the presence of obvious herpetic lesions, but viral shedding can also occur when there are no visible lesions

  1. Sexually transmitted
  2. Herpes virus travels up sensory nerve fibers to the sensory nerve ganglia, where it replicates, then returns along the sensory nerve fibers to produce skin lesions.

• Clinical:
1. GINGIVOSTOMATITIS (COLD SORES): painful group of vesicles on the lips and mouth, which ulcerate, and heal usually without leaving a scar. Often accompanied by fever and “viral” symptoms

  1. REACTIVATION of gingivostomatitis occurs in immuno-compromised individuals or when individuals are “stressed out.” Similar eruptions of vesicles as with primary gingivostomatitis, but the vesicles are less painful and last for fewer days
  2. HERPETIC KERATITIS OF THE EYE: Recurrence is common. This is the most common cause of corneal blindness in the U.S.
  3. ENCEPHALITIS (#1 cause of viral encephalitis in the U.S.): infection (most cases are reactivation of latent HSV-1) of the brain results in cell death and brain tissue swelling, manifested as fever, headache, and neurologic abnormalities
  4. GENITAL HERPES: painful group of local vesicles on the cervix, or on the external genitalia of men and women. Often associated with fever and viral symptoms. These vesicles usually do not scar.
  5. REACTIVATION of genital herpes: similar eruption of vesicles, but less painful and vesicles last for fewer days
  6. NEONATAL HERPES: acquired during the passage of a fetus through an infected birth canal. The risk of transmission is highest when a primary genital infection is present during delivery (One of the TORCH*ES Organisms)
    A. Disseminated
    B. CNS
    C. Skin
    D. Eye
    • Note: HSV-1 and HSV-2 can interchangeably cause any of the above diseases
  7. HERPETIC WHITLOW
  8. Disseminated herpes infection of organs

• Diagnostics:

  1. Tzanck prep: reveals multinucleated giant cells and intranuclear inclusion bodies
  2. Viral culture
  3. Polymerase chain reaction
  4. Serology
  5. Direct Fluorescent Antibodies (DFA): Ulcer base scrapings can be tested with antibodies against HSV. The antibodies will latch onto HSV if present, and will fluoresce
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16
Q

Varicella-zoster virus

  • Morphology?
  • Transmission?
  • Clinical?
  • Diagnostics?
Study These Flashcards
A

• Morphology:

  1. Double-stranded linear DNA
  2. Enveloped
  3. Icosahedral symmetry

• Transmission:
1. Varicella is highly contagious!
A. Aerosolized respiratory secretions
B. Contact with ruptured vesicles
2. Zoster: reactivation from dorsal root ganglion

• Clinical:
1. VARICELLA (CHICKEN POX)
A. 2 week incubation period
B. Fever and headache develop
C. Rash: the vesicles first erupt on the trunk and face, and spread to involve the entire body (including mucous membranes). The vesicles rupture and scab over. Note that the vesicles erupt in crops, so one crop forms as another crop scabs over. Patients are infectious until all of their lesions scab over.
D. Pneumonia or encephalitis can occur in immunocompromised patients

  1. ZOSTER (SHINGLES): painful eruption of vesicles isolated to a single dermatome distribution. The vesicles dry up and form crusts, which disappear in about 3 weeks. Pain in the dermatomal distribution can last for months in the elderly.
    - HERPES ZOSTER OPHTHALMICUS: Vesicles on one side of the forehead and on tip of the nose (the dermatomal distribution of the first division of cranial nerve V) may be associated with severe corneal involvement that (similar to HSV) can lead to blindness

• Diagnostics:
1. Vesicles are described as dew drops on the top of a rose petal: a red base with fluid filled vesicle on top

  1. Tzanck prep: reveals multinucleated giant cells
17
Q

Cytomegalovirus:

  • Morphology?
  • Transmission?
  • Clinical?
  • Diagnostics?
Study These Flashcards
A

• Morphology:

  1. Double-stranded linear DNA
  2. Enveloped
  3. Icosahedral symmetry

• Transmission:

