West Nile virus

Question 1

What is the scientific name of this?
-Leading cause of domestically acquired arboviral disease
in the U.S.
-single-stranded RNA virus of the family Flaviviridae

Answer 1

West Nile virus

Question 2

Incubation Period for WNV

Answer 2

2-6 days
but can range 2-14 days

Question 3

How is WNV transmitted?

Answer 3

Primary the Culex mosquito
blood transfusion/organ donation
mother to child

Question 4

WNV - Overview
(1) Outbreaks tend to occur between ____ months.
(2) ______ & ______correlate with increased WNV
transmission & infection.
—(a) The warmer & hotter it is, the more mosquitos will breed.
(3) Person-to-Person transmission is usually related to ________________.
(4) Mosquitoes become infected when they feed on infected ___; then spread virus to humans & other animals during bloodmeals.
(5) Horses & humans are considered ______ hosts.

Answer 4

1) mid-July and early September
2) Elevated temperatures and rainfall
3) blood transfusion and organ transplantation
4) birds
5) ‘dead-end’

Question 5

What should be considered in any febrile patient or acute neurologic
illness with recent exposure to mosquitoes during the summer months in WNV endemic areas?

Answer 5

West Nile Virus…

Question 6

__% of human WNV infections are subclinical or asymptomatic.

Answer 6

70-80

Question 7

What issue
-Occurs between mid-July and early September with elevated temperatures & rainfall
An acute systemic febrile illness may be accompanied by:
1) Headache, weakness, myalgia, or arthralgia
2) Gastrointestinal symptoms
3) Transient maculopapular rash

Answer 7

WNV

Question 8

What issue?
Clinically indistinguishable from viral meningitis due to other etiologies & typically presents with fever, headache, and nuchal rigidity.

Answer 8

WNV Meningitis

Question 9

What issue?
A more severe clinical syndrome that usually manifests with fever and altered mental status, seizures, focal neurologic deficits, or movement disorders such as tremor or Parkinsonism.

Answer 9

WNV Encephalitis

Question 10

True/False
There is no specific treatment for WNV disease, and no antiviral
treatment is available.

Answer 10

True

Question 11

True/False
There is no specific treatment for WNV disease, and no antiviral
treatment is available.

Answer 11

True

Question 12

first line management protocol for WNV

Answer 12

Vigorous supportive measures

Question 13

When is MEDEVAC warranted for WNV

Answer 13

if there are signs of encephalitis, meningitis,
or paralysis.

Question 14

True/False
WNV is preventable by vaccines

Answer 14

False
No WNV vaccines are licensed for use in humans

Question 15

WNV – Lab Diagnosis
Diagnosis via identifying what

Answer 15

IgM in serum or CSF analysis

Question 16

True/False
CBC is a reliable indicator of WNV disease

Answer 16

False

Question 17

WNV – Lab Diagnosis
______ is used to detect WNV IgM antibody

Answer 17

ELISA

Question 18

Due to the absence of a vaccine, prevention of WNV disease depends on:

Answer 18

(a) Community-level mosquito control programs to reduce vector
densities.
(b) Personal protective measures to decrease exposure to infected
mosquitoes
(c) Screening of blood and organ donors

Question 19

Disposition
Non-neuroinvasive WNV:

Answer 19

Most patients with non-neuroinvasive WNV disease recover
completely; however, fatigue, malaise, and weakness can
linger for weeks or months.

Question 20

Disposition
Neuroinvasive WNV
(a) Patients who recover from WNV encephalitis or
poliomyelitis often have residual ____________.
(b) Among patients with neuroinvasive disease, the overall case
fatality ratio is approximately ___%.

Answer 20

a) residual neurologic deficits
b) 10