Related Experiment Video
Updated: May 12, 2026

Intradermal Inoculation of Mycobacterium avium in the Mouse Ear
Published on: July 3, 2025
Hypersensitivity pneumonitis with Mycobacterium avium complex among spa workers
Stephanie Ann Moraga-McHaley1, Michael Landen, Heidi Krapfl
1Epidemiology and Response, New Mexico Department of Health, Santa Fe, NM 87108, USA. stephanie.moraga-mc@state.nm.us
Spa workers exposed to aerosolized water during filter cleaning developed hypersensitivity pneumonitis (HP) linked to Mycobacterium avium complex (MAC). Environmental sampling confirmed a potential source, leading to recommendations for improved ventilation and respiratory protection.
Area of Science:
- Environmental Health
- Occupational Medicine
- Microbiology
Background:
- Two cases of hypersensitivity pneumonitis (HP) in spa workers were investigated.
- Laboratory confirmation of Mycobacterium avium complex (MAC) was established in affected workers.
- The investigation coincided with worker protection and pool regulatory assessments.
Purpose of the Study:
- Identify additional unreported cases of HP.
- Determine the source(s) of worker exposure to MAC.
- Implement measures to prevent future occupational exposures.
Main Methods:
- Surveyed 57 spa employees regarding symptoms and potential exposures.
- Categorized job roles based on self-reported exposure to aerosolized water.
- Compared environmental MAC isolates from spa water/filters with patient isolates.
Main Results:
- Workers with higher aerosolized water exposure reported significantly more HP-like symptoms (OR=9.6 for highest, OR=6.5 for intermediate).
- Two of 13 environmental isolates showed close genetic relation to one patient isolate.
- A strong association was found between occupational exposure and HP symptom development.
Conclusions:
- Spray cleaning of cartridge filters in poorly ventilated areas likely caused worker exposure.
- Recommendations include controlling organism growth in spa water systems.
- Enhanced ventilation and appropriate respiratory protection are crucial for spa maintenance workers.
Related Concept Videos
Atypical Pneumonia
Pulmonary Tuberculosis I
Causative Organism
The primary infectious agent causing tuberculosis is Mycobacterium tuberculosis, a slow-growing, acid-fast, aerobic rod that exhibits sensitivity to heat and ultraviolet light. Instances of Mycobacterium bovis and Mycobacterium avium contributing to the development of TB infection are rare.
Mode of...
Pulmonary Tuberculosis II
Here is a detailed explanation of its pathophysiology:
Transmission: The process begins when a person inhales droplet nuclei containing M. tuberculosis. These are typically released into the air when an individual with pulmonary or...
Pulmonary Tuberculosis IV
Several diagnostic approaches are used to detect TB. The conventional method is the Tuberculin Skin Test (TST), also known as the Mantoux test. However, this method has...
Pneumonia I: Introduction
Pneumonia I: Introduction
Risk Factors
Various factors influence the likelihood of developing pneumonia. Age plays a crucial role, with infants, children under two, and individuals over 65 at increased risk due to their...