Pertussis diagnosis in the 21st century: Progress and pitfalls, part II

Bordetella pertussis is the causative agent of pertussis, also called whooping cough or the cough of 100 days. Infection can result in significant morbidity and mortality, particularly in young infants. Prior to the availability of effective vaccines, pertussis was a major cause of childhood disease. With the advent of such vaccines, the incidence of disease declined dramatically into the 1970s. However, pertussis is still present, with peaks occurring every 3 to 5 years, and the number of cases has been increasing in the United States since the 1980s. With recent reports of numerous outbreaks of pertussis, there is heightened interest in the control and diagnosis of the disease. Efforts to increase immunity through vaccination and also to improve the clinical and laboratory diagnosis of the disease are very important. Part II of this two-part article will discuss methods for the diagnosis of pertussis infection with an emphasis on laboratory tests using PCR and serology. The advantages of newer testing methods include increased sensitivity and decreased time to result. There are potential problems, however, related to specificity and cross reactions that can complicate the interpretation of test results for pertussis diagnosis.