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Tick-Borne Illness

The Delaware Division of Public Health (DPH) reminds Delawareans that simple precautions reduce a person’s chances of getting tick-borne or mosquito-borne infections this summer.

Lyme disease is the most common disease spread by ticks in Delaware. Other tick-borne diseases such as Rocky Mountain Spotted Fever and Ehrlichiosis are diagnosed much less frequently in Delaware.

It takes 24-36 hours of attachment before a disease is transmitted from a tick to a person. Individuals who are infected with tick-borne diseases may be treated with antibiotics. Early diagnosis and intervention are key to appropriate treatment and improved health outcomes. People who have been bitten by a tick and do not have symptoms (detailed below) do not require treatment, but they should monitor their health closely and contact a physician if symptoms develop. Diagnosis of tick-borne diseases are all based on individual patient symptoms and can generally be confirmed with blood testing.

Lyme disease is transmitted to humans by the bite of infected deer ticks. Ticks are active all year, but most cases of Lyme disease occur during the spring and summer months when humans enjoy outdoor activities. In 2007, Delaware had 711 confirmed cases compared to 478 cases in 2006. Symptoms can include a "bull's-eye" rash (seen in approximately half of Lyme disease cases), fever, fatigue, headache, muscle and joint aches. Late manifestations including chronic joint, heart and neurological problems may occur.

Diseases from mosquitoes include West Nile Virus (WNV), Eastern Equine Encephalitis (EEE) and several other diseases that cause brain inflammation (encephalitis).

West Nile Virus is transmitted to humans by the bite of infected mosquitoes---primarily the common house mosquito. In 2003, there were 17 confirmed human cases of WNV, two of which were fatal. Additionally, there were 63 stricken horses in 2003. In 2004 and 2006, no cases of WNV were confirmed in humans or horses; in 2005 two human cases were confirmed, with no horse cases. During 2007, one human case was confirmed.

Delaware has not had a confirmed human case of EEE since 1979.

Since the virus is carried by birds, and is transmitted to humans through infected mosquitoes that have bitten infected birds, the risk of human infection appears present even though there are no reports of people contracting the infection. Approximately 80 percent of human infections are very mild and cause no outward symptoms. Nearly 20 percent of those infected develop a mild illness (West Nile fever), which includes fever, body and muscle aches, headache, nausea, vomiting, and rash. A very small percentage of patients, usually the elderly, develop severe neurological disease that results in meningitis or encephalitis.


DPH reminds residents to take the following protective measures to avoid tick and mosquito bites:

Tick Prevention

  • Wear light colored clothing to allow you to see ticks crawling on your clothing.
  • When possible, wear long sleeves and long pants. Tuck your pant legs into your socks.
  • Apply tick repellants. Repellents containing permethrin can be sprayed on boots and clothing and will last for several days. Repellents containing DEET can be applied to the skin but will last only a few hours before reapplication is necessary. Use insect repellent containing less than 50 percent DEET for adults. Use repellent containing less than 30 percent DEET on children. The American Academy of Pediatrics (AAP) Committee on Environmental Health updated their recommendation for use of DEET products on children in 2003, citing: "Insect repellents containing DEET (N,N-diethyl-m-toluamide, also known as N,N-diethyl-3-methylbenzamide) with a concentration of 10 percent appear to be as safe as products with a concentration of 30 percent when used according to the directions on the product labels." AAP recommends that repellents with DEET should not be used on infants less than 2 months old.
  • Upon return from outdoor activities in potentially tick-infested areas, search your body for ticks.
  • Check children for ticks, especially in the hair. Additionally, ticks may be carried into the household on clothing and pets.

Tick Removal

  • Use fine-tipped tweezers or shield your fingers with a tissue, paper towel or rubber gloves. Avoid removing ticks with bare hands whenever possible.
  • Grasp the tick close to the skin surface and pull upward with steady, even pressure.
  • Do not squeeze, crush, or puncture the body of the tick since its fluids (saliva, body fluids, gut contents) may contain infectious germs.
  • After removing the tick, cleanse the site with an antiseptic or soap and water, and wash your hands.
  • Delaware’s DPH does not recommend the use of home remedies such as petroleum jelly or hot matches for tick removal. These methods do not work.

Mosquito Prevention

  • Limit outdoor activities when mosquitoes are active, such as at dusk.
  • When working outside, wear protective clothing such as shoes, long-sleeved shirts, and pants.
  • Mosquito netting can also be used to protect one’s face and neck or used on infant carriages, strollers and playpens.
  • Apply mosquito repellent, as above, under tick prevention guidelines.

Mosquito-Proof Your Home, Help Your Community

  • Keep windows and doorways tightly sealed and maintain window and door screens to prevent mosquitoes from entering the house.
  • Electronic repellents that emit high frequency sounds do not repel mosquitoes, or other pests. Additionally, electronic bug zappers do not control mosquitoes or other flying pests. In fact, they work indiscriminately, killing many beneficial insects that prey on pests.
  • Eliminating or managing standing water around your house is the best method to prevent mosquitoes from breeding in your backyard:
  • Change birdbath water every week.
  • Regularly drain pet dishes and plant pot saucers.
  • Regularly clean and repair gutters to prevent them from retaining water.
  • Regularly check and drain plastic covers and tarps used outside such as pool covers, Jacuzzi covers, garbage can lids, compost covers and gardening tarps.
  • Store water-trapping containers such as wading pools, wheelbarrows and buckets upside down or inside shelters.
  • Manage habitats in and around water bodies such as ornamental and retention ponds, ditches and catch basins.
  • Manage weeds; keep vegetation short around water. Adult mosquitoes are attracted to dense, tall vegetation around water.
  • Remove unnecessary floating structures or debris from ponds. Mosquitoes are often found around floating debris.
  • Keep drains, ditches and culverts clean to allow proper drainage.
  • Consider stocking ornamental or permanent, self-contained ponds with insect-eating fish, such as goldfish.
  • Shape pond edges to a shelf or steep slope. Mosquitoes prefer shallow pond edges.

Further information regarding tick prevention can be found at:

Further information regarding mosquito prevention can be found at: