Hypersensitivity pneumonitis resulting from community exposure to Canada goose droppings: when an external environmental antigen becomes an indoor environmental antigen

Background: In the past, hypersensitivity pneumonitis has been attributed to occupational, agricultural, or home environmental exposure. Objective: This report describes the first case of hypersensitivity pneumonitis due to community exposure to droppings from Canada geese migrating through a suburban environment. Method: Clinical and serologic information was used in making the diagnosis of hypersensitivity pneumonitis. Results: Serologic analysis demonstrated precipitating antibodies against goose droppings and against an extract made from washings from a filter taken from the patient's office. These studies also showed that the antigens in the office filter were goose dropping antigens. Conclusion: Hypersensitivity pneumonitis can result from exposure to goose dropping antigens in the community that enter buildings through ventilation systems. This represents a new form of an old disease.