STATE REPORTS FIRST 2003 FINDING OF EASTERN EQUINE ENCEPHALITIS

Delaware City Area Sentinel Chicken Tests Positive for EEE; Indications of West Nile Increase

Delaware's Department of Natural Resources and Environmental Control (DNREC), Division of Public Health (DPH), and Department of Agriculture (DDA) announce the first finding this year of Eastern Equine Encephalitis (EEE) in Delaware. The Delaware Public Health Laboratory has confirmed for Mosquito Control that a sentinel chicken from the Delaware City area of New Castle County tested positive for EEE.

In reaction to this finding and in response to locally severe infestations of mosquitoes, last Friday evening the Mosquito Control Section sprayed by truck to kill adult mosquitoes in or around the towns of New Castle, Delaware City and Port Penn. Depending upon the continual severity of mosquito infestations in these and other areas, spraying by aircraft may also be done. Mosquito Control has 20 sentinel chicken stations statewide to help monitor for both EEE and West Nile virus, the primary mosquito-borne human health threats in Delaware.

In comparison to the invasion of West Nile virus over the past four years, EEE has long been in Delaware and fortunately is much rarer. EEE can be much more threatening to the unfortunate few who contract the disease, having a significantly higher fatality rate than West Nile. Both EEE and West Nile are concerns for the elderly or people with weakened immune systems; EEE can also be very serious for infants and children and often problematic even to healthy adults.

Transmission of EEE to humans is usually linked to saltmarsh mosquitoes or closely-related freshwater wetland species, versus the container-breeding mosquitoes found in populated areas more closely associated with West Nile virus. EEE is more likely to be found downstate in Kent or Sussex Counties and finding EEE north of the C&D Canal in the Delaware City sentinel chicken is considered an unusual event based on past experience. The presence of EEE in both horses and humans from North Carolina south to Florida indicates that EEE could become more common this summer all along the Atlantic seaboard. Since mid-July, three horses from Maryland's Eastern Shore have died from EEE, and two mosquito collections from the Pocomoke Swamp area have also tested positive for EEE. Four mosquito collections have recently been found positive for EEE in New Jersey.

In addition to the first appearance of EEE in Delaware this year, West Nile virus continues to spread throughout the state. To date in 2003, 37 wild birds have tested positive for West Nile, including birds found near Milford, Milton, Lewes, and Bethany Beach. The virus appears to be well established again in eastern Sussex County as well as New Castle and Kent counties. This year West Nile virus has also infected five downstate horses from near Clayton, Dover, Wyoming, Harrington and Georgetown.

Return to hotter summer temperatures could increase EEE and WNV within mosquitoes themselves, which could increase disease outbreaks in late August.

People should take additional personal protection measures to reduce or avoid mosquito bites. This is more important than ever given this year's abundant mosquito populations from high rainfall since spring and present tidal flooding.

The Mosquito Control Section and the Division of Public Health also advise residents to take common-sense precautions against insect bites, such as wearing long-sleeved shirts and long pants outdoors, applying insect repellent containing 30 percent or less DEET for adults and 10 percent or less DEET for children, and to avoid mosquito-infested areas or times of peak mosquito activity around dusk, dawn or throughout the evening.

Within limits of available resources, the Mosquito Control Section will expand its monitoring efforts in areas where West Nile virus has been detected, increasing nightly light trap collections of adult mosquitoes plus more landing rate counts taken by field inspectors, in addition to investigating public reports of high numbers of biting mosquitoes. DNREC will use trucks or aircraft to apply, as warranted, insecticides registered by the U.S. Environmental Protection Agency to reduce adult mosquitoes. In accordance with EPA determinations, these products pose no unacceptable risks to human health, wildlife or the environment.

Water management practices and using insecticides to control larval mosquitoes in their breeding habitats will also continue to the extent practicable. However, the overwhelming amount of freshwater breeding habitats currently found throughout much of Delaware from this year's heavy and frequent rains greatly diminishes for a yet indeterminate period-of-time Mosquito Control's ability to achieve any discernable relief from mosquito infestations by larviciding inland areas, although larviciding saltmarsh breeding habitats will continue.

To help reduce the spread of West Nile virus, DNREC recommends residents drain mosquito-breeding areas such as upright wheelbarrows, old tires, discarded cans and barrels, flower pot liners, and clogged gutters. Water in birdbaths and children's wading pools should be changed frequently.

According to the Division of Public Health, humans infected with either West Nile virus or EEE typically have only mild flu-like symptoms such as fever, headache, body aches, nausea and vomiting, if they have any symptoms at all. In rare cases, humans infected with these diseases develop severe symptoms, including sudden onset of high fever, severe headache, stiff neck, mental confusion, and muscle weakness. EEE is more likely than West Nile virus to cause severe disease, and may lead to chronic neurologic debilitation. Individuals with these symptoms should see their physician immediately.

The DDA's State Veterinarian urges horse owners to contact their veterinarian if they suspect a horse has EEE or West Nile virus. Symptoms in horses include listlessness, muscle spasms in the head and neck, tremors or staggering, and hind-limb weakness. Both EEE and West Nile equine vaccines are available through your veterinarian.

DNREC encourages individuals who find sick or dead crows, blue jays, or hawks or owls suspect to have contracted West Nile virus to call the Mosquito Control Section, Monday through Friday from 8 a.m. to 4 p.m., at the following numbers, which should also be used to report mosquito problems. Residents should wear gloves and avoid direct skin contact if they handle sick or dead birds.

• New Castle County: 302-836-2555
• Kent or Sussex County: 302-422-1512

For questions about mosquito control or mosquito biology, call DNREC at 302-739-3493.
For human health questions about EEE or West Nile virus, call DPH at 302-739-5617.
For questions about EEE or West Nile in animals, call DDA at 800-282-8685 and ask for Poultry-Animal Health.

Delaware Health and Social Services is committed to improving the quality of the lives of Delaware's citizens by promoting health and well-being, fostering self-sufficiency, and protecting vulnerable populations.