Diseases and Diseases and DisordersDisorders

Diseases and Diseases and DisordersDisorders

Unit 8Unit 8Chapters 23-24-25Chapters 23-24-25

Unit 8Unit 8Chapters 23-24-25Chapters 23-24-25

Causes of Causes of Infectious Infectious DiseasesDiseases

Pathogens-invade the body and attack Pathogens-invade the body and attack its cells and tissues.its cells and tissues.

Most pathogens are parasites.Most pathogens are parasites.

Parasites live in or on another Parasites live in or on another organism and derive nourishment from organism and derive nourishment from it.it.

EX: BACTERIA, VIRUSES, RICKETTSIAS, EX: BACTERIA, VIRUSES, RICKETTSIAS, PROTOZOANS, AND FUNGIPROTOZOANS, AND FUNGI

BACTERIABACTERIASingle cell organismSingle cell organism

Classified in 3 categories: spherical, Classified in 3 categories: spherical, rod-shaped, and spiral-shapedrod-shaped, and spiral-shaped

EX: Streptococcus, Staphylococcus, and EX: Streptococcus, Staphylococcus, and E. coliE. coli

StreptococcusStreptococcus

Strep throat - a sore, red throat, Strep throat - a sore, red throat, sometimes with white spots on the sometimes with white spots on the tonsilstonsils

Scarlet fever - red rash on the bodyScarlet fever - red rash on the body

Impetigo - a skin infectionImpetigo - a skin infection

Cellulitis and necrotizing fasciitis Cellulitis and necrotizing fasciitis (flesh-eating disease)(flesh-eating disease)

StaphylococcusStaphylococcusSkin infectionsSkin infections

PneumoniaPneumonia

Food poisoningFood poisoning

Toxic shock syndromeToxic shock syndrome

Blood poisoning (bacteremia)Blood poisoning (bacteremia)

E. ColiE. ColiIntestinal bacteriaIntestinal bacteria

Symptoms: diarrhea, food poisoningSymptoms: diarrhea, food poisoning

Goes away untreated in 5-10 days.Goes away untreated in 5-10 days.

Treatment for Treatment for Bacterial Bacterial InfectionsInfectionsAntibiotics-kill bacteria or stop it Antibiotics-kill bacteria or stop it

from reproducingfrom reproducing

Antibiotics Antibiotics DO NOTDO NOT kill viruses: kill viruses:

ColdsColds

FluFlu

Most coughs and bronchitisMost coughs and bronchitis

Sore throats, unless caused by strepSore throats, unless caused by strep

VirusesVirusesSmallest known type of infectious agentSmallest known type of infectious agent

1/2 to 1/100 the size of the very 1/2 to 1/100 the size of the very smallest bacteriumsmallest bacterium

Consist of an inner core of genetic Consist of an inner core of genetic material surrounded by a protective material surrounded by a protective protein shell and are entirely protein shell and are entirely dependent on living cells for survival dependent on living cells for survival and reproduction. and reproduction.

HOW HOW

A A

VIRUSVIRUS

WORKSWORKS

Examples of Examples of Viruses?Viruses?

Human Immunodeficiency Virus (HIV), Human Immunodeficiency Virus (HIV), which is the virus that causes AIDS.which is the virus that causes AIDS.

herpes simplex virus, which causes cold herpes simplex virus, which causes cold sores, smallpox, and the human sores, smallpox, and the human papilloma virus, now believed to be a papilloma virus, now believed to be a leading cause of cervical cancer in adult leading cause of cervical cancer in adult women.women.

RickettsiasRickettsiasResemble small bacteria but work Resemble small bacteria but work like a virus, they must invade the like a virus, they must invade the cell of another life form.cell of another life form.

Usually invade the intestinal tracts Usually invade the intestinal tracts of fleas, mice, ticks, and mitesof fleas, mice, ticks, and mites

When humans are bitten they can When humans are bitten they can contract the rickettsias and contract the rickettsias and contract typhus and Rocky contract typhus and Rocky Mountain spotted fever.Mountain spotted fever.

What is What is Typhus/Rocky Typhus/Rocky

Mountain Spotted Mountain Spotted FeverFeverTyphus occurs throughout the world Typhus occurs throughout the world

where people and rats occupy the same where people and rats occupy the same living area or building.living area or building.

