Status of Pertussis in Iran

BACKGROUND: Pertussis is a respiratory and contagious disease which is mostly caused by Bordetella pertussis and B. parapertussis. It usually spreads from person to personduring the incubation or catarrhal phase of the disease. Despite of large-scale vaccination, whooping cough is still an endemic disease with several outbreaks. OBJECTIVES: The aim of this study was to determine the prevalence of pertussis and identify its causative agents, B. pertussis or B. parapertussis, from specimens collected from Iranian patients from 2004 to 2008. PATIENTS AND METHODS: Nasopharyngeal swab samples from 347 suspected pertussis cases were collected from 18 provinces of Iran. The patients were in different age groups and were either unvaccinated or vaccinated for pertussis with whole cell vaccine (WCV). Bacterial culture, agglutination tests and quantitative PCR (qPCR) targeting IS481 and IS1001 for B. pertussis and B. parapertussis were done for every specimen, respectively. RESULTS: The results showed that seven nasopharyngeal swab samples (2%) were positive for B. pertussis (1.7%) and B. parapertussis (0.3%) by culture and agglutination test and 30 patients had positive qPCR test results (9%). CONCLUSIONS: Despite the fact that bacterial culture is the golden standard for the detection of B. pertussis, direct detection of bacteria from nasopharyngeal specimens can be performed by a rapid qPCR assay. In this study, high percentage of positive qPCR cases may indicate that the patients might have recovered from pertussis following antibiotic treatment before samples were collected. Rapid detection by qPCR could be important for immediate diagnosis and treatment of patients with pertussis.