“…commonest cause of HP in Japan), [18] a single case of bird fancier's lung in a 12-year-old boy in the Western Cape, [19] and a single case (antigen not stated) in a series of 42 children in KwaZulu-Natal Province with chronic lung disease. [20] What makes chronic HP a particularly challenging diagnosis is that it is not always preceded by acute disease, which is more easily recognisable; standardised and validated antigen preparations and immunoassays for diagnosis are not available; cut-off values for quantitative immunoglobulin G assays have not been validated; and lymphocytosis on bronchoalveolar lavage is not always present.…”