The U.S. Department of Agriculture is reporting new cases of avian flu across the country and in Pennsylvania.A backyard chicken flock in East Lampeter Township, Lancaster County, is among the latest to test positive.The flock is one of two in the Susquehanna Valley to be impacted by the latest outbreak.The other flock is a commercial turkey farm in York County with 25,000 birds.Pennsylvania Farm Bureau leaders say the new outbreak is a reminder of how to stop the virus from spreading."Make sure that you're checking your vehicles on the way in, making sure you're wearing dedicated clothes and shoes, removing those before you leave the premises. You know, just basic, simple but commonsense bio-security to make sure that we don't have spread of these terrible illnesses that can affect birds throughout Pennsylvania and have been," said Grant Gulibon of the Pennsylvania Farm Bureau.There are currently 18 commercial and three backyard poultry flocks in Pennsylvania that have tested positive, according to the USDA. About 4.2 million birds have been impacted. Report avian flu casesIf you suspect live poultry is infected, you are asked to report it to the Pennsylvania Bureau of Animal Health and Diagnostic Service at 717-772-2852.That number is available 24 hours a day, seven days a week.Symptoms of avian fluSymptoms of avian flu in poultry include a lack of energy and appetite.While avian flu is deadly to birds, it's still safe to eat chickens and eggs.Video below: Wild turkey breaks into home.