Exam 2 Flashcards
What is zoonosis
an infection or infectious disease transmissible under natural conditions from vertebrate animals to humans
what is a vector
an insect or any living carrier that transports an infectious agent from an infected individual or its wastes to a susceptible individual or its food or immediate surroundings
what is vector-borne infection
interaction between the infectious agent and the human host
examples of zoonotic diseases
rabies, anthrax, salmonellosis, hantavirus, plague
examples of vector borne diseases
malaria, leishmaniasis, plague, lyme disease, and rocky mountain spotted fever
Malaria
- present in more than 100 countries
- more than 50 percent of the world population is at risk
what are the infectious agents of malaria
Parasitic Protozoan
- plasmodium falciparum - most deadly
- plasmodium vivax
- plasmodium ovale
- plasmodium malariae
transmission of malaria
- complex life cycle of mosquitos , the vector, and human hosts
- transmitted through the bite of an infected mosquito of the anopheles type
- symptoms of malaria occur approximately 9-14 days after being bit by an infected mosquito
costs of malaria
Direct Costs
- treatment
- disease prevention
Other Costs
- lost productivity
- lost earnings
- negative impact on tourism and agricultural labor
Estimated global direct economic costs - 12 billion USD annually
How has malaria been controlled
- in the US, malaria was endemic until the end of the 1940s
- use of DDT and synthetic antimalaria drugs found to be efficacious in the mid-20th century
-DDT no longer used due to the harm caused to wild life - south africa still sprays DDT annually, but only indoors
what causes leishmaniasis and what are the three forms
- parasitic disease caused by the protozoa, Leishmania
- three forms- visceral, mucocutaneous, and cutaneous
leishmaniasis transmission
- cutaneous form is transmitted from the reservoir to the human host by a sand fly
- after being bitten by the fly, the human host develops distinctive sore skin that forms after an incubation period of several weeks or months
environmental factors associated with observed increases in leishmaniasis
- movement of human population into endemic areas
- increasing urbanization
- extension of agricultural projects into endemic areas
- climate change due to global warming
leishmaniasis control methods
- periodic application of long-acting insecticides to dwelling units
- use of screens to prevent sand flies from entering housing
- elimination of breeding areas for the phlebotomus fly
- destruction of rodent burrows and control of domestic dogs
what causes the plague and what are the symptoms
- bacterium yersinia pestis infects both animals and humans
- called black death during the middle ages
- begins with non specific symptoms
plague transmission
- transmitted by the bite of a flea harbored by rodents
- respiratory droplets from a pneumonic plague infected person can transfer the bacterium to other individuals
plague control methods
- encourage the public to avoid enzootic areas, especially rodent burrows, and direct contact with rodents
- preventing rats from entering buildings and removing food sources that could enable rats multiply
- rats can be transferred onto ships in cargo containers
lyme disease transmission and treatment
- black legged ticks act as the disease transmission vector
- antibiotic exists for successful treatment if diagnosed in the early stages of the disease
Lyme disease
- caused by the bacterium Borrelia burgdorferi
- concentrated in the northeastern, mid-atlantic, and upper midwestern regions of the US
Rocky Mountain Spotted Fever
- caused by Rickettsia rickettsii - a rickettsial agent
- symptoms are sudden onset moderate-high fevers that may last up to three weeks
- case fatality rate is up to 25 percent of untreated patients
- treatable with antibiotics
- transmitted through bite of an infected tick
viral hemorrhagic fevers
- hantavirus pulmonary syndrome, dengue hemorrhagic fever, ebola
- a severe, multi system syndrome characterized by damage of overall vascular system and impairment of body’s ability to regulate itself. symptoms often accompanied by hemorrhage
- viruses that cause most infections are zoonoses; causative virus requires animal or insect host
- viruses are limited to geographic areas where the host species reside
arthropod-borne viral diseases
- group of viral diseases that can be acquired through the bite of blood-feeding arthropod vectors
- the cycle of transmission involves a non human vertebrate and an arthropod vector
- humans may or may not be part of the infection cycle
what are the four main clinical symptoms of arboviral disease
- acute central nervous system illness
- acute self-limited fevers, with and without rash
- hemorrhagic fevers
- polyarthritis and rash, w/wo fever and of variable durations
arboviral encephalitis
- caused by virus that produces acute inflammation of sections of the brain, spinal cord, and meninges
- majority of infections are asymptomatic. Presents as a mild illness with fever and headache, severe illness, high fever, disorientation, and death
- most arboviral encephalitis are transmitted by the bite of an arthropod- primarily mosquitoes
west nile fever
- caused by west nile virus, a mosquito borne viral fever
- etiology agent is flavivirus wnv, which can spread rapidly across wide geographic regions in the US
- neuroinvasive disease is the most severe form
- mosquitos become carriers after feeding on infected birds
emerging zoonoses
- zoonotic diseases caused by either new agents or known agents emerging in areas or species previously unaffected by them
