So how do you do a risk assessment and what are the factors involved to consider? You should always consider at least three major factors: 1) the biological agent – what are you working with, 2) the procedure or protocol that you are using – what are you doing, and 3) the worker and their level of skill and competence – who is doing the work. While these are not the only factors to consider they are the major elements that will contribute to the likelihood and consequences of an incident occurring in the laboratory or vivarium. We will now explore all three of these.

Understand the biohazard
As many of you know from working in biomedical facilities, there are a wide variety of biohazardous organisms that are potentially present in your facility. Beginning with just the basic microorganisms – like the bacteria and their toxins, archaea, viruses, protists, fungi and others. These are all well described in many of the microbiology manuals that you’ve used in school. A number of organizations have classified these basic microorganisms into different risk groups based on their inherent risk. I will describe risk groups in a few minutes. In addition to the basic natural microorganisms, there is the also the potential hazards of recombinant microorganisms that are being created through manipulation of the organism’s genome (DNA or RNA). There’s also a growing field called synthetic biology where people are taking microorganisms and creating new life forms. Furthermore, there’s another field called nanotechnology. It’s the marriage between engineering and biology where scientists are again creating small biological entities, that may be biohazardous. I encourage you to look up nano technology and the synthetic biology and learn more.

This brings us to step one of the agent-based risk assessment, where you ask yourself – what is known about the biohazard that you’re working with. What information is in the literature about the agent? What’s known about its transmissibility, the infectious dose, the route of infection, and can it cause disease in people? Is there a known LD50 an ID50, or a TCID50? The literature may or may not tell you, based on a particular route of exposure. What is known about the agent’s virulence or pathogenicity? What is the toxicity of the agent? Is the agent associated with cancer, such as hepatitis B virus causing liver cancer? Does the agent, or any byproducts induce allergic reactions? What is the host range? Is it restricted or broad – does it infect humans, animals or maybe even plants? To what extent do infected animals transmit the disease? What is the communicability? Are there reports of epidemics or laboratory infections? It is really important to know if this agent can or has caused disease and outbreaks. What do you know about how it’s moves from host to host? What is the transmission route – direct contact or is it vector borne? Is the transmission through ingestion or inhalation? These factors are very important to understand, because later on you will see that biosafety focuses a lot on trying to prevent routes of transmission. What is known about environmental stability? Is it very stable in the environment or does it die once it leaves the host? Is it resistant to disinfection? And lastly, one other important factor. Is there any treatment, vaccine or prophylaxis available? If you do get infected or exposed to this potential pathogen, can you do anything about it? All these factors have to be considered when you do the initial risk assessment steps.

A number of organizations around the world have taken the basic biological microorganisms and classified them into risk groups. Follow the links I have provided to learn more. Most organizations have classified pathogens into four risk groups – 1 to 4 – based upon increasing risk. Depending on what country you’re in – risk group 1 is high or 1 is low. Risk groups look at the severity of the disease; the individual and community risk; the host range and route of transmission; the availability of treatment or prophylaxis and the endemicity and the environmental stability. Risk groups provide a guide to the pathogen’s inherent danger or risk.

Let’s now look at the different risk groups. Risk group 1 (or risk group 4 in some countries), has no or low individual or community risks and is unlikely to cause human or animal disease. So really very low risk microorganisms. Risk group 2 (or risk group three in some countries), has moderate individual risk and low community risk – can cause disease, but is not likely to be a serious hazard. Laboratory exposures may cause serious infection, but effective treatment or preventive measures are available. Risk group 3 (or risk group 2 in some countries), has high individual risk and low community risk and usually causes serious human or animal disease, but does not ordinarily spread. Effective treatment prevention measures are available. Finally, the worst risk group – risk group 4 (or risk group 1 in some countries). These agents have high individual and high community risk; usually cause serious human or animal disease; are readily transmitted and effective treatment measures and prophylaxis are not usually available.

To obtain further information about a pathogen, their transmissibility, and protective measures you can also consult the pathogen safety data sheets, published by the Canadian government. Follow the link shown in green. They have very good information on many pathogens, but not all of them.

Biosafety levels and risk groups. I want you to be very clear that these are not the same. A lot of people get these confused and they talk about biosafety level agents or organisms. Biosafety levels are a combination of controls needed to mitigate risk and risk groups are based on the innate characteristics of the agents. The risk group really talks about how dangerous the pathogens are, on a scale of 1-4 and biosafety levels talk about all the controls that are used to mitigate the risk from the pathogens (also on a scale of 1-4). Therefore, you have to be careful to make sure you talk about the right thing in the right way.

Summary
There are a wide variety of biohazardous agents in a biomedical facility, including basic microorganisms, newly synthesized organisms, engineered organisms and toxins. Not all strains of biohazardous agents have the same level of virulence, pathogenicity or transmissibility. The more you can learn about the particular pathogens that are being used in your facility, the more you can understand what the potential risks are. Many pathogens have been classified into risk groups based upon various factors to help guide you when doing a risk assessment. Risk groups and biosafety levels are not the same thing.

Remember that this is only step one in doing a risk assessment. Next you want to consider what is being done with the pathogen and where it is being used.