Pathogens
Skill 3: Name the two most common causes of infectious diseases. They are also called contagious or communicable diseases.
Skill 4: Differentiate between injury, disease, and infectious disease.
Skill 5: Learn the four rules of Koch's postulates.
Skill 6: What are antibiotics and how do they work?
Skill 7: Identify the basic steps the immune system uses to keep you free from infectious diseases.
Who wants to go into a medical profession?
Who wants to go into a medical profession?
Today, we'll see if you are a "hand washing hero."
Today, we'll see if you are a "hand washing hero."
Sadly, we cannot do this class activity until we are back in school.
Sadly, we cannot do this class activity until we are back in school.
In his activity, we put fake germs on our hands, which show up under black lights. Then, we wash our hands and put them under the black light again, to see how well we washed them. Usually, it's not too well!
In his activity, we put fake germs on our hands, which show up under black lights. Then, we wash our hands and put them under the black light again, to see how well we washed them. Usually, it's not too well!
Skill 3: Name the two most common causes of infectious (contagious) diseases.
Skill 3: Name the two most common causes of infectious (contagious) diseases.
Bacteria and viruses are the two most common causes of infectious diseases in humans. Things which can cause infectious diseases are called, "pathogens."
Bacteria and viruses are the two most common causes of infectious diseases in humans. Things which can cause infectious diseases are called, "pathogens."
Skill 4: Differentiate between injury, disease, and infectious disease.
Skill 4: Differentiate between injury, disease, and infectious disease.
Injury - damage to the body from an outside source, excluding germs. Examples: cuts, bruises, broken bones.
Injury - damage to the body from an outside source, excluding germs. Examples: cuts, bruises, broken bones.
Disease - disruption to the functions of the body, not caused by an injury. It is an "infectious disease" if it is contagious, or can be "caught" from someone else. These diseases are also called "communicable" in medicine.
Disease - disruption to the functions of the body, not caused by an injury. It is an "infectious disease" if it is contagious, or can be "caught" from someone else. These diseases are also called "communicable" in medicine.
Practice
Practice
Is it a disease or an injury? Ask yourself these questions to decide:
Is it a disease or an injury? Ask yourself these questions to decide:
1. Is it an injury? Injuries are trauma caused to the body from external forces, such as a hit or a fall.
1. Is it an injury? Injuries are trauma caused to the body from external forces, such as a hit or a fall.
2. Is it a disease? A disease disrupts the normal body functions, but is not caused by an injury.
2. Is it a disease? A disease disrupts the normal body functions, but is not caused by an injury.
3. If it is a disease, is it infectious (contagious)? It is infectious if you can catch it from another person.
3. If it is a disease, is it infectious (contagious)? It is infectious if you can catch it from another person.
Try these examples:
Try these examples:
Broken leg
Broken leg
Cancer (Your own body cells reproduce too fast and build up into a tumor.)
Cancer (Your own body cells reproduce too fast and build up into a tumor.)
Cold
Cold
Bruise
Bruise
Diabetes (Your pancreas can no longer produce enough insulin to keep your blood sugar in check.)
Diabetes (Your pancreas can no longer produce enough insulin to keep your blood sugar in check.)
Flu
Flu
Cut
Cut
Mitochondrial disease (Inherited disease of the mitochondria; inherited from your mother.)
Mitochondrial disease (Inherited disease of the mitochondria; inherited from your mother.)
HIV (AIDS) (STI)
HIV (AIDS) (STI)
Check with a teacher to see if you are correct.
Check with a teacher to see if you are correct.
The Germ Theory of Disease
The Germ Theory of Disease
Louis Pasteur and Robert Koch (pronounced "Coke") discovered that germs, such as viruses and bacteria, are the cause of infectious diseases.
Louis Pasteur and Robert Koch (pronounced "Coke") discovered that germs, such as viruses and bacteria, are the cause of infectious diseases.
Louis Pasteur (1822-1895)
Louis Pasteur (1822-1895)
Louis Pasteur was a French microbiologist who lived in the 1800's. He is famous for many things, including development of the vaccination for rabies. The process of pasteurizing milk is named after him.
Louis Pasteur was a French microbiologist who lived in the 1800's. He is famous for many things, including development of the vaccination for rabies. The process of pasteurizing milk is named after him.
Robert Koch (1843 - 1910)
Robert Koch (1843 - 1910)
Robert Koch was a German microbiologist who lived in the 1800's and died in 1910. He is famous for Koch's Postulate, which was named after him.
