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Unit 2 Disease Transmission Disease Transmission INFECTIOUS DISEASE: An infectious disease occurs when a microorganism in the body multiplies and causes damage to the tissues. Disease Transmission Differences between pathogenic & nonpathogenic Pathogenic: disease causing Nonpathogenic: non-disease causing Microorganisms that cause disease are PATHOGENS Disease transmission Opportunistic pathogens: Cause diseases only when given a special opportunity to enter deeper tissues of the body or to accumulate to levels that can harm the body They wait for the opportunity to cause disease. Types of Infectious Diseases: ENDOGENOUS: caused by microbes normally present on or in the body without causing harm But something happens that allows them to express this disease-producing potential Examples: dental caries, periodontal disease Opportunistic- endogenous Types of Infectious Diseases: EXOGENOUS: caused by microbes that are not normally present on or in the body But contaminate the body from the outside Examples: Strep Throat, Measles, “Common” Cold, Hepatitis (various forms), HIV-Human immunodeficiency virus Steps in development of Infectious Disease: Source of Microorganism Escape of microorganism from the source Spread of microorganisms to new person Entry of microorganism into new person Infection (survival & growth of microorganism) Damage to body Chain of Infection HAREM entry Steps in development of Infectious Disease: 1) Source of microbe: major source of disease agents in the dental office are the mouths of the dental patients. Since we can’t tell who may harbor these pathogens, All patients must be treated the same As if they are contagious/infectious Steps in development of Infectious Disease: 2) Escape of the microbe from the source During a variety of natural mechanisms such as coughing, sneezing, talking Anything removed from patient’s mouth can carry microbes (instruments, film holders, etc) Air/water spray can aerosolize microbes— microbes can attach to water in spatter Steps in development of Infectious Disease: 3) Spread of the microbe to another person Transmission can be: – DIRECT CONTACT – INDIRECT CONTACT – AEROSOL/DROPLET Steps in development of Infectious Disease: 4) Entry of the microbe into new person: the microbes are introduced into a new host 5) Infection (survival and growth of microbe) – the multiplication and survival of microorganisms on or in the body 6) Damage to the body – infecting microorganism usually must multiply to a harmful level for disease to occur Universal Precautions ALL PATIENTS SHOULD BE TREATED AS IF THEY HAVE A COMMUNICABLE DISEASE OR AS IF THEY ARE INFECTIOUS WHY? Universal Precautions: Why? We can’t tell by looking at a person if they are carrying an infectious microorganism. We must treat everyone the same. Some patients may not know they are carrying infectious microorganisms. Some patients may not tell us. CDC on Standard Precautions CDC Disease Transmission ASYMPTOMATIC CARRIER Asymptomatic – having no symptoms of disease (or at least none that are obvious) Carrier – a person who may harbor pathogenic agents and not get the disease but who may pass it on to others Disease Transmission Asymptomatic carrier Could be someone who has had a disease and recovered from it and may be a potential carrier of the pathogenic microorganism. Carrier transmitted: Tuberculosis, Hepatitis B, Human immunodeficiency virus Stages of an infectious disease: Incubation stage Prodromal stage Acute stage Convalescent stage Stages of infectious disease: Incubation stage – period from the initial entrance of the infectious disease agent into the body until the first signs and symptoms of the disease appear. Can range from a few hours to years, depending on the potential of the microbe Stages of infectious diseases: Incubation: the entering microorganism must multiply to sufficient numbers to cause symptoms (e.g., fever, swelling, skin discoloration, ulceration, pain, bleeding, watery eyes, “running nose”, etc) Influenza & Respiratory – 2-3 days Others can be weeks or even years Stages of infectious diseases: Prodromal stage: appearance of early symptoms Means “running before” First symptoms commonly called Malaise (not feeling well) Can be a slight fever and headache Can be an upset stomach Stages of infectious diseases: Acute stage: Symptoms of disease are maximal. PERSON IS OBVIOUSLY ILL. Usually these patients are not likely to come to the dental office except in an emergency It would be better for these patients to delay dental treatment. Stages of infectious diseases: Convalescent stage: Recovery phase Numbers of microorganisms may be declining but infectious agents (pathogens) are present and may be spread during this stage Modes of Disease Transmission Direct contact – contact with microbe at the source such as in the patient’s mouth Indirect contact – contact with items contaminated with patient’s microorganisms such as instruments, film holders Droplet/Aerosol /Airborn– contact with sprays, splashes, aerosols, or spatter containing microorganisms Routes of Entry: Inhalation Ingestion Mucous Membrane Breaks in skin Pathogenic Properties of Microbes Enhance Infection Interfere with host defenses Damage cell or tissue Host Defense mechanisms Physical Barriers Mechanical Barriers Antimicrobial barriers Cellular barriers Immunity The state of being resistant to the harmful effects of a microbe. Activated by ANTIGENS. Body produces antibodies Natural or Acquired ( Artificial) active or passive Active Survive disease (natural) Immunize (acquired) Passive These are LONG TERM Breastfeed Take antibiotics Terms Allergen Histamine Antihistamine Antigen Urticaria anaphylaxis