factors associated with the rise of emerging zoonoses
- Ecological changes resulting from agricultural practices, such as deforestation, conversion of grasslands, irrigation
- Human population and behavior changes
Hantavirus pulmonary syndrome
- severe and sometimes fatal respiratory condition
- hantavirus is the causative agent
- main host and vector- north american deer mouse
- transmitted through inhalation of aerosolized urine and droppings from infected rodents
Dengue fever
- caused by the falviviruses
- dengue hemorrhagic fever is life-threatening fever with abdominal pain and bleeding phenomena
- dengue shock syndrome is potentially fatal
- transmitted through mosquito bite
- affected areas are primarily tropical and subtropical areas
zika virus
- mosquito borne, linked with developing febrile rash and has been associated with adverse birth outcomes in women infected while pregnant
ebola viral hemorrhagic fever
- people get ebola through contact with the bodily fluids of an infected dead person
rift valley fever
- caused by the phlebovirus
- can produce epizoodic or widespread disease through mosquitoes among domestic animals, and infected mosquitos transmit rvf to humans
- can also be contracted through the bodily fluids of infected animals
- endemic areas for rvf include south africa, sub-sarahan africa, and madagascar
other zoonotic disease
- monkeypox
- anthrax; caused by spore forming bacterium and commonly occurs among herbivores
- rabies, caused by virus transmitted through saliva from the bites of infected animals
- tularemia; rabbit fever; bacterial disease broadly distributed in the US linked with wild animals like rodents and hares
- Psittacosis (parrot fever): infectious disease associated with bacterial agents and conveyed by dried bird droppings
- Flu A virus
control and prevention of mosquito-born diseases
- use sentinel chickens and birds to monitor for the presence of viruses
- Drain standing water
- introduce mosquito-eating fish into ponds
- wear repellants and protective clothing
- repair window screens
dioxin is in agent orange and caused by the burning process
what do toxic metals include
heavy metals like lead, mercury, nickel and other metallic compounds like aluminum, iron, and tin
how much do heavy metals exceed the specific gravity of water
five or more times
what are the effects of acute exposure to toxic metals at high levels
- rapid onset of dramatic and severe symptoms
- symptoms based on ingestion; gastrointestinal
- symptoms based on inhalation; neurological effects
Effects of chronic exposure to toxic metals at lower levels - reduced cognitive functioning
- difficult to differentiate from those of chronic medical condition
CERCLA priority list of hazardous substances
a rank of hazardous substances that pose the most significant potential threat to human health
National Priority List NPL
- prioritized by ATSDR and EPA
- lists most serious uncontrolled or abandonded hazardous waste sites in the United States identified for possible long-term remedial action under superfund
five metals in the top 20 hazardous substances
- Arsenic
- Lead
- Mercury
- Cadmium
- Chromium
types of media people can be exposed to metal through
air, soil/dust, water, biota/food
heavy metal effects in women
- differences due to hormonal and metabolic processes
- some toxic heavy metals have the ability to cross the placental barrier, with the potential to cause fetal brain damage
heavy metal exposure effects in children
- more hazardous due to small body weight
- toxic effects may be irreversible
toxic effects include: - impairment of physical and mental development
- damage to internal organs and the nervous system
- some forms of cancer
- mortality
what is the classification of major toxic metals
metals that are toxic to life forms and not necessary to sustain life
- As, Pb, and Hg
what is the classification of essential metals with potential for toxicity
metals that are considered essential for life when present in trace amounts, but amounts greater than trace levels have the potential to be toxic
- Fe, Cu, Mn, and Zn
what is the classification for metals related to medical therapy
metals used in medical therapy
bioaccumulation
toxic substances become more concentrated and potentially more harmful as they move up the food chain
properties and exposure possibilities of arsenic
- acutley poisonous material that is ubiquitous in nature - in soil and water
- by product of refining gold and other metals. Has been used in pesticides, wood preservatives, and some manufacturing
- inhalation and ingestion can occur through industrial process or drinking contaminated drinking water
health effects of arsenic
Non-cancerous
- peripheral vascular disease
- cerebrovascular disease
- cardiovascular disease
- adverse pregnancy outcomes
Cancer
- lung cancer
- skin, bladder, kidney, and liver
historical arsenic poisoning
- blackfoot disease in taiwan in 1950s
- miners and ag workers exposed through arsenic containing pesticides
- low-level chronic exposure associated with melanosis
characteristics and possible exposure sites of beryllium
- lighter than aluminum but stronger than steel
- workers in the metal industry are most likely to be exposed. Most frequent method of occupational exposure is inhalation
- general public exposure results from coal burning emissions
- emissions form coal-burning plants may contaminate agricultural products
health effects of beryllium
Non-Cancer
- inhalation can result in berylliosis, also known as chronic beryllium disease (CBD).
