Disease and ImmunityDisease and Immunity

TB

Herpes

Polio Measles

PathogensPathogens

Any foreign invader that enters the body and Any foreign invader that enters the body and causes diseasecauses disease

Pathogens include:Pathogens include: BacteriaBacteria VirusesViruses protistsprotists

A disease that can spread to others is called:A disease that can spread to others is called: InfectiousInfectious ContagiousContagious communicablecommunicable

The Body’s The Body’s ReactionsReactions

The first defense is our skin and mucous The first defense is our skin and mucous membranesmembranes Sweat and oil is toxic to some bacteriaSweat and oil is toxic to some bacteria Mucus will trap invadersMucus will trap invaders

Fever – an elevated body temperature Fever – an elevated body temperature will suppress bacterial growth and speed will suppress bacterial growth and speed up our immune responseup our immune response Normal = 98.6 degree F / 37 degrees CNormal = 98.6 degree F / 37 degrees C

The Body’s The Body’s Reactions to a Reactions to a

localized (small) localized (small) infectioninfection

Inflammatory responseInflammatory response Injured cells release chemical alarm signalsInjured cells release chemical alarm signals Capillaries respond by swelling and leaking Capillaries respond by swelling and leaking

fluid and white blood cellsfluid and white blood cells Swelled area is warmSwelled area is warm White blood cells arrive to attackWhite blood cells arrive to attack

Pus in wounds is dead pathogensPus in wounds is dead pathogens

BacteriaBacteria

Can be pathogenicCan be pathogenic

Characteristics of BacteriaCharacteristics of Bacteria How they eatHow they eat

Heterotrophic Heterotrophic Eat other thingsEat other things

Autotrophic Autotrophic Make their own food like plantsMake their own food like plants

Oxygen requirementsOxygen requirements Anaerobic Anaerobic

Undergo fermentation (no oxygen)Undergo fermentation (no oxygen) AerobicAerobic

Use oxygen Use oxygen

Bacteria ClassificationBacteria Classification

Two Kingdoms:Two Kingdoms:

1.1. Eubacteria – Eubacteria – mostmost common common bacterial formsbacterial forms

1.1. All pathogenic bacteriaAll pathogenic bacteria

2.2. Archaebacteria – Most Archaebacteria – Most primitive bacterial forms that primitive bacterial forms that live in extreme environmentslive in extreme environments

Kingdom EubacteriaKingdom Eubacteria Most commonMost common 3 basic shapes:3 basic shapes:

RodRod SphereSphere SpiralSpiral

Prefix Prefix strep strep = Chains= Chains

Prefix Prefix staphlo staphlo = Clusters= Clusters

Gram stainingGram staining

Bacteria can also be classified by whether or Bacteria can also be classified by whether or not they retain color when stained by a not they retain color when stained by a certain chemical.certain chemical.

Whether or not they retain the color is based Whether or not they retain the color is based on the components of their outer membraneon the components of their outer membrane

Gram-positive bacteria retain the color Gram-positive bacteria retain the color (violet)(violet)

Gram-negative bacteria do not retain the Gram-negative bacteria do not retain the color and are dyed with a secondary dye color and are dyed with a secondary dye which turns them pink. which turns them pink.

Different types of antibiotics are needed to Different types of antibiotics are needed to treat infections based on whether the treat infections based on whether the bacteria is Gram-negative or Gram-positivebacteria is Gram-negative or Gram-positive Some antibiotics kill bacteria by damaging their Some antibiotics kill bacteria by damaging their

peptidoglycan cell wall peptidoglycan cell wall Which bacteria would be resistant to an antibiotic that Which bacteria would be resistant to an antibiotic that

worked in this fashion?worked in this fashion?

