PH 150 B- Environmental Health

GBD
Global Burden of Disease, C^4 (combined, complete, consistent, coherent) database adopted by WHO, system of checks and balances in resource allocation.
DALY
Disability Adjusted Life Year, type of HALY
=YLL(NxLi) + YLD (IxDWxLe)
=(number of deaths x standard life expectancy) + (number of incident cases x disability weight x avg duration of cases until remission or death)
best measure of ill-health
loss of healthy life years due to disease or disability. universal. only difference in life expectancy should be age and sex. everyone should have access to the same life expectancy
occam’s razor
principle of parsimony, don’t make anything more complicated than necessary
Child cluster disease
kills 1.4 million children/yr (10 mil die each yr total) includes measels, tetanus, pertussis, diptheria, poliomyelitis. all preventable by vaccinations!
Top three global DALY’s (2000)
ARI, Perinatal, HIV
Top three DALY’s for US
cancer, depression, heart. targets of PH intervention
disease categories
I. Traditional, communicable: decline during dx
II. Modern, non-communicable: increase during dx
III. Injuries, non-transitional: are unaffected by dx
attributable risk
amount of ill-health that would not exist today if the risk factor had not occured.
% determined by the order of other risks assesed. when totaled can add up to more than 100%
toxicology
study of how poisons produce injury which cause adverse effects in body. begins w/ absorption of toxicant.
toxins
natural substances produced by living organisms
toxicant
anything not produced by a living organism
Paracelsus
only dose determines the poison, dose-response relationship. experimentation necessary
EPA
Environmental Protection Agency-regulates pesticides and general chemicals
TSCA of 1976
Toxic Substances Control Act, grandfathered in at least 62,000 chemicals- never been fully tested
toxicity
the degree to which something is poisonous or can cause injury. mutagens, carcinogens, reversible or irreversible
systemic poisons
substances that interfere w/ vital f(x) in the body and target specific organs
asphyxiants
agents that deprive tissues of O2-cause anoxia by CO binding to hemoglobin reduces amount available to deliver O2.
irritants
materials that cause inflammation of membranes
mutagenesis
chromosal damage in a sperm or egg cell of the parent that can have adverse effects in the offspring
teratogenesis
exposure of embryo or fetus to agent that causes some type of dx issue
DES
diethylstilbesterol, given to 5 mil women at high doses to prevent miscarriage. teratogen, mutagen, and carcinogen would effect 2 generations after exposure
thalidomide
given to mothers to prevent morning sickness, type of teratogen
carcinogenesis
increase in activity of genes that instruct cell division, decrease in activity of genes that instruct cell to stop dividing.
dose-response
correlative relationship btwn exposure and health effect, shows rate of accumulation, min. dosages of effect, causal relationship. slope shows potency, steeper= more potent.
threshold
the no effect level. falls somewhere between NOAEL and LOAEL, but on graph will look like NOAEL.
NOAEL
no observed adverse effect level, highest point.
LOAEL
Lowest observed adverse effect level, starting pt for carcinogens b/c there is no NOAEL
LD50
for ingested toxins, the lethal dose for 50% of the population
ADI
acceptable daily intake. NOAEL for most sensitive species divided by some uncertainty factor. if only have the LOAEL divided by an uncertainty facto that is one magnitude greater.
Lead poisoning
~called the downfall of Rome?
~acute symptoms: irritable, aggressive bx, reduced sensations, anemia, spontaneous abortions, seizures, coma.
~chronic symptom: accumulates in bones and teeth, permanent neurological damage, kidney damage, death.
~in kids correlated to educational failure and delinquency. greater risk b/c more able to absorb it and it replaces calcium and iron, generally more sensitive. also correlated to socioeconomic inequalities, therefore racial inequalities as well. also workers of battery recycling plants very at risk.
~once found in house paint, gas, car batteries, soil and dust, toys, furniture, bullets, pewter dinnerware
~outlawed in mid-70s though known to be dangerous since 1915
~routes of exposure: ingestion or inhalation
~IARC: Group 2A
IARC
International Agency for Research on Cancer
1. is a carcinogen
2a.probably a carcinogen
2b. possibly a carcinogen
3. not known
4. is not a carcinogen
Mercury
~different forms, organic is most toxic. elemental=shiny white metal/liquid, can be vapor damage nervous system. inorganic=vapor, inhaled can cause tremors.
~kidney damage with all kinds. cerebral palsy and other birth defects,neurological diseases. tunnel vision, bx change, slurred speech, unsteady gait.
~chlorine chemical plants, auto scrap recyclers, coal-fired plants, alchemy, thermometers, electrical switches, medicines, dentistry. fish contain organic methylmercury.
~ingested or inhaled.
