Pathogens and Disease What are pathogens l l

What are pathogens? l l A pathogen is an infectious agent (“germ”) that causes

Key Terms Parasite l Any organism that has a negative effect on another organism

Key Terms Vector l The item that transfers the pathogen to its host. l

Key Terms Transmission l The passing of disease from an infected individual to unaffected

Key Terms Endemic l A common disease that occurs at a constant, but low,

Key Terms Epidemic l When an endemic disease occurs more frequently than expected, in

Key Terms Pandemic l It is an epidemic of infectious disease that has spread

What is a Pathogen? Any microbes (organism or virus) that cause disease l Including:

Viruses Ebola Considered Non-Living l Two Parts: l l. A Capsid: protein coat l

Virus Examples HIV: Human Immunodeficiency Virus l Influenza l Polio l Ebola l Herpes

Bacteria Escherichia coli Staphylococcus aureus Most are not pathogenic l All unicellular l Parasitic

Bacteria Examples Streptococcus (Strep Throat) l Escherichia coli l Bacillus anthracis (Anthrax), l Helicobacter

Fungi Decomposers that occasionally don’t wait until an organism is dead to feed on

Protozoa are unicellular l Pathogenic examples include: l l Giardia l Many vectors have

Flatworms Many are parasitic l Examples include: l l Tapeworms l Flukes (liver fluke)

Roundworms range in size from macroscopic to microscopic l Many parasitic roundworms inhabit the

Disease Transmission l Direct Contact: Person to person – communicable (mononucleosis) l Kissing l

Disease Transmission l Indirect Contact: l Objects – doorknobs, telephones, ect. . . l

Disease Transmission Portals of Entry Respiratory Tract – nose, mouth, lungs l Gastrointestingal Tract

Opportunistic Pathogens MDR TB and Staph Infections l Malaria (hiding in liver cells) l

Prevention/Treatment Options l Antibiotics l Attack existing bacterial infections only l Began with Penicillin

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Pathogens and Disease

What are pathogens? l l A pathogen is an infectious agent (“germ”) that causes disease or illness in a host. The host is the organism in which a parasite or pathogen does damage.

Key Terms Parasite l Any organism that has a negative effect on another organism with which it has close contact. l All pathogens are parasites.

Key Terms Vector l The item that transfers the pathogen to its host. l Vectors are “vehicles” that transport pathogens from one host to another. l Examples: water, blood, ticks, mosquitoes…

Key Terms Transmission l The passing of disease from an infected individual to unaffected individuals. l Passed by means of a vector.

Key Terms Endemic l A common disease that occurs at a constant, but low, rate in a specific population. l Example: Malaria in Liberia (Africa) is said to be endemic, as it is at a low rate, but constant enough that is it expected that the majority of the population will contract it at some point in their life.

Key Terms Epidemic l When an endemic disease occurs more frequently than expected, in a given area (i. e. Kingston) over a given time period. l Example: The flu would cause an epidemic if more than the usual number of people in a winter got the flu.

Key Terms Pandemic l It is an epidemic of infectious disease that has spread over a larger area (continent, worldwide…). l Examples: HIV/AIDS since 1990, SARS and Avian Flu in the mid 2000 s. Swine Flu in 2010.

What is a Pathogen? Any microbes (organism or virus) that cause disease l Including: l l Viruses l Bacteria l Fungi l Protozoa l Flatworms l Roundworms

Viruses Ebola Considered Non-Living l Two Parts: l l. A Capsid: protein coat l A Nucleic Acid: DNA or RNA HIV Function: Reproduction l Method: Hijack a living host cell and use it’s cellular machinery to replicate and build new virus particles. l

Virus Examples HIV: Human Immunodeficiency Virus l Influenza l Polio l Ebola l Herpes (different simplexes) l

Bacteria Escherichia coli Staphylococcus aureus Most are not pathogenic l All unicellular l Parasitic strains and those that produce toxic byproducts are pathogenic l

Bacteria Examples Streptococcus (Strep Throat) l Escherichia coli l Bacillus anthracis (Anthrax), l Helicobacter pylori (causes peptic ulcers) l

Fungi Decomposers that occasionally don’t wait until an organism is dead to feed on it l Examples: Athletes Foot (skin) l Most are surface/epidermal, some (rarely) become invasive l

Protozoa are unicellular l Pathogenic examples include: l l Giardia l Many vectors have insect Giardia

Flatworms Many are parasitic l Examples include: l l Tapeworms l Flukes (liver fluke) l Schistosoma

Roundworms range in size from macroscopic to microscopic l Many parasitic roundworms inhabit the intestines of a host organism l Examples include: l l Pinworms like Enterobius vermicularis l Hookworms like Necator and Ancylostoma l Trichinella spiralis (larvae migrate to muscle)

Disease Transmission l Direct Contact: Person to person – communicable (mononucleosis) l Kissing l Shaking hands l Touching open wounds or sores l Sexual contact – body fluids

Disease Transmission l Indirect Contact: l Objects – doorknobs, telephones, ect. . . l Air (tuberculosis) l Food (botulism) l Water (typhoid fever) l Vectors l Animal Bites – disease to organism to humans (rabies, West Nile virus)

Disease Transmission Portals of Entry Respiratory Tract – nose, mouth, lungs l Gastrointestingal Tract – throat, stomach, intestines l Mucous Membranes – nose, eyes, etc. l Penetration – bites, cuts, injections l

Opportunistic Pathogens MDR TB and Staph Infections l Malaria (hiding in liver cells) l HIV attacking T-cells and rapid mutation l Influenza and Rhinovirus rapid mutation rate (flu shots every year) l

Prevention/Treatment Options l Antibiotics l Attack existing bacterial infections only l Began with Penicillin (1928 – Fleming) l Resistance observed rapidly l Overuse, Incompletion of Prescription, Livestock application l Vaccinations l Prepare an immune system in advance of a viral (usually) or bacterial infection (i. e. tetanus) l Dead or inactive parts of a pathogen or synthetic