TICK & MOSQUITO DISEASES AND PREVENTION
The Delaware Division of Public Health (DPH) reminds Delawareans that simple precautions reduce a person’s chances of getting
tickborne or mosquitoborne infections this summer.
Lyme disease is the most common disease spread by ticks in Delaware. Rocky Mountain Spotted Fever and Ehrlichiosis occur less frequently.
It takes 24-36 hours of attachment before a disease is transmitted from a tick to a person. Individuals who are infected with tickborne
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.
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 2005, Delaware had 618 confirmed cases
compared to 478 cases in 2006. Symptoms can include a "bull's-eye" rash (seen in nearly half of Lyme disease cases), fever,
fatigue, headache, muscle and joint aches. Occasionally, chronic joint, heart and neurological problems may occur.
In Delaware, Rocky Mountain Spotted Fever is transmitted by the American dog tick. In 2005, Delaware had 7 confirmed or
probable cases compared to 20 cases in 2006. Symptoms can include fever, nausea, vomiting, severe headache, muscle pains and appetite
loss; followed by rash, abdominal pain, joint pain and diarrhea. Rocky Mountain Spotted Fever can be a severe disease, and many patients
require hospitalization. Approximately 3-5 percent of cases are fatal.
Ehrlichiosis infection can be mild to severe with some patients requiring hospitalization. Symptoms can include fever,
headache, malaise, muscle aches, nausea, vomiting, diarrhea, cough, joint pains, confusion and occasionally rash. In 2006, 21 confirmed
cases of Ehrlichiosis were reported in Delaware. The lone star and the blacklegged tick transmit Ehrlichiosis in Delaware.
Diagnosis of Lyme disease, Rocky Mountain Spotted Fever and Ehrlichiosis are all based on individual patient symptoms and can generally
be confirmed with blood testing.
Diseases from mosquitoes include West Nile Virus (WNV), Eastern Equine Encephalitis (EEE) and several other diseases that cause brain
West Nile Virus is transmitted to humans by the bite of infected mosquitoes. West Nile Virus first appeared in Delaware
birds and horses in 2003. Delaware’s first confirmed human case occurred in 2002, and was not fatal. In 2003, 17 human cases and
two deaths were reported in Delaware. Since then, Delaware has confirmed only two cases of WNV in 2005. No cases were reported in 2006.
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.
Eastern Equine Encephalitis (EEE) is transmitted to humans by the bite of infected mosquitoes. As the name suggests, EEE
occurs in the eastern half of the US. Because of the high death rate, it is regarded as one of the more serious mosquito-borne diseases
in the United States. Delaware has not had a confirmed case of EEE since 1979. However, like WNV, the risk of human infection is present.
Symptoms range from mild flu-like illness to encephalitis (inflammation of the brain), coma and death.
DPH reminds residents to take the following protective measures to avoid tick and mosquito bites:
- 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.
- Use fine-tipped tweezers or shield your fingers with a tissue, paper towel or rubber gloves. Avoid removing ticks with bare hands
- 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
- After removing the tick, cleanse the site with an antiseptic or soap and water, and wash your hands.
- Delaware’s Division of Public Health does not recommend the use of home remedies such as petroleum jelly or hot matches for
tick removal. These methods do not work.
- Limit outdoor activities when mosquitoe 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: http://www.cdc.gov/ncidod/ticktips2005/
Further information regarding mosquito prevention can be found at: http://www.cdc.gov/ncidod/dvbid/westnile/qa/prevention.htm
For questions concerning mosquito control, or to report a dead bird, please call Department of Natural Resources Environmental Control
- New Castle County (302) 323-4492
- Kent/Sussex Counties (302) 422-1512
- Weekends (800) 523-3336
For additional information contact DPH, Bureau of Epidemiology at: 1-888-295-5156.
Categories of Health Alert messages:
- Health Alert: Conveys the highest level of importance; warrants immediate action or attention.
- Health Advisory: Provides important information for a specific incident or situation; may not require immediate action.
- Health Update: Provides updated information regarding an incident or situation; unlikely to require immediate action.
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