Cancer
- beryllium is a carcinogen for lung cancer
cadmium properties and possible exposure sights
- found in all soils and rocks and coal and fertilizers derived from minerals
- used in batteries. Released as a byproduct of the mining industry and manufacturing of fertilizers and pesticides
- fish, plants, and animals contain a certain amount of cadmium
primary sources of cadmium exposure
primary sources of environmental exposure:
- cigarette smoke
- vegetables grown in cadmium-containing soil
- bioaccumulates in shellfish
- some species of mushrooms
Occupational exposure to cadmium:
- production of nickel-cadmium batteries
- zinc smelting
- paint manufacturing
- soldering
- metal factories
Health effects of cadmium
Non-Cancer:
- osteoporosis
- loss of height
- kidney damage
- elevated BP
- Cardiovascular disease
- Itai-itai disease
Cancer:
- lung, trachea, and bronchus cancer
chromium properties and sources of exposure
- naturally occurring element in the earth’s crust
common forms of chromim: - Cr: from human industrial activities
- Cr3+: an essential nutrient
- Cr6+: from human industrial activities classified as a carcinogen
health effects of Cr6+
Non-cancerous:
- exposure via ingestion: digestive issues, damage to organs such as the kidney and liver
- topical exposure: skin ulcers
- exposure via inhalation: respiratory issues
Cancer:
- GI squamous cell carcinoma
- respiratory lung cancer
what did the film erin brockovich call attention to
erin brockovich was a lawyer who helped the residents of hinkley, california win claims against a company responsible for groundwater contamination with hexavalent chromium
mercury properties and possible exposure
naturally occurring metal existing in three major forms
- metallic mercury
- inorganic mercury
- organic mercury
has also been used as medical treatment in the past
mercury exposure
- released into the environment as a by-product of industrial processes. Low levels can be magnified through methylation and biaccumulation
- particular hazard to fetuses
bioaccumulation
causes mercury levels to become more concentrated in aquatic invertebrates
health effects of mercury
nervous and developmental impairments
historical mercury poisoining
minamata disease
- 1956: neurologic disease resulted among people who ate fish that were contaminated with methylated mercury
lead exposure
- historical environmental exposure included gas, tap water, and paint
- primary source of exposure is through ingesting contaminated food or water, or inhaling ambient lead particles
- secondary exposure may occur when workers transfer lead particles on their clothing from their workplace to their homes
health effects of lead
- lead is a neurotoxin
- toxic level in children in 5 microgram/dL
- probable human carcinogen
nickel properties and possible exposure
- heavy metal
- one of the the constituents of the earths crust
- human exposure to low levels of nickel is unavoidable
- used in the production of many appliances, tools, and batteries
nickel exposure
- welding workers exposed through inhalation
- occupational exposure also happens via skin contact
health effects of nickel
Non-cancerous:
- nickel allergy
- cardiovascular disease
- renal diseases
- fibrosis of the lungs
Cancer
- nasal cancer
- lung cancer
essential metals with potential for toxicity
- copper, zinc, and iron
if these metals are absent from the diet, human beings can fail to thrive. However, if these levels are exceeded, toxic effects and lethality can occur
copper possible properties and possible exposure sites
- naturally occurring earths rocks and soil
- present in electrical wires, pipes and in alloys
routes of copper exposure
inhalation
- inhaling fumes and dust generated during the welding and grinding of copper metal
- ingestion of copper containing food and water
- direct contact with the skin
health effects of excess copper
Non-cancerous:
- respiratory and GI disturbances
- very high levels can cause liver damage, renal damage, and death
properties and possible exposure sites of zinc
- frequently occurring element found in earth’s crust
- used as a coating to protect against rust, used in batteries
- important nutritional element
health effects of excess zinc exposure
Non-cancerous
- ingestion can cause GI problems, anemia, and damage to pancreas
- inhalation can cause metal fume fever
iron properties and possible exposure sites
- one of the most ubiquitous metals in earth’s crust
- important for the growth of cells and transport of oxygen. 66 percent of the iron in the body is used in hemoglobin
health effects of excessive amounts of iron
hemochromatosis is iron toxicity from the build up of iron
- GI problems
- liver injury
- neurological problems
