First Positive Test in 2023 for Eastern Equine Encephalitis in Worcester County


The Worcester County Health Department received notification from the State of Maryland that a mosquito pool in the Whaleyville area of Worcester County recently tested positive for Eastern Equine Encephalitis (EEE). The mosquito species that tested positive feeds primarily on birds. This is the first positive test for EEE in the county this year.   

Additional Information from the Worcester County Health Department:

Arboviruses, such as the EEE virus, are most common during the summer and fall months. The
viruses are transmitted by infected mosquitoes and spread to humans, birds, horses and other
animals. Since mosquitoes can breed in as little as a quarter inch of water, eliminating standing
water is critical for the control of mosquito populations. Many factors impact when and where
outbreaks occur, such as weather, numbers of mosquitoes that spread the virus, and human
The Worcester Health Department is providing the following tips to help prevent contact with
mosquitoes and reduce risk of infection with EEE or other mosquito borne illnesses:

● Remove standing water around your home; as little as one-half inch of water will
support dozens of mosquitoes. Remove or turn over buckets, bottles, and other

containers; discard old tires or drill drainage holes in tires used for playground
equipment; clean rain gutters; store canoes, wheelbarrows, and plastic wading
pools upside down; flush birdbaths and the bottom of plant holders twice a week;
remove pet food and water dishes that are not being used; adjust tarps (over pools,
boats, etc.) to eliminate standing water; fix dripping faucets.
● Wear clothing that covers the arms, legs, and feet whenever you are outdoors.
● Use an Environmental Protection Agency (EPA) approved mosquito repellent
sparingly on exposed skin. Consult a physician before applying EPA approved
mosquito repellent to young children. Avoid applying repellents to the hands of
children and do not use repellents on children under 3 years of age.
● Follow package instructions carefully.
● Spray clothing with EPA approved mosquito repellent as mosquitoes may bite
through thin clothing.
● Minimize outdoor activities at dawn, dusk, and in the early evening when
mosquitoes are most active.
● Inspect window and door screens and repair any holes found.

Signs and Symptoms
Signs and symptoms of Eastern Equine Encephalitis include fever, headache, irritability,
restlessness, drowsiness, vomiting, diarrhea, cyanosis, convulsions, and coma. People with
milder illnesses typically recover on their own, although symptoms may last for several weeks.
In more severe cases, patients need to be hospitalized to receive supportive treatment. Anyone
with possible symptoms of EEE should contact a health care provider immediately.
Horse owners can protect their horses from EEE with a vaccine, contact your veterinarian for
Mosquito spraying is expected to be conducted in the Whaleyville area in response to this
report. Details regarding date, amount of area and method of distribution will be provided as
they become available and will be weather dependent.
For more prevention tips and information about Eastern Equine Encephalitis (EEE) visit