July 19, 2006 - (STOCKTON) - San Joaquin County Public Health Services announced today that a female between the ages of 18-65 living in the southern area of San Joaquin County has tested positive for West Nile Virus (WNV).  The San Joaquin County Public Health Laboratory confirmed her as positive for WNV. She is reported as having West Nile Neuroinvasive Disease.  This is the first reported infection in a human in San Joaquin County in 2006.  “West Nile Virus is here to stay, and it is important that everyone take necessary precautions to avoid mosquito bites,” said Dr. Karen Furst, Health Officer of San Joaquin County.

About one in five patients infected with WNV will develop symptoms of headache, fever and fatigue. In some people the fatigue may last several weeks to months. About one in 150 people infected with WNV will develop severe illness with symptoms of neurological disease that can include any of the following: neck stiffness, confusion, coma, tremors, convulsions, muscle weakness, numbness, and/or paralysis.  Symptoms may last several weeks and neurological effects may be permanent.  The risk of severe disease is highest in people over 50 years old and those with other health problems effecting their immune systems.  People with diabetes are also at increased risk of severe disease from WNV.

WNV is transmitted to humans and animals through the bite of a mosquito.  Mosquitoes become infected with the virus when they bite infected birds.  Birds carry the disease from site to site.  San Joaquin County Mosquito & Vector Control District performs aggressive surveillance and control of local mosquito populations in response to increased detection of WNV.  Mosquito control activities include spraying aquatic sources where mosquitoes breed, spraying for adult mosquitoes, using mosquito-eating fish, providing public education and information, and legal enforcement where necessary.

Individuals can reduce their risk of mosquito-borne diseases by taking these precautions:

• Apply insect repellent containing the active ingredient DEET or Picaridin when outdoors, according to label instructions.
• Avoid spending time outside when mosquitoes are most active, at dawn and dusk, and especially for the first two hours after sunset.

• When outdoors, wear long pants, long-sleeved shirts and other protective clothing.
• Exclude mosquitoes from your home with tight fitting screens on doors and windows.
• Eliminate all sources of standing water on your property that can support mosquito breeding.
• Contact your veterinarian for information on vaccinating equine against WNV.
• Report dead birds to 1-877-WNV-BIRD (1-877-968-2473) or on line at www.westnile.ca.gov.
• Report significant mosquito infestations to San Joaquin County Mosquito & Vector Control District at 209-982-4675 or 1-800-300-4675.

In 2005, there were 36 human cases, 19 horse cases, 38 groups of mosquitoes, and six flocks of sentinel chickens that tested positive for WNV in San Joaquin County.

For more information about West Nile virus:

• San Joaquin County recorded information line:  (209) 469-8200
• San Joaquin County WNV website: www.sjgov.org/oes
• Statewide information can also be obtained from 1-877-WNV-BIRD (1-877-968-2473) or on line at www.westnile.ca.gov.

Return to Other Environmental Health News