- acute iron intoxication is a common childhood poisoning
aluminum properties and possible exposure
- most abundant metal in earths crust
- in pots and pand
- used in medicines as a buffer, found in antiperspirants, certain antiacids, and various cosmetics
aluminum exposure and effects
- inhalation can cause coughing or exacerbation of asthma
- neurotoxicant, possible link to Alzheimer’s disease
advantages and disadvantages of hazardous chemicals
Advantages
- used for manufacturing clothing, phones, computers, cars, building materials, toys, and furnishings
Disadvantages
- health and human hazards
- damage and pollute the environment
top five chemicals released in chemical incidents in the US
carbon monoxide, ammonia, chlorine, hydrochloric acid, sulfuric acid
organic compound
substances containing mainly carbon, hydrogen, nitrogen, and oxygen
aromatic compound
organic compound that contains a benzene ring
hydrocarbon
organic compound containing only carbon and hydrogen
persistent organic pollutants
toxic chemicals that can be transported by wind/water. Persist for long periods of time in the environment, and accumulate and pass from one species to the next through the food chain
polycyclic aromatic hydrocarbons
a group of over 100 different chemicals that are formed during the incomplete burning of coal, oil, and gas, garbage, or other organic substances
volatile organic compounds
organic compounds that evaporate readily into the air.
pesticide
- chemical substance used to prevent, destroy, repel, or mitigate pests
- exposes people to possible health hazards and can have adverse health effects on the environment
- environmental health officials regulate pesticide use
pesticide vs. insecticide
pesticides - divided on the basis of their target
insecticides - pesticides specifically used for controlling insects
four major classes of pesticides and insecticides
organophosphates, organocarbamates, organochlorides, and pyrethroids
organophosphate pesticides
- most widely used for agricultural purposes
- inexpensive
- control a wide range of insects
- insects have not built up a resistance
- does not persist in the environment
effects of organophosphate poisoning
Acute effects
- anticholinesterase activity causes impairment and disruption of the neural impulse transfer mechanism
- nerves and muscles may become uncoordinated, producing resp paralysis, seizures, loss of consciousness, cramping, and death
Long-term effects
- delayed polyneuropathy manifested by numbness, loss of sensory abilities, and weakness
organophosphate exposure incident
- methyl parathion is used to control insects and is a category I pesticide meaning it is among the most toxic pesticides
- lorain county, ohio. It was sprayed illegally for pest control in private residences over a period of years
- 49 residents were hospitalized, 1 died, and many household pets died
carbamates
- dissipate quickly from the environment - break down into other substances
- used on anurmals to control ticks and fleas
methyl isocyanate (MIC release in bhopal, india
- intermediate chemical used for the manufacture of carbamate pesticides
- extremely toxic to life-forms
- accidental release of MIC in 1984 accident killed more than 3,800 people overnight
organochlorines
- derived from chlorinated hydrocarbons
- used to produce DDT and PCBs
- characteristically stable, persistent in the environment, fat-soluble, bioaccumulates in the food chain
- exposure causes immune system suppression
DDT
- historically was used worldwide to control insects carrying malaria
- use in the US was prohibited in 1972 due to concerns of possible adverse effects on humans and wildlife
effects of DDT
- not highly toxic, but a highly stable chemical that persists in the environment causing bioaccumulation and concentrating in the fatty tissues of the body
- estimated half life in the human body is about 10 years
exposure is linked to - non-hodgkins lymphoma, pancreatic, and breast cancers
- reproductive effects
- impaired lactation
- falling sperm counts
- impaired neurologic function
pyrethrins
- derived from natural sources
- degrade rapidly by the action of sunlight and are not very toxic to animals, but highly toxic to some beneficial insects
herbicides
- atrazine- one of the most widely used weed killers in the US. Turns male frogs into female frogs. Some association found with prostate cancer
- paraquat - highly toxic chemical. some marijuana in US was contaminated, inhalation of this will cause lung damage
- agent orange - used during the vietnam war in drums marked with orange stripes
exposure and effects of agent orange
- used in Vietnam War to prevent thick jungle foliage from camouflaging people
- contained small amounts of dioxins that originated form the manufacture
