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?

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

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 USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

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. USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

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.

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

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 USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

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 USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006 Listeria

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 http://www.merckvetmanual.com Centers for Disease Control: http://emergency.cdc.gov/agent/anthrax/needtoknow.asp

Bacteria are ALIVE! What does it mean to be alive? Bacteria are alive because they can… reproduce (make more of themselves) need to eat USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

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 USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

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: http://informedfarmers.com/horse-strangles-disease/ http://www.valleyvet.com/ct_detail.html?pgguid=30e07521-7b6a-11d5-a192-00b0d0204ae5 http://pediatrics.about.com/od/childhoodinfections/ig/Strep-Throat-Tests/A-Positive-Culture-for-Strep.htm References: http://www.omafra.gov.on.ca/english/livestock/horses/facts/03-037.htm

Viruses

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: http://www.sciencephoto.com/images/imagePopUpDetails.html?pop=1&id=770501166&pviewid=&country=67&search=&matchtype=FUZZY Rabies Virus HIV

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

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

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

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

Kingdom Protista

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.

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

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

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

Fungi

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

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

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

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

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!

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