This document provides information on performing risk assessments for various types of biosafety work. It discusses risk assessments for microbiological work, animal biosafety, genetically modified plants, and genetically modified organisms. For each type of risk assessment, it identifies key factors to consider such as pathogenicity, routes of infection, survival in the environment, and availability of treatments. It emphasizes that risk assessments should be performed by those most familiar with the specific organisms, equipment, and facilities being used.

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Biosafety risk
assessments

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Contents
 Risk Assessment
 Types of Risk Assessments
 Microbiological Risk Assessments
 Risk Assessments in Animal Biosafety
 Risk Assessments of Genetically Modified Plants
 Risk assessments of genetically modified organisms (GMOs)

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Risk Assessment
Risk assessment (RA) can be described as;
“A process of evaluation including the identification of the attendant uncertainties, of the
likelihood and severity of an adverse effect(s)/event(s) occurring to man or the environment
following exposure under defined conditions to a risk source(s)”
Risk assessment is the backbone of the practice of biosafety. A risk assessment is the best
method for determining the proper biosafety level and safety practices for the work. Although
there are many tools available to assist in the assessment of risk for a given experiment but still
the most important one is the professional judgment. Risk assessments should be performed by
the individuals most familiar with the specific characteristics of;
 The organisms being considered for use
 The equipment and procedures to be employed
 Animal models that may be used
 The containment equipment and facilities available
The laboratory director or principal investigator is responsible for ensuring that adequate and
timely risk assessments are performed. Once performed, risk assessments should be reviewed
routinely and revised when necessary.
Types of Risk Assessments
Types of risk assessments include:
 Microbiological Risk Assessments
 Risk Assessments in Animal Biosafety
 Risk Assessments of Genetically Modified Plants
 Risk assessments of genetically modified organisms (GMOs)

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Figure: Biological risk assessment and risk management
Microbiological Risk Assessment
Risk Groups have been assigned to biohazardous agents. They indicate how dangerous a
particular bacterium, virus, or other biohazard is. First, determine the risk group of the agent(s)
with which you are working. Other factors include;
 Pathogenicity/Virulence: Is the agent able to infect and cause disease in humans or
animals (i.e., pathogenicity)? What is the degree of disease severity in individuals (i.e.,
virulence)?
 Route of Infection: How does the agent gain entry in to the host (i.e., ingestion,
inhalation, mucous membranes, subcutaneous, genitourinary)?
 Mode of Transmission: How does the agent travel to the host (e.g., direct contact,
indirect contact, casual contact, aerosolized droplet or airborne transmission, vectors,
zoonosis, intermediate host)?
 Survival in the Environment: How stable is the agent outside the host? Under what
environmental conditions can it survive and for how long?

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 Infectious Dose: What amount of agent is required to cause an infection in the host
(measured in number of organisms)?
 Availability of Effective Preventative and Therapeutic Treatments: Are effective
preventative measures available (e.g., vaccines)? Are effective treatments available (e.g.,
antibiotics, antivirals)?
 Host Range: What are the primary, intermediate, and dead-end hosts? Does the agent
cause infection in a wide range of species, or is the host range more restricted?
 Natural Distribution: Is the agent present in specific area? Is it prevalent in a particular
location, region, or human or animal population? Is the agent non-indigenous?
 Impact of Introduction and/or Release into the Environment or the Public: If the
agent were introduced into the population or released into the environment, what would
be the economic, clinical, and biosecurity impact?
 Aerosol Generation: Are equipment or procedures that may generate aerosols being
used (e.g., pipetting, centrifugation, homogenization)? Personnel can be exposed to
infectious aerosols by direct inhalation of aerosolized droplets or by ingestion of droplets
that settle on surfaces or hands.
 Concentration of the Pathogen: The concentration of the agent may vary depending on
the work being performed (e.g., diagnostic specimens may contain a lower concentration
of pathogen than pure cultures).
 Either non-pathogenic or attenuated bacterial strains should be used when possible,
especially in teaching laboratories. This practice will help reduce the risk of students
and/or their family members becoming ill.
 Severity and duration of illness (acute versus chronic effects)
 Availability of vaccines or antitoxins
 Use of chemical safety practices appropriate to the techniques used (i.e., solvents, acids)
Risk Assessments in Animal Biosafety
Risk assessments in case of model animals should be following:
 Specie of the animal should be known and only permissive species should be allowed to
be used in the labs.

