1. How are they classified?
Objective 8.L.1 – Summarize the basic characteristics of viruses, bacteria, fungi, and parasites relating to the spread, treatment, and prevention of disease.
KEY QUESTIONS
What are Pathogens?
How are they classified?
Are they good or bad?

2. What are Pathogens?
A pathogen or infectious agent is a Microorganisms that are capable
of causing disease or illness to its host.

3. What are some characteristics of Pathogens?
Pathogens can be single celled organisms (one cell that carries out all life processes)
Pathogens can be multicellular celled organisms (many cells work together to carry out all life processes)
Pathogens can be Eukaryotic (genetic material is enclosed in nucleus)
Pathogens can be prokaryotic (lack a distinct nucleus and membrane bound organelles)
Pathogen can be parasites (an organism that lives in or on another organism (its host) and benefits by deriving nutrients at the host's expense).
E. coli
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4. What are examples of pathogen?
A biological organism such as Bacteria, Viruses, Fungi, and Protozoa that make you sick.
Why do they make you sick?
To get the energy they need to survive and reproduce
How do they make you sick?
They produce poisons (toxins) that result in fever, headache, vomiting, and diarrhea and destruction of body tissue.
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University of Tennessee, Knoxville 2006

5. Where do you get a pathogen?
Direct or indirect Contact
indirect
Inhalation of dust or water droplets that have come into contact with, or produced by an infected host
Direct person to person contact
with an infected host
indirect
Indirect contact with objects/foods that have been contaminated
Contact with vectors carrying the bacterium.

6. What are bacteria? Single celled organisms
There are countless numbers of
bacteria on the Earth but less than
1% of them cause diseases.
Very small, Need a microscope to see
Some people can be infected by
bacteria and not show symptoms,
these people are known as carriers.
This is a pore in human skin and the yellow spheres are bacteria
Streptococcus can cause strep throat.
This E. coli helps you digest food.
Anthrax

7. What do they look like? Three basic shapes
Rod shaped called bacilli (buh-sill-eye)
Round shaped called cocci (cox-eye)
Spiral shaped
Some exist as single cells, others
cluster together
Bacilli
Cocci
Spiral
Cluster of cocci
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University of Tennessee, Knoxville 2006

8. What are some common bacteria?
Bad bacteria can cause food poisoning (botulism)
E. coli O157:H7
Pathogenic E. coli
(like O157:H7)
Found in ground beef, contaminated fruits and vegetables
Salmonella
Found in raw meats, poultry, eggs, sprouts, fruit and vegetables
Listeria
Found in deli foods, lunch meats, smoked fish and vegetables
Salmonella
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University of Tennessee, Knoxville 2006
Listeria

9. Common Bacterial Diseases
Body System
Symptoms
Examples
Dermatitis
Skin
Inflammation, pruritus (itching)
skin lesions (bumps, blisters, scales, crusts)
Staphylococcus aureus
Pyoderma
Purulent exudate (pus) from skin lesions
Staphylococcus intermedius
Keratocunjunctivitis
Eye
Inflammation of cornea and conjunctiva , pain, sensitivity to sunlight, tears, squinting
“Pinkeye” is common name
Otitis Externa
Ear
Inflammation of external ear canal with reddening, drainage and itching
Staphylococcus
Rhinitis and Sinusitis
Respiratory
Inflammation of the membranes of the nasal passages and sinuses. Mucus nasal discharge, open-mouth breathing, sneezing.
Strangles in horses caused by Streptococcus equi
Pneumonia
Deep cough and difficulty breathing
Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), Streptococcus species
Gastroenteritis
Digestive
Inflammation of stomach and intestines, excessive salivation, vomiting, diarrhea, straining, abdominal pain.
Salmonellosis, colibacillosis, eneterotoxemia
Metritis
Reproductive
Inflammation of uterus. Purulent vaginal discharge, abortion, premature birth.
Contagious Equine Metritis (CEM)
Abortion
Premature birth (expelling) of fetus by pregnant female.
Brucellosis, leptospirosis and camphylobacteriosis (vibriosis)
Mastitis
Inflammation of mammary gland or udder tissue. Swollen, warm and painful mammary glands.
Pseudomonas aeruginosa and many other bacteria
Anthrax
Skin, Digestive, Respiratory
Sudden death in cattle
Varied in humans depending on exposure method
Bacillus anthracis is reportable disease responsible for outbreaks in cattle. Zoonotic, possible bioterrorism agent
References:
Veterinary Assistant Handbook
Floron C. Fairies, Jr.
Instructional Material Service
Texas A&M University
First Edition
Pages X-1-1 through X-1-4
Merck Veterinary Manual
Centers for Disease Control:

10. Bacteria are ALIVE!
What does it mean to be alive? Bacteria are alive because they can…
reproduce (make more of themselves)
need to eat
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University of Tennessee, Knoxville 2006

11. How do bacteria reproduce?
Grow in number not in size
Humans grow in size from child to adult
Make copies of themselves by dividing in half. This is done very quickly.
Human parents create a child
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University of Tennessee, Knoxville 2006

