MCB2004 Exam 3 Study GuideChapters 14-20, Lectures 20-28Lecture 201. Define pathology, etiology, infection, and disease.a. Pathology: The precise study and diagnosis of diseaseb. Etiology: The study of the cause of a disease c. Infection: Growing and multiplying of pathogens in the host d. Disease: An abnormal state in which the body is not functioning normally; “dis-ease” = “lack of ease”***Infection ≠ Disease2. Define normal, transient microbiota, and opportunistic infections.a. Normal microbiota: permanently colonize the hosti. Probiotics ii. Symbiosis is the relationship between normal micrbiota and the host.1. Reestablishment of a healthy host = parasitismcommensalismmutualism2. Infectious disease process begins = mutualismcommensalismparasitismb. Transient micriobiota: may be present for days, weeks, or monthsc. Opportunistic infections:i. In the general realm of biology, an opportunist is an organism that is able to sustain its life from a number of different sources, but when favorable conditions arise, the organism immediately takes advantage of the opportunity to thrive.ii. Opportunistic microorganisms are typically non-pathogenic microorganisms that act as a pathogen in certain circumstances. They lay dormant for long periods of time until the hosts’ immune system is suppressed and then they seize the opportunity to attack.iii. Sometimes normal microbiota can be opportunistic; examples include: E. coli, environmental bacteria, or microbiota in immunocompromised hosts3. Compare and contrast commensalism, mutualism, and parasitism.a. Commensalism: one organism is benefited and the other is unaffectedb. Mutualism: both organisms benefitc. Parasitism: one organism is benefited at the expense of the other4. Understand Koch’s postulates and the exceptions.a. Postulates:1) Microorganisms are isolated from a diseased or dead animal.2a) The microorganisms are grown in pure culture.2b) The microorganisms are identified.3) The microorganisms are injected into a healthy laboratory animal.4) Disease is reproduced in a laboratory animal.5a) The microorganisms are isolated from the animal and grown in pure culture.5b) Microorganisms are identified.b. Rules for the postulates:i. The same pathogen must be present in every case of the disease.ii. The pathogen must be isolated from the diseases host and grown in pure culture iii. The pathogen from the pure culture must cause the disease when it is inoculated into a healthy, susceptible lab animal 1iv. The pathogen must be isolated from the inoculated animal and must be shown to be the original animal c. Exceptions:i. Some pathogens can cause several disease conditions or the same pathogen can cause different disease symptoms.ii. Some pathogens cause disease only in humans.iii. Some pathogens need cofactors (not all develop disease).iv. Development of some diseases takes years.5. Understand predisposing factors for disease.a. Infectious diseases:i. Noncommunicable disease: A disease that is not transmitted from one host to another ii. Communicable disease: A disease that is spread from one host to another iii. Contagious disease: A disease that is easily spread from one host to another b. Occurrence of disease:i. Sporadic disease: Disease that occurs occasionally in a population ii. Endemic disease: Disease constantly present in a population iii. Epidemic disease: Disease acquired by many hosts in a given area in a short time iv. Pandemic disease: Worldwide epidemic 6. Define reservoir of infection.a. Continual sources of infectioni. Human : AIDS, gonorrhea1. Carriers may have inapparent infections or latent diseasesii. Animal : Rabies, Lyme disease1. Some zoonoses may be transmitted to humansiii. Nonliving : Botulism, tetanus1. Soil, water7. Explain three methods of disease transmission.a. Contact:i. Direct: Requires close association between infected and susceptible host (touching, kissing, sexual intercourse).ii. Indirect: fomites (tissues, towels, bedding, diapers, drinking cups, toys, moneys etc).iii. Droplet: Transmission via airborne droplets.b. Vehicle: Transmission by an inanimate reservoir (food, water, air)c. Vectors: Arthropods, especially fleas, ticks, and mosquitoesi. Mechanical: Arthropod carries pathogen on feet, ex. flies transfer pathogens (typhoid fever) from feces of infected to food.ii. Biological: Pathogen reproduces in vector (Lymes, WNV).8. Define epidemiology.a. Epidemiology literally means “the study of what is upon the people”. It applies only to human populations.b. The branch of science dealing with the spread and control of diseases, computer viruses, concepts, etc., throughout populations or systems. 29. Know the contribution of John Snow, Ignaz Semmelweis, and Florence Nightingale.10. Identify the function of the CDC. a. Stands for Centers for Disease Control and Preventionb. Collects and analyzes epidemiological information in the United States 11. Define the terms: morbidity, mortality, and notifiable disease a. Morbidity: incidence of a specific notifiable disease b. Mortality: the proportion of deaths from a notifiable disease c. Notifiable disease: any disease that is required by law to be reported to government authorities3John Snow 1848-1849 Mapped the occurrence of Cholera in LondonIgnaz Semmelweis 1846-1848 Showed that hand washing decreased the incidence of puerperal feverFlorence Nightingale(prominent English nurse, writer, and statistician)1858 Showed that improved sanitation decreased the incidence of epidemic typhusLecture 211. Define nosocomial infections and explain their importance. a. A nosocomial infection is any infection that is acquired during the course of stay in a hospital, nursing home, or other health care facility. b. About 5 to 15% of all hospitalized patients acquire nosocomial infections. c. Joseph Lister (1827-1912) used carbolic acid to prevent nosocomial infectionsd. Certain normal microbiota are often responsible for nosocomial infections when they are introduced into the body through such medical procedures as surgery and catheterization.4e. Opportunistic, drug-resistant Gram-negative bacteria are the most frequent causes of nosocomial infections.f. Patients with burns, surgical wounds, and suppressed immune systems are the most susceptible to nosocomial infections. 2. A compromised host is a patient with acquired or congenital immunologic deficiency at increased risk for infectious disease complications.3. List several methods of
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