October 13, 2004
Second and Third Human West Nile
Virus Infections Detected in San Joaquin County
(Stockton, CA ) — San Joaquin County Public Health Services announced today that a
74 year-old man and 73 year-old woman both living in the French Camp area of San Joaquin
County have tested positive for West Nile Virus (WNV). These are the second and third
documented WNV infections in humans in San Joaquin County. Both individuals live in the
95231 ZIP code area of San Joaquin County.
The infection was detected in the man when his physician tested him after he developed a
fever of over 104°F with shaking chills. The man was hospitalized for six days and he is at
home recovering. He has had no other symptoms and is feeling well at this time. The man does
not recall being bitten by a mosquito and he has not recently traveled outside of San Joaquin
The woman developed a fever to 102°F and was hospitalized for five days. She has
returned home and is feeling well at this time but continues to have some mild fevers. She does
not recall being bitten by a mosquito and has not traveled outside of San Joaquin County
The first case of WNV in a human in San Joaquin County was reported on September 27.
It was detected in a Manteca man who donated blood to a Sacramento blood bank. The man had
shown no symptoms of illness. There have been 732 human cases of West Nile Virus reported
in California as of Oct. 12, with 19 deaths.
This finding comes on the heels of the announcement of nine additional horses with West
Nile Virus in the county since September 29, bringing the total horse count to 11. WNV positive
horses have been located in Tracy, Manteca, Escalon, Linden, Lockeford, Lodi, Clements, Galt
and Acampo. Other significant WNV activity continues to be found in San Joaquin County,
with 41 dead birds, 2 mosquito pools (Farmington zip code 95325 and Manteca zip code 95337)
and one sentinel chicken flock (Roberts Island) testing positive to date.
WNV is transmitted to humans and animals through the bite of a mosquito. Mosquitoes
become infected with the virus when they feed on infected birds. Symptoms of West Nile Virus
West Nile Virus Task Force
The Task Force is established to ensure timely, accurate, and consistent information is presented to the
media for immediate dissemination to the citizens of San Joaquin county.
News Release, continued – Second & Third Human WNV Cases
may include fever, severe headache, skin rash, enlarged lymph nodes, neck stiffness, muscle
weakness and tremors, disorientation, convulsions and coma. Many people who are infected
with West Nile Virus have no symptoms. A small percent may develop severe infections (e.g.
viral meningitis or encephalitis), that can result in long term or permanent neurological effects
or, in rare cases, even death. The risk of severe disease is highest in people over 50 years old and
those with lowered immune systems.
Individuals can reduce their risk of mosquito-borne diseases by taking these precautions:
ßAvoid spending time outside when mosquitoes are most active, at dawn and dusk, and
especially for the first two hours after sunset.
ßWhen outdoors, wear long pants, long-sleeved shirts and other protective clothing.
ßApply insect repellent containing the active ingredient DEET when outdoors, according
to label instructions.
ßExclude mosquitoes from your home with tight fitting screens on doors and windows.
ßEliminate all sources of standing water on your property that can support mosquito
People can protect their horses by ensuring that their WNV vaccinations are up to date. Of
the horses that develop clinical illness, approximately 40 percent die or must be destroyed, and
another 17 percent have been shown to suffer from long-term debilitation. WNV testing in
horses does not rule out the possibility of rabies. To ensure human health, all horses that die
from WNV will be tested for rabies.Information on symptoms of WNV in horses can be found
on the website for the California Department of Food and Agriculture at
Report mosquito infestations to San Joaquin County Mosquito & Vector Control District at
209-982-4675 or 1-800-300-4675.
For more information on symptoms of WNV, consult with your health care provider, or go to
http://www.cdc.gov/ncidod/westnile/qa/symptoms.htm , the web site for the Centers for Disease
Evidence of West Nile Virus in California was first discovered in August of 2003 near the
Salton Sea in Southern California. Because of the rapid spread of this disease, which was first
discovered during 1999 in New York, San Joaquin County West Nile Virus Taskforce has been
preparing for this situation. The Taskforce consists of the San Joaquin County Mosquito &
Vector Control District, Public Health Services, Environmental Health Department,
Agricultural Commissioner, and Office of Emergency Services.
For information about West Nile Virus, visit the Web sites: www.sjgov/oes,
www.westnile.ca.gov or www.cdc.gov . For local recorded information call 209-469-8200.
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Connie Cassinetto,Information Officer,
San Joaquin County Public Health
pg: (209) 983-7314
Dale Bishop,M.D.Assistant Health Officer,
San Joaquin County Public Health