12. How are Bacteria infections treated?
Body fluids can be sampled and cultured to grow and identify the bacterial pathogen.
Antibiotics are the usual treatment for bacterial infections, but treatment can vary.
Bacteria adapt quickly and may become resistant to antibiotics.
Strangles in horses is caused by
Streptococcus equi bacteria
A broad spectrum antibiotic
A positive culture for Streptococcus bacteria
Images from:
References:

13. Viruses

14. What are Viruses? Considered Non-Living and Viruses are not cells
A virus consists of two parts: a piece of genetic material (RNA) that is housed within a protective coat.
The virus reproduces by hijacking the cell of another organism (host) and getting the host cell to reproduce more viruses.
Influenza
Ebola
Currently, viruses are not considered living organisms, but there is debate among the scientific community on this topic.
Images from:
Rabies Virus
HIV

15. Why are Viruses not considered alive?
Viruses are not considered "alive" because they lack many of the properties that scientists associate with living organisms. Primarily, they lack the ability to reproduce without the aid of a host cell, and don't use the typical cell- division approach to replication

16. Is there a simple Treatment?
Treating viral infections is more difficult that treating bacterial infections because it is difficult to attack a virus without attacking host cells as well.
Treatments are usually involves treating the symptoms. This can include administering fever reducers and allowing the animal to rest. Mainly the virus had to run its course.
Focus on prevention by administering vaccinations
Prevention is the key
Get a vaccination

17. Not all bacteria cause disease but all virus' do
I know a PATHOGEN is a micro-organism that causes an infectious disease and that pathogens reproduce before they make enough toxins to make you feel ill
BACTERIA- single celled organisms
VIRUS
50 times bigger
50 times smaller
Can be seen by an ordinary light microscope
Cannot be seen by an ordinary light microscope. Can be seen by an electron microscope.
Reproduces by dividing in two
Reproduces by taking over and using the reproductive structures of another cell.
Can be killed buy antibiotics because it kills or inhibits the bacteria’s ability to divide and reproduce
Cannot be killed by antibiotics
Photo credit: © 2006 Jupiterimages Corporation
Not all bacteria cause disease but all virus' do

18. Diseases cased by Viruses
Avian or Bird Flu
Swine Flu
Meningitis
Mononucleosis
Warts
Hepatitis
Bronchiolitis
Colorado Tick Fever
Encephalitis
Common Cold
HIV-AIDS
Influenza (Flu)
Measles (Rubella)
Mumps
Polio
Rabies
Smallpox
Hepatitis
Herpes

19. Kingdom Protista

20. Protista can be Pathogens
The Protista kingdom includes Algae, and Protozoans. They may have features like those of plants, animals, and fungi. They may be single celled or multicellular.

21. Protozoa Protozoa are animal-like protists
This means they are single-celled eukaryotic organisms
The three classes of protozoa are classified according to their structure and movement:
Many have insect
vectors

22. Groups are based on movement . This includes movement by
How do Protozoa move ?
Groups are based on movement . This includes movement by
flagella, cilia, pseudopods .
false feet’
Amoeba
Paramecium
Euglena
Hair like
structure
Streaming
cytoplasm
Whip like
structure

23. What are Parasites?
Is an organism that lives in or on another organism (its host) and benefits by deriving nutrients at the host's expense
Insects are major vectors of disease in plants and animals. (Both carried by mosquitoes, malaria is from a protozoa and Zika virus is from a virus)
Ticks and mites are examples of arthropods that infect humans. (Lyme disease carried by ticks caused by a bacteria)
Flatworms belong to a group called platyhelminthes
Many are parasitic
Examples include:
Tapeworms
Flukes (liver fluke)
Roundworms are nematodes
Many parasitic roundworms inhabit the intestines of a host organism
Examples include:
Pinworms

24. Fungi

25. What is a Fungi?
Fungi are Eukaryotic heterotrophs and are unicellular and multicellular
Some live as saprophytes (live on rotting organic matter)
They perform a crucial role in nature by decomposing dead organisms
Some live in a mutually beneficial symbiotic relationship

26. Examples of Fungi molds yeasts Mushrooms mildews
Yeast: Candida albicans
mildews

27. Diseases caused by Fungi?
Decomposers that occasionally don’t wait until an organism is dead to feed on it
Examples: Valley Fever (lung), Ringworm (skin), Athletes Foot (skin)
Most are surface/epidermal, some (rarely) become invasive
Treatment
Fungal infections can be treated with fungicides and antifungal treatments

28. How can I avoid getting sick from pathogens?
Wash your hands often
Warm water with soap for 20 seconds, rub hard between fingers and nails
Cook food thoroughly to kill any pathogens that may be in your food
Store food properly to limit pathogen growth
Cold temperatures (40F)
Use Antiseptic and Disinfectants .
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

29. Review Bacteria are prokaryotic and unicellular.
Bacteria have cell walls.
Bacteria have circular DNA called plasmids
Bacteria can be anaerobes or aerobes.
Bacteria are heterotrophs or autotrophs.
Bacteria are awesome!

30. Review Bacteria, Fungi, and Protista are living organisms
Most are harmless
A few are pathogens that make you sick
You can reduce the risk of getting sick by washing your hands and handling food properly.
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006