RNA Viruses Flashcards
Reoviruses
Rotavirus
Coltivirus
Rotavirus
non enveloped, icosahedral, dsRNA
primary cause of fatal diarrhea in children
infection –> severe D/V, dehydration, electrolyte abnormalities
Winter
Daycares, playgroups
Coltivirus
Colorado Tick fever
mountainous regions of Western US and Canada
Wood tick
acute, self limited, flu like illness
Picornaviruses
Poliovirus Echovirus Coxsackievirus Hepatitis A virus Rhinovirus
Enteroviruses
Poliovirus
Echovirus
Coxsackievirus
Poliovirus
anterior horn lesions
motor neurons of pons and medulla
SalK vaccine - injected Killed
Savin vaccine - oral, live
“saben alive”
Echovirus
infection –> aseptic meningitis, myocarditis, URIs
Summer out breaks
Dx: PCR of CSF
Coxsackievirus
aseptic meningitis
myocarditis and pericarditis
vesicular papular lesions of palms and soles
herpangina
hand, foot, mouth dz
febrile pharyngitis
Hepatitis A virus
fecal-oral transmission
Rhinovirus
“common cold”
Caliciviruses
Norovirus
Norovirus
viral gastroenteritis –> V/D
diarrheal outbreaks on cruise ships and nursing homes
point source outbreaks
fecal-oral route
Togaviruses
Rubella
Rubella
TORCH infection
“german measles”
- fever, LAD, arthralgia
- maculopapular rash
Pregnant contraction of virus –> congenital rubella syndrome
- cardiac defects: PDA, pulmonic stenosis
- cataracts
- deafness
Coronavirus
“common cold”
SARS
MERS
Retroviruses
enveloped RNA virus
HIV
Human T cell Leukemia Virus (HTLV)
use reverse transcriptase
Flaviviruses
Yellow Fever Dengue fever West Nile virus St. Louis Encephalitis Hep C virus
Yellow fever
50% fatal
Aedes mosquito
Subsaharan Africa, South America
high fever hemorrhagic dz: -hematemetis -epistaxis -gum bleeding -petechia -purpura -coffee ground emesis - black jaundice
Dengue fever
Most prevalent mosquito-borne viral dz worldwide
over 50M annual infections
severity mild to life-threatening
Classic dengue fever: “break bone fever” - muscle/joint pain, HA, retro-orbital pain
Hemorrhagic fever: developed by less than 20% of dengue pos - life threatening
Tourniquet test:
WHO field test for hemorrhagic fever
BP inflated to point between SBP and DBP for 5 min
If excess petechiae = increased capillary wall fragility and thrombocytopenia
West Nile virus (WNV)
Birds reservoir (amplifying host), mosquitos vectors - humans, horses, dogs incidental hosts
Usual sx: HA, malaise, back pain, myalgia, anorexia for 3-6 days
Severe sx in 1/150: meningitis +/- encephalitis including muscle weakness and flaccid paralysis (via anterior horn involvement), alterations in consciousness, possible death
Dx: serology for IgM anti-WNV Abs - serum or CSF
Tx: supportive
RNA virus encephalitis
Arboviruses - vector carried
St. Louis encephalitis virus
Eastern equine encephalitis virus
Western equine encephalitis virus
California encephalitis virus
Orthomyxovirus
enveloped, ssRNA
Hemagglutinin promotes viral attachment to host cell
Neuramindase helps release progeny virians
Influenza virus
Complications of influenza virus
viral pneumonia
secondary bacterial infections
-S. pneumo, S. aureus
–> death
Influenza virus vaccines
Trivalent vaccine: 2A, 1 B
Quadrivalent vaccine: 2A, 2B
Vaccine over 6 mo
Intranasal - live attenuated, 2-49 yo, healthy, nonpregnant
Avian influenza
H5N1 - 60% mortality
spreads only from bird to human, fears of human to human spread
Sx: URI, Diarrhea, fever, pancytopenia, elevated ALT, AST
Dx: reverse transcriptase PCR or viral cx
Tx: oseltamivir (tamiflu)
Swine flu
H1N1
Derived from 2 swine flu, 1 human, and 1 avian strain
Sx: typical flu + GI sx
Tx: oseltamivir or zanamivir to high risk or severely ill pts
Paramyxoviruses
parainfluenza virus respiratory syncytial virus rubeola virus mumps virus rabies virus
Parainfluenza virus
Croup
laryngotracheobronchitis
6 mo - 3 yrs - leading cause of hospitalization in children younger than 4 yrs
Sx: “barking seal” cough, respiratory distress - mimic asthma, inspiratory stridor
Clinical dx
CXR - “steeple sign” - subglottic narrowing
Tx: cool mist humidifier (no proven benefit), racemic epinephrine, one dose dexamethasone, supportive, O2 as needed
Respiratory syncytial virus (RSV) bronchiolitis
enveloped virus
F protein (fusion protein) -infected cells bind to uninfected cells –> syncitia of cells
Primary pneumonia in hospitalized kids
Bronchiolitis +/- pneumonia - young kids
Winter - same as flu season
Sx: characteristic brassy cough, wheezing, respiratory distress (mimic asthma)
Passive immunization w/ palivizumab (monoclonal RSV immunoglobin) monthly during winter months in premies or infants w/ chronic lung dz
Tx: supportive
Rubeola virus
Measles
Enveloped, highly contagious
head cold - coryza (runny nose), cough, conjunctivitis
Koplik’s spots - blue-grey speck surrounded by base of red on buccal mucosa
–> widespread maculopapular rash
begins on head, works way down body
Complications: Fetal loss premature delivery encephalitis - subacute sclerosis pan encephalitis (SSPE) -progressive --> death
Giant cell pneumonia - immunocompromised host
Mumps virus
enveloped
parotitis - 1 or both
orchitis –> sterility
meningitis
Rabies virus
enveloped RNA
infection after exposure to infected animal - bite
virus travels through peripheral nerves to CNS
negri bodies - eosinophilic cytoplasmic inclusions w/ viral nucleocapsids
Bullet shaped caspid “Old Yeller took a bullet”
Sx less than 1 mo up to 1 yr after exposure
-fever, malaise, N/V
-strange behavior, hallucinations
hydrophobia
coma –> death
Rabies vaccine post exposure tx
Hanta virus
hemorrhagic fever
pulmonary syndrome: fever, progressive pulmonary edema –> respiratory failure
aerosolized mouse urine - deer mouse
Ebola virus
Prevention key
Infected blood or fluids
contact and droplet isolation
10^9/mL fluid
2-21 days
sx 1-2 weeks
Fever, HA, myalgia
- -> V/D - fluid loss, electrolyte imbalances
- -> multi organ failure, shock, death
Tx: supportive
Marburg virus
hemorrhagic fever
