Legionella and Air Transport: A Study of Environmental Contamination

Introduction: There is growing interest in the public health and transport sectors in research into exposure to biological hazards, considering not only the risks arising from inter-human contagion, but also those related to exposure to the flight environment itself. The aim of this paper is to report data from an investigation into the water and air-conditioning systems of commercial aircraft for the presence of Legionella contamination, with a total of 645 water samples taken during the period 2007–2021. Methods: The investigation involved 126 aircraft of six different commercial aircraft types: MD80, Airbus A320 F, Embraer 175/190, AIRBUS A330, Boeing 767 and Boeing 777. Water samples were taken from the water systems (toilet taps, galley and boilers). Each sample was preliminarily subjected to an evaluation of the following parameters: temperature, pH and residual chlorine. The ScanVit® Legionella kit was used for bacteria detection and enumeration. Results: Samples were considered positive if the number of colony-forming units/liter (CFU/L) was >100. For the entire observation period, 45% of the investigated aircraft tested positive. Regarding the overall number of samples analyzed, 68.4% (441/645) were below 100 CFU/L, and thus within the limits allowed by the Italian Guidelines. Conclusions: Water system contamination with Legionella in the air transport field is a real public health issue that should not be underestimated given the heavy passenger traffic. Infection should be considered an occupational risk to which crew members are exposed.

[1]  M. Verani,et al.  Quantitative Microbial Risk Assessment Applied to Legionella Contamination on Long-Distance Public Transport , 2022, International journal of environmental research and public health.

[2]  D. Malz Beware of Legionella in Water Distribution Systems , 2021, Journal AWWA.

[3]  G. Messina,et al.  Rapid detection of Legionella spp in water samples by ScanVIT method: comparison of acid vs heat treatment. , 2020, Annali di igiene : medicina preventiva e di comunita.

[4]  Sharon L. Norris,et al.  The Airplane Cabin Microbiome , 2018, Microbial Ecology.

[5]  Nicola Christie,et al.  Airborne biological hazards and urban transport infrastructure: current challenges and future directions , 2016, Environmental Science and Pollution Research.

[6]  M. Höfle,et al.  Legionella species diversity and dynamics from surface reservoir to tap water: from cold adaptation to thermophily , 2015, The ISME Journal.

[7]  C. Adley,et al.  Bacteria that Travel: The Quality of Aircraft Water , 2015, International journal of environmental research and public health.

[8]  J. Winchell,et al.  Current and Emerging Legionella Diagnostics for Laboratory and Outbreak Investigations , 2015, Clinical Microbiology Reviews.

[9]  T. Constantinidis,et al.  First report of Legionella pneumophila in car cabin air filters. Are these a potential exposure pathway for professional drivers? , 2013, Scandinavian journal of infectious diseases.

[10]  P. Zucs,et al.  Legionnaires disease in Europe, 2009-2010. , 2013, Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin.

[11]  Anna Maria Ferriero,et al.  Legionella on board trains: effectiveness of environmental surveillance and decontamination , 2012, BMC Public Health.

[12]  T. Funato,et al.  Is driving a car a risk for Legionnaires' disease? , 2009, Epidemiology and Infection.

[13]  R. Bentham,et al.  Legionella, Protozoa, and Biofilms: Interactions Within Complex Microbial Systems , 2009, Microbial Ecology.

[14]  K. Wallingford,et al.  Monitoring microbial populations on wide-body commercial passenger aircraft. , 2008, The Annals of occupational hygiene.

[15]  M. Masia,et al.  Prevalence study of Legionella spp. contamination in ferries and cruise ships , 2006, BMC public health.

[16]  S. Kelley,et al.  Molecular survey of aeroplane bacterial contamination , 2005, Journal of applied microbiology.

[17]  A. Mangili,et al.  Review Transmission , 2022 .

[18]  T. File,et al.  Distribution of Legionella species and serogroups isolated by culture in patients with sporadic community-acquired legionellosis: an international collaborative survey. , 2002, The Journal of infectious diseases.

[19]  P. Visca,et al.  Legionnaires' disease on a cruise ship linked to the water supply system: clinical and public health implications. , 1999, Clinical infectious diseases : an official publication of the Infectious Diseases Society of America.

[20]  R. J. Carter,et al.  Outbreak of Legionnaires' disease among cruise ship passengers exposed to a contaminated whirlpool spa , 1996, The Lancet.