Prevent & Controlof Disease Intro

Definition:

A condition that impairs normal functioning of a human, plant or animal body and has distinguishing signs and symptoms.

Do you know the name of some diseases????

What is a disease?

Chronic Disease —A disease or health condition that lasts longer than three months, sometimes for the remainder of one's life.

Acute Disease —A disease or health condition that occurs and subsides within three months, usually within days or weeks.

Infection or Disease?

What is the difference between an infection and a disease?

Infection, often the first step, occurs when bacteria, viruses or other microbes that cause disease enter your body and begin to multiply.

For instance, a person gets the disease malaria if he/she carries an infection caused in his/her body by the bit of the female Anopheles mosquito.

(not in notes)

What is the difference?

Communicable vs non-communicable

COMMUNICABLE

A disease that can be passed from one person

to another person, animal, or object.

NON-COMMUNICABLE

Diseases that are not transmitted from one

person to another.Sometimes called infectious or contagious diseases.

Communicable diseases are caused by several kinds of tiny life forms.

These microorganisms that cause diseases are called pathogens.

Sometimes you will hear pathogens called “germs”.

They are specialized to infect body tissues where they reproduce and cause damage that gives rise to the symptoms of the infection.

An infection is a condition that occurs when pathogens enter the body, multiply, and damage cells.

Communicable Disease

Types of PathogensThe two most common kinds of pathogens are:

• bacteria

• viruses  

Others include:

• fungi

• parasites

• prions

Let’s look at each type in more detail.

BacteriaBacteria are one-celled microorganisms too small to see with the naked eye. They exist in virtually all environments in the world.

They are possibly the most numerous types of organisms on the planet.

They can live EVERYWHERE! They can live in sub freezing cold temperatures and boiling hot temperatures. They can live high in the sky and deep below the ocean.

Some bacteria are harmful, but most are harmless or even helpful.

In general, a bacterial infection can be treated with antibiotics, but viral infections cannot.

Bacteria were the first organisms to appear

on earth, about 4 billion years ago. Our oldest

known fossils are of bacteria-like organisms.

Escheria coli (e. coli) bacterium

Streptococcus bacteria

Diseases spread by bacteria

Caused by Bacteria

o Streptococcus pyogenes – (AKA strep throat) The throat gets irritated and inflamed, causing a sudden,

severe sore throat

o Pneumonia - lung inflammation caused by bacterial or viral infection, in which the air sacs fill

with pus and may become solid

o Meningitis - an infection of the membranes covering the brain and/or spinal cord

o Salmonella –  bacterium that occurs mainly in the intestine, especially a serotype causing food

poisoning

o Whooping cough -  most affecting children, characterized by convulsive coughs followed by a

whoop

More Diseases from Bacteria

Some of the most deadly diseases and devastating epidemics in human history have been caused by bacteria. 

In the year 1900 pneumonia, tuberculosis and diarrhea were the three biggest killers in the USA.

As water purification improved, vaccines and immunization programs evolved, and antibiotic treatment became more advanced - the human death toll in the USA from bacterial diseases has dropped significantly (as well as in the rest of the developed world).

In developing countries, success rates have depended on several factors, such as the strategies implemented by local health authorities, and whether countries enjoyed periods of peacetime (no wars).

Strep Throat

Typhoid fever

Plague – aka “Black Death”

VirusesViruses are the smallest disease-causing organism. They are even smaller than a bacteria.

They depend upon a host to survive, grow and reproduce. They can’t live outside of other living cells.

The host is who/what they live in or on.

Once they are inside the body, viruses can spread and make people sick. They reproduce by injecting their genes into a cell to produce thousands of new viruses.

Different viruses attack specific cells – so the flu virus attacks the cells of the respiratory system while the virus which causes meningitis attacks the cells of the membranes which cover your brain.

Diseases spread by viruses

Caused by Viruses

o common cold -causes inflammation in the mucous membranes lining the nose and throat.

o influenza -the flu - a viral infection of the respiratory tract.

o chicken pox

o cold sores

oHand-Foot-and-Mouth Disease - viral illness that usually

affects infants and children younger than 5 years old. Symptoms

include fever, blister-like sores in the mouth and a skin rash.

Shingles

Cold sore

Warts

Chicken poxMononucleosis

Hand-Foot-and-Mouth Disease

Fungi

Fungal diseases are often caused by fungi that are common in the environment.

