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week 1

4 Pages

Health Studies
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Caroline Barakat

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(Reading) Week #1 | Sherman Ch. 1, 2 Chapter 1 The Nature of Plagues - Legionnaires disease - symptoms: high fever, chills, headache, muscle aches, pains > cough, chest pains, shortness of breath, vomiting, diarrhea > lungs filled with fluid and pus, experiencing confusion, disorientation, hallucinations, loss of memory - transmission was not from person to person - air was implicated as the probable pathway of spread of the disease, and the most popular theory was that infection resulted from aspiration of bacteria (called Legionella) in aerosolized water from either cooling towers or evaporative condensers - unlike infections caused by inhalation, aspiration is produced by choking - secretions in the mouth get past the choking reflex and, instead of going into the esophagus and stomach, mistakenly enter the lungs - protective mechanisms that normally prevent aspiration are defective in older people, smokers, and those with lung disease - fatality rate of 15% - toxic shock syndrome (TSS) - begins with vomiting and high fever followed by lightheadness and fainting, the throat felt sore, and the muscles ached - a day later, a sunburn-like rash appeared, and the eyes became bloodshot - within three to four days, victims suffered confusion, fatigue, weakness, thirst, and a rapid pulse; the skin became cool and moist; and breathing became rapid - this was followed by a sudden drop in blood pressure; if it remained low enough for a long enough period, circulatory collapse produced shock - gender-specific disease: women - peak death rate of 4% - linked to the use of certain types of tampons, especially those containing cross-linked carboxymethyl cellulose with polyester foam, which provided a favorable environment for the toxin-producing S. aureus - elevated vaginal temperature and neutral pH, both of which occur during menses, were enhanced by the use of these superabsorbent tampons - tampons obstruct the flow of menstrual blood and may cause reflux of blood and bacteria into the vagina - SARS - symptoms: fever, dry cough, sore throat, headache > difficulty in breathing - survivors sowed the seeds of infection that led to more than 8,000 cases and 800 deaths in 26 countries, representing every continent - transmission is from person to person via droplet secretions from the nose and mouth - new and old diseases can erupt and spread throughout the world more quickly because of the increased and rapid movements of people and goods - new diseases may be related to advances in technology Living Off Others - Incubation period: interval of time required for development of a disease - Latent period: seemingly inactive period between exposure to an infection and subsequent illness - Parasite virulence: capacity of a parasite to cause disease Modes of Disease Transmission - Direct transmission - from person to person - Indirect through a common route / vector, e.g. contaminated air / water, mosquito Portal of entry: - Dermal through the skin, e.g. fungus - Ingestion through the mouth, e.g. E.coli in water - Inhalation during respiration, e.g. particulate matter Aspiration airway entry Types of diseases - Clinical Disease - Classical and severe disease - Moderate severity mild illness - Subclinical Disease - Infection without clinical illness (asymptomatic infection) - Exposure without infection Types of disease outbreaks Three main types 1) Endemic usual occurrence of a disease within a given geographical area 2) Epidemic occurrence of a disease in excess of normal expectancy 3) Pandemic worldwide epidemic Attack rate ratio of the #people in whom a certain illness develops / total #people at risk - Parasites organism that grows, feeds, and is sheltered on or in a different organism and that does not contribute to the survival of its host - the business they practice, parasitism, is the intimate association of two different kinds of organisms (species) wherein one benefits (the parasite) at the expense of the other (the host), and as a consequence of this, parasites often harm their hosts - some may be composed of a fragment of genetic material wrapped in protein, such as a virus - Virus ultimate micro-parasite smaller than bacteria; neither cells nor organisms; can only reproduce within their host - others (bacteria, fungi, protozoa) consist of a single cell, and some are made up of many cells (roundworms, flatworms, mosquitoes, flies, ticks) - some parasites, such as tapeworms, hookworms, the malaria parasite, and HIV, live inside the body, whereas others (ticks and chiggers) live on the surface - smaller in mass than their host - resistance may develop in any population of hosts, and not every potential host will be infectedsome individuals may be immune or not susceptible because of a genetic abnormality or the absence of some critical dietary factor - more offspring will have a greater probability of reaching a host and setting up an infection - in this way, the parasite enhances its chances for survival
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