Published Date: 2002-09-13 23:50:00
Subject: PRO/AH/EDR> West Nile virus, human -USA (CA) (05): final confirmation
Archive Number: 20020913.5295
WEST NILE VIRUS, HUMAN - USA (CA) (05): FINAL CONFIRMATION
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Fri 13 Sep 2002
From: ProMED-mail <email@example.com>
Source: California State Department of Health [Fri 12 Sep 2002] [edited]
STATE HEALTH DIRECTOR ANNOUNCES CONFIRMED CASE OF WEST NILE VIRUS
SACRAMENTO--Laboratory test results have confirmed that a Los Angeles
County woman was infected with the West Nile virus, State Health Director
Diana M. Bontá, R.N., Dr.P.H., announced today. The woman, whose infection
with the virus was initially described as "probable," is the first reported
case of West Nile virus acquired in California. The results of the
confirmatory laboratory tests conducted at the University of California at
Davis were reviewed by the federal Centers for Disease Control and
Prevention, which is confident that the test results are valid. These tests
ruled out the possibility of infection by closely related viruses, such as
St. Louis encephalitis.
"Typically, an individual is exposed to West Nile virus through the bite of
an infected mosquito," Bontá said. "It is likely that this individual
acquired the virus in the same manner. However, our investigation
continues. "The woman became ill on Aug. 10 and was hospitalized on Aug.
12. She was diagnosed with aseptic meningitis and has fully recovered.
Although she reports no mosquito bites, blood transfusions or organ
transplants, or travel to areas where West Nile virus has been detected,
laboratory tests confirm that she has been exposed to West Nile virus. "The
test results were unequivocal," Bontá said.
With the arrival of West Nile virus in California, mosquito surveillance
and control efforts are being increased. Public health officials throughout
the state are intensifying surveillance for the virus in humans, horses and
West Nile virus, which can cause encephalitis, was first detected in the
United States in New York in 1999 and has been found in 43 states and the
District of Columbia. Most individuals who are infected with West Nile
virus have only mild symptoms such as fever, headache and body aches.
However, the virus can cause severe symptoms in the elderly and individuals
with lowered immune systems.
Bontá emphasized that the risk of any individual becoming ill from the bite
of a mosquito infected with West Nile virus is very low. Less than 1
percent of the bites from infected mosquitoes can cause severe disease. The
risk of disease is higher for individuals 50 years of age and
older.Individuals can reduce their risk of mosquito-borne diseases by
taking these precautions:
Avoid activity outside when mosquitoes are most active, especially at dawn
and dusk. When outdoors, wear long pants, long sleeve shirts and other
protective clothing. Apply insect repellant according to label
instructions. Make sure that doors and windows have tight fitting screens.
Repair or replace screens that have tears or holes. Eliminate all sources
of standing water that can support mosquito breeding. Contact your local
mosquito and vector control agency if there is a significant mosquito
problem where you live or work. Many species of birds get infected and die
from West Nile virus. Bontá asked the public to become part of the
California Department of Health Services' (CDHS) extensive monitoring
effort for the virus by reporting any crows, ravens, magpies and jays that
have been dead for less than 24 hours.
CDHS has established a toll-free line - 877-WNV-BIRD - for public reporting.
Additional information about West Nile virus in California can be found at
http://www.dhs.ca.gov. or by calling the CDHS West Nile virus information
line - 866-847-2246.
[Mod.MHJ reports that an LA county resident says the county is relatively
mosquito-free, & suggests container-borne mosquitoes as the source of this
case's infection in his comment on ProMED post "West Nile Virus, birds,
migratory - USA: RFI" 20020912.5290. Containers brought dengue mosquitoes
from East Timor to Australia during a dengue outbreak in 2000 -- see "Aedes
mosquitoes imported - Australia (NT) (03)" 20000320.0390. - Mod.JW]