FAQ: High containment (safety issues)

The minimal levels for working with CSFV in the laboratory are laid down in the “Diagnostic Manual establishing diagnostic procedures, sampling methods and criteria for evaluation of laboratory tests for the confirmation of classical swine fever” (Commission Decision 2002/106/EC, Chapter IX). Any laboratory working with CSFV has to have dedicated rooms for the work with CSFV. Dedicated outer clothing and disposable gloves must be worn and entry to the laboratory is limited to named and trained personnel only. Biological safety cabinets (class I or II), which should have double HEPA filtration of exhaust air, must be used for all manipulations of live virus. All equipment used for diagnosis must be available within the CSF unit. It is obligatory to keep CSF virus in secure storage. All ampoules must be clearly labelled and comprehensive records must be maintained. Personnel must wash and disinfect hands before leaving the unit, and the outer laboratory clothing must be sterilised before removal from the unit. Personnel is not permitted near pigs for 48 hours after leaving the unit. If extensive multiplication of virus is performed within the unit, additional requirements (e.g. complete change of clothes on entry, double HEPA filtration of exhaust air) are to be obeyed. Additional safety measures for the work with CSFV are also laid down by national legislation of the Member States.

The minimal levels for working with CSFV in the laboratory are laid down in the “Diagnostic Manual establishing diagnostic procedures, sampling methods and criteria for evaluation of laboratory tests for the confirmation of classical swine fever” (Commission Decision 2002/106/EC, Chapter IX). Any laboratory were animal experiments with CSFV are performed, must have a negative pressure controlled ventilation, double HEPA filtration of exhaust air, facilities for complete fumigation/disinfection at the end of experiment and facilities to teat all effluents (e.g. waste water) in a way, which ensures that the virus is inactivated. Personnel must completely change clothes on entry disposable gloves must be worn. Entry to the laboratory/stables is limited to named and trained personnel only. All equipment required for animal procedures must be available within the unit. All materials need to be sterilised before removal, or must be double wrapped in leakproof containers, which are surface disinfected, for transport to another CSFV laboratory. Animals are to be slaughtered and incinerated on completion of the trial. On leaving the unit a full shower has to be taken! Laboratory clothing must be sterilised before removal from the unit. Personnel is not permitted near pigs for 48 hours after leaving the unit. Additional safety measures for the work with CSFV are laid down by national legislation of the Member States.

EU and national legislation is in place to ensure that high bio-safety standards are kept at a high level. A variety of different bio-safety measures are available, which ensure that hazardous viruses do not escape the laboratory. The measures necessary depend on the nature of the agent, its biological properties and its bio-hazard potential and therefore might vary from virus to virus. In general, dedicated rooms or buildings must be available, which have to fulfil certain criteria (e.g. single or double HEPA filtration of exhaust air, negative pressure controlled ventilation). Entry to these units is always limited to named and trained personnel. All work on live viruses has to be performed within these specially equipped laboratories and extensive records have to be kept on viruses, which have to be kept in secure storage. Dedicated clothing must be worn within the unit, which must be sterilised before removal from the unit. Personnel is required to take precautions, when leaving the unit (e.g. washing and disinfecting hands or showering) and is not allowed near susceptible species for a certain period of time.

High Efficiency Particulate Airfilters (HEPA) are used for the exhaust air of high security laboratories and animal facilities. HEPA filters can remove up to 99.995 % of airborne particles and are a very effective means to prevent the spread of airborne bacterial and viral organisms and, therefore, infection. The efficiency of HEPA filtration can be increased even further by connecting them in series.

The bio-safety regulations for personnel working in microbiological or biomedical, especially for those working in high containment, aim at preventing or reducing exposure of individuals or the environment to potentially hazardous infectious agents. Regulations vary depending on the level of security that has to be applied.

Usually four distinct levels are defined, whereas level one requires the least bio-safety measures and level four is of the highest safety standard.

There are two main reasons for these regulations:

1. First of all it has to be assured that the personnel is not put at risk at any time during work. It has to be assured that laboratory personnel or people working with experimental animals do not become infected when working with pathogens.
2. Secondly it has to be assured, that personnel does not carry infectious agents into the environment and may thus cause an outbreak in either humans or animals.
   

Personnel have to be informed about the infectious agents it is working with and have to be specially trained for the job. Access to the laboratory or animal facilities is limited and areas with potential bio-safety hazard have to well marked with special signs and labels. Health hazards have to be defined and countermeasures have to be taken which shall prevent exposure.

Basic rules are:

• Eating, drinking and smoking in the laboratory are strictly forbidden.
  
• Personnel must wear protective clothing and gloves, pipeting devices must be used and pipetting using the mouth is absolutely forbidden.
  
• Facilities for washing and disinfecting of hands must be readily available and the laboratory surfaces must be easy to clean and disinfect.
  
• Vials containing known infectious substances may only be opened under a safety cabinet. 
• Detailed records on infectious substances have to be kept and tracking and tracing of biological stocks must be ensured.
  

Whereas in biological safety level the only containment may be a safety cabinet, from bio-safety level 3 on drastically increased regulations are in place. Entry to facilities (usually) requires a double door entry system with directional airflow inwards. Rooms must be sealed in order to prevent the pathogen from escaping from the laboratory. Respiratory protection might be indicated for the personnel depending on the pathogen. BSL-4 laboratories may only be entered in a special suit (“space suit”) with separate airflow from outside and elaborate procedures for entering the room, and decontamination procedures for leaving the room are prescribed.

International and national legislation on bio-safety are in place. In the European Union Council Directive 2000/54/EC of 18 September 2000 on the protection of workers from risks related to exposure to biological agents at work is the most important document. Here risk groups for biological agents are defined and instructions are given on which safety precautions have to be taken. This directive had to be transposed into national law, so that various national regulations are in place. In addition, bio-safety issues are also dealt with in the legislation on the transmissible animal diseases such as Council Directive 2001/89/EC on Classical swine fever or Council Directive 2003/85/EC on Foot-and-Mouth Disease.

The biological safety levels are defined according to the level of risk of infection of the individual and the relative danger to the surrounding environment. Council Directive 2000/54/EC on the protection of workers from risks related to exposure to biological agents at work defines for distinct groups:

• Group 1: Biological agent that is unlikely to cause human disease.
• Group 2: Biological agent that can cause human disease and might be a hazard to workers; it is unlikely to spread to the community; there is usually effective prophylaxis or treatment available.
  
• Group 3: Biological agent that can cause severe human disease and present a serious hazard to workers; it may present a risk of spreading to the community, but there is usually effective prophylaxis or treatment available.
  
• Group 4: Biological agent that causes severe human disease and is a serious hazard to workers; it may present a high risk of spreading to the community; there is usually no effective prophylaxis or treatment available.
  

The Centers for Disease Control and Prevention (CDC, USA) also define four distinct groups:

• BSL 1: This level is suitable for work involving well-characterized agents not known to consistently cause disease in healthy adult humans, and of minimal potential hazard to laboratory personnel and the environment.
  
• BSL 2: This level is similar to Biosafety Level 1 and is suitable for work involving agents of moderate potential hazard to personnel and the environment.
  
• BSL 3: This level is applicable to clinical, diagnostic, teaching, research, or production facilities in which work is done with indigenous or exotic agents which may cause serious or potentially lethal disease after inhalation.
  
• BSL 4: This level is required for work with dangerous and exotic agents that pose a high individual risk of aerosol-transmitted laboratory infections, agents which cause severe to fatal disease in humans for which vaccines or other treatments are not available.