Midterm Flashcards
Healthy People 2020 Goal for Environmental Health
“Promote health for all through a healthy environment”
Principle Determinants of Health Worldwide (Three P’s)
Population
Pollution
Poverty
Three Factors of Population Growth
Fertility
Infant Mortality
Longevity
How many Earth’s to maintain current population size and consumption rates?
1.5 Earth’s
TFR (Total fertility rate)
The number children a woman has given birth to by the end of childbearing
Estimated natural population replacement rate
2.1 births per woman
Demographic transition
Alterations over time in a population’s fertility, mortality, and make-up
Five stages of demographic transition
Stage 1: High fertility and mortality rates (small population)
Stage 2: High fertility and decreasing mortality rates (increasing population
Stage 3: Decreasing fertility rates, more even distribution of population
Stage 4: Fertility continues to drop
Stage 5: Population slowly decreases
Carrying capacity
The population that an area will support without undergoing environmental deterioration (tends to limit population size)
Population crashes
Animal populations experience population crashes when population growth exceeds carrying capacity
Hippocrates (three points)
- Greek philosopher often referred to as the “father of medicine”
- Emphasized influence of the environment on people’s health and health status
- Promoted doctrine of maintaining equilibrium among the body’s four humors (blood, yellow bile, black bile, and phlegm)
What did Ancient Romans do for environmental health?
Developed first infrastructure for maintaining public health (transport of water and sewage, heating devices for water and for rooms, communal baths)
Ramazzini (two points)
- Italian physician who was the founder of the fields of occupational medicine
- Highlighted the risks posed by hazardous chemicals, dusts, and metals used in the workplace
Public Health Act 1848
Clean water and control infectious disease
Walter Reed
Confirmed that yellow fever caused by mosquitoes rather than direct contact
Upton Sinclair
Food and Drug Act guy
Love Canal
Toxic waste burial
Fracking (what does it stand for, what is it, environmental consequences)
- Hydraulic fracturing
- Fracturing fluid pumped into well, causes rock surrounding pipe to crack
- Leads to groundwater contamination/air quality degradation + mini-earthquakes
Involved with design and installation of control systems/responsible for control of hazards that may affect workers/community
Industrial hygienist
Specializes in effects of toxic chemicals on the environment and living creatures
Toxicologist
Monitors and enforces government regulations
Environmental health inspector
Involved with cleanliness and safety of foods and beverages consumed by public
Food inspector/food safety specialist
Enforces various public health laws, sanitary codes, and regulations related to spread of disease by vectors
Vector control specialist
Ecological system
Theory that people encounter different environments which influence behavior
What is healthy People 2010/2020?
It is a 10-year agenda for improving the nations’ health
Boom-bust curve (population)
Boom in the population when it grows rapidly but it is followed by a bust when population falls back to minimal levels when carrying capacity is reached
What is environmental epidemiology?
The study of diseases and health conditions linked to environmental factors
Morbidity vs Mortality
Morbidity - Rate of illness in a population
Mortality - Rate of deaths from illness in a population
Two Classes of Epidemiological Studies (identify them and state the difference)
Descriptive: depiction of the occurrence of disease in populations according to classification by person, place, and time variables
Analytic: examines causal hypotheses regarding the association between exposures and health conditions
Prevalence vs Point prevalence (define difference, give formula)
Prevalence is the number of existing cases/deaths from disease at a designated period of time, point prevalence is the number of cases/deaths form disease at a particular point in time
Formula: number of ill persons at a point in time/Total number in group
Incidence vs incidence rate (defined and give formula)
Incidence is the occurrence of new disease/mortality in a defined period of observation
Formula for incidence rate: # of new cases over time period/total population at risk x multiplier
Cross-sectional studies
Observational, give snapshot of characteristics at single point in time, generally used to assess prevalence
Ecological studies
Study done at population levels, generally used in public health research and when data at individual level is unavailable
Case-control study
Retrospective studies done on those who already have disease compared to those who don’t
Cohort study
Study where individuals are followed over time to see who develops disease; groups exposed compared to non-exposed groups
Case-control study (Odds Ratio or Relative Risk)
Odds ratio
Cohort study (Odds Ratio or Relative Risk)
Relative Risk
Case-Control (issues, benefits)
Negatives: Often subject to recall bias
Positives: inexpensive, efficient, suitable for rare diseases with long latency periods
Cohort (issues, benefits)
Negatives: high selection bias, bad for studying rare diseases, expensive and inefficient
Positives: low recall bias, multiple outcomes can be studies simultaenously
Epidemiological triangle (host, vector, agent, environment)
Host: harbors the disease
Vector: spreads the disease
Agent: causes the disease
Environment
What is the criteria for causal association with diseases called?
Bradford Hill
Strength of association
Measured by relative risk (odds ratio)
Dose-response relationship
As dose increases, risk of disease also increases
Lack of temporal ambiguity
Exposure to factor must have occurred before disease developed
Biological plausibility
Coherence with current body of biological knowledge
Coherence of evidence
If a relationship is causal, findings expected to be consistent with other data
Specificity of association
When a certain exposure is associated with only one disease
Sir Percival Pott
London surgeon thought to be the first individual to describe an environmental cause of cancer (chimney sweeps had high incidence of scrotal cancer due to contact with soot)
Texas Sharpshooter Effect
Epidemiological correlations are overemphasized when it could be by chance
What are the limitations of environmental epidemiology? (3 things)
- Long latency periods
- Difficulties in exposure assessment
- Nonspecific effects
What are the three major requirements for a successful epidemiological investigation?
- Direct and accurate estimates of exposures
- Direct and accurate determination of the disease status of the individual members of the study group
- Appropriate statistical summary and analysis of the data pertaining to disease and exposure
How does the environment play a role in human health?