Infection occurs when rat fleas bite Infection occurs when rat fleas bite humanshumans

Rocky Mountain spotted fever occurs Rocky Mountain spotted fever occurs most commonly in the mountains of the most commonly in the mountains of the US and MexicoUS and Mexico

It is spread by ticks, carrying rickettsiasIt is spread by ticks, carrying rickettsias

ProtozoansProtozoans

Single-Cell Organisms, larger than Single-Cell Organisms, larger than bacteria with a more complex cell bacteria with a more complex cell structure.structure.

Most are harmlessMost are harmless

Most common in tropical areas with Most common in tropical areas with poor sanitationpoor sanitation

Water supplies and contaminated Water supplies and contaminated animalsanimals

FungiFungiSimple organisms that cannot make Simple organisms that cannot make their own foodtheir own food

Most are saprophytes or organisms that Most are saprophytes or organisms that feed off dead animals, insects, and feed off dead animals, insects, and leaves.leaves.

The most common are athlete’s foot The most common are athlete’s foot and ringwormand ringworm

Athlete’s FootAthlete’s Foot

RingwormRingworm

How Infectious How Infectious Diseases are Diseases are

SpreadSpreadDirect Contact-Human to HumanDirect Contact-Human to Human

Indirect Contact-bacteria and viruses Indirect Contact-bacteria and viruses can both enter the body through the can both enter the body through the lungs if droplets are exhaled, coughed, lungs if droplets are exhaled, coughed, or sneezed out.or sneezed out.

Animals Spread Animals Spread Infectious Infectious DiseasesDiseasesMad cow diseaseMad cow disease

MalariaMalaria

RabiesRabies

West NileWest Nile

TyphusTyphus

The Immune The Immune SystemSystem

It’s a network of cells, tissues, organs, It’s a network of cells, tissues, organs, and chemicals that fight off pathogens. and chemicals that fight off pathogens.

Inflammatory Inflammatory ResponseResponse

A reaction to tissue damage caused by A reaction to tissue damage caused by injury or infection. injury or infection.

What Happens?What Happens?Tissue damaged, blood vessels near Tissue damaged, blood vessels near injury expandinjury expand

Fluid and cells from bloodstream cause Fluid and cells from bloodstream cause swellingswelling

PhagocytesPhagocytes attack invading pathogens attack invading pathogens

Pathogens killed, tissue damage under Pathogens killed, tissue damage under control, body begins to repaircontrol, body begins to repair

Specific DefensesSpecific DefensesThe inflammatory response is different The inflammatory response is different than the immune response.than the immune response.

How the How the “Immune System” “Immune System”

RespondsRespondsAn antigen enters the body and causes An antigen enters the body and causes the immune system to respond.the immune system to respond.

Lymphocytes are specialized white Lymphocytes are specialized white blood cells that coordinate and perform blood cells that coordinate and perform many specific functions of immunity.many specific functions of immunity.

T cells and B cellsT cells and B cells

Immune System Immune System MemoryMemory

Your immune system has a memory of Your immune system has a memory of every antigen it has encountered.every antigen it has encountered.

Active Immunity develops naturally and Active Immunity develops naturally and artificially.artificially.

Vaccinations are prepared dead or Vaccinations are prepared dead or weakened pathogens that are weakened pathogens that are introduced into the body to stimulate introduced into the body to stimulate an immune response.an immune response.

Passive ImmunityPassive ImmunityYou acquire passive immunity when You acquire passive immunity when your body receives antibodies from your body receives antibodies from another person or animal.another person or animal.

This immunity is temporary.This immunity is temporary.

Emerging Emerging Diseases and Diseases and PandemicsPandemicsThese are emerging diseases whose These are emerging diseases whose

occurrence in humans has increased occurrence in humans has increased within the past two decades or within the past two decades or threatens to increase in the near future.threatens to increase in the near future.

Avian InfluenzaAvian Influenza

H1N1 VirusH1N1 Virus

Salmonella and E. ColiSalmonella and E. Coli

Recreational Water IllnessRecreational Water Illness

HIV/AIDSHIV/AIDS

How Diseases How Diseases Affect the WorldAffect the WorldPandemic-global outbreak of an Pandemic-global outbreak of an infectious disease.infectious disease.

5 Deadliest 5 Deadliest Pandemics in Pandemics in

HistoryHistoryThe Peloponnesian War Pestilence (430 The Peloponnesian War Pestilence (430 BC)BC)

The Antonine Plague (165 AD)The Antonine Plague (165 AD)

The Plague of Justinian (541-542 AD)The Plague of Justinian (541-542 AD)

The Black Death (14The Black Death (14thth Century) Century)

The Spanish Flu (1918)The Spanish Flu (1918)