Abstract: A method for the early diagnosis of Bordetella diseases based on the detection of Bordetella adenylate cyclase and the ability of this enzyme to catalyze the formation of cyclic adenosine monophosphate (cAMP). A sample secretion is taken from a suspected victim of a Bordetella disease (the most common of which in humans is whooping cough) and incubated under conditions to promote the formation of cAMP, which may then be measured as evidence of the presence of the disease. A sample of nasopharyngeal secretions is maintained in a nutrient medium pending assay. An adenylate cyclase assay is made by incubating the sample with adenosine triphosphate (ATP) and the calcium binding protein calmodulin to generate cAMP. The cAMP is measured by any of several known available methods.