Great diseases of the world exam 1

into, theories, diseases and food supply, immune system, vaccines, emerging diseases, hemorragic

Medicine is…

-the science of healing, practice of diagnosis, treatment, prevention of disease, promotion of health.

Australopithecus

-Genus of extinct hominids,

-ancestor to humans

-shared traits with humans and apes

-eastern+north Africa 3.5-4.9 MYA

“Lucy”

-Oldest human relative

-ethiopia 3.2 MYA

-called Australopithecus aphaeresis

-we are Hominids

Humans migrate because…

Food security (out of africa 70k years ago), crowding, disease, drought

Developed citvilization happened because…

agriculture and moving on from hunter and gatherer

Where is the fertile crescent

Iraq, syria, turkey, iran. Tigris+Euphrates River

Point of fertile crescent

Birth of agriculture, babylon (domestication of plants+animals+writing+pleagues)

1. Grains (wheat rye barley-bread+alch)

2. Domestication of pulses (beans lentils chickpeas)

3. Developed cuneiform (writing) 3500 BC which was a beer recipe

4. Domestication of animals (cattle,sheep,goat,pig,cat,goose NO horse)

How did Plagues start?

More people=more diseases

hunting v agriculture- more people, zoonoses, more social like

Lethal gift of agriculture

-crowding of communities

-more diseases (zoonotic from night soil, parasitic with flies, water contamination, animal to human transmission because of domestication)

-diversity of plants decreases but qualities increases

Prehistoric medicine

-Before reading and writing was a thing

-combination of natural and supernatural causes

-No concept of public health (no need for infrasturcture)

Geophagy

eating soil like earth substances, believed to treat cuts and wounds

Trepanning

drilling a hole into the human skull to “free body of demons”

osteoarthritis

Microfracture of spine and spondylosis-very common in prehistoric times

Life expectancy pre historically

18-25, then moved to 25-50 depending on region

Medications prehistorically

Used local herbs and info through word of mouth

Nomads medicine

-had more range of plants to use

-yarrow, mallow, rosemary, mushroom, birch polypore

Sickness healed by supernatural?

Appeasing the Gods through chants/prayer/sacrifice/spells

The Shaman/ medicine man

-Doctor for community (in charge of tribes health)

-plant based medicine

-herbs, roots, concoctions, spells, charms

-STILL exist

Disease definition

any condition that damages the normal function of the body

Infectious Disease

Diseases caused by infections with pathogens (aka germs), virus, bacteria, fungi, protozoa, helminths

Causative agent

The name of the pathogen that causes an infectious diseases

Chimp and human diseases

-chimps=same diseases as they did 100k years ago

-us=different diseases

why? the way WE live has changed

life expectancy in 1900 vs now

1900-32

2021-71

Top cause of death

Heart disease

top cause of death in low income countries

neonatal conditions because of lack of clean water and food

-poor infrastructure, sanitation, healthcare

Theories of disease transmission was attributed to

Religion like divine retribution (sins) or astrology

Miasma theory

-500 BCE to 1880 CE

-bad night air through decaying matter

-led to cleanliness and sanitation

Hippocrates

-father of medicine

-natural “humors imbalanced” NOT gods

-promotes health through fresh air, diet, and exercise

-patient care and prognosis not diagnosis

-Yellow bile, black bile, phlegm, blood

Girolama Fracastoro

-Theory of Contagion 1546

-observed patient with syphilis

-saw disease had multiplying bodies and were being transfered from infector to infectee

-how diseases spread

-proved by koch and pasteur

Antonie Van Leeuwenhoek

-father of microbio

-invented microscope

-grinded glass, bacteria, sperm cell

Theory of Spontaneous Generation

-Aristotle first preposed

-that life can arise from nonliving matter

Francesco Redi

-disproved theory of sponatneous generation by maggot bread experiment (maggots could only form when flies could lay eggs not spontaneously)

Lazzaro Spallanzani

-broth experiment with flasks

-microorganisms didn’t come from the broth but from the air

Germ Theory

-infectious diseases are caused by microbes (not sponteously)

-Pasteur proved that germs came from the air

Louis Pasteur

-boiling+cooling killed germs (pasteurization)

-germ theory

-swan neck flask experiment

Koch

-german microbes cause wounds to go septic

-discovered causative agent for tb cholera and anthrax

-established science of modern bacteriology

Kochs postulates

-microbe needs to be in all disease and not in healthy

-isolate microbe from diseased animal and grown in pure culture

-the healthy must produced the same diseases when inoculated with pure culture

-same microbe must be recovered from infected and grown again in pure culture

Joseph Lister

-carbolic acid as wound disinfectant

-spray for operating room

What is a pathogen

a biological agent or organisms that causes diseases or illness to its host

Pathogens from smallest to largest

Prion, virus, bacteria, protozoa, helminth

Prions

-infectious abnormally folded protein

-affects brain

-mad cow diseases, chronic wasting disease

Virus

-small

-not visible under microscope (only electron micro)

