https://openstax.org/books/microbiology/pages/1-1-what-our-ancestors-knew

8/28

Community→ a group of individuals that share the same interests

Community Health→ the health status of the individuals in the groups

Factors that affect community health:

Physical→ Geography, environment, community size, industrial development

↳EX: more infectious diseases in the tropics because there are only two seasons ie dry and wet

Social and cultural factors→ beliefs, economy, politics, and religion

Ten Essential Public Health Services →imgres

Four Levels of organizations involved in community health → Local (Jewish Hospital), State, National (government agency→ FDA, NIH, CDC, EPA) Quasi-Government agencies, non-governmental agencies), and World Health Organization (T-B)

Worldwide public health→ the lead international public health agency 

National:

USDA→ Inspects crops etc

EPA→ Inspect air and water quality

OSHA→ Establishes workplace safety standards

Homeland Security→ Protects US Homeland from foreign attack

CDC→ Started with the mission to control malaria in 1946

↳ today is involved in every aspect of human health

State: 

• Ohio department of health

↳counties and cities also have health departments

• These departments have boards and different specialties 

Notifiable Disease Scheme→ Imgres

Quasi-governmental Agency:

Clara Barton→ founder of the Red Cross

EX: American Cancer Society, CRS, and Bill and Melinda Gates Foundation

Healthy People 2030L

Vision→ a society in which all people live long healthy lives

Objective HDS-7: Reduce the proportion of adults with high total blood cholesterol levels

Target: 10% Improvement

Data: Percent of Adults 20 years and older with the total blood cholesterol levels of 240 mg/dl or greater

↳2005-2009 baseline 15% →Target 13.5 → 2009-2012 12.9 (target met early)

Higher protein in the blood, the lesser chance of heart attack

8/30

Lyme Disease→ ticks latch on deer who have the disease, then transmit it to other organisms

Epidemiology→ the study of how, when, and where diseases occur in the populations and communities

↳focus of how to prevent the spread

Disease→ any deviation from the state of health

↳ illness, injury etc

• Symptoms are something you can feel 

• Signs are something someone else can see

Categories of Disease: 

Infectious disease→ disruption of a tissue or organ caused by microbes or microbial products

↳ Infection is the establishment of a infectious disease agent in the host organism

• Infectivity→ The ability of a biological agent to enter and grow in the host

• Pathogenicity→ The ability of a microbe to produce a disease

• Most infectious disease are communicable, but some are non-communicable

Communicable Disease→ disease causing agent spread from one host organism to another

• EX: HIV, Salmonella, Blood-Borne Illness

Contagious Disease→ disease causing agent spreads easily from one host to another

• EX: COVID-19, Tetanus

↳ Tetanus causes lockjaw and paralysis 

• Tetanus is found in soil 

• Sporadic because you never know when you are going to get it

Non-communicable disease→ disease-causing agent cannot spread from one host to another

• EX: Cancer, Heart failure, liver disease

Acute Disease→ symptoms begin suddenly and stops in a short amount of time (typically infectious)

Chronic Disease→ Conditions that last over a year (Non-communicable) 

Endemic→ Particular to a region and is always occurring (Always)

Sporadic→ infectious disease which occurs infrequently

Undetected outbreak→ outbreak that isn’t detected

Epidemic→ widespread occurrence of an infectious disease in a community (excess)

Pandemic→ widespread occurrence of an infectious disease across the world (global)

Imgres

• People get more respiratory diseases in the cold months of the year because they spend more time inside 

How does epidemiology relate to public health?

• Provides data necessary for public health policy and regulations

• Females live longer than males because the females hormones reduces risks for heart disease and the telomere’s for female dna is longer

Epidemiological Rate is:

• Measure of illness, injury, disability, or death in a given population

• Within a given time period and expressed as per unit of the population

Rate= # population events at a given time

          —-----------------------------------------------

Population fjdklfldjskfdsjl

Incidence is important for infectious diseases, so we can track how fast the spread is

Prevalence is important for infectious disease because it provides an estimate of the diseases burden within the population

Rate is the only way we can compare data between different communities and countries

Primary Care→ illness, injury, acute medical problems, and referrals

• Flu shot

Secondary care→ requires specialists 

Tertiary care→Requires highly specialized equipment and care

Primary prevention→ aims to stop a disease before it occurs

• Education and personal action/behavior

• Public health measures

Controllable risk factors for noninfectious diseases:

Secondary prevention

Aim→ Stop the progression of a disease

Patients seek diagnosis after experiencing symptoms

• Doctor then orders tests

• Screening tests are secondary prevention

850 × 1,352

False negative results→ some people with the disease will test negative

False positive results→ some people without the disease will test positive

Examples of screening tests and follow up diagnostic tests:

