The state departments of Agriculture and Health have warned Pennsylvanians to take precautionary measures against mosquito bites for themselves and their animals — specifically horses — as the rare mosquito-transmitted viral infection Eastern equine encephalitis has been confirmed in Erie, Carbon and Monroe counties. So far this year, 18 cases have been reported to the Centers for Disease Control and Prevention, with the majority in northeastern or mid-Atlantic states. Several cases have been fatal.

First, a little background on Eastern equine encephalitis. The virus is carried by birds, so if a mosquito bites an infected bird, it can then transmit the virus to humans, horses and other birds. Because of the high mortality rate in horses and humans, Eastern equine encephalitis is regarded as one of the most serious mosquito-borne diseases in the United States, according to a state government press release.

The symptoms include high fever (103 to 106 degrees), a stiff neck, headache and lack of energy and typically show up four to 10 days after being bitten by an infected mosquito. Inflammation and swelling of the brain, called encephalitis, can develop. The disease gets worse quickly, and some patients could end up in a coma within a week. This disease can be fatal, as approximately a third of all people who get it die from it, the CDC reports.


As with West Nile virus, also a mosquito-borne sickness, the key is eliminating potential mosquito breeding grounds. Here are some tips from our September 2018 editorial on West Nile on where to look:

— Yard trash, including cups and even bottle caps, which can hold enough water for mosquito larvae.

— Clogged rain gutters and downspout extensions with standing water.

— Covered containers, wading pools and any other items that can hold standing water.

— Bird baths and animal water dishes should be changed regularly.

— Children’s yard toys capable of holding even small amounts of water.

— Trash and recycling cans.

— Flower pots, especially if there’s a saucer that could hold standing water.

— Ornamental ponds (fishless).

— Mower ruts, tires and wheelbarrows.

— Sewer grates on or near your property should be cleaned of debris (don’t blow grass clippings into the street).

Our editorial also noted, “If you have stagnant water that’s going to sit for five days or more, you can use Bti, naturally occurring bacteria, to kill mosquito larvae.

“It generally comes in small, disc-shaped portions, often called ‘mosquito dunks.’ The dunks are useful in small areas of standing water, such as birdbaths or puddles that accumulate in low-lying or uneven areas of the yard.”

In addition, the Pennsylvania Agriculture and Health departments want horse owners to proactively vaccinate their animals against both Eastern equine encephalitis and West Nile virus, keep animals indoors at night, and spray for mosquitoes. Pennsylvania’s recently confirmed cases include a wild turkey, pheasants and horses.

Protecting yourself

“The most effective way to prevent infection from Eastern equine encephalitis is to prevent mosquito bites,” the CDC says on its website. So in addition to taking the above steps to wipe out mosquito breeding grounds, people are advised to use insect repellent (always follow directions), wear long-sleeved shirts and pants, and treat clothing and gear.

The best repellents contain one of these active ingredients, the CDC notes: DEET, Picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol or 2-undecanone.

The CDC also has these tips for protecting babies and children:

— Don’t use insect repellent on infants younger than 2 months. Instead, dress the child in clothing that covers extremities. Cover strollers and baby carriers with mosquito netting.

— Don’t use products containing oil of lemon eucalyptus or para-menthane-diol on kids under 3.

— Don’t apply insect repellent to a child’s hands, eyes, mouth, cuts or irritated skin. Adults should spray repellent onto their hands and apply it to the youngster’s face.

We also encourage you to check out the CDC webpage for more information.

The presence of Eastern equine encephalitis in Pennsylvania is a serious issue. Even though the illness is uncommon, it’s potentially deadly, so we urge our readers to take preventive and protective measures — for themselves and their families.