Name:
Date:
Class Period:
Infectious Diseases
Human Body Lesson 7: Standard 10d. Students know there are important
differences between bacteria and viruses with respect to their requirements for
growth and replication, the body’s primary defenses against bacterial and viral
infections, and effective treatments of these infections.
Vocabulary
1.
: any change, other than an injury, that disrupts
the normal functions of the body
2.
: a disease-causing agent
3.
: the idea that
microorganisms (germs) cause infectious diseases
4.
: a series of rules used to
identify the microorganism that causes a specific disease
5.
: an animal that carries a pathogen from person to
person
6.
: compounds that kill bacteria without harming
the cells of the human or animal host. They work by interfering with the
cellular processes of microorganisms
The Germ Theory of Disease
 Before the ________________________
________________________ of disease, people
believed that diseases were caused by curses,
evil spirits, bad smells, and miasmas (stinky
clouds and fogs).

Now, we know that infectious diseases are
caused by ________________________ (germs)
1
Koch’s Postulates
Koch’s postulates are how scientists show that a specific microorganism causes a
specific disease.
1. The pathogen should ________________________ be present in a sick organism and
________________________ be present in a healthy one
2. The pathogen must be ________________________ from a sick host organism in a
laboratory and grown in ________________________ ________________________
3. When the cultured pathogens are put into a new host, they should cause the
________________________ ________________________ that the original host organism
had
4. The pathogen must be ________________________ from the second host and should
be ________________________ to the original pathogen
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Agents of Disease
•
Many microorganisms live in the human body ________________________
causing diseases.
•
Some microorganisms are even ________________________, such as
the bacteria that live in your gut.
•
Other microorganisms may ________________________ cells or
release ________________________ as they grow, causing
________________________.
•
Some disease-causing agents are carried to humans by
________________________ such as cats, mosquitos, and fleas
Viruses
•
Viruses are ________-________________, ________________________
invaders
•
Viruses consist of just a protein coat called a
________________________, a ________________________
________________________, and sometimes a bit of membrane
that is stolen from the host cell
•
Viruses can infect almost every type of
organism
•
Viruses inject their genetic material into
the ________________________ cell where it
goes to the nucleus and hijacks the
cellular machinery. When many new
viruses have been made, they are ________________________ from the cell.
Sometimes the cell bursts when new viruses are released
•
Some viral diseases include the common cold, the flu, smallpox, warts, and
HIV/AIDS
3
Bacteria
•
Most bacteria are harmless to humans
There are two ways that bacteria can cause
disease:
1. Some bacteria ________________________
________________________ human tissues for
food
2. Some bacteria release
________________________ that harm the
body
•
Examples of bacterial diseases are
strep infections, staph infections,
diptheria, botulism, and anthrax.
•
Many bacterial diseases can be treated
and cured with ________________________
Protists
•
Most protists that cause disease are also called parasites. They are
________________________.
•
________________________ is a disease caused by a protist called Plasmodium that
is carried by a mosquito ________________________. It causes cycles of fevers,
chills, and sweats. It is deadly if left untreated
•
________________________ disease is caused by the protist Typanosoma cruzi and
carried by “kissing bugs” (the vectors). It causes lesions (sores) on the heart
and slows down peristalsis, the movement that pushes partially digested
food through your gut. Some researchers believe that Charles Darwin died of
Chagas disease.
4
Worms
•
Worms are animals that can cause disease in
humans.
•
Tapeworms and hookworms infect the gut.
•
From the 1900s to the 1950s, some people
intentionally swallowed tapeworms to lose
weight
Fungi
•
Some fungi can also cause diseases in humans.
•
Tinea is a fungus that causes ________________________
________________________. It can also infect the scalp and cause
________________________.
•
Other fungi can infect the mouth, throat, fingernails, and
toenails.
How Diseases are Spread
•
________________________ ________________________:
Touching
Coughing on someone
Sexual contact
•
________________________ ________________________ and
________________________:
Undercooked food
Dirty water
•
________________________ ________________________:
Vectors carry diseases
Ticks & fleas
Reptiles
Wild animals
5
Fighting Infectious Diseases
•
Antibiotics can kill ________________________
•
Other prescription drugs can kill
________________________ and
________________________, though these are more
difficult to kill
•
________________________ -the________________________ drugs treat only the
________________________ of infections. They
cannot cure diseases
•
________________________ situations where you
may contract a disease and ________________________ your ________________________
frequently can help ________________________ the spread of infectious diseases
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