Unlocking the hidden contagions: a deep dive into the history, transmission, and prevention of laboratory-acquired infections

Background and objectives

Laboratory-acquired infections (LAIs) have been documented since the first report of typhoid fever in 1885 and continue to endanger laboratory professionals despite decades of biosafety advances. This review provides a comprehensive overview of LAIs, emphasizing their history, modes of transmission, and strategies for prevention.

Methods

A systematic review of historical records, case series, and biosafety guidance (1885–2025) identified documented LAIs, their transmission routes, and preventive measures. Data were extracted on pathogen spectrum, geographic distribution, incident outcomes, and the effectiveness of biosafety interventions.

Results

Historical analysis identified 50 laboratory-acquired typhoid infections with six deaths from 1885 to 1915, largely due to mouth pipetting and aerosol exposure. A sharp decline in fatal bacterial infections was observed following the introduction of Class II biosafety cabinets in the 1960s. From 2000 to 2021, 309 LAIs were reported across 94 studies, most commonly Salmonella enterica (56.6%), vaccinia virus (4.2%), and Brucella species (3.9%), with Brucella responsible for over half of hospital-laboratory cases (60 per 100,000 personnel-years). In Canada during 2023, 63 exposure events occurred, including three confirmed infections despite adherence to biosafety level protocols. Environmental persistence studies underscored surface-borne risks. The most effective preventative measures included abolishing mouth pipetting, mandatory use of gloves and eye/face protection, routine Class II biosafety cabinet use for aerosol-generating procedures, surface disinfection with 0.5% sodium hypochlorite, and annual competency-based biosafety training with incident reporting.

Conclusions

LAIs remain geographically widespread and pathogen-diverse. Quantitative historical trends and contemporary surveillance highlight critical transmission routes, including ingestion, inoculation, mucosal splash, and inhalation, while reinforcing evidence-based prevention strategies. Sustained investment in biosafety infrastructure, real-time exposure reporting, and pathogen-specific training is essential to further reduce LAI incidence and severity in the face of emerging antimicrobial resistance and novel agents.

Full text

https://www.xiahepublishing.com/2771-165X/JCTP-2025-00003

The study was recently published in the Journal of Clinical and Translational Pathology.

Journal of Clinical and Translational Pathology (JCTP) is the official scientific journal of the Chinese American Pathologists Association (CAPA). It publishes high quality peer-reviewed original research, reviews, perspectives, commentaries, and letters that are pertinent to clinical and translational pathology, including but not limited to anatomic pathology and clinical pathology. Basic scientific research on pathogenesis of diseases as well as application of pathology-related diagnostic techniques or methodologies also fit the scope of the JCTP.

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