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26 Cards in this Set
- Front
- Back
Define reservoir of infection
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Sites where pathogens exist and are maintained as a source of infection, once they leave the host (place or location where the pathogen goes)
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Describe the three types of reservoirs of infection for human diseases.
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1. Animal reservoirs
2. Human carriers 3. Nonliving reservoirs |
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Contrast human, animal, and nonliving reservoirs and give one example of each.
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Human carriers - Humans with active diesase are reservoirs of infection. Carriers asymptomatic but infective (w/o symptoms). S. aureus - from normal flora or infected persons by contact. Common cold viruses by inhalation of sneezed particles. HIV direct sexual contact or injection of contaminated products (IV drugs or blood transfusion) **After they get older their immune system gets compromised they are able to get disease**
Animals - Pathogens that infect domesticated or sylvatic (wild animals) can infect humans. Routes - direct contact with animal, animal wastes, eating animals, blood sucking arthropods. Rabies, plague, Brucella abortis, Plasmodium vivax, fungi that cause ringworm by contact with infected dogs and cats. Nonliving reservoirs - Soil, food, water, air |
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What is zoonotic disease?
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diseases spread from animal host to humans. >150 known
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Explain the three methods of disease transmission and give an example of each.
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*DID*
1. Direct contact - person to person, placental, fecal-oral 2. Indirect contact - formites (inadimate object carries pathogen) 3. Droplet transmission - mucous droplets, airborne transmission >1 meter *STD example of direct *Contaminated kleenex or sandwich is indirect |
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Distinguish between direct contact, indirect contact, and droplet transmission.
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Direct contact - person to person spread; touching, handshaking, animal bite, sexual intercourse (rabies, anthrax, syphilis, genital herpes)
Indirect contact - agent of disease is transmitted from its reservoir to a susceptible host by means of nonliving object (for mite) such as bedding, dishes, money, thermometer, contaminated needles. Droplet transmission - microbes spread in aerosol droplets (mucus droplets) discharged in air by sneezing, coughing, laughing, talking. Travel short distances (whooping cough, influenza, pneumonia) A meter or less away arms length distance over a meter is vehicle transmission. |
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Distinguish between waterborne airborne and foodborne and vehicle transmission.
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Waterborne transmission - spread by water contaminated with untreated sewage (cholera) fecal-oral infection is major source of disease in world. **Fecal-Oral route most common**
Food-borne - pathogens transmitted in or on food that has been improperly prepared, cooked, or stored (botulism, tapeworm, and Hep A) Air-borne - spread of agents in aerosol droplets that travel more than 1 meter from reservoir to host (measles virus, spores born by fungi that cause histoplasmosis) |
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Describe the main differences between biological vector transmission.
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Vectors are animals that carry pathogens from one host to another; specifically arthropods.
Mechanical - passive transport of pathogens on insects feet or other body part (house flies walk across feces of infected person to food of noninfected person) not required as host by pathogen Biological - vector such as insect carries pathogen in body; host is often part of pathogens life cycle, transmits pathogen to host when it bites host. |
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Identify and discuss the main factors affecting disease transmission
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overall health of the host, age 5<70, gender, lifestyle, occupation, emotional state, climate
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Identify and describe the portal of exit that pathogens take from the host body
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openings, secretions (nasal, saliva, sputum, respiratory droplets), blood, vaginal fluids, semen, urine, feces
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Define a compromised host
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Host competence, risk factors for infection are immunocompromised, lifestyle, occupation, trauma, travel, age.
A person or something having something wrong with them |
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Describe how neutropenia, organ transplants, and burns can affect host.
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neutropenia - when a person has fewer than normal neutrophils (WBC)
organ transplant - get put on drugs and more vulnerable to disease. burns - skin is compromised and allows for port of entry |
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Describe three conditions that create opportunities for normal microbiota to cause disease.
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Opportunistic disease, kidney disease, normal microbiota start turning
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Explain the "universal precautions" and their role in controlling nosocomial infections.
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handwashing, proper disinfecting, and cleaning of tubs, showers, bedding, etc. Proper handling of contaminated material. Education of staff
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Define nosocomial infections, and explain their importance.
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Hospital-acquired infections which range from mild to severe. A hospital can be seen as a high-density population made up of unusually susceptible people. 10% of patients admitted to a US hospital acquired a nosocomial infection.
1/3 infections are preventable. |
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Define epidemiology and discuss its importance
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The study of factors and mechanisms involved in the frequency and spread of diseases and other health-related problems within populations of humans, other animals, or plants.
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Contrast between incidence and prevalence.
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incidence - of a disease is the number of NEW cases contracted within a set population during a specific time period (100,000/yr)
# new cases / # people @ risk prevalence - of a disease, is the TOTAL number of people infected within the population at any time (old + new cases) # of old + new cases / # people @ risk |
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Morbidity
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number of individuals within a disease during a set period of time divided by the total population
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mortality
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number of deaths due to a specific disease during a specific period of time divided by the total population
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endemic
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disease that normally occurs at a relatively stable frequency within a given population or geographic area
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sporatic
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a disease that appears as a few scattered cases within a population or geographic area (random)
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epidemic
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a disease that occurs with a greater than usual frequency within an area population (flu)
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pandemic
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when an epidemic occurs on one or more continents at the same time H1N1 flu, aids
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common source outbreak
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group of people all exposed to a pathogen. arises from contact with contaminated substances (food, water)
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propagated epidemic
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amplification of infection as a result of person-to-person contact (cold/flu person to person contact)
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What is a nationally notifiable disease?
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A disease that is well-known. Health departments (local and state), Nationally (CDC) Worldwide (WHO)
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