-dna ORRR rna

-needs a living host to hijack

-cant be treated with anitbiotics

-measles smallpox rabies ebola

Bacteria

-much larger than virus

-prokaryotic

-can be treated with antibiotics

-can replicate without hosts

-many aren’t pathogens but in microbiome

-TB, plague,leprosy,cholera,syphilis

Eukaryotic

-plants, animals, fungi

Fungi

-eukaryotic

-Yeasts=unicellular

-molds=multicelluar

Protozoa

-unicellular

-eukaryotic

-free-living or parasitic (needs hosts)

-plasmodium (malaria)

Helminths

-eukaryotic

-multicellar

-free living or parasitic

-pinworm,tapeworm,hookworm

eukaryotics

protozoa, fungi, helminths

Chain of infection

-pathogen must enter body

-mechanism/barrier make it difficult for entry

-travel through bloodstream

-break ONE link can slow spread

Susceptible

can be infected

infected not infectious

pathogen is replicating but can’t transmit to others

Infected and infectious

infected and can transmit to others

Immune

resistant to infection-recovery typically gives immunity

Pathogen enters through

-respiratory, eye, skin, urogenital

Pathogen exits through

-Anus, mouth, eyes, skin, urogenital

Infections could be…

1. silent/subclinical/assymptomatic: no symptoms

2. Overt: symptoms

Infectious

infected who can transmit

carrier

infected with no evidence

Reservoir

agent where infection lives, grows, multiplies

Modes of transmission

Direct-person to person, droplets

Indirect-fecal oral, airborne, formites (objects)

Vector-insect bites

Zoonotic/zoonoses

germs causing diseases from animals to humans (reverse zoo is us giving it to them)

Incubation

Infection to symptoms

Latent

Infection to infectiousness

Infectious

Can transmit (starts before signs)

Why is sars 1 easier to control

you become infectious AFTER signs start

Endemic

Low frequency but regularly

Epidemic

occurs when theres a sudden increase from endemic

Outbreak

epidemic-but a smaller area

Pandemic

Epidemic over large areas (continents)

Epidemiological triad model of infectious diseases

Pathogen, host, environment

-results in infection, disease, recovery or death

Infectivity

the ability to infect the host

Pathogenicity

ability to cause disease/harm host

Virulence

the degree of harm caused by organism

What is a system

a network of cells, tissues,organs, and molecules that work together to protect the body from invasion

Immunology

the study of immune system, immune response to disease/tumor because of inadequate immune system

Cells

WBC (lymph, neutrophilis)

Microphages

Dendritic cells

mast cells

Tissues

blood

bone marrow

tonsils

mucous membranes

Organs

Lymph nodes

thymus

spleen

Molecules

antibodies

cytokine

complement

Blood

-Plasma (molecules)

-WBC (cells)

-RBC

T-lymphocytes develope in

Thymus

B lymphocytes develop in

bone marrow

Path of blood and lymph circulation

interstitual fluid can be infected in blood stream, travels to lymphatic capillaries, lymph nodes filter out, travels back to blood stream

How do pathogens gain access to the body

mucosal surfaces or skin

1st layer of defense

physical/mechanical

chemical and microbiome barriers

(coughing, saliva,acid in stomach and sweat, urine flow)

2nd layer of defense

innate immunity

existing mechanisms

3rd layer of defense

adaptive immunity

mechanisms developed after infection

What are the 2 arms of the immune system

innate and adaptive immunity

Innate immunity

-rapid, recognize path through cell receptors or serum protiens

-pain at site, fever, malaise, anorexia

-components: Molecules (cytokines+complement)

-5 days later-than adaptive

Complement

-causes inflammation

-consists of enzymes to kil pathogens by phagocytosis and making holes in membrane

Cytokines

-small glycoproteins

-signal between cells through receptors

-tells cell to tell body to react

-can be innate or adaptive

Adaptive immunity

-highly specific response to pathogen

-delayed response (at least 5 days)

-results in memory

-long lasting immunity

-B-cells: antibodies

-T-cells: cytokines

2 arms of adaptive immunity

Humoral immunity (antibody B-cell based)

Cell-Mediated Immunity (T-cell based)

Humoral immunity

-antibody based

-virus, toxic bacteria, extracellular bacteria, large parasites

-MEMORY B CELLS

Cell-mediated immunity

-t cell based

-virus, intracellular bacteria, fungal pathogens

Antibodies (immunoglobins)

glyco secreted by b cells that bind with antigen to neutralize toxin and kill by phagocytosis

Hematopoiesis

making blood cells in bone marrow

Pathogen is outside the cell

Humoral immunity

-B cells recognizes antigen

-antibodies released

-neutralizes virus/toxic

Pathogen is inside the cells

Cell mediated immunity

-antigen on MHC molecules

-T cell activated
-CD8 (cytotoxic T cell):kills infected host cell

-CD4 (helper t cells): releases cytokines which activate b cells, cytotoxic t cells and macrophages

flow of immune system

innate-fast-phagocytes

adaptive-B&T cells

Outside-B-antibodies

Inside-T-MHC (CD4 and CD8)