- evidence found that agent orange was associated with several forms of cancer
effects of environmental estrogens
- DDT is an endocrine disruptor acting as an antagonist to androgen
- has an abnormal influence on the reproductive systems of exposed humans and animals
- acts as a cancer promoter
people at risk of pesticide exposure
- agricultural workers
- children
- sensitive subpopulations: schools and homes near ag fields
biopesticides
pesticides derived from natural materials
- microbial pesticides, plant-incorporated protectants, biochemical pesticides
Dioxins
- chemical compounds that are unintentional byproducts of certain non-industrial, and natural processes usually involving combustion
- typically contains TCDD, most toxic forms of doin
- stable and persistent chemical
sources of dioxin
- natural sources: forest fires and volcanic eruptions
- man-made sources; burning trash, incineration of industrial and municipal wastes, burning of some fuels
- produced from bleaching of wood pulp in the manufacture of paper and application of some herbicides
- trace amounts of agent orange
- cigarette smoke
- can bioaccumulate in the food chain
health effects of dioxin
- dioxin is fat soluble
- chloracne, rashes, skin discoloration, liver damage, endocrine effects, excessive body hair, reproductive and developmental effects, possible cancer risks
polychlorinated biphenyls (PCBs
- organochlorines that are classified as dioxin-like chemicals.
- chemical stability, low flammability, inexpensive, insulating properties
- common use was insulating fluid in electrical transformers and capacitors
exposure to PCBs
- PCBs remain in the environment for long periods by binding to sediments and bioaccumulating
- hudson river is heavily contaminated
health effects of PCBs
Non-cancerous
- impacts to the immune and reproductive systems; impacts intellectual development
Cancer
- cause cancer in animals and designated as probable human carcinogens
- malignant melanoma and liver, biliary tract, and intestinal cancers
organic solvents
- organic liquid substances that are capable of dissolving other organic substances
- do not persist in the environment because of their volatility
tetrachloroethylene
- synthetic, nonflammable solvent used in the dry-cleaning industry as a metal degreaser
- evaporates easily has a distinctive odor
- exposure to high levels causes neurologic effects
- can cause liver and kidney cancer in lab animals with limited evidence in humans
trichloroethane
- solvent found in degreasing compounds and household cleaners
- cause diziness and unconsciousness
- potential harm to the ozone layer
- human carcinogen
toluene
- used to manufacture nail polish, paints, and adhesives
- causes reversible neurologic effects and adverse effects on the renal system
acetone
- used in nail polish, cleaners, and paints
benzene
- occurs naturally in gas and crude oil, is a component of cigarette smoke
- extremely toxic
- causes damage to blood and blood-forming organs; known carcinogen of myelogenous leukemia
styrene
- used to manufacture polystyrene resins
vinyl chloride
- used for the manufacture of polyvinyl chloride
- human carcinogen associated with liver cancer
radiation
- includes ionizing and nonionizing radiation
- propagation of energy through space, or some other medium, in the form of electromagnetic waves or particles
ionizing radiation vs. non-ionizing radiation
difference is their energy level
Ionizing Radiation
- contains so much energy it can knock electrons out of atoms, ionization
- damages DNA
- Radioactive sources
Non-ionizing Radiation
- has enough energy to move electrons in a molecule, but not enough energy to remove them
- Heating, photochemical
- Microwave, phone, heat-lamp, laser
Sources of Ionizing Radiation
Natural Sources
- geologic radioactive elements decay
- outer space cosmic rays
Anthropogenic sources
- medical X-rays and radiation diagnostic/therapy procedures
- leak from nuclear power plants
- radioactive fallout from above-ground nuclear weapon testing
- consumer products
natural sources of uranium
- common element in the earth’s crust, present in soil and geologic formations
- coal used to fuel electric plants. Fly ash that escapes from power plants into the environment can expose nearby residents to radioactive radionuclides
Natural Sources of Radon
- decay product in uranium decay chain
- inert, colorless, radioactive gas, alpha, that can float around and be inhaled from the air
- class A carcinogen, 2nd most frequent cause for lung cancer in US
- comes from the ground and accumulates in basements- remidiation ventilation and wall sealing
extraterrestrial radiation