Bacterial diseasesBacterial diseases

TetanusTetanus Bubonic plague (The Black Death)Bubonic plague (The Black Death) Bacterial pneumoniaBacterial pneumonia Sinus infectionSinus infection Strep throatStrep throat Tuberculosis (TB)Tuberculosis (TB)

Antibiotics and BacteriaAntibiotics and Bacteria Antibiotics only work against bacteria!Antibiotics only work against bacteria! Some antibiotics are made from chemicals Some antibiotics are made from chemicals

that bacteria and fungi produce naturallythat bacteria and fungi produce naturally Penicillin is made is from a type of fungusPenicillin is made is from a type of fungus

Other antibiotics have been created in Other antibiotics have been created in medical laboratoriesmedical laboratories

Amoxicillin, Zithromax, Tetracycline, Amoxicillin, Zithromax, Tetracycline, VancomycinVancomycin

Antibiotic Resistant BacteriaAntibiotic Resistant BacteriaRemember evolutionRemember evolution1) Bacteria have different 1) Bacteria have different

characteristics due to mutations.characteristics due to mutations.2) Some of these mutations help the 2) Some of these mutations help the

bacteria to survive an attack by bacteria to survive an attack by antibiotics.antibiotics.

3) The stronger (more resistant) 3) The stronger (more resistant) bacteria survive and infect a new bacteria survive and infect a new person (host).person (host).

TuberculosisTuberculosis Certain types of this pathogenic Certain types of this pathogenic

bacteria can no longer be treated by bacteria can no longer be treated by antibioticsantibiotics

How can you help to How can you help to

stop the spread of stop the spread of

antibiotic resistant antibiotic resistant

bacteria?bacteria?

Useful BacteriaUseful Bacteria1.1. Breakdown organic matter and recycle Breakdown organic matter and recycle

carbon and nitrogencarbon and nitrogen

2.2. Help with the production of foodHelp with the production of food

3.3. Clean up environmental disastersClean up environmental disasters

Intestinal Bacteria

ProtistsProtists

Single or multicelled organisms that Single or multicelled organisms that live in waterlive in water

Plant like or Plant like or

animal likeanimal like

Three representative Three representative protistsprotists

paramecium

Euglena

amoeba

Pseudopod “false foot”

cilia

eyespot

flagella

Protist (protozoan) diseaseProtist (protozoan) disease

MalariaMalaria Anopheles mosquitoAnopheles mosquito

plasmodiumplasmodium

African Sleeping sicknessAfrican Sleeping sickness Tsetse flyTsetse fly

TrypanosomaTrypanosoma

African Sleeping SicknessAfrican Sleeping Sickness

VirusesVirusesA paothgen that is unable to grow or

reproduce outside of a host cell.

It is considered non-living

Virology is the study of viruses

The Common Cold

Virus StructureVirus Structure

Viruses are extremely Viruses are extremely smallsmall

They have a :They have a : Nucleic acid (DNA or Nucleic acid (DNA or

RNA)RNA) Capsid - A protein coat Capsid - A protein coat

that protects the virusthat protects the virus Protein tail -used to Protein tail -used to

infect hostinfect host

Capsid/

Structure of Influenza VirusStructure of Influenza Virus

Protein

Glycoprotein

Capsid

Protein

RNA

Envelope

Used to attach to host cell

Adenovirus Common cold Common coldCommon cold

Flavivirus Hepatitis C (non-A, non-B)Yellow fever

HepatitisHepatitis, hemorrhage

Hepadnavirus Hepatitis B virus (HBV) Hepatitis, liver carcinoma

Herpesvirus

Epstein-Barr virus (EBV)Herpes simplex type 1Herpes simplex type 2Human herpesvirus 8 (HHV8)

Mononucleosis, nasopharyngeal carcinomaCold soresGenital lesionsChicken pox, shingles

Papovavirus Human papillomavirus (HPV) Warts, cervical carcinoma

Paramyxovirus MeaslesMumpsParainfluenza

MeaslesMumpsCommon cold, ear infections

Poxvirus Orthopoxvirus Smallpox (eradicated)

Retrovirus

Human immunodeficiency virus (HIV)Human T-cell leukemia virus (HTLV-I)

Acquired immunodeficiency syndrome (AIDS)Adult T-cell leukemia, lymphoma, neurologic disease

Rhabdovirus Rabies Rabies

Viruses and Their HostsViruses and Their Hosts

When a virus meets a host cell, it can When a virus meets a host cell, it can insert its genetic material into its host, insert its genetic material into its host, taking over the host's functions taking over the host's functions The infected cell stops producing its The infected cell stops producing its

own proteins and starts to make new own proteins and starts to make new viruses! viruses!

