Chapter 9 - Biological Hazards Flashcards
Biological Hazards
substances that are biological in nature and pose a threat to the health of living organisms
Bacteria, viruses, insects, plans, birds, animals, and humans
Health effects from skin irritation to infections
Anthrax
Bacillius anthracis
Primary occupations at risk- agricultural workers, handling goat hair wool and hides, and veterinarians
Ingestion, inhalation, or cutaneous routes
soil spores
impermeable clothing and equipment, prevention of skin contact, especially open wounds and the use of high-efficiency respiratory protection
Vaccine- only useful if administered well in advance of exposure
Annual boosters recommended
Leptospirosis
Bacterial disease caused by genus Leptospira- if untreated kidney damage, meningitis, liver failure and respiratory distress
Occupations of special interest include farmers, field worker, sugarcane workers, meatpacking house workers, sewer workers, miners, and military personnel
Animal urine contamination
Treated with antibiotics
Plague
Yersina pestis- infected animals
At risk populations- shepherds, farmers, ranchers, hunters, and geologists
Antibiotics are effective, but must be promptly treated
Preventative measure to control rodents and fleas around places where people live, work, and play -
Environmental sanitation, public education, and preventative antibiotic therapy recommended
Tetanus
Clostridium tetani
Found as spores in soil or as parasites in the gastrointestinal tract of animals
enters through break in the skin
Effective vaccine
Occupations at risk: those who work around domestic animals/soil
Tuberculosis
Mycobacterium tuberculosis
Spread through the air, - most infections asymptomatic/latent
Goals - ensure prompt detection, airborne precautions, and treatment of persons who have suspected or confirmed TB disease
Health-care settings- high risk exposure
Tularemia
Disease of animals and humans caused by Francisella tularensis
Human infection through ticks, deer fly bites, skin contact with infected animals, ingestion of contaminated water, or inhalation of contaminated dusts or aerosols
Steps to prevent tularemia include use of insect repellent, wearing gloves when handling sick or dead animals
Primary occupations at risk- forestry workers, butchers, meat plant operators
Cat scratch Fever
Bacterial disease caused by Bartonella henselae
Occupations at risk include animal laboratory workers, veterinarians, and animal housing employees
Hepatitis A
Acute infectious disease of the liver caused by HAV
Caused by fecally contaminated food or water - HAV contaminated cooked food- food prep inadequate
Occupations with greatest exposure - daycare, food prep workers, sewer and sanitation workers
Hepatitis B
HBV- incubation period from the time of exposure to onset of symptoms 6 months-6 weeks
Efficiently transmitted by percutaneous or mucous membrane exposure to infectious blood or body fluids that contain blood
Primary risk factors- unprotected sex, birth with infected mother, drug injection
CDC National strategy - routine screening of all pregnant women, routing infant vaccine, vaccination of children and adolescents, and unvaccinated adults
Occupational exposures - health-care industry and emergency medicine
Orf
Sore mouth disease caused by poxvirus
From scabs of infected animals serve as source of susceptible animals- contaminated bedding, feed, or trucks
People infected from infected animals - occupations of greatest exposures shepherds, stockyard workers, and shearers
Prevention- gloves and good hygiene
Rabies
preventable viral disease of mammals most often transmitted through the bite of a rabid animal- virus in saliva
Early symptoms similar to all viral disease- progression includes nervous/emotional symptoms, hydrophobia, hypersalivation and difficulty swallowing
Common reservoirs are raccoons, skunks, foxes, bats, and coyotes
Vaccination - post-exposure should include passive antibody human rabies immune globulin and vaccine
Psittacosis (Ornithosis)
Zoonotic infectious disease caused by Chlamydophil psittaci contracted from species of birds - most frequently pet birds and poultry
Infection from inhaling dried secretions from infected birds
Risky occupations include: bird owners, pet shop employees, and veterinarians- workers in poultry plants
Prevention - education PPE N9 respirator when handling infectious animals or bedding
Rocky Mountain Spotted Fever
most severe tick-borne rickettsial disease
Occupations at risk - military personnel, foresters, rangers, rangers, farmers, trappers, construction and lumber workers
Primary vectors - American dog tick and rocky mountain wood tick
Prevention- light colored clothing, tuck in socks, apply repellents, body checks
Q fever
Zoonotic disease caused by Coxiella buretii- cattle, sheep, and goats are primary reservoirs
Risky occupations include veterinarians, dairy farmers, ranchers, stockyard workers, slaughterhouse employees, wool handlers, and rendering plant workers
Human infection by inhalation organisms from barnyard dust contaminated with dried placental material, birth fluids, and excreta of infected animals
Prevention: education, clean birthing areas and dispose, restrict infected animals, pasteurized milk, sterilization of contaminated clothing, vaccination, quarantine, facilities for sheep away from urban areas
