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MICROBIOLOGY INFECTION AND DISEASE

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MICROBIOLOGY INFECTION AND DISEASE

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    1. MICROBIOLOGY INFECTION AND DISEASE Instructor Terry Wiseth Northland Community & Technical College

    2. 2 POPULATIONS OF MICROORGANISMS  The number of organisms at a site is determined by: The amount of oxygen pH Other organisms Nutrients Immune response of the host Availability of receptors for organisms

    3. 3 SYMBIOSIS Interaction between 2 organisms Mutualism - Both benefit Commensalism - One benefits while the other, neither benefits nor is harmed

    4. 4 SYMBIOSIS Synergism - Together both can accomplish what neither can achieve alone Parasitism - One benefits and causes harm to the other

    5. 5 PATHOGENICITY Colonizer Organism that live with a host without causing an immune or allergic response Pathogenic Organisms that cause disease

    6. 6 VIRULENCE a quantitative measure of pathogenicity measured in: Infectious dose (ID50) the number of organisms that will cause disease in 50% of test animals Lethal dose (LD50) the number of organisms that will cause death in 50% of test animals

    7. 7 ATTENUATION Loss or reduction of virulence Organisms can be treated with agents to achieve attenuation in order to be used as vaccines

    8. 8 CARRIERS Some individuals can be infected by a pathogen, but show no symptoms

    9. 9 SYSTEMIC Organisms spreading through the body

    10. 10 TYPES OF DISEASES Chronic disease microbial persistence in the host with symptoms over a long period

    11. 11 TYPES OF DISEASES Acute disease Symptoms appear quickly become intense and subside when the host's immune system disposes of the pathogen and toxic products

    12. 12 STAGES OF ACUTE DISEASE 1) Incubation From the time organisms enter the hosts until the first symptoms appear

    13. 13 STAGES OF ACUTE DISEASE 2) Prodromal Symptoms indicate the onset of disease e.g. Malaise, headache, fever, etc..

    14. 14 STAGES OF ACUTE DISEASE 3) Acme (Acute) Symptoms are at their peak and there is an immune response by the host

    15. 15 STAGES OF ACUTE DISEASE 4) Period of decline A recovery period with the decline of symptoms and, their is maximum antibody levels in the host

    16. 16 STAGES OF ACUTE DISEASE 5) Convalescence The body returns to normal

    17. 17 SOURCE OF DISEASE For organisms to be pathogenic they require a site to maintain their ability to infect and replicate Such a place is called a Reservoir The object, place or person from which organisms pass to the host is called the Source Sometimes reservoir and source are the same

    18. 18 HUMAN SOURCE Convalescent carriers are recovering from a disease Healthy carriers do not show symptoms of the disease but harbor the organisms

    19. 19 ANIMAL SOURCE Zoonosis e.g. Rabies, Plague

    20. 20 INSECT SOURCE Mechanical vectors Organisms are carried on the appendages of the insect

    21. 21 INSECT SOURCE Biological vectors Insects are the reservoir of the organisms and transmit them to humans or animals Insects are required for at least part of the developmental cycle of the organism

    22. 22 INANMIMATE RESERVOIR Soil, water and food Spores can be inhaled, then germinate, multiply and produce disease

    23. 23 INANMIMATE RESERVOIR Some bacteria that produce harmful toxins are indigenous to the soil e.g. Clostridium Pathogens can be passed into water and live in fish and shell fish Food is a reservoir for agents infectious to man

    24. 24 TRANSMISSION OF INFECTIOUS ORGANISMS contact water food fomites air

    25. 25 CONTACT Direct From person to person by close association e.g. kissing, sexual contact, sneezing etc..

    26. 26 CONTACT Indirect From one person to another through intermediates such as food, dust, water or fomites

    27. 27 WATER can be fecally contaminated Besides drinking, water borne pathogens can also enter the body through sweat glands, abraded skin etc..

    28. 28 FOOD Analysis must confirm the food as the source of the disease Factors that contribute to food infections are Improper storage temperatures poor hygiene contaminated equipment inadequate cooking

    29. 29 FOMITES Inanimate objects, other than food and water e.g. Catheters, needles etc..

    30. 30 AIR not a reservoir but is a means of transmission e.g. coughing and sneezing

    31. 31 PATTERNS OF DISEASE Endemic A continuous subepidemic level of disease in a specified community Outbreak A slight increase in the level of disease over endemic level

    32. 32 PATTERNS OF DISEASE Epidemic A large number of new cases of a disease, in a defined time, above the endemic level

    33. 33 PATTERNS OF DISEASE Pandemic World Wide epidemics Sporadic Disease occurs in an irregular pattern therefore no frequency can be calculated

    34. 34 END INFECTION AND DISEASE

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