Good morning, The symptoms sound similar to conjunctivitis, but it would be impossible to know for sure unless the bird was examined by a veterinarian. There are other avian diseases, such as Avian Pox, that can produce similar symptoms. In wild birds, conjunctivitis is most closely associated with house finches, but cases have been confirmed in American goldfinches, purple finches, evening grosbeaks, and pine grosbeaks. House sparrows, northern cardinals, and other species may also be susceptible. I am not familiar with any studies that have found the disease in swallows. It is hard to know how common the disease is without on-going monitoring, but the disease is known to occur in wild birds in Illinois. The best way to protect birds from this disease is to properly maintain bird feeders and bird baths. Conjunctivitis is contagious among birds, but does not pose a threat to humans or domestic pets. Wash bird feeders and bird baths with a diluted bleach solution (one cup bleach to 9 cups water) once a week. Let the feeder/ bath air dry. Fill the feeder with clean, dry seed. Rinse baths out with clean water and then refill with fresh water. Keep spilled seed raked up (i.e. do not leave seed on the ground to become wet or contaminated by droppings). Do not concentrate feeders in one area. Providing feeding stations around the yard will reduce the number of birds at any given feeder, thus cutting the risk that an infected bird will have close contact with healthy birds. Thanks for writing.