VTPB 221 Exam 1

Pandemic

epidemic of infectious disease spread across multiple continents

Two meanings of medicine

1) Science of Healing

2) Medications, drugs

Australopithecus

(Latin australis "southern", Greek "ape") closely related to the human genus Homo and may be ancestor around 3.5 to 4.9 millions years ago

Lucy

Ethiopia 3.2 million years ago, one of oldest relatives

Australopithecus apheresis

extinct species that lived between 3.9 and 2.9 million years ago

Why humans migrate

population growth

disease outbreaks

drought/climate change

crop failure

Fertile Crescent

modern Iraq, Syria, Egypt, Turkey, Iran

Tigris and Euphrates

two rivers that form the outside border of Mesopotamia

Wheat, Rye, Barley

First grain crops to be domesticated

Pulses (legumes), beans, lentils, chickpeas

Modern agriculture domestication of

Effect of Agriculture

1) Increase in population

2) animal husbandry (zoonoses)

3) social organization

Lethal gift of agriculture

1) communities and crowding

2) decreased variability of plants and animals

3) night soil and manure use - parasitic diseases, bacterial diseases, flies

4) water contamination

5) zoonotic diseases

Geophagy

the practice of eating earth, dirt or clay

Trepanning

Ancient practice where holes were drilled into ill person's head

Release evil spirits

18-25, -40

life expectancy prehistoric

Yarrow, mallow, rosemary, birch polypore

prehistoric medicinal herbs

Shaman

prehistoric Medicine-man in charge of their tribe's health and gathered plant- based medications, carried out rudimentary surgical procedures, and casted spells and charms

Disease

any condition that damages the normal function of the body

Infectious diseases

diseases caused by infections with pathogens (virus, bacteria, fungi, protozoa, helminths)

Causative agents

pathogen that causes infectious disease

Why diseases emerge

how we live, cultural and technological advancements

32, 71

life expectancy in 1900 vs 2021

heart disease, Alzheimers, stroke

three top causes of death in high income country

Miasma Theory

diseases were caused by a "miasma", a poisonous form of "bad air" or "night air" emanating from decaying organic matter- encouraged clenliness

Humorism

Hippocrates "Father of Medicine" began the belief that health was maintained by a balance of the four humors: blood, black bile, yellow bile, and phlegm.

Theory of Contagion

Fracastoro - observing patients with syphilis, proposed that each disease was caused by a different type of rapidly multiplying minute body and that these bodies were transferred by contact, soiled clothing, and air

Antonie van Leeuwenhoek (1673)

Father of Microbiology- invented early microscope and discovered bacteria, sperm cells, blood cells, roundworms

Theory of Spontaneous Generation

Aristotle- life can arise from nonliving matter

Francesco Redi

Italian physician who was the first to attempt to disprove the Theory of Spontaneous Generation; experiment to check whether maggots (baby flies) really came from decaying meat

Lazzaro Spallanzani

showed that a sealed flask of meat broth sterilized by boiling failed to grow microbes

Louis Pasteur

A French chemist who began The Germ Theory by spoilage of wine, developed a process for killing germs by boiling wine and then cooling it down

Robert Koch

Developed the culture plate method to identify pathogens (tuberculosis, anthrax, cholera), discovered microbes cause wounds to go septic, established new Science of Modern Bacteriology

Koch's Postulates

1. A particular microbe must be found in all cases of the disease and must not be present in healthy animals or humans

2. The microbe must be isolated from the diseased animal or human and grown in pure culture in the laboratory

3. The same disease must be produced when microbes from the pure culture are inoculated into healthy susceptible laboratory animals

4. The same microbe must be recovered from the experimentally infected animals and grown again in pure culture

Joseph Lister

introduced antiseptic solution to infection by using carbolic acid as disinfectant

viruses, bacteria, fungi, protozoa, helminths, (prions)

Five major categories of pathogens

Prions

infectious proteins (Kuru, Creutzfeld-Jakob, Mad Cow, CWD)

Viruses

-very small (20-400nm)

-genome DNA or RNA with protein shell and membrance

- need living host

-measles, smallpox, rabies, ebola

Bacteria

- larger, self sufficient, single celled

- prokaryotes

- treated with antibiotics

- part of microbiome

- E. coli, Salmonella, Listeria, Yersinia, Borrelia, Mycobacterium

- tuberculosis, plague, leprosy, cholera, syphilis

Fungi

- eukaryotes

- Yeast: unicellular (Candida)

- Molds: multicellular (Ringworm, Aspergillus)

Protozoa

- eukaryotic

- free-living/parasitic

- need to extract nutrients from host to survive and reproduce

- Plasmodium (malaria), Toxoplasma, Giardia (diarrhea)

Helminths

- eukaryotic

- multicellular, worm-like

- free living/parasitic

- Pinworms, Hookworms, Tapeworms

Chain of Infection

infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, susceptible host

Susceptible, Infected but not infectious, Infected and infectious, immune

Types of hosts in infection spread

Asymptomatic (also: silent,inapparent,subclinical)

no symptoms of disease

overt

symptoms of disease

Carrier

individual who is infected with an organism but shows no evidence of disease, although the disease may have been present earlier, and can be a source of infection to others