~12 oz/wk of big fish if info known=threshold value
~Minamata incident=long term exposure due to manufacturing of acetaldehyde.
~Iraq seeds treated with fungicide, used to make bread during drought
~group 2b
Dioxin
~class of contaminants
~reproductive and dx effects, endocrine disruption, neuro damage, cancer, chloracne.
~can happen anywhere
~combustion process, Agent Orange,
~ingested-contaminate food as the cycle through biosphere. accumulates in breast milk.
~Seveso disaster-explosion high levels of TCDD no human deaths, lots of animals
PCB’s
~polychlorinated biphenyls
~immunosuppression, neuro damage, brown pigmentation, low birth weight,
~has been banned (?)
~coolings liquids, electrical wire coating, adhesives, paints, caulking sealants.
~ingested in meat, fish and dairy. concentrates in breast milk.
~Japan and Taiwan: rice oil, heating it leeches PCB.
PBDE’s
~chronic symptoms: liver tumors, immunotoxin, endocrine disruptor, delays onset of puberty, thyroid! decreased levels of T4.
~banned in euro not us
~pjs, fabrics, plastics, indoor environment, used as flame retardant.
~uptake through lungs, GI, and skin
Asbestos
~mineral fiber, asmolite, chrysotile, crocidolite
~lung cancer, mesothelioma!
~South Africa and Canada, occupational exposure most common-industry kept use for a long time
~banned in 1980
~pipe insulation, roofing shingles, floor and ceiling tiles, fume hoods, popcorn ceilings.
~inhalation, sometimes ingestion
~group 1
Melamine
in China, added to formula,caused 47,000 children to be hospitalized
HAB
harmful algal blooms, dinoflagellate rapid growth due to eutrification of water. shellfish ingest.
~Paralytic Shellfish Poisoning: gonyaulax catenella, saxitoxin, tingling or burning of mouth, ataxia, paralysis of diaphragm
~Diarrhetic Shellfish Poisoning: worldwide distribution, caused by okadaic acid, diarrhea, nausea, chills, recover in 72 hrs
~Neurotoxic Shellfish Poisoning: Gulf of Mexico, muscular stiffness, depression, temperature confusion + all the others, can be inhaled in aerosol form causing respiratory distress. kill lots of animals, weeks in duration.
~Amnesic Shellfish Poisoning: domoic acid, northwestern coast and Canada,coma, CNS, potentially fatal within 24 hrs!
foodborne infection
infectious agents (bacteria and viruses) cause illness via food consumption
foodborne pathogens
trichinella spiralis: pork, trichinosis
taenia solium: pork, tape worms
saginata: beef, tape worms
food must be cooked all the way!
entamoeba histolytica
protozoan, type of foodborne intoxication, fecal oral route, causes cysts to dx in stomach, causes diarrhea-dysentery.
giardia lamblia
protozoan flagellate, type of foodborne intoxication. fecal oral route, animals too so any unfiltered water, cysts resist chlorination!
explosive diarrhea, fatigue, kids, immunosuppressed and those visiting endemic areas.
cryptosporidium
protozoans, foodborne intoxication, oocytes survive chlorination, fecal-oral route, mild diarrhea, nausea etc.
Foodborne viruses
type of pathogen, require a host cell for replication, contain single strand of RNA
Hepatitis A
fecal-oral route, causes liver infection, sometimes jaundice too, infected foodworkers handlers spread or contaminated water, fruit, vege, dairy, shellfish, sandwiches
Norovirus
fecal-oral route, creams and salad dressings, symptoms appear 24-48 hr after exposure and last for 24-60 hrs. low grade fever, stomach problems
Fungi
molds, yeasts can grow on pretty much everything
mycotoxins=mold metabolites that can cause illness or death, i.e. aflatoxin
Aflatoxin
peanuts, corn, and cotton, caused to grow by improper storage.
Turkey x disease? hemorrhaging, anemia, ataxia, cirrhosis, liver cancer
gram positive bacteria
have more peptidoglycan in cell wall, thicker
aerobic
i.e staphylococcus-creams, ham, rapid onset but not long duration. stomach problems
malaria
parasites (plasmodium-falciparum is most common, most lethal) infect mosquitos, transmit to ppl.
settles in liver, multiplies in RBC’s which rupture and cause spread within body, obstruct blood flow, decrease oxygen dispersal.
causes dizzinesss, fever, chills, coma, death
300-500 mil/yr, deaths=880,000/yr. every 30 sec a child dies.
rainfall, types of mosquito and proximity.
