Laboratory-acquired infections and bio-incidents

(Note: cette page n'existe qu'en anglais - Nota: deze pagina bestaat enkel in het Engels)




Laboratory-acquired infections (LAIs), also called occupational illness or laboratory-associated infections, are not new phenomena in microbiological laboratories. LAIs can arise in clinical laboratories as well as in animal facilities, R&D or production installations. It is sometimes difficult to determine if a worker's infectious disease is caused by a micro-organism that is present in the laboratory only or also in the community. LAIs are of public health concern, as an infected worker may present a risk of transmission to his colleagues, relatives, family members or other citizens.

Biological agent
(with links, when available, to the corresponding Material Safety Data Sheet (MSDS) from the Office of Laboratory Security, Health Canada
Class of risk or risk group
Classes of risk are given for human. More information on this page
Table 1 : "Top ten" laboratory-acquired infections (1979-1999)
Adapted from Collins, 1998 and Harding & Brandt Byers, 2000
Brucella spp. 3 Brucellosis
Coxiella burnetii 3 Q fever
Hepatitis B, C and D viruses 3
(class of risk 3 infectious agents that are normally not airborne pathogens)
Salmonella thyphi 3
(class of risk 3 infectious agents that are normally not airborne pathogens)
Typhoid fever
Francisella tularensis 3 Tularaemia
Mycobacterium tuberculosis complex 3 Tuberculosis
Trycophyton mentagrophytes 2 Dermatomycosis
Venuzeelan equine encephalitis virus 3 Venezuelan equine encephalitis
Chlamydia psittaci (avian) 3 Psittacosis
Coccidioides immitis 3 Coccidioidomycosis


Laboratory category Number Percentage
Table 2: Percentage of LAI per laboratory category
(From Pike, 1976)
Research 2307 58.8
Diagnostic 677 17.3
Production 134 3.4
Teaching 106 2.7
Unspecified 697 17.8


Exhaustive reports on LAIs are scanty and are based on voluntary reporting by laboratories (case reports) or on more elaborated and detailed inquiries. The underreporting of such infections is widely acknowledged due to fear of reprisal and the stigma associated with such events (Sewell, 1995). Some comprehensive publications referencing a large number of LAIs were published in the past decade (see references).

The link between LAIs and Biosafety is obvious. These concerns are also to be considered as one of the underlying reasons for the elaboration of containment measures and application of safe work practices.



Bio-incidents are defined as all irregularities that occur while handling biological agents (pathogenic organisms), including those which have been genetically modified, cell cultures and parasites which can cause any infection, allergy or toxicity. They can be due to human errors or technical failures.
Laboratory-acquired infections (LAIs) are defined as all infections acquired through laboratory or laboratory-related activities regardless of whether they are symptomatic or asymptomatic in nature.


How are infections acquired in the laboratory?

LAIs are resulting from occupational exposure to infectious agents. The most common route of exposure and accidental inoculation are the following:

  • Inhalation (see aerosols)
  • Percutaneous inoculation (needle and syringe, cuts or abrasions from contaminated items and animal bites)
  • Contact between mucous membranes and contaminated material (hands or surfaces)
  • Ingestion (aspiration through a pipette, smoking or eating)

Important factors to consider when assessing the risks for staff working in R&D, production or microbiology laboratory are the following:

  • Mode of transmission
  • Infectious doses for human (see Table below)
  • Persistence or viability of infectious agents in the environment
Biological agent Infectious dose* Route of inoculation
Escherichi coli 108 Ingestion
Escherichi coli O157: H7 10 Ingestion
Bacillus cereus > or = 105 per gram Ingestion
Campylobacter jejuni < or = 500 Ingestion
Treponema pallidum 57 Intradermal
Francisella tularensis 10 Inhalation, Ingestion
Bacillus anthracis 8 - 503 Inhalation, Ingestion
Mycobacterium tuberculosis and bovis < 10 Inhalation
Coxiella burnetii 10 Inhalation
Salmonella typhi 105 Ingestion
Shigella flexneri 180 Ingestion
Treponema pallidum 57 Intradermal
Vibrio cholerae 108 Ingestion
Yersinia pestis 100 - 500 Ingestion, Inhalation
Smallpox virus (V. major) 10 - 100 Ingestion, Inhalation (rare)
Poliovirus 2 Ingestion
Influenza A2 virus < 790 Inhalation
Venezuelan encephalitis virus 1 Subcutaneous
Hepatitis A virus 10 - 100 Ingestion, intravenous
Adenovirus > 150 Intranasal
Respiratory syncitial virus > 100 - 640 Intranasal
Plasmodium falciparum 10 Intravenous
Histoplasma capsulatum 10 (mice) Inhalation

*Dose is the number of micro-organism otherwise indicated. These data are collected from different peer reviewed resources. For discussion about the definition of "infectious dose" see: Johnson B. OSHA Infectious Dose White Paper. Applied Biosafety 2003; 8(4): 160-165.


Notifying a bio-incident or a laboratory-acquired infection

Following a bio-incident there is a legal provision requiring to notify:

  • Any accident or incident (in relation to a workplace) which may have resulted in the release of a biological agent (pathogenic and/or genetically modified organism) and which can cause serious illness or infection in humans;
  • Any incident (in relation to a "contained use" workplace) during the contained use where a significant amount of pathogenic and/or genetically modified organisms is unintentionally released in the environment with immediate or long term risk to human and animal health and the environment.

To help determining whether a particular bio-incident should be notified and what the notification requirements are, the SBB has developed a dynamic online tool
=> Online occupational bio-incident notification platform

Please use the Biological incident report form to notify and/or optimize the assessment and management of health and safety consequences posed by a bio-incident which occurred during an activity of contained use.

Further guidance can be obtained at the SBB (02/642.52.93 or


Laboratory-acquired infections in Belgium: an online survey

On request of the Flemish Agency for Care and Health, Public Health Surveillance, the Biosafety and Biotechnology Unit (SBB) has developed a survey aiming at mapping and evaluating the risk for “laboratory-acquired infections” (LAIs) related to bio-incidents with pathogenic organisms (genetically modified or not) over the period 2007-2012.
This survey was initially limited to the Flemish region with the aim to gather information on bio-incidents and LAIs in biological laboratories and to gain insight into the possible underlying causes in order to provide biosafety officers, prevention officers and occupational health practitioners with tools that can enhance biological safety in the laboratory.
The survey was available in Dutch and English. In total ~50 questions and sub-questions were addressed to each respondent, consisting of single-answer questions and multi-answer questions, most of them being mandatory.

In 2013 the online survey has been extended to Wallonia and the Brussels-Capital Region (same covered period: 2007-2012).