Microbiology 2: PATHOGENS

Ppt. by Robin D. Seamon

Disease: normal body functions are disrupted

Pathogen: any microbe that causes disease

Noninfectious disease: can’t be spread from person to person

• Genetic disorder (hemophilia)• Smoking• Lack of exercise• High fat diet

Infectious disease: passed from one organism to another

Immunity: ability to resist a disease

1.Air2.Contaminated objects3.person to person4.Animal vector (mosquito)5.Food & water

Vectors: organisms that transmit pathogens from a host to a new organism

Carrier: an organism with the infectious pathogen but no symptoms

You bring them in. The key: Wash

your hands properly. Experts advise

that friction (especially between the

fingers) and duration are both

important (CDC, 2013). Wash for 20 to

30 seconds, or the amount of time it

takes to sing "The Alphabet Song"

http://www.healthline.com/health-slideshow/germy-places#1

Wet laundryDirty laundry

T R A N S M I S S I O N

DIRECT CONTACT- communicable (mononucleosis)• Kissing• Shaking hands• Touching open wounds or sores• Sexual contact/bodily fluids

INDIRECT CONTACT- objects: doorknobs, telephones, etc.Air (tuberculosis)Food (botulism)Water (typhoid fever)Vectors

• Animal bites (rabies, West Nile Virus)

P O R T A L S O F E N T R Y

• Respiratory Tract nose, mouth, lungs

• Gastrointestinal Tract throat, stomach, intestines

• Mucous membranes nose, eyes

• Penetration bites, cuts, injections

B A C T E R I A L D I S E A S E S• many are contagious• prokaryotic, unicellular• everywhere- some are beneficial

• Digestion, decomposers, photosynthesizers, critical components of ecosystems, bioremediation

• Some are pathogens in food, water, cuts• Reproduce quickly, using nutrients the body needs-

sickness• Most pathogenic bacteria produce toxins that disrupt

normal cell functions- sickness• Antibiotics can kill or slow growth of bacteria• Sinus infections, Tuberculosis, Strep throat,

pneumonia, Lyme disease

1. Bacilli- rod-shaped

2. Cocci- spherical

3. Spirilla- long spiral

SHAPES

EXAMPLESCocci: Staphylococcus (Staph), Streptococcus (Strep Throat)

Bacilli: Escherichia coli (E. coli; 0157:H7), Bacillus anthracis (Anthrax), Clostridiumbotulinum (Botulism Toxin Producer)

Spirilla: Campylobacter jejuni (causes diarrhea esp. in children), Helicobacter pylori (causes peptic ulcers)

• Endospore: dormant version of the bacteria

• When conditions improve, endospore splits & bacteria become active again

• Scientists found bacteria inside an insect preserved in amber 30 million years ago; when endosperm was moistened, bacteria began to grow again!

http://archives.microbeworld.org/scientists/all_profiles/interview2.aspx

REPRODUCTION

Binary fission single cell divides into two identical daughter cells

V I R A L D I S E A S E S • All are pathogenic• Strange code names based on how

they were identified or isolated• Not alive

• Not made of cells- only reproduce• Lytic cycle: Need to hijack a living cell’s nucleus,

program it to make copies of itself to reproduce until that cell overworks, dies & spills out hundreds of copies of the virus

• Common cold- VECTOR: air/touch• HIV- VECTOR: bodily fluids• Influenza• Mononucleosis (mono)

ADVANCE

Capsid; protein coatNucleic Acid: DNA or RNA

Virus purpose: REPRODUCTION- to pass on genetic information

Bacteriophage

BACK

• Average person has 2 cold viruses a year: sore throat, sneezing, congestion, headache, runny nose

• Vaccines: contain dead pathogens so that the body fights a weak form of the invader; when the body encounters the live version in its lifetime, it will remember exactly how to kill it.

• Vaccines are given to young children so immune system can gain strength, to travelers

• Anti-viral medications: can help slow down some viruses

• Herd immunity- protects groups; if 90% of the population is vaccinated, epidemics never take hold

• In vaccinated communities, germs have fewer bodies in which to infect, multiply

• Germs have nowhere to breed so infection fizzles out

LINK: Animation of Herd immunity

Herd Immunization

Theory

PROBLEM: real populations of immunized & non-immunized aren’t as evenly distributed as they are in the models.

Apple Scab Bacterial Canker

Cedar Apple Rust

Dampening Off

http://www.planetnatural.com/pest-problem-solver/plant-disease/

Plants get diseases too.

P A R A S I T E D I S E A S E S

Protists- unicellular microorganisms; many have insect vectors• Giardia: nausea, cramps, diarrhea• Malaria: Plasmodium

Fungi- decomposers that don’t wait until death to start feeding on organism; usually on skin• Athlete’s foot: fungus- skin flakes & itches• Ringworm: fungus- skin itches in red circle patterns

ADVANCE

BACK

G. lamblia

Athlete’s Foot

Ringworm

BACK

Flatworms- parasitic• Tapeworms• Flukes (liver fluke)• Schistosoma

roundworms -nematodes; parasitic; most live in the intestines of host• Pinworms (Enterobius vermicularis)• Hookworms (Necator and Ancylostoma)• Trichinella spiralis (larvae migrate to muscle)

TapewormLiver fluke

Pinworms

BACK

Liver fluke life cycle

BACK

Hookworm Life Cycle

NEXT

BACK

Epidemic: when a large percentage of people become infected in a specific geographical areaPandemic: when it crosses country & continental borders

O T H E R : • Dangerous chemicals- poison body (lead in water &

air)- damages brain, kidney, liver, learning, behavioral problems

• Mutagens- substances that cause cells to mutate (change form)

