Pertussis Transmission in a Hospital Office that was Confirmed on the Basis of Loop-mediated Isothermal Amplification

Abstract

Objective A hospital clerk developed whooping cough and its infectious condition throughout the work place was investigated to clarify the spread of pertussis infection using highly sensitive Loop-mediated isothermal amplification (LAMP).

Materials and Methods LAMP for pertussis was performed against all employees in the personnel division of general hospital, then respiratory symptoms were noted in 12 (57%) of 21 clerical employees.

Results LAMP for pertussis was positive in 7 (58.3%) of the 12 employees. The judgment was indeterminate in the first test in one employee, but it became negative later. An asymptomatic LAMP-negative employee subsequently developed cough and turned to positive in the second LAMP test 20 days after the first test. Cough was not noted even in positive cases in the third LAMP test 35 days after second test, or thereafter, and conversion to LAMP-negative took 76 days on average. No outbreak of whooping cough occurred in any of the other departments in the hospital throughout the course, and no transmission of infection occurred.LAMP methods were useful for grasp of the situation of asymptomatic persons as well as symptomatic patients.

Conclusions It is difficult to diagnose whooping cough based on cough symptoms alone. The LAMP test was useful for understanding the spread of pertussis infection. To prevent outbreak of whooping cough in adults, periodic administration of DTap vaccine is desired.