Lecture 20 1 Define pathology etiology infection and disease a Disease An abnormal state in which the body is not functioning normally b Pathology The study of disease c Pathology is the precise study and diagnosis of disease Pathogenesis The development of d Etiology The study of the cause of a disease e Infection Growing and multiplying of pathogens in the host 2 Define normal transient microbiota and opportunistic infections a Transient microbiota may be present for days weeks or months Temporarily form part of the disease microflora b Normal microbiota permanently colonize the host i Microbial antagonism is a competition between microbes ii Normal microbiota protect the host by 1 Occupying niches that pathogens might occupy 2 Producing acids 3 Producing bacteriocins iii Probiotics are live microbes applied to or ingested into the body intended to exert a beneficial effect c Symbiosis d Some normal microbiota are opportunistic pathogens An infectious microorganism that is is the relationship between normal microbiota and the host normally a commensal or does not harm its host but can cause disease when the host s resistance is low 3 Compare and contrast commensalism mutualism and parasitism a b c In mutualism both organisms benefit In commensalism one organism is benefited and the other is unaffected In parasitism one organism is benefited at the expense of the other 4 Understand Koch s postulates and the exceptions a Koch s postulates are used to prove the cause of an infectious disease The same pathogen must be present in every case of the disease i 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 iv The pathogen must be isolated from the inoculated animal and must be shown to be the original animal b Exceptions Some pathogens can cause several disease conditions i ii Some pathogens cause disease only in humans iii Some pathogens need cofactors iv Development of some diseases takes years 5 Understand predisposing factors for disease a Predisposing factors include any factors that makes the body more susceptible to disease or can alter the course of a disease i i e gender climate age fatigue inadequate nutrition 6 Define reservoir of infection a Continual sources of infection AIDS gonorrhea i Human 1 Carriers may have inapparent infections or latent diseases no signs of disease to host 1 Some zoonoses diseases that affect wild or domestic animals may be transmitted to Rabies Lyme disease ii Animal humans iii Nonliving 1 Soil Botulism tetanus 7 Explain three methods of disease transmission a Contact i Direct Requires close association between infected and susceptible host touching kissing sexual intercourse Indirect fomites Tissues towels bedding diapers drinking cups toys moneys etc ii iii Droplet Transmission via airborne droplets 1 i e saliva mucous during coughing or sneezing b Vehicle Transmission by an inanimate reservoir food water c Vectors Arthropods especially fleas ticks and mosquitoes i Mechanical Arthropod carries pathogen on feet e g flies transfer pathogens typhoid fever from feces of infected to food ii Biological Pathogen reproduces in vector Lymes WNV 8 Define epidemiology Where and When diseases Occur a Study of epidemics John Snow cholera 1855 b Relationships of human and disease agents c Study of diseases in populations Disease that occurs occasionally in a population disease Disease constantly present in a population disease Disease acquired by many hosts in a given area in a short time disease Worldwide epidemic 1 Herd immunity immunity to a particular disease in most of a population d Surveillance notifiable diseases disease that is required by law to be reported to government 9 Know the contribution of John Snow Ignaz Semmelweis and Florence Nightingale a b John Snow 1848 1849 Mapped the occurrence of Cholera in London Ignaz Semmelweis 1846 1848 Showed that hand washing decreased the incidence of puerperal fever i Occurrence 1 Sporadic disease 2 Endemic 3 Epidemic 4 Pandemic ii Distribution iii Control and prevention authorities c Florence Nightingale English nurse writer and statistician 1958 Showed that improved sanitation decreased the incidence of epidemic typhus 10 Identify the function of the CDC a Collects and analyzes epidemiological information in the United States b Publishes Morbidity and Mortality Weekly Report MMWR www cdc gov 11 Define the terms morbidity mortality and notifiable disease a Morbidity Incidence of a specific notifiable disease i Morbidity rate Number of people affected in relation to the total population in a given time b Mortality Deaths from notifiable diseases i Mortality rate Number of deaths from a disease in relation to the population in a given c A notifiable disease is any disease that is required by law to be reported to government period time authorities Lecture 21 1 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 Can be either via direct contact or through formites b About 5 to 15 of all hospitalized patients acquire nosocomial infections Most often patients with burns surgical wounds or suppressed immune systems c Eighth leading cause of death in America Opportunistic drug resistant gram negative most frequent cause of nosocomial infections d History i Puerperal fever Holmes Semmelweis 1840s 1 Showed that hand washing decreased the incidence of puerperal fever ii Nightingale and nursing 1850s 1 Showed that improved sanitation decreased the incidence of epidemic typhus iii Germ theory of disease Pasteur Koch 1860s iv v Antibiotics hospital infections MRSA Methicillin resistant Staphylococcus aureus in Infection and surgery sterilization with carbolic acid phenol Joseph Lister 1860s vi Development of infection control discipline concerned with preventing nosocomial or 1975 healthcare associated infection 2 Define compromised host a a person who is less than normally able to resist infection because of immunosuppressive therapy immunologic defect severe anemia or concurrent disease or condition including human immunodeficiency virus infection 3 List several methods of disease transmission in hospitals a Certain normal microbiota are often responsible for nosocomial infections when they are introduced into the
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