Parvo, Papilloma, Polyoma, Pox, Arena, Bunya, Calci, Corona, Filo, Flavi, Reo Viruses Flashcards
1
Q
Parvovirus:
- Morphology, Characteristics
- Pathogenesis
- Transmission
A
- Naked icosahedral. The only linear ssDNA virus (*smallest DNA virus). Only B19 strain is important (erythrovirus)
- Infects immature erythroid progenitor cells
- Spread by respiratory droplets or vertical
2
Q
Parvovirus:
- Diseases (4 are listed)
- Diagnosis and Treatment
A
- TORCH in trimester 1: anemia, CHF, hydrops fetalis, spontaneous abortion
- Children: “slapped cheek fever” aka Fifth disease, an erythema infectiosum. Low grade fever, butterfly-shaped raised rash on face, moves downwards.
- Adults: rash, arthralgia due to HS type III
- Sickle cell and other inherited hemolytic anemias have high risk of aplastic crisis
- Diagnosis based on serology or PCR, no treatment
3
Q
Papilloma viruses:
- Morphology, Characteristics
- Transmission
- Diagnosis
- Treatment
- Prevention
A
- dsDNA icosahedral capsid, non-enveloped. Part of Papova virus family with Polyoma
- Spread by direct contact, sex
- PCR detects genotype
- Wart removal, Cidofovir antiviral possibly
- Capsid vaccine for 6, 11, 16, 18 (Gardasil)
4
Q
Papilloma viruses:
- Important serotypes and their disease associations
- Important viral genes
A
- 1-4: cutaneous warts
- 6, 11: benign warts on genitals (condyloma accumulata) or in larynx.
- 16, 18, 31, 33: risk of squamous cell carcinomas especially in the cervix, but also other regions of male/female reproductive organs and oral cavity (worse if immunocompromised)
-Serotypes 16, 18, 31, 33 have E6 gene that blocks p53, and E7 gene that blocks retinoblastoma.
5
Q
Polyomaviruses:
- Morphology
- Transmission
- Diagnosis
- Treatment
A
- circular dsDNA, naked. Part of Papova virus family with Papillomaviruses
- Respiratory transmission
- Diagnosis: ELISA, PCR
- No treatment
6
Q
Polyomaviruses:
-Important types and their diseases
A
- JC (John Conningham) virus -> PML (progressive multifocal leukoencephalopathy). JC virus is common but only harmful for immunocompromised. Demyelinating by killing oligodendrocytes. Multifocal, progressive.
- BK virus -> renal disease, hemorrhagic cystitis.
7
Q
Poxviruses:
- 3 types to know
- Morphology
- Transmission
- Diagnosis
A
- Variola (smallpox), Vaccinia (vaccination smallpox), Cowpox (used in first vaccine)
- dsDNA, enveloped, “brick-shaped” or oval capsid, 2 lateral bodies, largest virus
- Respiratory droplets or contact with vesicle
- Diagnosis: vesicle identification. IF, ELISA, etc. See Guarnieri bodies found in cytoplasm (poxvirus is the only DNA virus to replicate in cytoplasm)
8
Q
Poxvirus:
- Clinical picture
- Vaccination/historical significance
A
- Smallpox/variola: flu-like illness followed by rash that begins around mouth and spreads everywhere within 24 hours, densely-packed on the limbs. Macule-papule-vesicle-pustules that are all the same stage - “synchronous” (as compared to chicken pox w/ different stages). 20-60% mortality in adults, 80% in children.
- Vaccine derived from Cowpox by Edward Jenner in 1796. Smallpox was eliminated by 1980, only exists in labs, potential for bioweapon. Used to be one of the worst infectious diseases; killed as many as 500 million people in the 20th century.
9
Q
Arenavirus:
- Morphology
- Transmission
- What are LCM and Lassa? (these are given in the topic)
A
- negative-sense ssRNA, enveloped, ambi-sense (encodes positively or negatively), helical capsid, grainy appearance on EM (arena = sand), 2-segments
- Rodents are hosts (“robivirus” = ROdent BOrne). Transmitted by bites or feces in food or inhaled
- LCM: Lymphocytic Choriomeningitis: aseptic meningoencephalitis.
