PubH chapters 6-8

Environment

• where we live, including climate, geography, flora and fauna, social conditions

• anything that isn't you = environment

Natural environment

• landscapes and ecosystems that have remained in original state without significant human interference

Altered environment

environment that has changed, how we live, new things in envt

• -ex) built dams, agricultural fields, deforested areas

built environment

everything we construct

toxicology

causal mechanisms between exposures to agents and disease

law

Advocacy and regulation to limit exposure to agents

risk

the likelihood that an event will occur

risk assessment

 process of identifying bad consequences and likelihood it will occur

4 Step Risk Assessment process

1. Identifying hazard (what health problems are caused by the pollutant)

2. Dose-response assessment- only means something if individuals are exposed to it, how much exposure is necessary (what are the health problems at different exposures)

3. Exposure assessment (how much of the pollutant are people exposed to during a specific time period, and how many people are exposed)

4. Risk characterization (what is the extra risk of health problems in the exposed population)

Ames test

whether a given chemical can cause mutations in DNA

-A positive test indicates the chemical under study may act as a carcinogen

hazard

• the inherent capability of an agent or a circumstance to have an adverse effect on health

hazard identification

• what health effects are caused by pollutants?

• what is the evidence that exposure is toxic, how strong is the evidence of association, what is the route and timing of transmission, and how is the information derived

PCB (polychlorinated biphenyls)

-Polychlorinated biphenyls, used in paper, plastics, and paints/dyes

Risk Characterization

• what is the extra risk of health problems in the exposed population?

• ex) asbestos example

route of exposure

the way in which an individual might come into contact with an environmental hazard

preventative medicine

diagnosis and treatment of environmentally induced disease

dose response

the measured relationship between the amount (intensity) of exposure and the likelihood of a health effect

exposure assessment

• how many are exposed? How much of the hazard are people exposed to during a specific time period?

risk management

actions taken to control exposures (and thereby consequences) to toxic substances in the environment

communicable diseases

Illness due to a microorganism such as bacterium, parasite or virus that is transmitted person-to-person or animal/physical environment to humans via air, water, fomites, insect or animal bites

Bacterium

single-celled microorganism able to exist free-living or as a parasite

virus

microorganisms unable to exist independent of living cell

Parasite

organism living in, on, or with another organism in order to obtain nutrients

Vectors

an organism, usually an arthropod like a mosquito or tick, that carries and transmits infectious agents, such as viruses, bacteria, or parasites, between hosts

Fomites

inanimate objects that can transmit infectious microorganisms and be the source of disease

sporadic

-occurring irregularly

endemic

-confined to a particular country or area

epidemic

-A sudden, often unexpected, increase in the number of disease cases above what is normally expected for the population and area

Pandemic

-An epidemic that has spread over multiple countries or continents, affecting a very large number of people globally

Ignaz Semmelweis (1818-1865)

emphasized handwashing and cleaning hospitals to reduce maternal mortality from puerperal fever

Joseph Lister (1827-1912)

introduced antiseptic methods in surgery, basedon Pasteur's findings, to prevent wound infections

infectivity

ability of a bacteria, fungi, parasites or virus to enter into a living organism through horizontal transmission

agent

the specific microorganism or factor that causes the disease

Characteristics of a Disease That Make Eradication Possible

-No animal reservoir

-Short persistence in environment

-Absence of long-term carrier state

-The disease produces long-term immunity

-Vaccination produces long-term immunity

-Herd immunity protects those who are susceptible

-Easily identified disease

-Effective post-exposure vaccination

herd immunity

When a critical portion of a community is immunized against a contagious disease, most members of the community are protected against that disease because there is little opportunity for an outbreak

Noncommunicable diseases

Chronic conditions that do not result from (acute) infectious processes and are not communicable

Characteristics of Noncommunicable Diseases

Complex (multifactorial) causes

Long latency period

Prolonged course of illness

Functional impairment/disability

Common etiologies across dissimilar conditions

presumptive judgement

distinguishes apparently well persons from actually well persons.

sensitive test (screening)

when it is good at identifying disease when it is presen

specific test (screening)

Identifies healthy people in population (good for Blood pressure tests) —> leads to false negatives

Interaction Analysis Approach

Implies that to understand and control the impacts of environmental exposures, it is necessary to take into account the effect of two or more exposures

• Risk assessment approaches make assumption that each exposure stands on its own

Systems Analysis Approach

• intentional v unintentional injuries

• All-hazards approach

• reducing head injuries/ TBI

Lead time bias

• early detection without improved outcome

Genetic Counseling and Intervention

• Predictive genetic testing

• Incomplete penetrance

• Reproductive genetic testing

criteria for screening

• Disease produces substantial death and/or disability

• Early detection is possible and improves outcome

• There is a feasible testing strategy for screening

• Screening is acceptable in terms of harms, costs, and patient acceptance

Screening

•  use of tests on individuals who do not have symptoms of a specific disease/ Asymptomatic

R-naught factor

measures the average number of infections produced by an infected person (if greater than 1 that means the number of infections will increase over time and possibly produce an epidemic

chain of infection

susceptible host, pathogen, reservoir (any person, animal, or substance in which agent normally lives and multiplies), place of exit (ex. feces, urine), mode of transmission, port of entry