• Pap smear

• Mammogram

• Lipid profile

• Rapid colorectal cancer screen

• Tb skin test→ chest x ray is follow up

Imgres

Agent→ factor whose agent or presence causes a disease

- Groups: Physical, Chemical, Biological, Genetic, Nutrient, and Psychological

Physical Agents→ forces that cause injuries 

- EX: Impact(Car crashes), excessive heat/cold

Chemical Agents→ compounds that causes injuries and cellular damage

- EX: poisoning, burns, cancer, birth defects

- Many chemical agents have been associated with cancer

Biological Agents→ microorganisms and other parasitic organisms 

- EX: Bacteria, viruses, fungi, worms, and protozoa

↳ the bacteria Streptococcus pyogenes causes strep throat, biological VSV causes shingles, fungal a fungus causes ringworm, protozoan causes malaria, worms and mites are parasites 

Genetic Agent→mutated genes that cause disease

• Can occur during fetal development and through genes from your parents

• EX: a child develops cystic fibrosis if they inherit a mutant CFTR gene from their parents

• Their genetic information can influence their risk of developing a disease or illness

Cystic fibrosis→ mutant CFTR gene causes excess mucus production that disrupts air flow and lung function

↳ disrupts release of digestive enzymes by pancreas 

• Reduces life expectancy by 40 years

Nutrient Agents→ a chemical compound found in food and lack of these compounds causes disease

• Lack of necessary nutrients can result in nutritional deficiencies and diseases

EX: Lack of vitamin D can cause rickets– results in weak bones, abnormal bone development, and impaired growth 

• Sunlight, fish, and milk are very rich in vitamin d

EX: Lack of vitamin B3/niacin causes pellagra

• Niacin is necessary for cellular processes

• Pellagra is defined by the 4 D’s– Diarrhea, dermatitis, dementia, and death

Psychological Agents→cause mental disorders

• Very difficult to define and measure

EX: Stress

↳ extreme stress resulting from a violent event can result in PTSD and chronic stress can result in depression

Susceptible host→ person with the certain characteristics required to develop a certain disease

• Characteristics that influence susceptibility to an infectious disease are more understood than those that influence susceptibility to non-infectious disease

Non-specific innate defenses→ offer comprehensive protection against a wide variety of microbes

↳ EX: skin and mucous membranes provide physical barriers against invading microbes

↳EX: Body fluids (tears, saliva, urine) flush away invading microbes

Immune system→ a defensive system consisting of white blood cells and antibodies

↳ responsible for recognizing and attacking foreign items in the body

Molecules produced by white blood cells:

• Antibodies

• Signaling molecules

Immunocompetence→ ability of the immune to recognize and attack non-self cells and substances

• Lack of immunocompetence that results in susceptibility

Immune Tolerance→ ability of the immune system to recognize and NOT attack its own systems 

• Lack of immune tolerance can lead to autoimmune diseases

Memory cells→ can remember what items were attacked in the past and can quickly respond and attack if those items re-enter the body

Active immunity→ resistance to an infectious disease due to having it before via immune system memory

↳EX: vaccination and infection

• The immune system can recognize abnormal bodily cells and attack them

↳ attacks cancer

BRCA1 and 2: 

• Females with the BRCA1 and 2 gene have an 80% risk of developing breast cancer and a 20-40%(1) 10-20(2) risk of developing ovarian cancer

• Age influences susceptibility ie the older you are the more likely to develop a chronic disease and the younger you are the more likely you are to become injured due to an unintentional injury

• Medical conditions and their treatments can affect susceptibility(cancer and radiation treatment)  

• Lifestyle choices affect susceptibility (smoking, drinking, exercise)

Environment→ an external condition that can influence the development of disease

Natural environment→ landforms, bodies of water, climate, ecosystems, organisms

Built Environment→ housing quality, industries and businesses, urban vs rural, infrastructure, and pollution and waste disposal

Occupational Environment→ what you do for work

Socioeconomic Environment→ general economic conditions

Cultural Environment→ religious beliefs, understanding of health related terms and issues, social norms, and willingness to act on health related advice

Maternal and Infant Health

Family Planning→ determining the preferred number and placement of children and choosing the appropriate means to accomplish it

↳ half of US pregnancies are unplanned

Benefits of Family Planning to Individual, Family, and Community Health:

• More resources per child

↳ financial, clothing, food, educational, and medical/dental

• Greater educational opportunities for females

• Positives for individuals and families are positives for the community

Birth Control Methods:

• Surgical Sterilization→ Vasectomy and tubal ligation

• Birth control pills

• Vaginal ring

• IUD

• Implant

• Maternal, infant, and neonatal death rates are a measure of disease prevention and health promotion regarding diseases and illnesses relating to pregnant individuals and infants

• An infant’s health is completely dependent on that of the mother

↳ the mothers health and health behaviors dictates that of the baby EX: drinking while pregnant can cause the baby to be born with FAS

