Missouri Department of Health & Senior Services
September 16, 2004

Contact:
Dr. Howard Pue, DVM State Public Health Veterinarian or
Karen Yates DHSS Vector-Borne Disease Coordinator 573-751-6113

West Nile Virus-Related Death is Reported in Missouri

State public health officials confirmed today Missouri's first West Nile virus-related death this year. A 92-year-old woman from St. Louis County died September 7, 2004, according to State Public Health Veterinarian, Howard Pue, DVM. Diagnostic tests performed at the Missouri Department of Health and Senior Services (DHSS) State Public Health Laboratory indicate the woman was infected with West Nile virus (WNV). An investigation by
the St. Louis County Department of Health found that the woman had been hospitalized with symptoms consistent with West Nile viral encephalitis.

People can be infected with WNV through the bite of an infected mosquito. The U.S. Centers for Disease Control and Prevention (CDC) estimates that about 80% of WNV infections are asymptomatic (no symptoms). CDC says about 20% of infections lead to a flu-like West Nile fever and that severe West Nile disease, where the virus is found in the nervous system, occurs in less than 1% of infected people. As of Wednesday, September 15, 2004, the DHSS is reporting 17 human WNV cases, according to Pue.

"The risk of serious WNV illness to most people is low, but a death like this, of an elderly person, serves as a solemn reminder of the importance of avoiding mosquito bites," said Pue. "Serious complications from WNV
infection tend to occur in people over the age of 50. However, people of all ages can become ill, so it's important to remember that avoiding mosquito bites reduces your risk of getting this disease."

Missouri's state and local public health officials have urged Missouri residents to use insect repellants that contain DEET during the late summer and early fall season of peak virus transmission. According to Pue, products containing DEET are very safe when used according to the label directions. "Mosquitoes tend to be most active at dawn and dusk, and sometimes during midday, if the wind is still or the humidity high. Using an effective insect repellant, one that contains DEET, reduces the risk of being bitten," said Pue, "and allows people to carry out their outdoor activities with less fear of WNV infection."

"Up to this point, 2004 WNV activity in Missouri is very similar to what we saw in 2003," said Pue. "In spite of the cool weather this summer, the number of DHSS-verified cases is almost the same, 14 human cases in 2003 and 17 cases this year." A total of 64 human disease cases were identified in 2003, with eight WNV-related deaths.

"This time of year is the peak of mosquito breeding activity," said Karen Yates, Coordinator of the DHSS Vector Borne Disease Program. "Before a pregnant female mosquito can lay eggs," said Yates, "she must take a blood meal." Referring to human WNV disease case counts from 2002 and 2003, Yates says that human infections can continue to occur into the third week of October. "It's important for people to understand that it takes a
prolonged period of repeated hard freezes before these persistent pests give up for the season - not just a few frosty mornings."

To reduce the risk of being bitten by mosquitoes that carry WNV, the state public health department recommends the following protective measures:

• Apply a repellant with DEET on clothing and exposed skin when you go
  outdoors. After you return indoors, wash exposed skin with soap and
  water.
• Apply insect repellant when doing outdoor activities, especially around
  dawn and dusk, when mosquitoes are most active.
• Use just enough insect repellent to cover exposed skin - it is not
  necessary to use a heavy application. You can also apply it to clothing,
  such as shirtsleeves and trouser legs.
• Repair torn door and window screens to keep mosquitoes out.
• Seek out and eliminate places in your yard where mosquitoes can lay their
  eggs - look under shrubs and into tall flowerbeds for forgotten toys or
  containers that may hold water. Clean bird baths and pet dishes once a
  week.
• Remember that fall is a good time to check rain gutters so that water
  will not collect there.
• Call your local health department to find out what to do about reporting
  dead birds or standing water where mosquitoes breed.
  

DHSS lists all new human cases, as well as non-human indicators of WNV activity on its web site (www.dhss.mo.gov/WestNileVirus/index.html).

Human case data posted on the web site represent cases that are under investigation, and are therefore provisional and subject to change.

For more information on WNV, contact your local health department or the Department of Health and Senior Services at 1-866-628-9891 or 573-751-6113, or visit the DHSS web site at www.dhss.mo.gov/WestNileVirus/index.html

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