Robert Koch was a German microbiologist who lived in the 1800's and died in 1910. He is famous for Koch's Postulate, which was named after him.
Skill 5: Learn the four rules of Koch's postulates.
Skill 5: Learn the four rules of Koch's postulates.
Be sure you know the four steps of Koch's postulates, in order.
Be sure you know the four steps of Koch's postulates, in order.
Lyme Disease
Lyme Disease
Allen Steere, of Yale University, identified the microbe that causes Lyme Disease. This disease is very common in Loudoun County, Virginia. You probably know someone who has contracted it.
Allen Steere, of Yale University, identified the microbe that causes Lyme Disease. This disease is very common in Loudoun County, Virginia. You probably know someone who has contracted it.
Lyme diseases is often suspected due to the above pictured "bullseye rash" that shows up after an infected tick bite. Not all infections of Lyme disease result in such a rash, though. The scientific name of this disease is Borrelia burgdorferi and it is carried by deer ticks. Deer ticks are the "vector," meaning that they carry the disease from deer to humans and dogs, but they do not get sick with it. It is not transmitted directly from deer to other species. The infected organism is called a "host."
Lyme diseases is often suspected due to the above pictured "bullseye rash" that shows up after an infected tick bite. Not all infections of Lyme disease result in such a rash, though. The scientific name of this disease is Borrelia burgdorferi and it is carried by deer ticks. Deer ticks are the "vector," meaning that they carry the disease from deer to humans and dogs, but they do not get sick with it. It is not transmitted directly from deer to other species. The infected organism is called a "host."
Fighting infectious diseases
Fighting infectious diseases
Use word decoding to figure out what "antibiotics" do.
Use word decoding to figure out what "antibiotics" do.
Skill 6: What are antibiotics and how do they work?
Skill 6: What are antibiotics and how do they work?
Read the University of Utah's webpage below to learn how antibiotics work.
Read the University of Utah's webpage below to learn how antibiotics work.
Be sure to read at least the first two sections, "What is an antibiotic?" and "Antibiotics seek out bacterial cells." The rest of the page is optional to read if you are interested.
Be sure to read at least the first two sections, "What is an antibiotic?" and "Antibiotics seek out bacterial cells." The rest of the page is optional to read if you are interested.
Now, explain why antibiotics have no effect on viruses.
Now, explain why antibiotics have no effect on viruses.
Skill 7: Identify the basic steps the immune system uses to keep you free from infectious diseases.
Skill 7: Identify the basic steps the immune system uses to keep you free from infectious diseases.
Step 1: identify invaders
Step 1: identify invaders
Antigens don't have the same carbohydrate markers on the outside that your own cells have, so your immune system can identify them as "not self." Once the antigen, or invader, is identified as "not self," your immune system is triggered to attack.
Antigens don't have the same carbohydrate markers on the outside that your own cells have, so your immune system can identify them as "not self." Once the antigen, or invader, is identified as "not self," your immune system is triggered to attack.
Step 2: Catch them
Step 2: Catch them
Once the invaders are identified, antibodies "bind" the pathogens, or antigens. You can picture them as police officers that handcuff a criminal to each of their own hands to keep them from getting away.
Once the invaders are identified, antibodies "bind" the pathogens, or antigens. You can picture them as police officers that handcuff a criminal to each of their own hands to keep them from getting away.
Step 3: Destroy them!
Step 3: Destroy them!
A "macrophage" is a type of white blood cell. See if you can decode the word, "macrophage" to figure out what job they do as part of your immune system.
A "macrophage" is a type of white blood cell. See if you can decode the word, "macrophage" to figure out what job they do as part of your immune system.
This is a real life example of endocytosis and exoctyosis. Macrophages take the bacteria or viruses in, using endocytosis. After they digest and destroy them, using decomposing enzymes, they expell the waste products through exocytosis.
This is a real life example of endocytosis and exoctyosis. Macrophages take the bacteria or viruses in, using endocytosis. After they digest and destroy them, using decomposing enzymes, they expell the waste products through exocytosis.
Class activity - review the lytic and lysogenic cycles of virus reproduction
Class activity - review the lytic and lysogenic cycles of virus reproduction
Compare and contrast with bacterial reproduction.
Compare and contrast with bacterial reproduction.
Story time
Story time
I will read some expcerpts from "Hot Zone" by Richard Preston. It's a true story about the Ebola virus.
I will read some expcerpts from "Hot Zone" by Richard Preston. It's a true story about the Ebola virus.