Basically, it hijacks the cell!Basically, it hijacks the cell!

Viral PhasesViral Phases Lysogenic phaseLysogenic phase - viruses are - viruses are

dormant inside host cells for long dormant inside host cells for long periods. periods. The host is not sick.The host is not sick.

Lytic phaseLytic phase - The virus is stimulated - The virus is stimulated new viruses are formed, self-new viruses are formed, self-

assemble, and burst out of the host assemble, and burst out of the host cell, killing the cell and going on to cell, killing the cell and going on to infect other cells. infect other cells.

The host is now sick with a viral infectionThe host is now sick with a viral infection

Viral MutationsViral Mutations

Viruses are able to rapidly mutateViruses are able to rapidly mutate FluFlu HIVHIV

Attacks white blood cells – the cells that Attacks white blood cells – the cells that protect our bodies from germs and infectionsprotect our bodies from germs and infections

HIV is latent until another infection triggers the HIV is latent until another infection triggers the lytic stagelytic stage

Kills white blood cellsKills white blood cells HIV has a high rate of replication and mutation HIV has a high rate of replication and mutation

which has made it difficult to make a vaccinewhich has made it difficult to make a vaccine

Two Ways to Two Ways to Control VirusesControl Viruses

Vaccination – An injection of a harmless Vaccination – An injection of a harmless version of a virus which causes an version of a virus which causes an immune response.immune response. The body begins to produces antibodies The body begins to produces antibodies

against that virusagainst that virus Antiviral Drugs – Drugs that slow down or Antiviral Drugs – Drugs that slow down or

stop a viral infectionstop a viral infection TamifluTamiflu

Acquired Immunity – An Acquired Immunity – An immunity that develops after immunity that develops after

exposureexposure 2 kinds:2 kinds:

Active Immunity – When your body makes its Active Immunity – When your body makes its own antibodiesown antibodies

Getting sickGetting sick vaccinesvaccines

Passive Immunity – Passive Immunity – Antibodies are given to the personAntibodies are given to the person

Mother’s milkMother’s milk

White Blood Cells (WBC)White Blood Cells (WBC)

These are your immune cellsThese are your immune cells Most are made in your bone marrowMost are made in your bone marrow There are many typesThere are many types

LymphocytesLymphocytes LeucocytesLeucocytes NeutrophilsNeutrophils B cells, T cellsB cells, T cells

WBC that you need to knowWBC that you need to know

T cells T cells Killer cellsKiller cells Made in bone Made in bone

marrowmarrow Attacks a specific Attacks a specific

pathogenpathogen

B cellsB cells Made in bone Made in bone

marrowmarrow Attack a specific Attack a specific

pathogen by pathogen by making antibodiesmaking antibodies

They stick to the They stick to the surface of a surface of a pathogen and so it pathogen and so it cannot infect any cannot infect any other cellsother cells

Memory CellsMemory Cells

T cells and B cells that remain in the body T cells and B cells that remain in the body after an infection has been destroyed.after an infection has been destroyed.

They provide the body with active immunity They provide the body with active immunity in the future against that diseasein the future against that disease Your body made memory cells against chicken Your body made memory cells against chicken

pox when you had it as a kid. You now have life pox when you had it as a kid. You now have life long immunity to chicken pox!long immunity to chicken pox!

Why can’t we get life long immunity to the flu or Why can’t we get life long immunity to the flu or a cold?a cold?