  1. Virus present in milk, saliva, urine and tears
  2. Transmission occurs with prolonged exposure, such as between children in households or day care centers
  3. Sexual transmission
• Clinical: 
1. Asymptomatic infection (latent phase) 
2. Congenital disease (TORC*HES) 
3. CMV mononucleosis 
4. Reactivation in immunocompromised patients 
    A. Pneumonia 
    B. Retinitis 
    C. Esophagitis 
    D. Disseminated disease

• Diagnostics:
1. CMV shell viral culture: Blood buffy coat (white cells) is cultured over night. The following morning, the cells are centrifuged. This breaks up the white blood cells, releasing CMV antigens, which are detected with monoclonal antibodies

  1. Serology
  2. Histology: reveals enlarged (Cytomegalic) cells with intranuclear and cytoplasmic inclusion bodies
  3. CMV early antigens can be detected in white blood cells. These antigens are an early marker for infection in bone marrow transplant patients
  4. PCR testing for CMV DNA
18
Q

Epstein-Barr virus (EBV):

  • Morphology?
  • Transmission?
  • Clinical?
  • Diagnostics?
Study These Flashcards
A

• Morphology:

  1. Double-stranded linear DNA
  2. Enveloped
  3. Icosahedral symmetry

• Transmission:

  1. Intimate contact from asymptomatic shedders of EBV
  2. Infects human B-cells and transforms them
• Clinical: 
1. INFECTIOUS MONONUCELOSIS 
   A. Fever 
   B. Sore throat 
   C. Severe lethargy 
   D. Enlarged lymph nodes and spleen 
2. Associated with BURKITT'S B-CELL LYMPHOMA

• Diagnostics:

  1. Elevated heterophile antibodies
  2. Differential white blood cell count will show elevated “atypical lymphocytes”
  3. Serology: IgM against the viral capsid antigens (VCA)
19
Q

Human Herpesvirus 6 (HHV-6)

  • Morphology?
  • Transmission?
  • Clinical?
  • Diagnostics?
Study These Flashcards
A

• Morphology:

  1. Double-stranded linear DNA
  2. Enveloped
  3. Icosahedral symmetry

• Transmission:
- Transmitted by saliva

• Clinical:

  • Reseola (exanthum subitum):
    1. High fever lasting 3-5 days, which resolves, and is followed by a….
    2. Rash: located mostly on the trunk, which lasts just a day or two
20
Q

HHV-8

  • Morphology?
  • Transmission?
  • Clinical?
Study These Flashcards
A

• Morphology:

  1. Double-stranded linear DNA
  2. Enveloped
  3. Icosahedral symmetry

• Transmission:
- Sexual transmission, especially with homosexual men

• Clinical:
- Appears to be the cause of Kaposi’s sarcoma

21
Q

POXviridae:

  • Morphology?
  • Clinical?
  • Miscellaneous?
Study These Flashcards
A

• Morphology:

  1. Complex coat
  2. Double-stranded linear DNA
  3. The only DNA virus to replicate in cytoplasm

• Clinical:

  1. SMALLPOX: causes skin lesions and death. This disease has been eradicated from the earth!
  2. MOLLUSCUM CONTAGIOSUM: small white bumps with a central dimple (like a wart). Often found in the genital region.

• Miscellaneous:

  1. No animal reservoirs!
  2. Codes for DNA and RNA polymerase
22
Q

PAPOVAviridae:

  • Morphology?
  • Clinical?
  • Miscellaneous?
Study These Flashcards
A

• Morphology:

  1. Naked icosahedral
  2. Double-stranded circular DNA
  3. Replicates in nucleus

• Clinical:
1. Human papilloma virus (HPV): cause WARTS (over 50 viral strains)
A. Common warts (types 1, 2, 4 and 7)
B. Genital warts (types 6, 11, 16, 18 and others)
C. Laryngeal warts (6 and 11)
D. Cervical cancer (types 16 and 18)

  1. BK Polyomavirus: causes KIDNEY DISEASE in renal transplant patients, HEMORRHAGIC CYSTITIS in bone marrow transplant patients, and mild respiratory illness in children
  2. JC Polyomavirus: Progressive multifocal leukoencephalopathy, characterized by degenerative CNS white matter disease