Reservoir

habitat in which the agent/pathogen normally lives, grows, and multiplies

Methods of disease transmission

- Direct: person to person, droplet

- Indirect: fecal, airborne, fomites

- Vector: insect

Zoonotic Disease

disease that can be passed between animals and humans

Incubation period

interval between initial infection and first signs and symptoms

Latent Period

time from infection to onset of infectiousness or communicability

Infectious period

time during which the host can infect another host

Endemic Disease

infection or disease that occurs regularly at a low or moderate frequency in the human population (common cold)

Epidemic

occurs when there are sudden increases in frequency above endemic levels in the human population

Agent, Host, Environment

epidemiological triad causing disease

The Immune System

-Cells: leukocytes, macrophages, dendritic cells, mast cells

-Tissues: blood, bone marrow, tonsils, mucous membranes

-Organs: lymph nodes, thymus, spleen

-Molecules: antibodies, cytokines, complement

Antibodies, Complement, Cytokines

Plasma molecules immune system

mucosal surfaces or skin

How a pathogen gains access to the body

Physical/mechanical/chemical/microbiological barriers, innate, adaptive

Three layers of body's defense

neutrophils, eosinophils, basophils, monocytesm lymphocytes

immune cells in blood

1st Layer Defense

-Lysozyme enzyme digests cell wall of bacteria

-tears and saliva wash away

-fatty acids in sebum, antimicrobial peptides, microorganisms on skin

-urine flushes

cilia and goblet cell

Mucous defenses in respiratory epithelium

Innate and Adaptive Immunity

Innate - bacteria, viruses, fungi, parasites

Adaptive - unique molecular features of different pathogens

innate immunity

-general types of pathogens recognized

-results in inflammation

-does not cause lasting immunity

-activates adaptive immunity

Adaptive immunity

- specific response

-delayed-at least 5 days

- immunological memory and long lasting immunity

-B cells, T cells, Antibodies, cytokines

Hematopoiesis

process of formation of blood cells from bone marrow derived stem cells

Phagocytosis and Inflammation

Innate Immune Response results in

Cytokines

Chemicals released by the immune system communicate with the brain.

Complement

a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promotes inflammation, and attacks the pathogen's plasma membrane.

Humoral (Antibody) and Cell-Mediated (T-cell)

Two arms of Adaptive immunity

Humoral immunity

specific immunity produced by B cells that produce antibodies that circulate in body fluids (viruses, toxin bacteria, large parasites)

Cell-mediated immunity

type of immunity produced by T cells that attack infected or abnormal body cells (viruses, intracellular bacteria, fungal)

Antibodies

Specialized proteins secreted by B cells that bind to antigens with high specify

T cell antigen recognition

- requires processed foreign peptides to be present on host cell surface in association with MHC molecules

- MHC molecules influence your ability to produce T cell responses to an antigen

Cytotoxic T cells

kill pathogen infected host cells

Principle of Vaccination

Administration of a formulation to induce pathogen-specific adaptive immunity and memory B and T cell responses

Edward Jenner's Experiment

-pus from cowpox infected milkmaid collected

-used to inoculate boy who gets mild case

-inoculated then with smallpox and is unaffected

Edward Jenner

Father of Vaccinology

Pasteur Fowl Cholera Experiment

Vaccinated chickens with aged cholera bacteria-first attenuated bacterial vaccine

1978

Smallpox eradicated, costing 300 million

2010

Rinderpest eradicated

Herd immunity

The resistance of a group to an attack by a disease to which a large proportion of the members of the group are immune

R0

the number of secondary infections that result from a single infected individual entering a population of entirely susceptible individuals

Live attenuated vaccines

Weakened pathogen

Closely mimic an actual infection

Confers lifelong cellular and humoral immunity

Inactivated vaccines

killed form of pathogen

Subunit vaccines

purified proteins of pathogen

Recombinant vectored vaccines

harmless viruses producing proteins of the pathogen

Nucleic Acid Vaccine

DNA or mRNA coding for protein of pathogen

Effects of Vaccines

-local effects: swelling, sore

-systemic effects: fever, malaise, anaphylaxis

GUILLIAN-BARRE' SYNDROME

Peripheral nerve irritation to the epineurium leads to sensory and LMN losses

Andrew Wakefield

Created a scare through his false scientific research stating the MMR vaccine was linked to autism.

Flu types

-A: humans and animals, moderate to severe

-B: humans, moderate

-C: rarely humans

-D: cattle

Influenza A

-8 RNA segments

-subtypes of HA and NA proteins

Hemagglutinin

One of the enzymes found on the surface of the Influenza virus. It is responsible for binding the virus to the cell that is being infected.

Neuraminidase

One of the enzymes found on the surface of the Influenza virus. It promotes the release of progeny viruses from infected cells.

Type/Origin/StrainID/Year (HANA)

flu naming for human origin

Type/host/origin/strain/year (HANA)

flu naming for non-human origin

water birds

natural reservoir for influenza A with Subtypes H1-H16 and N1-N9

18, 11

Influenza A viruses of humans, mammals, and birds represent combinations of 1 of __ HA subtypes and 1 of __ NA subtypes

H1N1

1918 Spanish Flu