epidemic=low immunity ppl traveling to endemic areas, introduction of parasite to new area, unusually wet weather, mass population movement
reemergence? inefficient eradication, decreased or inconsistent spraying of DDT, pesticide and drug resistance, global warming, antigenic variation
salmonella
gram-negative, 2-4 mil in US/yr, 500-1000 deaths
food, h2o, and fecal-oral
fever and stomach problems
onset 12-72 hrs
duration 1-4 days
poultry=main reservoir but potential cross contamination
typhi:
asymptomatic ppl can spread as well- bacteria enters GI and get into lymph nodes
seafoods can concentrate toxins
outbreaks:
PB recently killed 8 ppl
prevention:
good hygiene, proper storage, freezing, pasturizing,
dengue fever
mosquito-borne illness, A. aegypti and Aedes albopictus
can cause leaky capillaries (dengue hemorrhagic fever)
great global impact: 35-60 mil/yr, mortality=5-15%
4 strains, no cross-protective immunity. Only prevention is removal of vector.
spreads extremely quickly, greatly effecting Central and South America currently.
Clostridium
anaerobic bacteria found in soils
~perfingens: basically the 24 hr flu, probably 10,000 cases a yr due to cooked food being allowed to sit at room temp
~botulinum: anaerobic, heat resistant spores germinate and produce toxin, can be prevented if spores killed before packaging, 7 types, one of the most lethal substances in the world! onset 4 hr-8days if untreated kills within 3-6 days, symptoms=vertigo weakness, double vision, difficulty breathing (death from asphyxiation), meats, canned vegetables, seafood
campylobacter
most commonly identified bacterial cause of diarrheal illness
raw milk, untreated water, undercooked chicken
~jejuni:grow with little oxygen and survive for a long time
2-4 mil/yr. can cause Guillain-Barre!
e.coli
gram negative bacteria
O157:H7=bloody diarrhea, can cause uremic syndrom that can lead to kidney-failure and death
vibrio cholerae
gram negative
causes cholera, colonizes lining of intestine
Peru 322,562 Peruvians!
AIDS/HIV
retrovirus (gets into DNA!) infects helper T cells. transmitted via blood, bodily fluids, pregnancy.
AIDS=advances stages, opportunistic infection cause respiratory disease-coma. doesn’t kill you back makes it so many other things can.
global impact: 30-36 mil in 2007, greater than 1 mil=kids
tuberculosis
once the leading cause of death in US- vaccinations!
mycobacterium attacks lungs, then spred by aerosolized saliva
can lay dormant for yrs, b/c our own immune system protects
greatly effects
global bacteria: bacillus infects 1/3 world pop, 3 mil deaths/yr
(MDR)-TB
multidrug-resistant, caused by inconsistent or partial treatments allow bacilli to build up resistance and become too strong. also prescribing wrong drugs.
rates high in former Soviet Union
60 mil deaths predicted btwn 1998 and 2030
HIV and TB
lethal combo, HIV+ much more likely to become ill when infected w/ TB bacilli than HIV- person
(XDR)-TB= super drug resistant, related to the HIV/TB combo serious threat to TB control
DOTS
directly observed treatment-short-course
expensive and takes time, requires surveillance of treatments so decrease resistant strains forming. but still there are some
influenza
type c ain’t no thang
types a & b: responsible for epidemics, fever, extreme fatigue, respiratory symptoms, death in old, young, and debilitated.
global impact:3-5 mil/yr, 250k-500k deaths/yr
pandemics=Spanish Flu 1918, Asian Flu 1957, Hong Kong 1968
birds to humans in China 1997
antibiotic resistance
response to wide distribution of antimicrobials
i.e. cholera, staphylococcus
even resistance to Vancomycin at 7.9% in 1994
Risk Assessment Framework
1.Hazard Id or Source Assessment
2a.Exposure Assessment/2b.Effect Assessment (exposure-response)
3.Risk Characterization
4.Risk Management/Communication
PAF
Population Attributable Fraction
=F(RR-1)/F(RR-1) + 1

F=proportion exposed
rr=exposed/unexposed

rBGH
recombinant bovine growth hormone
cows frequently injected with it, bad for humans b/c IGF-1 causes breast, colon, prostate cancers
organochlorines
DDT-low toxicity to humans, but breakdown products DDD and DDE can have chronic effects
low volatility, chemical stability, lipid soluble, slow rate of biodegradation, persistent, biomagnifies in food chains
organophosphates
nerve toxins, inhibits AChE causing ACh to build up in nerve junctions
not as persistent in environment,
can cause coma, death, wheezing, vomiting, salivation, tearing, perspiration
i.e. parathion, malathion
glyphosate
round up/nonselective herbicide
GM plants resistant, means increased use
exposure correlates to risk of lymphoma
GM
allergies due to proteins made by DNA of new species, spread antibiotic resistance b/c linked to transgene
more use of pesticides lead to increases in cancers
no monitoring!!