Aspergillosis
Found in soil, plants, decaying plant matter - spores
Farmers and grain workers are primary occupational expposure
Allergic bronchopulmonary aspergillosis or invasive aspergillosis (damages tissues in the body)
Prevention- avoidance of dust exposure, n95 respirators, EEPA filtration
Candidiasis / Thrush
fungal infection of a Candida species, usually albicans
Occupational risk - dishwashers, bartenders, cooks, bakers, poultry and packinghouse workers
Usually localized as skin or mucosal membranes of oral cavity, pharynx, or esophagus, the gastrointestinal tract, urinary bladder or genitalia
Sexually transmitted
Prevention - frequent hand washing and avoidance of hand to mouth or genitalia when handling contaminated items
Coccidioidomycosis - Valley fever
Fungal disease caused by Coccidioides species in soil of semi-arid areas
Occupational exposures - construction, agriculture, military field training, and archaeological exploration
Histoplasmosis
Fungal - primarily affects the lungs
Disseminated histoplasmosis affects other organs and can be fatal if untreated
Found in soil or material contaminated with bat or bird droppings. Spores become airborne when soil disturbed
Occupations at greatest risk include environmental remediation workers, farmers, poultry workers and veterinarians
Primary containment
protect personnel and the immediate lab environment from exposure to infectious agents
Secondary containment
protection of the envrionment outside of the laboratory
Three basic elements to a containment program
laboratory practice and technique
safety equipment
facility design
Laboratory Practice and Technique
SOP, training,
limited access to lab, work areas decontaminated daily, contaminated materials decontaminated before disposal, no food or drink, frequent handwashing, protective clothing, decontamination station may be required
Safety Equipment
biological safety cabinets, fume hoods, personal protective equipment, and safety centrifuge cups
Biological Safety Cabinet Class I
Partial containment
Room air flows through fixed front opening
Not appropriate for experimental systems vulnerable to airborne contamination
minimum velocity of 75 linear fpm
Prevents aerosols generating in cabinet from escaping to room
Biological Safety Cabinet Class II
Laminar flow cabinet
Protects worker and research material
Curtain of room air entering the grille at forward edge of opening to the work surface
Partial recirculation of HEPA-filtered air
Downward flow of HEPA-filtered air creates contaminant- free zone
Biological Safety Cabinet Class II Type A
Fixed work opening
Minimum inflow velocity of 75 linear fpm
70% recirculation
Minimum vertical velocity of 75 linear fpm
Not for flammable solvents, toxic agents, or radioactive materials
Biological Safety Cabinet Class II B1
Vertical sliding sash
100 linear fpm at 8-inch work opening
50 linear fpm downward vertical air velocity
70% of air flowing through work area is exhausted
Not recommended for explosive vapors
Biological Safety Cabinets Class II Type B2
HEPA downflow air is from lab or outside air
minimum inflow velocity of 100 fpm
100% exhaust to outside through HEPA, no recirculation within cabinet
used for low to moderate risk biological agents, toxic chemicals and radionuclides
Biological Safety Cabinet Type B3
HEPA downflow air is from lab or outside air
minimum inflow velocity of 100fpm
70% recirculated air is exhausted to outside through HEPA
used for low to moderate risk biological agents, minute or trace amounts of toxic chemicals, and radionuclides
Biological Safety Cabinet Class III (Gas Tight, Negative Pressure)
Provides physical barrier between agent and worker
Highest degree of worker protection
Arm-length rubber gloves and sealed front panel
Air drawn into cabinet through HEPA filtration
Facility Design and Construction
Primary purpose is to prevent the escape of hazardous materials or agents outside of the controlled environment
Biosafety Level 1
basic containment - relies on standard microbiological practices
no special primary or secondary barriers required except for handwashing facilities
Biosafety Level II`
Use of standard microbiological techniques
training of personnel
Collection of baseline serum samples taken and stored
Warning signage
Personal protective equipment
Include Class I or II biological safety cabinet
Access to laboratory limited
Decontamination of equipment and instruments
Adequate for most medical laboratories
Biosafety III
Greater emphasis on primary and secondary barriers
Perform manipulations of agents in biosafety cabinet or other enclosed equipment
Strict controlled access to laboratory environment
Use of biosafety cabinets (I, II, or III) strictly enforced
For work with indigenous or exotic agents with potential for respiratory transmission that may cause serious and potentially lethal infection
Biosafety Level IV
highest level of protection
Practices and techniques to prevent infection or escape hazardous agents
All manipulations in biological safety cabinets
sealed openings to laboratory
standard microbiological practices
warning signage
frequent hand washing
Special engineering
air lock between laboratory and public areas to prevent escape of hazardous agent
OSHA blood borne Pathogen Standard
found in 29 CFR 1910.1030
