St. Joseph County Vector Program

In medicine, a vector is a carrier. The best way to understand a vector is to recall its origin as a word. Vector is the Latin word for a "bearer."  Therefore, a vector of disease is an insect or organism that does not cause disease itself, but is a carrier of disease and spreads infection by conveying pathogens such as a fungus, virus, bacterium, etc., from one host to another.

Mosquito borne diseases have been the most significant public health threats in recent years. The vector program’s primary focus is to inform the public and limit the interaction between the people of St. Joseph County and those mosquito populations that significantly threaten public health. This can best be accomplished through education, response to public concerns and monitoring virus patterns and disease occurrence. 

Mosquito-borne Diseases

The four mosquito-borne arboviruses of main concern in St. Joseph County and their most recent incidence in county residents are:

  • West Nile Virus – 3 cases in 2006 (there were no cases confirmed in 2007)
  • La Crosse Encephalitis – 1 case in 2002
  • St. Louis Encephalitis – 1 case in 1975
  • Eastern Equine Encephalomyelitis – 0 human cases, EEE has been detected in horses.

West Nile Virus (WNV), being the most prominent of these arboviruses in St. Joseph County and an emerging disease in the United States, has been monitored and studied for the past several years as the focal point of the program.  Compilation of the data has allowed us to identify trends and form strategies for future program needs.
REDUCE YOUR EXPOSURE TO MOSQUITOES

Larval Control

Mosquitoes that transmit WNV tend to breed in containers (gutters, buckets, and unused swimming pools), street catch basins, culverts and smaller stagnant natural habitats rather than larger or flowing water bodies. Due to this characteristic, mosquito larvae populations are considerably more isolated and accessible than adult mosquitoes that have taken flight and dispersed.  Therefore, source reduction (modification or elimination of the breeding site) is always the preferred method of control.  Where source reduction is not feasible, larviciding can be used because it attacks mosquitoes at the most vulnerable point in their life cycle (Purdue).

Larvicides containing a biological control agent such as Bti (Bacillus thuringiensis israelensis), a naturally occurring soil bacterium registered as a larvicide, are becoming widely available at hardware stores and home/garden centers for homeowner use. These products area available in donut-shaped briquettes called “dunks” which are convenient for treating small areas of standing water such as low spots in your yard or a culvert under your driveway.  Larvicides are also available in granular form for treating larger areas such as backyard ponds.  Always follow all label instructions carefully when using pesticides of any kind.

Personal protection from mosquitoes is your best defense against arboviruses.

  • Apply insect repellent containing DEET sparingly to exposed skin when you go outdoors. Even short trips outside can be long enough to get a mosquito bite. Picaridin and oil of lemon eucalyptus are alternative repellents for those who prefer not to use DEET. Additional information regarding insect repellents can be found on these CDC Web sites: Updated information regarding insect repellents or Repellent Q&A.
  • Clothing can help reduce mosquito bites.  When possible, wear long sleeves, long pants and socks when outdoors.  Mosquitoes may bite through light-weight or loose-weave fabrics, so spraying clothing with repellent can give extra protection.
  • The hours between dusk and dawn are peak biting time for many species of mosquitoes.  Be sure to use repellent and protective clothing during evening and early morning or consider avoiding outdoor activities during these times.

Protect your home from mosquitoes:

  • Maintain window screens in good repair.
  • Discard or empty and invert buckets, barrels or any other container that may hold water in your yard.
  • Clean and chlorinate swimming pools and hot tubs.
  • Eliminate trapped water in tarps and covers over boats and swimming pools.  It is best to dismantle swimming pools that will not be used as the water that collects on pool covers will support mosquito breeding.
  • Change water in bird baths and pet bowls regularly.
  • Make sure roof gutters are clean and draining properly.
  • Discard unused tires or store them inside.
  • Maintain an operating pump or stock top feeding fish such as bluegills or sunfish in ornamental ponds.

For more information about vector control visit the Indiana State Department of Health Web site.

Issues of Public Health Significance and Arthropod Nuisances:

Ticks
Bed Bugs
Dead Birds

Additional Links:

Purdue Extension information:  Entomology

EPA Citizen’s Guide to Pest Control and Pesticide Safety
National Pesticide Information Center:  1-800-858-7378  Web site:  http://npic.orst.edu/

 


  
 
       

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