Delaware County Health Department Announces First Human Case of West Nile Virus in 2023

Released: October 3, 2023

Delaware County Health Department Announces First Human Case of West Nile Virus in 2023

The Delaware County Health Department (DCHD) announces that it has identified the first human case of West Nile virus in Delaware County in 2023. Human West Nile virus cases are not uncommon and are typically identified in Delaware County in most years. Mosquito bites and West Nile virus are commonly associated with warmer months; however, mosquitoes are still active into the fall and can cause illnesses like West Nile virus.

There are several ways the Delaware County Health Department works to control mosquito populations in the county. However, the public’s help is important. “It is everyone’s job in Delaware County to prevent the spread of West Nile virus,” said Delaware County Health Department Director Melissa Lyon. “Thankfully, it is an easy one, routinely inspecting your property and dumping out standing water sources reduces the chances of West Nile virus positive pools and cases.”

Most people (8 out of 10) infected with West Nile virus do not develop any symptoms. About 1 in 5 people who are infected develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or rash. Most people who develop symptoms of West Nile virus recover completely, but fatigue and weakness can last for weeks or months. About 1 in 150 people who are infected develop a severe illness affecting the central nervous system such as encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes that surround the brain and spinal cord).

Since 2008, the annual number of human cases among Delaware County residents has fluctuated between 0 to 7 cases, with peak seasons in 2012, 2018, and 2021. The last five years have varied in severity, with 5 cases in 2018, no cases from 2019-2020, and 4 cases seen in 2021. There were two cases of West Nile virus in 2022.

The most effective way to prevent the spread of West Nile virus is to keep mosquitoes from breeding on your property. Residents are encouraged to remember the ‘Three Ds’:

DRAIN - Anything that can hold water and breed mosquitoes, from soda bottle caps to discarded tires. Check your property for these sources of standing water and dump them out. At least once or twice a week, empty water from flowerpots, pet food and water dishes, birdbaths, swimming pool covers, buckets, barrels, cans, wheelbarrows, boats, cargo trailers, toys and any other items outside your home. Empty and store wading pools for kids on their side, as well as any other sources of standing water outside your home.

DRESS - Wear clothing like long-sleeved shirts, long pants, and hats to protect against bug bites. You can further protect yourself by tucking your pants into your boots. Wearing long-sleeved shirts and pants is a great way to prevent not only mosquito bites but tick bites as well.

DEFEND - Wear insect repellent with DEET, Picaridin, or Oil of Lemon Eucalyptus on exposed skin when outdoors. Another effective repellent is Permethrin. Be sure to carefully follow the instructions on the labels when using these repellants.

More information is available on the Delaware County Health Department West Nile Virus webpage.

https://delcopa.gov/health/pages/westnile.html

To report mosquito problems or for more information on how to prevent West Nile virus, visit, call, or email:

The Delaware County Health Department Wellness Line: (484) 276-2100

Email: Environmental@co.delaware.pa.us