• Miscellaneous:
- Second smallest DNA virus

23
Q

ADENOviridae:

  • Morphology?
  • Clinical?
  • Miscellaneous?
  • Treatment and prevention?
Study These Flashcards
A

• Morphology:

  1. Naked icosahedral
  2. Double-stranded linear DNA
  3. Replicates in nucleus

• Clinical:
1. Childhood upper respiratory tract infections:
A. Rhinitis
B. Sore throat
C. Fever
D. Conjunctivitis
2. Epidemic keratoconjunctivitis (Pink Eye)

  1. Epidemic diarrheal illness in infants and children

• Treatment and Prevention:
- Illness is self-limited

24
Q

PARVOviridae strain B-19:

  • Morphology?
  • Clinical?
  • Treatment and prevention?
  • Miscellaneous?
Study These Flashcards
A

• Morphology:

  1. Naked icosahedral
  2. The only single-stranded linear DNA virus (negative stranded)
  3. Replicates in nucleus

• Clinical:
1. ERYTHEMA INFECTIOSUM (Fifth disease): affects children between the ages of 4 to 12
A. Fever
B. “Slapped cheek” rash

  1. TRANSIENT APLASTIC ANEMIA CRISIS: Occurs when the Parvo virus stops the production of red blood cells in the bone marrow

• Treatment and prevention:

  • Illness is self-limited
  • I.V. immunoglobulin can be used with aplastic crisis

