Arboviral Disease Surveillance in Kansas


Arboviral diseases are those that are spread from arthropods, such as mosquitoes and ticks to humans. West Nile virus is the leading cause of arboviral disease in the United States and Kansas. Infection with West Nile virus ranges from febrile illness to neuroinvasive disease, such as meningitis or encephalitis, and can cause death. From 1999 – 2015 there were a total of 43,937 cases and 1,911 deaths in the United States from West Nile virus; 533 cases of WNV and 19 deaths have occurred in Kansas. There is no available vaccine to prevent human infection. Personal protection measures to reduce exposure to mosquito bites is the primary method of West Nile virus disease prevention. The Kansas Department of Health and Environment works with partners to estimate the risk of human disease to help guide prevention efforts for both communities and individuals.

West Nile Virus Risk Level and Surveillance Results

West Nile virus is the most common mosquito borne disease in Kansas and the United States. Several species of mosquitoes are responsible for transmission of arboviruses but Culex species are the primary vector for West Nile virus in Kansas and the United States. In 2017 the Kansas Department of Health and Environment, with funding from the Centers of Disease Control and Prevention, expanded the mosquito surveillance from 1 to 3 counties (Reno, Sedgwick, and Shawnee). In addition, we collect mosquito surveillance data from 4 additional partners throughout the state. We use this data to develop weekly risk levels from mid-May through mid-October, and they serve as a proxy for West Nile virus transmission risk for the entire state.

The risk of acquiring WNV infection depends on various factors including time of year, number and location of infected Culex species of mosquitoes, and the number of days with sufficient heat. The risk of WNV transmission is lower in the spring but rises through the early and midsummer months and usually reaches peak transmission during July, August, and September.

In 2017 WNV risk levels have been developed for Kansas based on the following criteria:

  • Presence of Culex spp. of mosquitoes
  • Human cases of WNV reported to KDHE
  • Increase in the number of Culex spp. mosquitoes
  • Historical data indicators for the weeks of increased WNV human cases.

Regardless of the West Nile virus risk level for your area, there is no such thing as being ‘risk-free’. Take precautions when you are out in areas where mosquitoes are present.

Kansas West Nile Virus (WNV) Weekly Surveillance and Transmission Risk Report

Week Ending August 18, 2017 (Week 13)

West Nile virus Transmission Risk Level* by Region

West Nile  virus Transmission Risk Level* by Region

Ket to West Nile Virus Risk Levels Mosquito Proof Your Home

Highlights this Week:

  • The West Nile virus risk level remained high for all regions this week.
  • No additional West Nile virus (WNV) positive mosquitoes were identified in Sedgwick, Reno, and Shawnee this week.
  • No additional human cases of WNV were identified this week.
  • Five WNV human case investigation are in progress.
  • No veterinary cases of WNV were identified this week.
 This Week’s West Nile Virus Risk Report

Zika Virus Surveillance

Zika virus disease is caused by the Zika virus, which is spread to people primarily through the bite of an infected Aedes species mosquito. The most common symptoms of Zika are fever, rash, joint pain, and conjunctivitis (red eyes). The illness is usually mild with symptoms lasting for several days to a week after being bitten by an infected mosquito. Zika virus infection during pregnancy can cause serious birth defects including microcephaly. Zika virus can also be spread through sexual contact. Learn more about Zika virus at http://www.cdc.gov/zika/index.html.

There has be no local transmission of Zika virus in Kansas.

The two mosquitoes that can spread Zika virus are Aedes albopictus and Aedes aegypti; both are non-native invasive mosquito species in Kansas.

Kansas Zika Cases by Region (all travel-associated)

Updated June 23, 2017

Northeast

17

Southeast

0

North Central

1

South Central

4

Northwest

0

Southwest

1

Total

23

Zika Virus Mosquito Survey

In 2016, the Kansas Biological Survey (KBS) conducted a survey to determine the range of Aedes aegypti and Aedes albopictus in Kansas. The maps below estimate the range of these mosquito species on the results of the survey.

Aedes aegypti

Aedes albopictus

Aedes aegypti

Aedes albopictus

The Aedes species mosquito distribution maps were created from data obtained during a point-in-time survey of the state in 2016 by Dr. Christopher Rogers with the Kansas Biological Survey in partnership with KDHE. These maps are approximations of the distribution of these mosquitoes and will change over time. These maps are not meant to represent risk for spread of disease.

Mosquito Bite Prevention

Avoid mosquito bites by following the three Ds:

  • DRAIN – eliminate standing water where mosquitoes live and breed
    • Empty standing water from tarps, old tires, buckets, and other places where rainwater collects. Use larvicide in low-lying areas where water cannot be removed.
    • Refresh water for bird baths, pet bowls, and wading pools at least every three days.
  • DRESS – cover your skin with clothing when outdoors
    • Wear protective clothing when practical (long sleeves and pants).
    • Limit outdoor activities when mosquitoes are most active.
  • DEET – use insect repellents that contact DEET or other EPA-approved repellents
    • When used as directed, EPA-registered insect repellents are proven safe and effective, even for pregnant and breastfeeding women.

For more information on arboviral disease surveillance in Kansas call the Kansas Department of Health and Environment’s Infectious Disease Epidemiology and Response section at (877) 427-7317 or email at kdhe.epihotline@ks.gov.

Reports:

Additional Resources:

Kansas Biological Survey –
               http://kbs.ku.edu/

Centers for Disease Control and Prevention –
               Arbonet Maps - http://www.cdc.gov/ncidod/dvbid/westnile/usgs_frame.html
               La Crosse encephalitis - http://www.cdc.gov/lac/
               St. Louis encephalitis - http://www.cdc.gov/sle/
               West Nile virus -http://www.cdc.gov/ncidod/dvbid/westnile/index.htm
               Zika virus - http://www.cdc.gov/zika/index.html

Kansas State University College of Veterinary Medicine –
               Information about West Nile virus in horses - https://www.vet.k-state.edu/vhc/services/equine/internal-medicine/west-nile.html

Kansas Department of Health and Environment –
               Information on number of cases of any reportable disease - http://www.kdheks.gov/epi/annual_summary.htm

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