- primary cosmic rays originate from outer space and interact with earth’s atmosphere to produce secondary cosmic rays
- cosmic rays have the ability to penetrate and cross the human body easily
nuclide
nucleus with a specific atomic mass, atomic number, and specific energy state
isotope
different forms of the same element contain equal numbers of protons but different numbers of neutrons
radioactive decay
- reduction in activity of a quantity of material disintegration of its atoms
radionuclide
an atom with an unstable nucleus
half-life
the time in which half the atoms of the radioactive nuclide disintegrate
types of ionizing radiation and characteristics
Alpha particles
- a fast moving subatomic particle made up of helium nucleus ejected from a radioactive atom
- alpha particles can be stopped by skin or paper
Beta particles
- a high energy electron emitted from the nucleus of a radioactive atom
- beta particles can be stopped by plastic, glass, or aluminum foils
Electromagnetic waves
- gamma rays and x-rays are high energy photons
- can be stopped by thick/dense materials like lead plates
measurement of ionizing radiation
Geiger counter- hand held device used for environmental measurement of beta and gamma radiation
Film badge- used in the workplace as person measurement of exposure to gamma radiation. Contains dental X-ray film that darkens in proportion to the degree of exposure to radiation
effective dose
the amount of radiation absorbed by a person, adjusted to account for the type of radiation received and the effect of particular organs
factors that affect the amount of ionizing radiation exposure
- total time exposed to radioactive
- distance from the radioactive source
- degree of radioactivity of the material
health effect of ionizing radiation
- damages tissue and DNA in genes
- radiation burns, radiation sickness, skin cancer, and other cancers
- bone cancer - radium jaw
- probability of effect is directly proportional to the dose
- severity is independent of the dose
- stochastic effects are associated with long-term, low-level exposure
- carcinogenesis and genetic damage
hormesis
low dose of non-nutritional toxic substance that has beneficial effects
- can stimulate biological defense mechanisms
effects of nuclear bomb explosion
- the blast, damage and destruction to buildings
- heat; thermal burns and radiation-induced skin injuries
- intense light damage to eyesight
- ionizing radiation
- radioactive fallout
Dirty Bomb/Radiological Dispersal Device RDD
- explosion caused by conventional explosives but not by nuclear reaction
- major injuries come from the explosion itself
- main impact is psychological
- dirty bomb is not a weapon of mass destruction but rather a method of mass disruption
nonionizing radiation
includes radiation of low frequencies. Powerlines, radio, microwave, infrared, visible light, and ultraviolet
sources of nonionizing radiation
Natural sources
- sun
- heat
Anthropogenic source
- UV lamp, light bulb, thermal process
- microwave ovens, cell phones
- radar, radio antennas, radio communication transmitters
- electric power lines
health effects of nonionizing radiation
Nonthermal segment
- extremely low frequency, 50-60 Hz, induces low current on the body and does not produce significant health effects
Thermal segment
- 1 MHz to 100 MHz produces heating effects on or near the skin’s surface
- microwave radiation penetrates more deeply into the body, causing internal layers to heat up
- ocular effects like cataracts
optical radiation
combined spectrum of UV, visible light, and infrared
ultraviolet radiation
Sources
- welding, tanning beds, flood lamps, halogen lamps, electric sparks, tanning
Health Effect
- targets skin and eyes
Dermal effects - short term burns, photoaging of skin, nonmelanoma skin cancer, malignant melanoma
Ocular effects- acute temporary blinding, retinal damage, lens opacities, and MM of the pigmented portion of the eye
- UV-B is considered to be the most harmful to human health
photosensitivity, photoallergy, and phototoxicity
- photosensitivity- heightened sensitivity to sunlight
- photoallergy- type of dermatitis activated by sunlight
- phototoxicity- severe reaction to sunlight; sometimes occurs in conjunction with drugs
photoaging and malignant melanoma
- photoaging- leathery appearance, loss of elasticity, and occurrence of brown spots
- malignant melanoma- most serious and potentially fatal form of skin cancer attributed to long-term UV exposure
ocular effects caused by UV and IR
- UV radiation can cause photokeratitis, burn of the cornea, aka snow blindness
- UV radiation can cause rare cancer - ocular melanoma
- sunlight exposure can cause cataracts or retinal burns
- infrared radiation can also cause retinal burns, corneal burns, and cataracts