• Miscellaneous:
- Smallest DNA virus

25
ARBOVIRUS: TOGAviridae * Genus/Species * Morphology? * Clinical Findings? * Treatment? * Miscellaneous?
• Genus/Species: - Alpha virus: 1. Western equine encephalitis (WEE) 2. Eastern equine encephalitis (EEE) 3. Venezuelan equine encephalitis (VEE) 4. Chikungunya virus - Rubivirus • Morphology: 1. Positive (+) single-stranded RNA 2. Nonsegmented 3. Icosahedral symmetry 4. Replicates in the cytoplasm 5. Enveloped 6. Vector = mosquito for WEE, EEE, VEE, and Chikungunya 7. No insect vector for Rubivirus, so not an arbovirus. Spread by respiratory secretions. ``` • Clinical Findings: ALPHA VIRUS: 1. WEE, EEE, VEE symptoms: A. Headache and fever B. Altered level of consciousness C. Focal neurologic deficits 2. Chikungunya symptoms: 1. Initially: fever, rash, joint pain 2. Chronic arthritis ``` RUBIVIRUS - Rubella: (German measles/3 day measles) A. Fever, lymphadenopathy and mild flu-like symptoms B. Rash: from forehead to face to torso to extremities (last 3 days) C. Congenital defects: occurs when a women in her first trimester of pregnancy gets exposed. The fetus may develop defects of the heart, eyes, or CNS • Treatment: - Prevention: MMR vaccine (live attenuated) • Miscellaneous: - The "R" in TORCHES
26
ARBOVIRUS: FLAVIviridae: * Genus/Species * Morphology? * Clinical Findings? * Treatment? * Miscellaneous?
• Genus/Species: 1. Yellow fever virus 2. Dengue virus 3. St. Louis encephalitis 4. Japanese encephalitis 5. Hepatitis C virus 6. West Nile Virus • Morphology: 1. Positive (+) single-stranded RNA 2. Nonsegmented RNA 3. Icosahedral symmetry 4. Replicates in the cytoplasm 5. Enveloped 6. Vector = mosquito - Aedes: yellow fever and dengue fever - Gulex: St. Louis, Japanese, and West Nile encephalitis ``` • Clinical Findings: 1. YELLOW FEVER: A. Hepatitis (with jaundice) B. Fever C. Backache ``` 2. DENGUE FEVER: "Break bone fever" A. "Painful fever": high fever along with 1. Headaches 2. Muscle aches 3. Joint aches 4. Backache B. Dengue hemorrhagic fever: hemorrhage, thrombocytopenia, and septic shock 3. St. Louis, Japanese, West Nile encephalitis: encephalitis and fever 4. Hepatitis C virus 5. West Nile: fever, meningitis, encephalitis, or myelitis that produces flaccid paralysis • Treatment: - Prevention: mosquito control - Vaccination required when traveling to and from endemic countries • Miscellaneous: 1. Diagnosis: A. Viral culture B. Serology 2. With repeat infections, individuals are at higher risk of developing the HEMORRHAGIC form of dengue fever 3. West Nile: serology is much more sensitive than PCR, although because of cross-reactions with other flaviviruses, it is less specific
27
ARBOVIRUS: BUNYAviridae ????? * Genus/Species * Morphology? * Clinical Findings? * Treatment? * Miscellaneous?
* Genus/Species * Morphology? * Clinical Findings? * Treatment? * Miscellaneous?
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PICORNA VIRUS: ENTEROviridae * Genus/Species * Morphology? * Clinical Findings? * Treatment? * Miscellaneous?
• Genus/Species: - Poliovirus - Coxsackie A - Coxsackie B - ECHOviruses - Enteroviruses - Rhinovirus 113 serotypes • Morphology: 1. Positive (+) single-stranded RNA 2. Naked icosahedral symmetry 3. Replication occurs in the cytoplasm • Clinical Findings: POLIOVIRUS: 1. MILD FEBRILE ILLNESS: often occurs in infants in less developed nations 2. ASEPTIC MENINGITIS: fever and stiff neck. Recovery in one week. 3. PARALYTIC POLIOMYELITIS: get flaccid paralysis due to necrosis of the large motor neurons in the anterior horn of the spinal cord COXSACKIE A: 1. "Cold" rashes, viral meningitis 2. HERPANGINA: fever, sore throat and small red-based vesicles over the back of the patient's throat 3. HAND FOOT AND MOUTH DISEASE: occurs in children less than 5, Vesicles erupt on hands, foot and mouth, which are highly contagious COXSACKIE B: 1. Viral meningitis 2. Myocarditis/pericarditis: arrhythmia, cardiomyopathy, heart failure 3. Pleurodynia: fever and sharp, pleuritic chest pain ECHOvirus: 1. "Cold", rashes, viral meningitis 2. Pericarditis Enteroviruses: 1. Respiratory infections (often severe with enterovirus D68) 2. "Polio-like" acute flaccid paralysis (associated with E71 and possibly D68) RHINOVIRUS - Common cold • Treatment: - vaccine ``` • Miscellaneous: 1. Transmission: A. Fecal-oral B. Respiratory secretions 2. The chance of developing paralytic poliomyelitis increases as one gets older ``` - Note: The PICORNA viruses are the smallest RNA viruses
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CALCIviridae?? * Genus/Species * Morphology? * Clinical Findings? * Miscellaneous?
• Genus/Species: - Norwalk virus and other related Caliciviruses • Morphology: 1. Positive (+) single-stranded RNA 2. Naked icosahedral symmetry 3. Replication occurs in the cytoplasm 4. Fecal-oral transmission ``` • Clinical Findings: - VIRAL GASTROENTERITIS: (explosive, but self-limited): A. Fever B. Abdominal pain C. Vomiting D. Diarrhea (no blood, no pus) ``` • Miscellaneous: 1. Infants die secondary to loss of fluids and electrolytes 2. Note: Hep E is probably a species of Caliciviruses
