4.BIOLOGICAL RISK FACTORS

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.