Airborne Endotoxin Predicts Symptoms in Non–Mouse-sensitized Technicians and Research Scientists Exposed to Laboratory Mice

Abstract

Research scientists, laboratory technicians, and animal handlers who work with animals frequently report respiratory and skin symptoms from exposure to laboratory animals (LA). However, on the basis of prick skin tests or RASTs, only half are sensitized to LA. We hypothesized that aerosolized endotoxin from mouse work is responsible for symptoms in nonsensitized workers. We performed a cross-sectional study of 269/310 (87%) workers at a research institution. Subjects completed a questionnaire and underwent prick skin tests (n = 254) or RASTs (n = 16) for environmental and LA allergens. We measured airborne mouse allergen and endotoxin in the animal facility and in research laboratories. Of 212 workers not sensitized to mice, 34 (16%) reported symptoms compared with 26 (46%) of mouse-sensitized workers (p < 0.001). Symptomatic workers were more likely to be atopic, regardless of mouse sensitization status. Symptomatic non-mouse-sensitized workers spent more time performing animal experiments in the animal facility (p = 0.0001) and in their own laboratories (p < 0.0001) and had higher daily endotoxin exposure (p = 0.008) compared with asymptomatic coworkers. In a multivariate model, daily endotoxin exposure most strongly predicted symptoms to mice in non-mouse-sensitized workers (odds ratio = 30.8, p = 0.003). We conclude that airborne endotoxin is associated with respiratory symptoms to mice in non-mouse-sensitized scientists and technicians.

Endotoxin Exposure: Predictors and Prevalence of Associated Asthma Outcomes in the United States

“…We found that endotoxin was strongly positively associated with asthma at low levels of specific IgE against dog, mouse, and rat but negatively associated with asthma at high levels of IgE against mouse and rat. Likewise, in a sample of laboratory scientists and technicians, Pacheco and colleagues looked at the association of aerosolized endotoxin with symptoms related to mouse by sensitization status and concluded that endotoxin predicts respiratory symptoms related to mice in non-mouse-sensitized participants (31).…”

Mouse Models for Atopic Dermatitis Developed in Japan

“…The development of LAA is due to the presence of IgE antibodies directed against animal proteins, and incidence rates are rapidly increasing. Hair shaving increases the chance of direct exposure of the researcher to the animal proteins, and the worst possible outcome of LAA is death by anaphylactic shock (Pacheco et al, 2003, Schweitzer et al, 2003, Matsui et al, 2004, Curtin-Brosnan et al, 2010. Therefore, a hairless model on an AD-prone genetic background would be an ideal and powerful tool for basic research, such as the discovery of the genes responsible for AD, and for drug development, such as the development of new ointment for the treatment of AD.…”

A multi‐faceted approach to risk assessment of laboratory animal allergens at two facilities

“…Second, exposure to these irritants alone can also predispose individuals to asthmatic symptoms [Medina-Ramón et al, 2005;Massin et al, 2006]. Third, respiratory symptoms following exposure to laboratory animals may be a consequence of exposure to endotoxins, rather than to animal allergens as such [Pacheco et al, 2003]. Despite these confounding factors, few research groups have attempted to address the problematic question of threshold levels of allergens.…”