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REOviridae * Genus/Species * Morphology? * Clinical Findings? * Miscellaneous?
• Genus/Species: - Rota virus • Morphology: 1. Double stranded RNA 2. Segmented (11 segments) 3. Naked icosahedral symmetry 4. Fecal-oral transmission • Clinical Findings: - VIRAL GASTROENTERITIS: causes profound dehydration, especially in infants. Fever, abdominal pain, vomiting and diarrhea - No blood, No pus in diarrhea - This is a major cause of infant death in underdeveloped countries and the MOST COMMON CAUSE of diarrhea in infants less than 3 years of age • Miscellaneous: - Responsible for almost 50% of infant diarrhea cases that require hospitalization in the U.S.
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CORONAviridae: * Morphology? * Clinical Findings? * Treatment? * Miscellaneous?
• Morphology: 1. Positive (+) single-stranded RNA 2. Nonsegmented 3. Helical symmetry 4. Enveloped 5. Replication in the cytoplasm • Clinical Findings: - Upper respiratory tract infection ("common cold")
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RHABDOviridae: * Genus/Species * Morphology? * Clinical Findings? * Miscellaneous?
• Genus/Species: - Rabies virus • Morphology: 1. Bullet shaped 2. Negative (-) single-stranded RNA 3. Nonsegmented 4. Helical nucleocapsid is coiled into a bullet shape 5. Replication in the cytoplasm 6. Zoonotic (all warm blooded animals): dogs, cats, skunks, coyotes, foxes, raccoons, and bats are reservoirs in the U.S. 7. Transmitted via an animal bite • Clinical Findings: RABIES - Incubation can be from 2 weeks to a year 1. Prodrome: fever, headache, sore throat and very sensitive nerves around the healed wound site 2. Acute encephalitis: hyperactivity and agitation leading to confusion and seizures 3. Classic brain stem encephalitis: A. Cranial nerve dysfunction B. Painful contraction of pharyngeal muscles when swallowing liquids, resulting in hydrophobia and "foaming of the mouth" 4. Death: due to respiratory center dysfunction • Miscellaneous: 1. Diagnosis: Microscopic examination of the CNS reveals Negri bodies. These are collections of virions in the cytoplasm where replication occurs 2. Note: Spread of this virus through the peripheral nerves to the CNS is very slow 3. This is one of the only diseases where you can get vaccinated AFTER exposure
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Filoviridae: * Genus/Species * Morphology? * Clinical Findings? * Treatment? * Miscellaneous?
• Genus/Species: 1. Marburg virus 2. Ebola virus • Morphology: 1. Negative (-) single-stranded RNA 2. Nonsegmented 3. Helical symmetry 4. Enveloped 5. Replication in the cytoplasm 6. Humans and monkeys in Sub-Saharan Africa are infected in rare epidemics 7. Unknown reservoir • Clinical Findings: - Acute Viral hemorrhagic fever: high mortality rate (50-90%) 1. Transmission secondary to contact with infected body fluids: contaminated medical instruments, and close contact with sick or dead patients and their body fluids. Most likely mechanism is via skin or mucous membrane contact with virus-infected body fluids (blood, vomit, diarrhea, semen). Rare airborne transmission cannot be ruled out. 2. A 2 to 21 day incubation period followed by ABRUPT onset of fever, headache, and myalgia, abdominal pain, diarrhea, pharyngitis, hiccups, cough, and somnolence may develop. Progression to bleeding from needle stick sites and all mucous membranes follows. Death results from multi-organ failure. • Miscellaneous: - Diagnosis: PCR, ELISA
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Arenaviridae: * Genus/Species * Morphology? * Clinical Findings? * Treatment? * Miscellaneous?
• Genus/Species: 1. Lymphocytic choriomeningitis virus (LCM) 2. Lassa virus 3. South American hemorrhagic fever viruses • Morphology: 1. Negative (-) single-stranded RNA 2. Segmented (2 segments) 3. Helical symmetry 4. Enveloped 5. Replication in the cytoplasm 6. Zoonotic: responsible for asymptomatic infections in rodents 7. Spread of infection: Contact with rodent urine • Clinical Findings: 1. Lymphocytic choriomeningitis: Influenza-like illness, sometimes associated with a viral meningitis. Occasionally fatal. 2. Lassa fever: fever, sore throat, abdominal pain, with intractable vomiting and hypotension. Fatal in up to half of cases 3. Gradual onset of fever, myalgias, nausea, abdominal pain, conjunctivitis, sometimes generalized lymphadenopathy. Later, bleeding/petechiae. Sometimes tremor, seizures, diarrhea • Miscellaneous: - Diagnosis: by examining the blood for a rise in titer of virus-specific antibodies.

MOD Exam 3 (6 decks)

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