Arboviruses Flashcards
What are arboviruses?
Arthropod borne viruses
What is a characteristic of all of the viral hemorrhagic fever viruses?
They are RNA viruses
What are the four clinical syndromes of arboviruses?
- Systemic Febrile Illness
- Fever with Arthritis
- Encephalitis
- Hemorrhagic Fever
What virus is commonly associated with fever and arthritis?
Chikungunya virus
On CSF, what are the findings in a person with Eastern Equine Encephalitis?
Primarily lymphoctyes
With a DDx of WNV or EEE, what type of information on the history would suggest EEE Dx?
Living near a swap (Cicero)
What is the general life/transmission cycle of EEE?
Normally b/w mosquito and bird with horses and humans being dead-end hosts
Characteristics of EEE?
- Togaviridae family
- Genus: alphavirus
- (+) ssRNA
What 4 bugs are in the alphavirus genus?
- EEE
- WEE
- Venezualen EE
- Everglades
Syx of the alphaviridae?
Range from inapparent to influenza like illness to syndrome of encephalitis
What would be a clue on the history that suggests Japanese encephalitis?
Travel to endemic area (Thailand)
Japanese encephalitis virus characterisitics
- Family: Flaviviridiae
- (+) ssRNA
- single serotype
- 5 genotypes
Characteristics of JEV vector?
- Night feeder
- Hangs out in rice fields/marshes
- Highest activity in rainy season
- Year round transmission can occur especially near rice fields
Life/transmission cycle of JEV?
B/w mosquito and birds/pigs with humans/horses as dead end hosts
What is the spectrum of JEV infection?
- Febrile headache -> aseptic meningitis -> encephalitis
What is our best weapon against JEV?
Two vaccines!
What are some adverse rxns to the yellow fever vaccine?
- Immediate hypersensitibity or anaphylactic rxn
- YF vaccine-associated neurologic disease
- YF vaccine-associated viscerotropic disease
What is the clinical course of YF AVD?
Febrile illness for 3-5 days after vaccination followed by organ failure
Characterisitcs of YF?
Family: Flaviviridiae
Genus: Flavivirus
What is the geographic distribution of YF?
Northern South America, Subsaharan Africa
Typical life/transmission cycle of yellow fever?
Typically Mosquito and primate but transfer occurs to humans where life cycle can occur as well
Describe the acute phase of yellow fever
- Incubation - 3-6 days
- Mild, nonspecific, febrile illness
- Bradycardia despite a rising temperature (Faget sign)
Describe the hemorrhagic phase of the of yellow fever
- Coffee-ground hematemesis, melena, metorrhagia, petechiae
- Volume depeletion secondary to vomiting/plasma leakage
- Renal failure
Describe the convalescent phase of YF
- Profound weakness
- Late death (rare)
- Elevations of serum transaminase
Syx of Dengue Fever?
- Maculopapular rash
- High crit (due to plasma loss)
Characteristics of Dengue virus
- Family: Flaviviridae
- Genus: Flavivirus
- Four serotypes: Infection by 1 serotype does not result in resistance to others!
Dengue lifecycle?
Aedes aegypti mosquito - Daytime feeder!
Dengue clinical manifestations
- Fever 6-7 days
- Generalized macular rash followed by maculopapular rash
- Peripheral WBC count depression and throbocytopenia
Describe the characteristics of secondary Dengue Fever
- Hemorrhagic manifestations - petechiae, peistaxis, intestinal bleeding
- myocarditis
What is the hallmark of dengue hemorrhagic fever?
Plasma leakage
What is the most common arbovirus causing human infection in the subtropical and tropical regions of the world?
Dengue
