West Nile Virus - 1
Nursing CE
Author: Kristi Hudson RN MSN CCRN
Written: July 10, 2005
Updated: September 28, 2009
Course
Objectives Upon
completion of this course the student will be able to:
Describe the history of West
Nile Virus
Discuss the 2005 prevalence
of West Nile Virus in the United States
List 3 risk factors for
being infected with West Nile Virus
State 3 prevention
techniques to avoid being infected with West Nile Virus
Describe 3 symptoms of a
mild case of West Nile Virus
Describe 3 symptoms of a
severe case of West Nile Virus
Explain treatment options
for patient with West Nile Virus
Discuss the care and
management of a patient with viral encephalitis that is caused by West
Nile Virus
The
History of West Nile Virus:
West Nile Virus was first
discovered in 1937 in the West Nile District of Uganda. It was in
August of 1999 when the West Nile Virus was first reported in the
United States (New York City).
In 1999 great concern over
this new virus came about when there were reports of 62 confirmed cases
of West Nile Virus in New York City. Seven of the 62 patients
hospitalized in the 1999 New York City outbreak died (about 12%), with
virtually all deaths among encephalitis patients.
The most common causes of
death were neuronal dysfunction, respiratory failure, and cerebral
edema. Case-fatality rates among hospitalized patients have ranged from
4% in Romania (1996) to 12% in New York (1999) and as high as 14% in an
outbreak in Israel (2000).
However, among hospitalized
patients more than 70 years of age, the case-fatality rate ranges from
15% to 29%. Since the initial 1999 New York City outbreak, the cases of
West Nile Virus have been relatively limited. In 2002, there were a
total of 480 reported cases in humans and 24 deaths (as of August 28,
2002).
In 2005, the virus was found
in mosquito pools and in birds (Nevada), which produced an increase in
“non-traveling” people who were
contracting the virus.
By 2006, the
number of reported deaths to the CDC totaled 800 people in the United
States alone.
In 2009, with such strong
campaigns as the CDC’s “fight the bite”;
reported cases of West Nile Virus are thought to be on the decline.
Using New York State as an example, in 2005 there were 7 deaths and 55
people hospitalized with the virus.
The summer of 2009 has New
York reporting zero hospitalized infections or deaths due to West Nile
Virus.
What
is West Nile Virus? The
microbe that causes the infection belongs to a group of disease-causing
viruses known as flaviviruses. These viruses are usually spread by
ticks or mosquitoes. Other well-known diseases caused by flaviviruses
include yellow fever, Japanese encephalitis, dengue, and Saint Louis
encephalitis. How
is West Nile Virus Transmitted? West
Nile virus is spread to humans by the bite of an infected mosquito. A
mosquito becomes infected by biting a bird which carries the virus.
West Nile Virus is not contagious and cannot be spread by human touch. Risk
Factors: People
over the age of 50 Being
outdoor during mosquito season/frequent travel abroad Prevention: When
dealing with West Nile virus, prevention is your best bet. Fighting
mosquito bites reduces your risk of getting this disease, along with
others that mosquitoes can carry. Specific prevention methods are as
follows:
Proper Clothing - When
possible, wear long-sleeves, long pants and socks when outdoors.
Mosquitoes may bite through thin clothing.
Mosquito Sprays - Spraying
clothes with repellent containing permethrin or DEET
(N,N-diethyl-meta-toluamide), will give extra protection. Don't apply
repellents containing permethrin directly to skin. The CDC also
recommends the use of Picaridin (KBR 3023).
Be Aware of Mosquito Peak
Hours - The hours from dusk to dawn are peak mosquito biting times for
many species of mosquitoes. Take extra care to use repellent and
protective clothing during evening and early morning -- or consider
avoiding outdoor activities during these times.
Drain Standing Water
– Mosquitos lay their eggs in standing water, so limit the
number of places around the home for mosquitos to breed.
Install Repair Screens -
Some mosquitoes like to come indoors to get away from the heat. Keep
them outside by having well-fitting screens on both windows and doors.
Report Dead Birds
– Dead birds may be a sign that West Nile Virus is
circulating between birds and mosquitos. Over 130 species of birds are
known to have been infected with West Nile Virus.
Mosquito Control Programs
– Check local health authorities to see if there is organized
mosquito control programs in your area. If not, work with local
government officials to establish such a program.