Maternal Mortality→ deaths due to pregnancy and birth related causes

↳common causes of MM: infection, hemorrhaging, high blood pressure, etc…

Key Features of Prenatal Care:

• Monitor and treat pre existing conditions 

• Screen for reproductive health infections

• Assessment of mothers health and looking for developmental complications (Preeclampsia, gestational diabetes, etc…)

• Make sure the fetus is developing correctly

• Guidance for nutrition

Nutrients of Importance during Prenatal:

• Folic acid→ prevents neural tube defects such as spina bifida

• Calcium→ decreases risk for osteoporosis later in life, if mother doesn’t have enough during pregnancy the fetus will take from her bones

• Iron→ provides oxygen for fetus through red blood cells

Infant Mortality Rate→ 5.9 deaths per 1000 live births

Neonatal Mortality Rate→ 4.1 deaths per 1000 live births

Leading Causes of Infant Mortality:

• Birth defects/congenital malformations

• Low birth weight

• SIDS

• Maternal complications

• Unintentional injuries

Leading Causes of Neonatal Mortality (Birth to 28 days):

• Low birth weight

• Birth defects

• Maternal complications

• Complications regarding placenta, umbilical cord, and membranes

• Blood infection

Low Birth Weight→ less than 5 pounds 8 ounces

Very Low Birth Weight→ Less than 3 pounds 5 ounces

Most Common Reasons for LBW/VLBW:

• Premature birth

• Maternal diet/ lack of weight gain

• Lack of prenatal care → using drugs/alcohol while pregnant

New Concerns of Pregnancy:

Zika Virus→ spread by mosquitoes, pregnancies while infected can result in miscarriage +stillbirth, not all fetuses will develop birth defects due to zika

↳symptoms→ fever, rash, joint pain, red eyes, muscle pain, headache

Congenital Zika Syndrome→ severe microcephaly, decreased brain tissue with specific pattern of damage, damaged brain tissue during first trimester, damage to retina, joints with limited range of motion, too much muscle tone

Prevention of CZS and Zika:

• Use of condoms and birth control

• Controlling mosquito populations

• Don’t travel to zika areas while pregnant

History of Public Health

• There is evidence that some communities had bathrooms, drains, and sewer systems many years ago

Ancient Health Related Findings:

• Code of Hammurabi→ included laws about physicians and health practices

• Book of Leviticus→ provided instructions concerning hygiene, diet, sanitation, and separation from lepers

Ancient Greece Findings:

• Emphasized individual health, exercise, and strength

• They developed logical explanations for why disease occurred instead of supernatural

↳ not all the way true, some just began the development of the idea

Hippocrates→ Father of Medicine

• Said that all things are made of 4 types of atoms:

- Earth atoms→ solid and cold

- Air atoms→ dry 

- fire atoms→ hot

- water atoms→ wet

• Stated that the body is made up of 4 types of humors

  - Phlegm→ Earth and Fire atoms

- Yellow Bile→ Fire and Air atoms

- Black Bile→ Earth and Air atoms

-  Blood→ Fire and Water atoms

↳ disease is a result of an imbalance of the four humors

• Used for 2000+ years

• Said that fever is a result of too much blood→ resulted in the treatment of bloodletting

• He was the very first epidemiologist 

- noted ways that disease might spread and found some explanations as to how it is spread→ Air/winds, geographical distribution and disease, water sources, and personal behaviors

• His concepts were more correct than his treatments

Geographical diseases:

• Lyme disease, yellow fever, malaria, dengue

His contributions to medicine included

1. Developed tools for surgery

2. Transformed medicine as discipline

3. Hippocratic Oath→ ethical basis for medical graduate- prescribe medicine to benefit patients

4. Described diseases based on observations and evidence rather than superstitions 

Roman Empire:

• Government instituted measures included→ building codes, sewers/drains, garbage collection and street cleaning, public baths, aqueducts, and education for physicians

• Disease contributed to the roman empires collapse

↳ 500 years of malaria epidemics weakened the populations, then the bubonic plague killed 100 million people

• The plagues death toll caused people to lose faith on fact based medicine and they turned to spiritual 

Dark Ages:

• All diseases were seen as a punishment by God for sins 

• Immoral to see one’s own body→ caused hygiene to be non existent 

• Famine was common

Medieval Period:

• Idea of disease as God's punishment continues

• Governments and individuals couldn’t prevent diseases

• Black Death

↳ Evidence states that certain cities tried to limit the spread of it by isolating themselves

Renaissance Period:

• Spirit of inquiry became common→ doctors began studying diseases and could start telling one disease from another

• Increased travel, trade, and population which lead to the further spread of disease

