San Joaquin County Health Officer, Dr. Karen Furst, confirmed that a 65 year old male living in Stockton is the first human with West Nile Virus (WNV) infection in San Joaquin County this year. The man has been reported as an asymptomatic blood donor. Although for reporting purposes this does not meet the case definition for the California Department of Public Health to count as a case, it does indicate that there is currently active transmission of WNV to people in San Joaquin County. Last year, San Joaquin County’s first detection of WNV infection in a human was also diagnosed about the same time in July.
West Nile Virus is most commonly transmitted to humans and animals through the bite of a mosquito infected with the virus. Hot weather, abandoned swimming pools and standing water create ideal conditions for the development of mosquitoes and the subsequent spread of the virus. “It is very important that people take precautions to protect themselves and their families from mosquito bites,” advises Dr. Furst.
Most individuals who are infected with WNV will not experience any illness. About one in five people infected with WNV will develop West Nile Fever with symptoms of headache, fever and fatigue. However, some individuals -- less than 1 percent -- will develop serious neurologic illness such as encephalitis or meningitis.
Individuals 50 years of age and older have a higher chance of getting sick and are more likely to develop serious symptoms when infected with WNV. Recent data also indicate that those with diabetes and/or hypertension are at greatest risk for serious illness.
Dr. Furst recommends that individuals prevent exposure to mosquito bites and West Nile Virus by following the “Four Ds”:
- DEET – Apply insect repellent containing DEET, picaridin, oil of lemon eucalyptus or IR 3535 according to label instructions to keep mosquitoes from biting you. Apply repellents only to exposed skin and/or clothing. DEET can be used safely on infants and children 2 months of age and older
- DAWN AND DUSK – Mosquitoes that carry WNV tend to bite in the early morning and evening so it is important to wear repellent at this time. Make sure that your doors and windows have tight-fitting screens to keep out mosquitoes. Repair or replace screens with tears or holes.
- DRAIN – Mosquitoes lay their eggs on standing water. Eliminate all sources of standing water on your property, including flower pots, old car tires, rain gutters and pet bowls. If you have a pond, use mosquito fish or commercially available products to eliminate mosquito larvae. Neglected swimming pools are also prime habitat for mosquito development. The San Joaquin County Mosquito Vector Control District is available to help with neglected pools in the prevention of mosquito development. To request District service, call 209-982-4675, 1-800-300-4675 or visit the District website at www.sjmosquito.org .
Resources for Additional Information on West Nile Virus are:
• San Joaquin County Public Health Services website, www.sjcphs.org
• California Department of Public Health West Nile Virus website, www.westnile.ca.gov. This website includes the latest information on West Nile Virus activity in the state.
• Centers for Disease Control and Prevention, http://www.cdc.gov/westnile/index.html