Avoid Crowds -
Especially when in mass gatherings (crowds) where the CO2 given off by
the crowd attracts more mosquitoes from a greater distance
Signs
and Symptoms of West Nile Virus: Most
people who are infected with West Nile virus either have no symptoms.
If infection does occur; it usually takes 3 to 14 days before a person
becomes ill. If symptoms are present they usually last 3-6 days and
include the following:
Fever
Headache
Body ache
Mild rash
Swollen lymph glands
In
some cases (particularly with the elderly), West Nile Virus can cause
serious illness by affecting brain tissue (encephalitis). This can and
has led to permanent neurological damage and also can lead to death.
Symptoms of viral encephalitis occur in about 1 out of 150 people who
are diagnosed with West Nile Virus and include:
Rapid onset of severe
headache
High fever
Stiff neck
Confusion
Loss of consciousness
Muscle weakness
Ataxia and extra-pyramidal
signs
Optic neuritis
Cranial nerve abnormalities
Polyadiculitis
Seizures
Diagnostic (test) for West
Nile Virus:
Medical history/Symptoms
Risk assessment (exposure to
mosquitos/recent travel)
Blood test for confirmation
(virus can also be found in tissue and CSF)
Treatment: If
asymptomatic there is no need for treatment. Mild West Nile Virus will
present as flu-like symptoms and should be treated as if one has the
flu. Hospitalization is required for those patients who show signs of
meningitis or encephalitis. Unfortunately, there is no West Nile Virus
specific treatment. Treatment plans would be based on the degree of
Neurologic deficit. Care and management of the patient with viral
encephalitis caused by West Nile Virus includes:
Acyclovir - inhibits viral
DNA replication and is often used for patients with viral encephalitis.
Acyclovir is cleared through the kidney, so patients with renal
insufficiency require dosing adjustments.
Anticonvulsant medications
– used for seizure activity
Monitor I & O
carefully as patients with viral encephalitis are at risk for cerebral
edema and Syndrome of inappropriate anti-diuretic hormone secretion
(use hypertonic IV solution if necessary)
Frequent neuro assessments
with emphasis on LOC and cranial nerve abnormalities
Monitor vital signs
Monitor respiratory status
(mechanical ventilation often required for these patients)
If intubated, respiratory
toilet
Monitor serum and urine
electrolytes
Provide nasogastric feeding
for nutrition
DVT prophylaxis
Skin ulcer prevention
Prevention of secondary
infection
Isolation is NOT a
requirement for viral encephalitis causes by West Nile Virus
Nursing
Diagnosis (NANDA):
Alteration in tissue
perfusion; cerebral
Ineffective Airway
Alteration in comfort; pain
Potential for Injury Risk
Potential for Skin Integrity
Risk
Potential Alteration in
Nutrition
Ineffective Family Coping
Knowledge Deficit
Potential for infection
(secondary)
References
Centers
for Disease Control. (2009). West nile virus: Fight the bite. Retrieved
on September 7, 2009 at:
Association
of Professionals in Infection Control and Epidemiology. (2005). West
Nile Virus. Retrieved July 10, 2005 from:
http://www.apic.org/Content/NavigationMenu/PracticeGuidance/Topics/WestNileVirus/West_Nile_Virus.htm Bring
Health.com (2005). West Nile Virus; Spread of mosquito-borne illness.
Retrieved July 10, 2005 from:
http://bringhealth.com/west_nile_virus.html Center
for Disease Control. (2005). West Nile Virus fact sheet. Retrieved July
10, 2005 from:
http://www.cdc.gov/ Donson,
David. (2005). West Nile Virus. Retrieved on July, 10, 2005 from
www.emedicinehealth.com/index.asp McKendall,
R., R. MD. (2004). Best practice of medicine. Retrieved July 11, 2005
from:
http://merck.micromedex.com/index.asp?page=bpm_report&article_id=BPM01ID01§ion=report&ss=3 University
of Maryland. (2005). Viral Encephalitis. Retrieved July 11, 2005 from:
http://www.umm.edu/altmed/ConsConditions/EncephalitisViralcc.html United
States Department of Health and Human Services. Division of
Vector-Borne Infectious Disease. (2005). West Nile Virus. Retrieved on
July 10, 2005 from
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