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 The nature of the animals, i.e. their aggressiveness and tendency to bite and scratch
should be known.
 that principal investigator (PI) should identified the risks involved, routes of exposure
(nature/ lab settings), signs/symptoms of infection ,potential for shedding from animals,
at risk personnel (those contraindicated from work) and serum banking, immunizations,
screening/evaluation.
 An appropriate medical surveillance programme for the staff must be instituted. A safety
or operations manual must be prepared and adopted.
 Biohazard warning signs should be posted on doors and other appropriate places.
 Heating, ventilation and lighting of the room containing cages must be adequate. If
mechanical ventilation is provided, the airflow must be inwards. Exhaust air is discharged
to the outside and should not be recirculated to any part of the building. Access must be
restricted to authorized persons.
 No animals should be admitted other than those for experimental use.
 There should be an arthropod and rodent control programme.
 After use, work surfaces must be decontaminated with effective disinfectants
 Biological safety cabinets (Classes I or II) or isolator cages with dedicated air supplies
and HEPA-filtered exhaust air must be provided for work that may involve the generation
of aerosols.
 Animal bedding materials must be removed in a manner that minimizes the generation of
aerosols and dust. All waste materials and bedding must be decontaminated before
disposal.
 Animal cages must be decontaminated after use.
 Animal carcasses should be incinerated.
 All injuries, however minor, must be treated appropriately, reported and recorded.
 There must be mechanical ventilation to ensure a continuous airflow through all the
rooms. Exhaust air must pass through HEPA filters before being discharged to the
atmosphere without recirculation. The system must be designed to prevent accidental
reverse flow and positive pressurization in any part of the animal house.
 There must be medical supervision of staff.

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 Personal assessment factors should be known that include personal protective
equipments/clothing and the working area.
Figure: Handling of animal cages
Risk Assessments of Genetically Modified Plants
Risk assessment of GM plants starts with problem formulation including hazard identification,
hazard characterization, exposure characterization, risk characterization, risk management
strategies, and an overall risk evaluation. Risk assessment of genetically modified organisms
considers seven specific areas of concern that includes:
 Persistence and invasiveness of the GM plant or its compatible relatives, including plant-
to-plant gene transfer.
 Plant-to-micro-organism gene transfer
 Interaction of the GM plant with target organisms
 Interaction of the GM plant with non-target organisms, including criteria for selection of
appropriate species and relevant functional groups for risk assessment
 Impact of the specific cultivation, management and harvesting techniques; including
consideration of the production systems and the receiving environment

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 Effects on biogeochemical processes
 Effects on human and animal health
Risk Assessments of Genetically Modified Organisms
(GMOs)
Before a GMO is released into the environment, a determination of the possible associated risks
to the environment, including to human health, should be undertaken.
 The pre-market safety assessment should be undertaken following a structured and
integrated approach and be performed on a case-by-case basis.
 It comprises hazard identification, hazard characterization, exposure assessment and risk
characterization. The sequential steps in risk assessment of GMOs identify characteristics
which may cause adverse effects, evaluate their potential consequences, assess the
likelihood of occurrence and estimate the risk posed by each identified characteristic.
 The safety assessment of GMOs and derived products consists of two phases, i.e., a
comparative analysis with their non-GM counterparts to identify differences, followed by
an assessment of the environmental and food safety or nutritional impact of the identified
differences, including both intended and unintended differences.
Risk assessments for work with GMOs should consider the characteristics of donor and
recipient/host organisms.
Hazards Arising Directly from the Inserted Gene (Donor Organism)
Assessment is necessary in situations where the product of the inserted gene has known
biologically or pharmacologically active properties that may give rise to harm, for example:
toxins, cytokines, hormones and oncogenic gene sequences.
The consideration of such cases should include an estimation of the level of expression required
to achieve biological or pharmacological activity.
Hazards Associated with the Recipient/Host
 Susceptibility of the host
 Pathogenicity of the host strain, including virulence, infectivity and toxin production

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 Modification of the host range
 Recipient immune status
 Consequences of exposure
Hazards Arising from the Alteration of Existing Pathogenic Traits
Many modifications do not involve genes whose products are inherently harmful, but adverse
effects may arise as the result of alteration of existing non-pathogenic or pathogenic traits.
Modification of normal genes may alter pathogenicity. In an attempt to identify these potential
hazards, the following points may be considered.
 Is there an increase in infectivity or pathogenicity?
 Could any disabling mutation within the recipient be overcome as a result of the insertion
of the foreign gene?
 Is treatment available?
 Is eradication of the GMO achievable?