PHILADELPHIA (CBS) — Wildlife officials in Pennsylvania and Delaware are investigating after dozens of songbirds have died from what they’re calling an “unknown” disease. There have been deaths in multiple mid-Atlantic states and Washington, D.C.

According to the Delaware Department of Natural Resources and Environmental Control, the disorder includes swollen eyes and crusty discharge. Some of the neurological symptoms include erratic flight behavior and stumbling.

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Delaware reported “more than 50” birds dying from this disease. The Pennsylvania Game Commission released numbers on their own cases, saying they’ve received 34 cases across 27 counties.

PennVet is helping investigate the deaths and Dr. Scott Weber says this a strange situation.

“We were shocked,” the wildlife expert said. “We’ve been testing them for a variety of different pesticides, different parasites, bacteria infections, viral infections.”

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PennVet has confirmed 12 of Pennsylvania’s reported bird deaths are because of the mysterious disease, and experts aren’t ruling any causes out. Weber told CBS3 they are investigating pesticides, toxins and even a fungus linked to the recent cicada swarms.

Anyone who sees birds experiencing these symptoms, or finds a dead bird with these symptoms, should report it to their local wildlife office. Pennsylvania residents can file a report here.

In the meantime, wildlife officials gave the following tips for homeowners:

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  • Cease feeding birds and providing water in birdbaths until this wildlife mortality event has concluded to prevent potential spread between birds and to other wildlife.
  • Clean feeders and birdbaths with a 10% bleach solution.
  • Avoid handling dead or injured wild birds. Wear disposable gloves if it’s necessary to handle a bird.
  • Keep pets away from sick or dead birds as a standard precaution.
  • To dispose of dead birds, place them in a sealable plastic bag and discard them with household trash. This will prevent disease transmission to other birds and wildlife.

CBS3’s Stephanie Stahl contributed to this report.