Most fungi are not dangerous, but some types can be harmful to health.

There are approximately 1.5 million different species of fungi on Earth, but only about 300 of those are known to make people sick.

Some fungal diseases may be more common than previously realized, and rare but newly-emerging fungi are becoming increasingly problematic.

Antibiotic penicillin is made from the fungus Penicillium notatum.

Brewers' and bakers' yeast are types of fungi that grow as individual cells. They have been used for many centuries in the production of beer, wine and bread.

Diseases such as athlete's foot, ringworm, oral and vaginal thrush are examples of fungal infections.

Athletes footringworm

Thrush caused by candida yeast

ParasitesA parasite is an organism that lives on or in a host organism and gets its food from or at the expense of its host (who/what it is in or on) . 

Parasites can cause anything from mild disease to death to the host. Parasites can also spread diseases from one organism to another.

Protozoa are one-celled organisms that can be free-living or parasitic in nature.

Malaria is a disease caused by a protozoa that live in certain kinds of mosquitoes. If an affected mosquito bites a human, the person will be infected. Out of all the parasitic diseases, malaria causes the most deaths globally. It kills approximately 627,000 people each year.

People living in the poorest countries are the most vulnerable to malaria. In 2012, 90% of all malaria deaths occurred in the WHO African Region, mostly among children under 5 years of age.

Parasitic organisms which affect the health of people include fleas and head lice which live on the outside of the body and tapeworms which live inside the body.

Elephantiasis is the result of a parasitic infection caused by three specific kinds of round worms.

Lyme Disease is caused by a bacteria carried primarily by deer ticks

Rocky Mountain Spotted Fever

Guinea worm disease

PrionsDuring the past two decades, evidence has linked some degenerative disorders of the central nervous system to infectious particles that consist only of protein. All known prion diseases frequently result in brain tissue that is riddled with holes.

The known prion diseases include Creutzfeldt-Jakob disease (in humans), scrapie (in sheep), and bovine spongiform encephalopathy ("mad cow disease" in cattle).

While some prion diseases are inherited, others are apparently due to infection by eating infected tissue or inadvertently through medical procedures such as tissue transplants.

When pathogens enter in to your body you get sick.

Pathogens enter the body in the following ways: 

Airborne or droplet infection (colds, flu). Animal borne or insect borne infection (rabies, malaria, Lyme Disease). Blood borne infection (HIV, hepatitis). Food borne or water borne infection (salmonella, giardia). Sexually transmitted (chlamydia, gonorrhea, syphilis). Other direct contact (some kinds of warts, scabies). Indirect contact (colds and flu carried from person to person on dirty

tissues, money, door knobs, phones, computer keyboards).

How are pathogens spread?

Preventing Disease1. Good hygiene – wash hands often

2. Clean utensils before using

3. Cough & sneeze into your sleeve

4. Avoid touching your eyes, nose, and mouth. Especially when sick.

5. Do NOT share personal items – water bottles, toothbrushes etc.

6. Use insect repellent

7. Stay home when sick

8. Clean and disinfect commonly used surfaces

9. Get vaccinated

10.Avoid touching wild animals

Your Body’s DefensesThree Lines of Defense

1. Eyes, Skin, Stomach, Saliva and Mucus

2. Immune Systema. Nonspecific Response – inflammation and increased blood flow

b. Specific Response – targets the pathogen in a specialized way

3. Lymphatic System – carries fluid known as lymph and produces

white blood cells known as lymphocytes.

There are 2 kinds of lymphocytes:

1. B-cells

2. T-cells

Lymphatic system

Kinds of Lymphocytes

B-Cell

• Formed in the bone marrow

• Release antibodies

• Produce specific antibodies

• These antibodies remain in the body

T-Cells

• Produced in the thymus gland

• Attack pathogens directly

• Killer T-cells attack directly

• Helper T-cells activate B-cells

ImmunityNatural Immunity:

- present at birth- includes the skin, mucus, and white blood cells

Acquired Immunity- develops over time- includes passive and specific immunity- Passive Immunity is when mom passes antibodies to her child.- Active Immunity is when you body makes specific antibodies for a

pathogen

Vaccines- dead or weakened pathogens - will not cause illness- triggers body to make antibodies

ANY QUESTIONS?