↳during the 1500s there was a massive syphilis epidemic which spread to troops

Syphilis→ multistage disease, each stage has signs and symptoms

3 Concepts that came from Syphilis:

1. Diseases can come from certain behaviors

↳ sex rather than supernatural causes

2. Certain diseases can be treated through chemicals 

↳ the quicksilver cure

3. Certain diseases can be prevented

↳ overcoat

Colonial Period:

• Epidemics continued in Europe

↳ smallpox

• Europe's diseases were brought to new lands (America’s) and killed many Natives

Small Pox→ contagious disease caused by the variola virus

• Fatality rate is 30%

Smallpox impact on world history:

• Killed several European monarchs

• Assisted Colonialism

↳50% of Aztecs died in South America following the Eurpeans arrival, British soldiers gave Native Americans smallpox covered blankets (germ warfare)

Smallpox Prevention:

• Variolation→ material from a lesion from a mild case of smallpox is inhaled, results in immunity, but there is a chance of getting smallpox

Bernardo Ramazzi, Occupational Health:

• Interested in the relationship between work and health

- identified lead and mercury poisoning, lung disease due to inhalation of fine particles, and nerve damage can be caused from irregular motions and postures while working 

• Came up with the idea for workplace injury prevention (ventilation and eye protection)

• Injured and sick workers were replaced easily, so his ideas weren’t taken seriously

James Lind, Nutrition and Health:

• Investigated cause of scurvy in sailors

• Believed that “thick” air caused it, but had an open mind

• Conducted a diet study that separated sailors and put them in different groups in order to give them different diets

↳ found that sailors given citrus fruits recovered quickly from scurvy→ scurvy was able to become one of the first preventable diseases because of this

Edward Jenner, Vaccination and Disease Prevention:

• Noticed that milkmaids who had cowpox seemed protected from smallpox

• Demonstrated that skin inoculation with material from a cowpox lesion results in an immunity to cowpox

↳ safer than variolation because there is no risk of getting smallpox from inoculation

Smallpox Vaccination Result:

• Became first disease to become preventable by vaccination 

• Vaccination led to a slow steady decline in smallpox cases over a period of 180 years

• Was declared eradicated in 1977

Beginning of Modern Era:

• In late 1800s people thought diseases were spread through miasmas (vapor)

• Medical profession still followed hippocratic beliefs

• Evidence began building that diseases were caused by microbes

Ignaz Semmelweis:

• Suspected that doctors were transmitting childbed fever to women during childbirth

• Required handwashing in chlorine solution

• Cases of childbed fever dropped from 50% to 1%

• He wasn’t believed and was ridiculed by other doctors

John Snow, Father of Epidemiology:

• Mapped distribution of cholera in London, hoping to find the cause of the outbreaks

• Found that 500 fatal cases occurred in 10 days within 250 yards of a specific intersection

• Found that people who got water from the Broad Street pump were typically people who were infected with cholera→ people who got their water from other sources were not ill at the same rate

• The Broad pump was removed→ Cholera epidemic ended soon after

• Snow found the link between cholera and its spread without actually knowing its cause

Joseph Lister:

• Used carbolic acid to clean up surgical dressings and instruments to control infection

• Concept that cleanliness could prevent the spread of disease was finally accepted by doctors

Louis Pasteur:

• Showed that microbes were everywhere including the air

• Linked microbes to food spoilage

• Demonstrated that heat could kill microbes→ Pasteurization 

• Suspected that microbes could cause disease

• Discovered that microbes that were too weak to cause disease could be used for immunity

↳ his research group found vaccines against anthrax, rabies, and cholera 

Germ Theory of Disease→ many diseases are caused by microorganisms

Robert Koch: 

• Provided the key evidence by demonstrating that a specific bacterial species causes anthrax in animals

• Developed techniques for growing bacteria in labs

• Discovered the bacterial causes for tuberculosis and cholera 

Koch's Postulates:

1. Germ must be present in sick animals, but not in healthy ones

2. The microbes must be isolated from diseased organisms and grown in pure culture

3. The cultured microbes should cause disease when it comes into contact with a healthy organism

4. The microbes must be reisolated from the diseased experimental host and identified as being identical to the original one

Constraints of Koch’s Postulates: 

• Not all bacteria are culturable 

• Many bacteria can be found in both healthy and sick organisms 

• Doesn’t apply to viruses

The Great Sanitary Movement:

• Based on the idea held by social reformers that many diseases could be prevented by removing “filth”

↳ dead animals, waste, and garbage

• Provided evidence that dirty water was the cause of cholera

• Massachusetts was the first state to create a board of health program, 39 other states would soon follow

Since 1900:

• The work of social reformers showed that disease could be prevented with community wide improvements

• Life expectancy increases dramatically

• Progress with sanitation, hygiene, discovery of drugs to help illness, development of medical procedures to help disease/illness, development of vaccines 

Lady Mary Montley Monagu→