Arboviruses

Question 1

What are arboviruses?

Answer 1

Arthropod borne viruses

Question 2

What is a characteristic of all of the viral hemorrhagic fever viruses?

Answer 2

They are RNA viruses

Question 3

What are the four clinical syndromes of arboviruses?

Answer 3

• Systemic Febrile Illness
• Fever with Arthritis
• Encephalitis
• Hemorrhagic Fever

Question 4

What virus is commonly associated with fever and arthritis?

Answer 4

Chikungunya virus

Question 5

On CSF, what are the findings in a person with Eastern Equine Encephalitis?

Answer 5

Primarily lymphoctyes

Question 6

With a DDx of WNV or EEE, what type of information on the history would suggest EEE Dx?

Answer 6

Living near a swap (Cicero)

Question 7

What is the general life/transmission cycle of EEE?

Answer 7

Normally b/w mosquito and bird with horses and humans being dead-end hosts

Question 8

Characteristics of EEE?

Answer 8

• Togaviridae family
• Genus: alphavirus
• (+) ssRNA

Question 9

What 4 bugs are in the alphavirus genus?

Answer 9

• EEE
• WEE
• Venezualen EE
• Everglades

Question 10

Syx of the alphaviridae?

Answer 10

Range from inapparent to influenza like illness to syndrome of encephalitis

Question 11

What would be a clue on the history that suggests Japanese encephalitis?

Answer 11

Travel to endemic area (Thailand)

Question 12

Japanese encephalitis virus characterisitics

Answer 12

• Family: Flaviviridiae
• (+) ssRNA
• single serotype
• 5 genotypes

Question 13

Characteristics of JEV vector?

Answer 13

• Night feeder
• Hangs out in rice fields/marshes
• Highest activity in rainy season
• Year round transmission can occur especially near rice fields

Question 14

Life/transmission cycle of JEV?

Answer 14

B/w mosquito and birds/pigs with humans/horses as dead end hosts

Question 15

What is the spectrum of JEV infection?

Answer 15

• Febrile headache -> aseptic meningitis -> encephalitis

Question 16

What is our best weapon against JEV?

Answer 16

Two vaccines!

Question 17

What are some adverse rxns to the yellow fever vaccine?

Answer 17

• Immediate hypersensitibity or anaphylactic rxn
• YF vaccine-associated neurologic disease
• YF vaccine-associated viscerotropic disease

Question 18

What is the clinical course of YF AVD?

Answer 18

Febrile illness for 3-5 days after vaccination followed by organ failure

Question 19

Characterisitcs of YF?

Answer 19

Family: Flaviviridiae

Genus: Flavivirus

Question 20

What is the geographic distribution of YF?

Answer 20

Northern South America, Subsaharan Africa

Question 21

Typical life/transmission cycle of yellow fever?

Answer 21

Typically Mosquito and primate but transfer occurs to humans where life cycle can occur as well

Question 22

Describe the acute phase of yellow fever

Answer 22

• Incubation - 3-6 days
• Mild, nonspecific, febrile illness
• Bradycardia despite a rising temperature (Faget sign)

Question 23

Describe the hemorrhagic phase of the of yellow fever

Answer 23

• Coffee-ground hematemesis, melena, metorrhagia, petechiae
• Volume depeletion secondary to vomiting/plasma leakage
• Renal failure

Question 24

Describe the convalescent phase of YF

Answer 24

• Profound weakness
• Late death (rare)
• Elevations of serum transaminase

Question 25

Syx of Dengue Fever?

Answer 25

• Maculopapular rash
• High crit (due to plasma loss)

Question 26

Characteristics of Dengue virus

Answer 26

• Family: Flaviviridae
• Genus: Flavivirus
• Four serotypes: Infection by 1 serotype does not result in resistance to others!

Question 27

Dengue lifecycle?

Answer 27

Aedes aegypti mosquito - Daytime feeder!

Question 28

Dengue clinical manifestations

Answer 28

• Fever 6-7 days
• Generalized macular rash followed by maculopapular rash
• Peripheral WBC count depression and throbocytopenia

Question 29

Describe the characteristics of secondary Dengue Fever

Answer 29

• Hemorrhagic manifestations - petechiae, peistaxis, intestinal bleeding
• myocarditis

Question 30

What is the hallmark of dengue hemorrhagic fever?

Answer 30

Plasma leakage

Question 31

What is the most common arbovirus causing human infection in the subtropical and tropical regions of the world?

Answer 31

Dengue