Pathogenic Organisms

Types of Pathogens  There are 5 different types of pathogens. organisms that cause disease Pathogens – organisms that cause disease  Viruses  Bacteria (prokaryotic)  Fungi (eukaryotic)  Protozoa (eukaryotic)  Pathogenic Animals (eukaryotic)

VIRUSES BACTERIA

FUNGI PROTOZOA

PATHOGENIC ANIMALS

VIRUSES  Viruses are considered to be nonliving  Infection of a virus can be broken down to the basics: 1. Viral nucleic acid (either DNA or RNA) enters the cell 2. Viral nucleic acid is used to make proteins (enzymes) 3. Viral proteins take over activities of the cell to make more viruses 4. New viruses exit the cell through exocytosis or by rupturing the cell  Retroviruses (viruses with RNA) mutate easily  The only proven way to treat most viruses is to allow the body’s immune system to eradicate it  Medicines may be prescribed to inhibit the virus’s ability to reproduce  OTC medicines can only treat symptoms of viral infections

BACTERIA  Bacteria are classified in 3 ways: 1. Function (aerobic v. anaerobic) 2. Staining properties (Gram positive v. Gram negative) 3. Shape/Size  Bacteria cause infection in 3 ways: 1. Releasing toxins that damage tissues (Clostridium botulinum) 2. Becoming parasites within cells (Midichloria mitochondrii) 3. Colonize and take over health tissues (Escherichia coli, Actinomyces, and Lactobacilli)  Bacteria are usually treated with antibiotics*

FUNGI  Fungi in nature may have chlorophyll, but the ones the infect humans do not  Fungal infections are usually not detected until the fungus has reached reproductive maturity  Fungal infections will require multiple treatments with anti-fungal medications

PROTOZOA  Protozoa are like bacteria because they are unicellular but they contain organelles (including a nucleus)  There are 4 types of protozoa 1. amoebas (use pseudopodia for movement) 2. Flagellates (use flagella for movement) 3. Ciliates (use cilia for movement) 4. Sporozoa (contain structures for burrowing into tissues)  Many protozoa use a vector to help in transmission between hosts an organism that causes disease in another organisms (usually by transmitting a pathogen) Vector – an organism that causes disease in another organisms (usually by transmitting a pathogen)

PATHOGENIC ANIMALS  Often are called metazoa  Signs/Symptoms of metazoan infection are caused by the parasitic nature of the pathogen  There are 3 different types of metazoa 1. Nematodes (round worms) 2. Platyhelminthes (flat worms) 3. Arthropods (spiders and insects)  Metazoa are often vectors  Prevention of these types of diseases (and the diseases they spread) is usually accomplished by eliminating the pathogen from an environment

LEARNING GOALS  I can … … describe each of the 5 pathogenic organisms discussed in class …compare and contrast how the different pathogenic organisms are classified …compare and contrast how the different pathogenic organisms cause infection …compare and contrast how the different pathogenic organisms are transmitted from person to person …compare and contrast how the different pathogenic organisms are treated