Chemical exposures and air pollution can cause health problems (such as respiratory, heart, diseases, etc.)
What is the estimated global burden of disease linked to environmental sources?
25-33%
What was the cumulative case fatality rate of the H5N1 virus?
50-70%
By what percentage has the mortality from asthma in the U.S. increased since 1980?
A decrease in 23.1% until now but from 1980 to 1989 it was 46%
What is the number of years required for the world’s population to double?
Approximately 43 years
What will the percentage of urban residents be by 2030?
66%
Zoonosis
An infection or infectious disease transmissible under natural conditions from vertebrate animals to humans
Arthropods
Mosquitoes, ticks, sand flies, biting midges
What percentage of world’s population at risk from malaria?
Over 40%
Annual death toll for malaria
More than 1 million people
Malaria vector
Female anopheles mosquitoes
Most deadly malaria agent?
Plasmodium falciparum
Agent of malaria
Plasmodium parasite
Malaria symptoms
Spleen enlargement, flu-like fever, muscular fatigue, chills/sweating, dry cough
Estimated global direct economic costs of malaria
$12 billion US annually
Mosquito control measures (4 ways)
- Anti larval measures
- Anti adult measures
- Protection against mosquito bites
- Legislative control
Sickle cell disease
Inherited disease of red blood cells that affects hemoglobin and interrupts blood flow by blocking small blood vessels
Hand Foot Syndrome-Dactylitis
The sickle red calls cause painful swelling of the hands and feet
Connection between Malaria and Sickle cell
People inherit malaria if they inherit two faulty copies of the gene for hemoglobin
Leishmaniasis agent
Parasite Leishmania
Leishmaniasis vector
Sandfly
Forms of leishmaniasis
Cutaneous leishmaniasis (one or more sores on skin, swollen glands near sores)
Visceral leishmaniasis (fever, weight loss, spleen/liver enlargement, abnormal blood tests, low blood counts)
Plague agent
Bacterium Yersinia pestis
Plague vector
Bite of a flea harbored by rodents and prairie dogs in the U.S.
Most common vector-borne disease in the United States
Lyme disease
Lyme disease agent
Bacterium
How is lyme disease transmitted to humans?
Black-legged ticks puncturing skin of the host
Lyme disease symptoms
Characteristic bulls-eye skin rash, febrile symptoms
Rocky Mountain Spotted Fever (RMSF) agent
Bacterium
Rocky Mountain Spotted Fever (RMSF) case fatality rate
Up to 25% among untreated patients
Rocky Mountain Spotted Fever (RMSF) vector
Infected tick
Rocky Mountain Spotted Fever (RMSF) treatment
Antibiotic doxycycline
Who exposed DDT issues?
Rachel Carlson (Silent Spring)
Difference between bioaccumulation and biomagnification
Bioaccumulation is the process by which toxins enter the food chain through individual organisms whereas biomagnification is the process by which toxins pass from one trophic level to another within a food web
What is one example of a vector-borne disease?
Malaria/leishmaniasis/plague/lyme disease/RMSF
Alphonse Laveran
The guy that found the plasmodium for malaria
Explain how climate change may be helping the expansion of zoonotic and vector borne disease.
It alters the conditions for pathogens and vectors of zoonotic diseases and can improve many characteristics of the arthropod life cycle (arthropods oftentimes being the vectors of many diseases)
What are arboviral diseases?
Group of viral diseases that can be acquired through blood-feeding arthropod vector
Four main clinical symptoms of arboviral diseases
- Acute CNS illness
- Acute benign fevers of short duration
- Hemorrhagic fevers
- Polyarthiritis and rash
Arboviral encephalitides
Virus that produces an acute inflammation of sections of the brain, spinal cord, meninges
Arboviral encephalitides transmitted how?
Through bite of mosquitoes from the reservoir (wild birds/small animals) to human host
West Nile virus agent
Flavivirus
West Nile virus vector
Culex mosquitoes who become carriers after feeding on infected birds
Are there any vaccines for West Nile Virus?
No
West Nile symptoms percentage
1 in 5 develop febrile symptoms
1 in 150 develop a serious, sometimes fatal, illness
Name two factors associated with the rise of emerging zoonoses
- Ecological changes that result from agricultural practices (deforestation, conversion of grasslands, irrigation)
- Wars, migration, urbanization
Hantavirus Pulmonary Syndrome (HPS) agent
Viral family Bunyaviridae
Hantavirus Pulmonary Syndrome (HPS) transmission
Inhaled airborne urine and droppings from infected rodents
Hantavirus host
Deer mouse
Dengue fever agent
Flaviviruses
Dengue fever vector
Aedes aegypti mosquito
Dengue fever stages
Febrile phase
Critical phase
Recovery phase
Zika virus vector
Aedes mosquito
Are there vaccines or medicine for Zika?
No
What are the two ways ebola can be transmitted?
Direct contact with an infected animal or a sick or dead person infected with Ebola virus
Where was ebola virus discovered?
DRC/West Africa
Anthrax agent
Bacteria known as Bacillus anthracis
4 kinds of anthrax
Cutaneous anthrax
Inhalation anthrax
Gastrointestinal anthrax
Injection anthrax
Psittacosis agent
Bacteria chlamydia psittaci
Psittacosis transmission
Exposure to infected birds
Psittacosis affects?
Lungs and may cause pneumonia
What animals are Rift Valley Fever most commonly seen in?
Domesticated ones in sub-Saharan Africa
Rift Valley Fever vectors
Mosquitoes and contact with infected animals
Monkeypox agent
Virus
Tualaremia agent
Bacterium
Who transmits tualaremia?
Tick and deer fly bites
Rabies agent
Virus
What animal transmit rabies?
Bats, all mammals