• X-rays, cigarette smoke, sunlight/UV- skin cancer

H I S T O R Y - F I G H T I N G D I S E A S E

Until the 20th C. surgery patients died of bacterial infections.Pasteurization- mid 1800s

• Louis Pasteur (French) discovered microorganisms that cause wine to spoil- bacteria

• Devised a method to kill the bacteria by heating it: pasteurization

Alexander Fleming- 1928 discovered the first antibiotic• Found a mold growing in his Petri dishes & noticed

that the fungus was exuding a chemical that was killing the bacteria in his dish: named it penicillin

Edward Jenner (English) 1796 1st successful vaccination:

Jonas Salk- 1950’s American virologist who developed the polio vaccine (viral disease affecting the nerves, leading to paralysis

1979 WHO said smallpox was wiped out due to vaccination

TODAY• Pharmaceutical companies study disease & medicine• CDC- Center for Disease Control- US Government

agency that studies infectious disease

Atlanta, Ga

SIZES:1 inch = 250,000 virus germs end-to-end1 inch = 25,000 bacteria end to end1 inch = 5,000 protist end-to-end1 inch = 2,500 fungus spore end to end

M I C R O B U G S - T H E B I G 4

1. Fungus/molds• Athlete’s foot• Thrush• Ringworm• Fungal nail infections

2. Protist/Protozoa• Plasmodium- malaria• Trypanosomes- sleeping sickness

3. Bacteria• Tuberculosis• Cholera• Gonorrhea• Syphilis• Diptheria• Whooping cough• Typhoid• Skin infections: boils, impetigo, stomach ulcers• Food poisoning• Diarrhea

4. Virus- 1- 1,000 in a few hoursAll are pathogenic- they hijack host-cells

• Colds- flu• Rubella• Cold sores• Herpes• Rabies• Chicken pox• Measles• AIDS• Hepatitis• yellow fever• Cervical cancer

H1N1- Swine Flu

“ S U P E R B U G S ”

• As living things multiply, slight mutations may occur in genetic material

• The vast numbers of pathogens as they multiply mean that mutations are likely

• Sometimes a chance mutation gives the bug a partial or complete resistance to the drug

• The resistant bug multiplies & spreads until scientists find a new drug to kill it

• Using antibiotics too often has caused a problem

PROBLEM: Nightmare Bacteria

• Recently, scientists & doctors have documented populations of bacteria that are pan-resistant: no form of antibiotic will kill it

• Nightmare bacteria (CDC’s term) can pass resistance between different strains of bacteria outside of a host (in other vectors such as water)

• Some are able to lie dormant in carrier hosts, avoiding detection, thus spreading to others unknowingly

WHAT DOES THIS MEAN FOR THE FUTURE OF

DISEASE-CONTROL?

PAST PANDEMICS/EPIDEMICS-Bubonic plagueTuberculosisSmallpox

CURRENT PANDEMICS/EPIDEMICS-HIV/AIDSRegular flu- influenza (viruses called orthomyxoviruses)-some spread from animals to people

P A S T P A N D E M I C S

Tuberclosis

1800- 1922

Bubonic Plague

Smallpox Epidemic 1870

Flu pandemics/epidemics• Every year the ‘regular’ or ‘seasonal’ flue kills 40,000 US

citizens• 1918-1920- Spanish Influenza killed 80 million people• H1N1 Swine Flu Virus- contains parts of several

different viruses that previously had affected pigs, birds & then humans

• Influenza viruses spread-• Coughing• Sneezing• Touching contaminated objects to

nose/mouth

R E C E N T P A N D E M I C S

Bird Flu- (Avian Influenza)1997 flu first jumped to humans4 main virus strains (H5N1)• Infects humans in contact with infected poultry- birds’

fluids enter human nose, mouth, cut• Symptoms: fever, headache, joint ache, sickness, sore

eyes, nose, throat• Kills 2/3 of sufferers• Antiviral drugs ease symptoms

Swine Flu2009- Mexico & USVirus flue type H1N1 may have been in pigs for years before jumping to people• Spreads person-to-person• Kills fewer than 1 in 250 sufferers• Vaccines were developed quickly

African sleeping sickness• Most parasites don’t kill host • Take nutrients from it- sickens/weakens host• Often attacks digestive or circulatory systems• This parasite destroys red blood cells that carry oxygen

through the body, making person tired & lethargic (sleepy)

Tsetse fly

African Sleeping Sickness

HIV/AIDSHuman Immunodeficiency Virus- targets T-Cells (immune cells)Leads to AIDS- auto immune deficiency• Transmitted via sexual contact, used hypodermic

needles• Rapidly mutates differently in each host• Not a cause of death- subsequent infections kill the

host b/c immune system is compromised

2008 Data

Ebola1976 West Africa, named for the Ebola River in the CongoPossible vectors- other primates• virus spread through bodily fluids of a sick individual

entering cut/eyes/nose • person is contagious only AFTER feeling sick/showing

symptoms (2 week incubation period)• does NOT travel through the air, water, or food• fever, headache, soreness, leading to deadly symptoms of

hemorrhaging, organ failure & death• patients can be treated so that their own bodies fight the

disease- no cure or vaccine currently• CDC stats: http://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/

• As of Jan 25, 2015: 21797 cases; 8,675 deaths

I N F E C T I O U S D I S E A S EP R E V E N T I O N

• Good hygiene or keeping yourself clean• Washing your hands and bathing regularly• Cover your mouth when you sneeze or cough

• don't use hands, use arm• Killing pathogens

• antibiotics kill bacteria but not viruses• vaccines prevent both

• Certain medications help body build up immunity

CDC- prevention brochure

Wash for the length of the Alphabet song!