West Nile virus cases double

The number of West Nile virus cases in Iowa has doubled from nine on Aug. 21 to 18 as of Aug. 30. Sixteen others are under investigation. There have been two deaths attributed to West Nile virus this season.

The State Hygienic Laboratory tests for the virus and confirms other tests performed by local laboratories.

The peak season for the virus in Iowa is August through mid-September. West Nile virus has been in the United States since 1999, and in Iowa since 2002. Mosquitos that bite infected birds may transmit virus to people, horses and other mammals.

About 80 percent of people with the virus develop no symptoms. The other 20 percent may have a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea or rash. Most people recover completely from West Nile virus, but may suffer fatigue and weakness for weeks or months.

About one in 150 people infected develop a severe illness such as encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes that surround the brain and spinal cord). People 60 years and older, and those with certain medical conditions are most at risk.

“West Nile virus is in Iowa,” said IDPH Deputy Epidemiologist Ann Garvey. “This death related to West Nile is tragic, and reminds us to protect ourselves and our families from mosquitoes. Until the state's first hard frost, whether it's for work or play, being outside means there's a risk for West Nile virus."

Take the following steps to reduce the risk of exposure to West Nile virus:

Use insect repellent with DEET, Picaridin, oil of lemon eucalyptus or IR3535. Always read the repellent label and consult a health care provider if you have questions when using these types of products for children. Oil of lemon eucalyptus should not be used on children younger than 3 years, and DEET should not be used on children younger than 2 months old.
Avoid outdoor activities at dusk and dawn when mosquitoes are most active.
Wear long-sleeved shirts, pants, shoes and socks outdoors whenever possible.
Eliminate standing water where mosquitoes often lay eggs. Empty water from buckets, cans, pool covers and pet water dishes. Change water in bird baths every three to four days.

Because the virus is seasonal, health care providers are asked to consider its possibility in patients that present with clinical symptoms during the current transmission season. West Nile virus is a reportable illness in Iowa.

If patients test positive for IgM antibody to West Nile virus in serum collected within 8 to 14 days of illness onset or cerebrospinal fluid (CSF) collected within eight days of illness onset using an enzyme immunosorbent assay, laboratories are asked to send the specimen to the State Hygienic Laboratory for confirmation.

In 2017, 12 Iowans were diagnosed with WNV and of those two died. More information about mosquito and tick illnesses transmitted in Iowa is available on the IDPH website.