Hypersensitivity pneumonitis with Mycobacterium avium complex among spa workers.

Background: The New Mexico Department of Health (NMDOH) investigated the cause of two cases of hypersensitivity pneumonitis (HP) in spa maintenance workers with laboratory confirmed Mycobacterium avium complex (MAC). The investigation occurred in tandem with worker protection and swimming pool regulatory investigations by the New Mexico Environment Department at the spa where the workers were employed.

Objectives: The investigation was conducted in order to identify unreported cases, exposure source(s), and to prevent further worker exposure.

Methods: NMDOH surveyed 57 spa employees about symptoms and exposures, categorized jobs according to self-reported exposure to water, and computed odds ratios for symptom reporting by exposure category. Environmental isolates from spa water and filter swabs were cultured and compared to patient isolates by the Environmental and Applied Microbiology Team, Centers for Disease Control and Prevention (CDC).

Results: Workers with the highest exposure reported more HP-like symptoms (OR = 9.6), as did intermediate exposure workers (OR = 6.5), compared to workers with no aerosolized water exposure. Two of 13 environmental isolates were closely related to one of the patient isolates.

Conclusions: Workers were likely exposed during spray cleaning of cartridge filters in a poorly ventilated work space. Recommendations include inhibiting organism growth in spa systems, assuring the use of respiratory protection, and adequately ventilating work spaces where filters and equipment are cleaned.