- Lassa fever: hemorrhagic fever, high mortality. Appears similar to ebola, occurs in West Africa.
10
Q
Bunyavirus:
- Morphology
- Important viruses within the bunyavirus family + their diseases
- Diagnosis
A
-negative sense ssRNA, 3 circular segments, glycoprotein projection. Obtains envelope from host Golgi body
- Hantavirus: spread by rodent urine, causes pulmonary edema and pre-renal azotemia via capillary leakage, also causes hemorrhagic fever
- Other viruses spread via mosquitos or ticks (arboviruses = use arthropod vector), causing seizures and encephalitis
-Diagnosis: PCR or serology ELISA
11
Q
Calicivirus
- Morphology
- Medically important virus
- Transmission
- Disease
A
- linear pos-sense ssRNA, naked. ssRNA replicates in cytoplasm
- Norwalk virus / Norovirus: produces one long poly-protein that is cleaved by viral proteases to become active. A common cause of gastroenteritis.
- Reservoir is human GI, transmitted fecal-oral
-Causes viral gastroenteritis on cruise ships, in day-care centers, and at sea food buffets. Watery non-inflammatory diarrhea, nausea, vomiting. Self-limiting.
12
Q
Coronaviruses:
- Morphology
- Diseases associated with different coronaviruses
A
-Helical, pleomorphic, pos-sense ssRNA, enveloped
- Can cause respiratory or enteric infection
- Common cold (2nd most common cause)
- SARS (severe acute respiratory syndrome) spread by SARS-CoV. Had a limited outbreak in early 2000s, mostly in China, not seen since 2004, ~10% mortality rate. Severe flu-like symptoms.
- MERS (Middle East Respiratory Syndrome (camel flu): present since 2012, mostly in Saudi Arabia.
-Diagnosis: PCR, serology for SARS 21 days after outbreak of disease
13
Q
Filoviruses:
- Morphology
- Transmission
- Important Diseases
A
- negative sense ssRNA, enveloped, helical, lasso-shaped
- Transmission: direct contact with reservoir animals or from secretions (blood, other bodily fluids) from infected human. Risk for healthcare workers.
- Viral Hemorrhagic Fever: includes both Ebolavirus and Marburg Virus. Fever, petechial rash, hemorrhagic shock, end organ failure.
- Marburg related to workers handling lab monkeys; was one limited outbreak in Germany/ Yugoslavia in 1960s.
- Ebolavirus probably has fruitbat or monkey reservoir. There were limited outbreaks until the large 2014 one. In 2016, a vaccine was found to probably be effective, but not certain yet. Seen in West / Central Africa.
14
Q
Flaviviruses:
- Morphology
- 2 diseases given in topic: Yellow Fever, Dengue
A
- pos-sense ssRNA, enveloped, generally arboviruses
- Yellow Fever: Aedes mosquito vector. Damages kidney/liver, causes jaundice, backache, bloody diarrhea, vomiting. Live attenuated vaccine. South America, Africa.
- Dengue: Aedes aegypti mosquito vector. Infects bone marrow. Flu-like symptoms, maculopapular rash, leukopenia. Rarely hemorrhagic fever due to thrombocytopenia. Renal failure. Asia.
15
Q
Reoviruses:
- Morphology
- Most clinically-important species (of the 4 ones that are listed in the topic) and its disease
- Diagnosis
- Treatment
- Prevention
A
- dsRNA (unique), replicates in cytoplasm, naked, icosahedral, 11 segments
- Rotavirus: #1 cause of severe infantile gastroenteritis with watery diarrhea. Fecal-oral transmission, can be nosocomial. NSP4 toxin-mediated (increase Cl- permeability). Lasts 3-8 days. Seasonal in winter. Kills many children in developing countries.
- Diagnosis with ELISA of stool, PCR, CF
- Self-limiting, give water/electrolyte replacement.
- Oral live attenuated vaccine
