VIEWS: 90 PAGES: 24 POSTED ON: 12/9/2011
BIOLOGICAL HAZARDS …health hazards associated with exposure to biological agents 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, cocci, viruses, molds, etc. 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) RECENT INCREASED AWARENESS OF BIOHAZARDS Newest subset of focus Contributing to awareness Legionnaires’ disease AIDS epidemic rDNA technology anthrax Specialists exist but their numbers are small S/H/E professionals have become involved Occupational hazards… Healthcare – Hepatitis, tuberculosis, infections – Infections categorized as: Community acquired – transmitted to either patients or workers Occupationally acquired – resulting from worker exposure Nosocomial – hospital-acquired infections of patients Research facilities – Q fever, hepatitis, typhoid fever, tuberculosis, dermatomycosis – Percutaneous inoculation (needles/syringes, cuts or abrasions from contaminated items, and animal bites/scratches); inhalation of aerosols, contact between mucous membranes and contaminated material (hands and surfaces), and ingestion Agriculture – Workers may be exposed to infectious microorganisms that are associated with the plants or animals – Food and grain handlers, farmers, laborers – may be exposed to parasitic diseases – Processors who handle animal products – may acquire bacterial skin diseases from working with contaminated hides, infected with contaminated fish, meat or poultry, Bacterial infections from exposure to feces from infected turkeys, geese, ducks, etc. Animal facilities/Veterinary practices – Bites, scratches, parasites, diseases, allergens Biotechnology facilities – Genetically engineered bacteria, fungi, plant and animal cells for development of products Miscellaneous occupations – Workers maintaining water systems (legionella); pet shops; zoos; wood-processing facilities (fungi); sewage workers (bacteria, virus, parasites); forestry workers (Rocky Mountain spotted fever, lyme disease, viruses and bacteria from ticks, fungi); child care workers (bacteria (shingles), viruses (measles, chickenpox); public safety workers (bloodborne pathogens, viral respiratory diseases (influenza). 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 Classification of Biohazards Microorganisms Allergens – Examples: viruses, bacteria, – Examples: from higher plants fungi, protozoa, algae – Reactions: Dermatitis, rhinitis, – Reactions: infection, exposure, asthma allergic reactions Protein Allergens Arthropods – Examples: vertebrate animals – Examples: crustaceans, (urine, feces, hair, saliva, dander) arachnids, insects – Reactions: allergic reactions – Reactions: skin inflammation, Parasites allergic reactions, systemic intoxication, transmission of – Examples: ticks, hookworms, infectious agents pinworms – Reactions: skin reaction, inflammatory response, allergic reaction Some common biological agents Bacteria Viruses Rickettsiae Fungi Parasites BACTERIA Simple, one-celled organisms Cocci, bacilli, spirilla Some are pathogenic, some are harmless, some are even useful Broken skin is particularly vulnerable “Food poisoning” in mass VIRUSES Smallest known organisms Living (?) non-cellular entities Are “obligate parasites” & cannot survive without living cells Common occupational exposures to animal virus, poxvirus & arbovirus RICKETTSIAE Bacteria-like but smaller Are obligate parasites Transmitted to humans via bloodsucking arthropods (fleas, ticks & lice) or through the air Responsible for typhus and Rocky Mountain spotted fever FUNGI Broadest spectrum among biological agents Are either parasitic or saprophytic Hypersensitivity due to inhaled fungal antigens Fungal disease is rare but includes ringworm & athlete’s foot PARASITES Parasitic to plants or animals Diseases include malaria and other blood and GI infections Dermatitis and other skin-related ailments due to mites and chiggers, etc. Legionnaires’ Disease Caused by legionella pneumophila, a bacterium Presence possible if moisture, elevated temperature, oxygen and nourishment available Clearly can be transmitted through air and perhaps other ways Symptoms resemble a form of pneumonia and can be treated accordingly About 15% of known cases have been fatal 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% SUMMARY A tremendous variety of biological materials exists as potential exposure agents. Effects of bio-hazardous agents are subtle and slow in developing. There is increasing concern about, and interest in, biological materials. Bottom-line: biohazards are (and must be) treated with extraordinary caution.
Pages to are hidden for
"BIOLOGICAL HAZARDS"Please download to view full document