BIOLOGICAL RISK FACTORS
DEFINITIONS Biohazard – organisms or products of organisms
that present a risk to humans
Organism – a living thing, such as a germ, plant,
animal, or human that may consist of several parts, with each part specializing in a particular function
Microorganism – a minute organism, such as
microbes, bacteria, viruses, molds, etc.
 High exposure also found in
agriculture, manufacture of food products, services to individuals and households, research and development, and sanitation activities
DEVELOPMENT OF BIOSAFETY Army at Fort Detrick – Frederick, Maryland Researching biological warfare agents
1941 – Chemical Warfare Services American Society of Microbiology served as advisors to
CWS
1970’s – Recombinant DNA technology 1980’s - Appearance of HIV 1991 – OSHA’s Bloodborne Pathogens Program (29
CFR 1910.1030)
BIOHAZARDS ARE… Inherently different from chemicals, physical
agents, carcinogens, etc. BUT, recognition, evaluation and control still can
be applied
BIOLOGICAL MATERIALS TYPICALLY….. Have no threshold level of exposure, i.e., dose and
response relationship
Are ubiquitous in the environment so the idea of
“permissible exposure limits” is inappropriate
Are affected by biological competition rather than
behaving in an additive or synergistic way
Interact with the host and its environment to produce
the adverse effects
FOR ILLNESS TO OCCUR….. The agent must be pathogenic. There must be a reservoir of sufficient number. The agent must escape the reservoir. The organism must be able to move through the
environment.
There must be a portal of entry for the host. The host must be susceptible to the agent.
FACTORS AFFECTING INFECTION AND EXPOSURE Modes of transmission Contact (direct/indirect, zoonotic); vector-borne, airborne Routes of entry Infectious dose (infective dose) Number of microorganism Viability and virulence of agent Viability - Ability to replicate Virulence – Ability to cause disease Host susceptibility Skin disorders, immune system, vaccination allergy, infection of fetus, work practices
SOME COMMON BIOLOGICAL AGENTS Bacteria Viruses Fungi Parasites
BACTERIA Simple, one-celled
organisms
Cocci, bacilli, spirilla Some are pathogenic, some
are harmless, some are even useful
Reactions: infection,
exposure, allergic reactions
VIRUSES Smallest known organisms Living non-cellular entities Are “obligate parasites” and
cannot survive without living cells
Common occupational
exposures to animal virus, poxvirus & arbovirus
FUNGI Broadest spectrum among
biological agents
Are either parasitic or
saprophytic
Hypersensitivity due to
inhaled fungal antigens
Fungal disease is rare but
includes ringworm and athlete’s foot
PARASITES Parasitic to plants or
animals
Examples: ticks,
hookworms, pinworms
Reactions: skin reaction,
inflammatory response, allergic reaction
Diseases include malaria
and other blood and GI infections
TUBERCULOSIS (TB) Bacterial disease caused by Mycobacterium
tuberculosis Some populations are at greater risk Transmitted by inhalation of infectious droplet nuclei
suspended in air Symptoms : Early on: fatigue, fever, weight loss Later: Hoarseness, cough, hemoptysis (blood-tinged
sputum), lesions in respiratory tract
ACQUIRED IMMUNE DEFICIENCY SYNDROME (AIDS) Caused by HIV, a virus Transmitted via sexual contact, sharing of needles and transfused
blood
Symptoms include tiredness, fever, night sweats, weight loss No single test as diagnosis Treatment (at present) cannot cure or restore the immune system
ANTHRAX Caused by spore-forming
bacterium Bacillus anthracis
Found in imported animal
products
Types of anthrax; Cutaneous anthrax Inhalational anthrax Gastrointestinal anthrax
CUTANEOUS ANTHRAX Most common naturally
occurring infection Incubation period of 1-12 days Symptoms: small, raised bump ulcer with black center fever, headache, malaise
INHALATIONAL ANTHRAX Most lethal form Incubation period of 1-7 and
possible 60 days Symptoms: sore throat, fever, muscles aches respiratory failure and shock
Fatality rate of approximately 75%
GASTROINTESTINAL ANTHRAX Follows consumption of raw or
undercooked meat Incubation period of 1-7days Symptoms: sore throat, fever loss of appetite nausea & vomiting
Fatality rate between 25%-60%
GENERAL PRECAUTIONS Determinin sensitive people with periodic scanning, Training of staff, Determining the mode of action to be followed when working, Suitability of laboratory, Proper insulation and disinfection precautions, Active immunization,
GENERAL PRECAUIONS IN LABORATORY Not to use pipette with mouth, Paying attention to bubble formation while working with
pipette,
Not to use needles and syringes instead of pipette, Carrying out all dangerous operations in the Biosafety Cabinet, Disposing used needles and injectors directly into sturdy
containers with narrow rims,
The prohibition of eating, drinking and smoking in
laboratories,
Washing hands while leaving, leaving aprons in laboratories
must be necessary.
BIOLOGICAL AGENTS IN THE WORKPLACE SITUATION IN THE EU 320,000 workers die worldwide every year of communicable diseases caused by biological agents 5,000 of these fatalities in the European Union At least 15% of all new cases of cancer worldwide are caused by viruses, bacteria or parasites (e.g. aflatoxin B1 from Aspergillius flavus, hepatitis B, wood dust) 1,900 cases of recognised occupational diseases due to biological agents in the EU-15 in 2001 Long workplace absences due to infectious diseases
PANDEMICS AND OSH RISKS (1) New pathogens emerge (SARS, avian flu, Marburg) & “old” ones re-emerge (cholera, dengue, measles, yellow fever) Over ¾ of human diseases are zoonoses A new contagious virus could spread worldwide in less than 3 months due to high speed/volume of international transport. 89 Dutch poultry workers infected with A/H7N7 in 2003
PANDEMICS AND OSH RISKS (2) In 2003, 2 nurses and 1 doctor died from SARS in Toronto, after contact with an infected individual from China. This outbreak led to 128 SARS infections, mostly in medical staff. High risk of dengue fever in international trade of goods: California: in 2001, Aedes albopictus found in 14 tyreresellers - was introduced by a cargo ship from China. France: 1st found in 1999 in a tyre plant national monitoring system
PANDEMICS AND OSH RISKS (3) 3 million health care workers (out of 35 millions) exposed to HBV, HCV and HIV every year via percutaneous injuries. In 2005, 24.5 million workers lived with HIV out of 38.6 infected persons worldwide. Also affects sex workers, transport and mobile workers. Pandemics are not only a workplace issue because it affects the workforce, but also because the workplace can play a crucial role in limiting transmission Need to be dealt with globally and in cooperation between various disciplines, such as OSH, public health, animal health, environmental protection and food safety.