Microorganisms and Human Disease

Microbiology - Virology

Microbiology refers to the study of life and organisms that are too small to be seen with the naked eye.

Virology – Study of viruses

Microbes = Microorganisms

Minute living things that individually are too small to be seen by the naked eye.

They include bacteria, protozoa, fungi and microscopic algae.

It also includes viruses, those noncellular entities sometimes regarded as being at the boarder of life and nonlife.

Microbes can be present on any surface

Soil Air Food Solids Liquids

Bacteria

Are alive. They can reproduce without a host. Some are Heterotrophs, they eat organic material waste.

Single-celled. Prokaryote – genetic material is not enclosed in a

nucleus. Opposite of Eukarote. Generally reproduce by dividing into two equal daughter

cells – called binary fission. Shape – Most commonly are rod-like, spherical, ovoid

and spiral. Uncommon shapes include star-shaped and square.

Cocci Bacilli Spirilla

Simplest Forms of Life!!!!

Bacteria are very small.

The average bacterium is about one micron in length that means you could line up about 1000 bacteria end to end on the head of a pin.

If you were to add up the weight of all the bacteria on the planet, it would come out to about 20 times the weight of all the people, animals, and plants on earth! That’s a lot of bacteria!

A mountain or the tip of a pin?

Oh no we are outnumbered!

So you may be wondering, with so many bacteria out there, why don’t we get sick more often? That’s because there are actually very few kinds of bacteria that make people sick.

Pathogenic bacteria – disease producing or cause bacterial disease

Many bacteria are beneficial.

Good Bacteria

Archaebacteria – bacteria that make their homes in extreme environments

Thermoacidophiles – live in extreme heat

Methanogens – live in anaerobic (no oxygen) environments

Halophiles – live in highly salty environments

Bacteria Video

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What is making me sick?

Before the discovery of microbes people believed the cause of illness and death was due to cast spells, touching toads, and punishments from God.

The first Observations

In 1665 the first microbes were viewed with the help of a crude microscope.

Between1673-1723, Anton van Leeuwenhoek wrote and drew pictures of what he called “animalcules” that he scraped from his teeth.

Strep Throat – Where at school can you catch it?

MRSA – Staphylococcus aureus – where at school can you catch it?

Lyme Disease – Where at school can you catch it?

Tetanus – Where at school can you catch it?

Tooth decay

Streptococcus pneumoniae and Neisseria meningitidis

Antibiotics: A fortunate accident.

Are powerful medicines that fight bacterial infections

The first antibiotic was discovered in 1928.

Alexander Fleming was about to throw out some culture plates contaminated by mold when he noticed that bacteria had stopped growing around the area of mold.

Antibiotic Video

Do you have any questions so far?

Viruses

In 1935, an American chemist, William M. Stanley, isolated the tobacco mosaic virus. At about the same time the invention of the electron microscope made it possible to see viruses for the first time.

Viruses

Are smaller in size than bacteria. They are acellular. They are simple in structure – a core

with either DNA or RNA Have to have a host cell in order to

multiply. Antibiotics do not cure viral diseases Shape – crystal, cylinder, sphere, spacecraft

Shapes

Viral Disease

A viral infection is any type of illness or disease caused by a virus.

A viral infection occurs when a virus enters the body through such processes as breathing air contaminated with a virus, or insect bite.

Vaccines can give one immunity from viral disease

Virus Video

Introduction_to_Viruses.asf.lnk

Varicella – Chicken Pox

Mumps & Measles

Epstein-Barr Virus: Mono - “The Kissing Disease”

Human Papillomavirus “Warts”

Hepatitis C

Immunity Video

Immunity_and_Vaccination.asf.lnk

Any questions about viruses?

Ticks and Fleas and Ticks and Fleas and Mosquitoes! Oh my!Mosquitoes! Oh my!

A A vectorvector is an insect or any living is an insect or any living carrier that transmits an infectious carrier that transmits an infectious agent. agent.

Bubonic PlagueBubonic Plague

The The Black DeathBlack Death, a medieval , a medieval pandemic pandemic that swept that swept through Asia and Europe. It reached Europe in the late through Asia and Europe. It reached Europe in the late 1340s, killing an estimated 25 million people. The Black 1340s, killing an estimated 25 million people. The Black Death lingered on for centuries, particularly in cities. Death lingered on for centuries, particularly in cities.

ParasitesParasites – an organism that – an organism that derives nutrients from a living derives nutrients from a living

hosthost Head Lice - causes itchingHead Lice - causes itching Tapeworms - causes malnutritionTapeworms - causes malnutrition Malaria – causes deathMalaria – causes death Giardia – causes diarrheaGiardia – causes diarrhea

MutagenMutagen – – an agent in the environment an agent in the environment that causes mutations in DNA that causes mutations in DNA

(Deoxyribonucleic acid(Deoxyribonucleic acid)) Caused by chemicals – Fetal Alcohol Caused by chemicals – Fetal Alcohol

Syndrome – Syndrome –

Alcohol (wine, beer, or liquor) is the Alcohol (wine, beer, or liquor) is the leading known preventable cause of leading known preventable cause of mental and physical birth defects in mental and physical birth defects in the United States. the United States.

Caused by radiation – even Caused by radiation – even ultraviolet lightultraviolet light

Now that your totally grossed Now that your totally grossed out do you have questions?out do you have questions?

Yikes! Can I Catch It?Yikes! Can I Catch It?

Infectious DiseaseInfectious Disease A disease that can be A disease that can be

transmitted from:transmitted from: Person to personPerson to person Animal to personAnimal to person Insect to personInsect to person

AIDSAIDS ColdsColds FluFlu

Noninfectious diseaseNoninfectious disease A disease that cannot be A disease that cannot be

shared from one person shared from one person to another.to another.

AsthmaAsthma CancerCancer EpilepsyEpilepsy

Personal conditions that Personal conditions that promote disease. promote disease.

Poor hygienePoor hygiene Weak immune systemWeak immune system A break in skinA break in skin Overuse of antibioticsOveruse of antibiotics

How do we catch a How do we catch a disease?disease?

By inhalation - “catching a cold”By inhalation - “catching a cold” By ingestingBy ingesting Through any body opening Through any body opening Through a break in the skinThrough a break in the skin

How does my body How does my body defend itself?defend itself?

Skin, hair, mucus, tearsSkin, hair, mucus, tears

Stomach acidStomach acid

Inflammation, fever, vomiting, diarrheaInflammation, fever, vomiting, diarrhea

Immune systemImmune system

EpidemicEpidemic or or PandemicPandemic??

Conditions Conducive to Conditions Conducive to diseasedisease

PovertyPoverty Unsanitary food and waterUnsanitary food and water OvercrowdingOvercrowding AnimalsAnimals Poor sanitationPoor sanitation

What does our future What does our future hold?hold?

Even though the United States has Even though the United States has continued to grow in population, the rate continued to grow in population, the rate of deaths by infectious disease has of deaths by infectious disease has decreased. decreased.

Do you think the US will continue to Do you think the US will continue to sustain this trajectory? Why or why not?sustain this trajectory? Why or why not?

Last chance for Last chance for questions!questions!