4.3 Encephalitis (West Nile Disease) Flashcards
How is west nile spread to people
mosquito bites from infected mosquito to person
How do mosquitos become infected with West Nile
feeding on blood of infected bird
notably ravens, crows, magpies, and jays
Is bird to human transmission of west nile common?
not believed to occur
unless dead infected birds are handled without precautions.
How long do symptoms of west nile develop after exposure
2-14 days
What population is more commonly affected by west nile
children 10 and up
Neuroinvasive disease affects less than 1% of cases, and mostly older adults, but can be severe and has a mortality rate of approximately 10%
Does everyone with west nile exhibit signs
no- only about 20% of patients infected show any signs
What are the typical symptoms of west nile
nonspecific - fever, headache, muscle aches, rash, lymphadenopathy, weakness, anorexia, n/d/v, abdo pain
What symptoms may a child with a severe west nile infection exhibit
high fever
headacahe
stiff neck
vision loss
stupor
coma
tremor/convulsions
numbness
paralysis
west nile can be neuroinvasive
Encephalitis (brain inflammation) secondary to west nile is becoming ___
increasing common in Canada
If a women contracts west nile while pregnant does the infant typically show signs of west nile
no
but monitor carefully for congenital anomalies etc.
How do you test for west nile
serum
can do CSF as well
best to do by day 7-9 of infection as most likely to be positive
Collect serial titers 2 to 3 weeks apart to compare acute and convalescent samples.
Confirm positive tests by other specific WNV tests; if tested early in the disease the virus’s RNA may be detectable in the serum.
MRI or CT scan (or both) are indicated if the individual has neurologic findings.
What is the treatment for mild west nile
supportive care
rest, ever control, hydration, n/v
Who needs to be hospitalized with west nile
those with neurological symptoms
such as those from meningitis, encephalitis, severe muscle weakness, paralysis, dysphagia, or dysarthria.
FYI
Patient and Family Education. To prevent disease, avoid mos-
quito bites. Institute mosquito community abatement programs
to reduce mosquito breeding grounds. Counseling includes:
* Stay indoors during the mosquitoes’ most active times—dawn
and dusk; if you must be outdoors during these times, wear
light-colored, long-sleeved shirts and long pants.
- Apply insect repellent with either N,N-diethyl-3-methylbenza-
mide (DEET), picaridin 5% to 10%, oil of lemon eucalyptus,
or soybean oil to exposed skin (permethrin and DEET can be
applied to clothing). DEET concentration depends on time
length of expected mosquito or tick exposure: 10% DEET
confers approximately 2 hours of protection; 30% about 5
hours. Children over 6 months old may use a concentration of
no more than 30% DEET. Apply according to length of pro-
tection needed. Use sparingly and wash DEET off with soap
and water when the child is inside (AAP, 2018b).
* Do not use DEET on skin or clothing of children younger than
2 months old. Do not apply to face, hands, or open wounds/
cuts (AAP, 2018b).
* Do not use combination sunscreen and DEET products
because sunscreen needs to be reapplied more frequently; the
DEET component applied too frequently can be toxic.
* Inventory outdoor areas for standing water mosquito breeding
areas (e.g., old tires, pots or containers, birdbath [change once
a week], neglected swimming pools, pool or spa covers). Keep
pools and spas clean and chlorinated.
