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Cards (61)

  • Pathology
    The study of disease
  • Etiology
    The study of the cause of a disease
  • Pathogenesis
    The development of disease
  • Pathogen
    Have special properties that allow them to invade the human body or produce toxins
  • Infection
    Colonization of the body by pathogens
  • Disease
    An abnormal state in which the body is not functioning normally
  • Normal Microbiota (Flora)

    • Microbial Antagonism due to competition between microbes
    • Resident Flora (normal) acquired at passage through birth canal
  • Resident Flora (normal)
    • Establish permanent colonies on/inside body without producing disease
    • Protect the host by occupying niches that pathogens might occupy (Competitive exclusion)
    • Protect the host by producing acids
    • Protect the host by producing bacteriocins
    • Protect the host by stimulation of immune system
  • Protective role of Resident Flora
    • Prevent pathogens from attaching
    • Consume available nutrients
    • Produce toxic compounds that inhibit other microbes
  • Transient Microbiota (Flora)
    Certain microbes are present for various periods (days, weeks, or months) – then disappears
  • Probiotics
    Live microbes applied to or ingested into the body, intended to exert a beneficial effect
  • Dynamic nature of resident flora: changes due to age, type of food consumed, Hormonal state, antibiotics
  • Various Co-existence Relationships Between Bacteria and Host
    • Symbiosis
    • Mutualism
    • Commensalism
    • Parasitism
  • Opportunistic pathogens

    Cause disease under special conditions (mutualistic relationship becomes parasitic)
  • Healthy carriers of pathogenic organisms
  • Cooperation among microorganisms: One microorganism may make it possible for another to cause disease or produce more severe symptoms
  • Koch's Postulates: Proof of Etiology of Infectious Diseases
    • The same pathogen must be present in every case of the disease
    • The pathogen must be isolated from the diseased host and grown in pure culture
    • The pathogen from the pure culture must cause the disease when it is inoculated into a healthy, susceptible lab animal
    • The pathogen must be isolated from the inoculated animal and must be shown to be the original microbe
  • Exceptions to Koch's Postulates
    • To establish disease etiology for viruses and bacteria, which cannot be grown on artificial media
    • Some diseases, e.g.: pneumonia and nephritis, may be caused by a variety of microbes
    • Some pathogens, such as S. pyogenes, cause several different diseases
    • Certain pathogens, such as HIV, cause disease in humans only
  • Symptom
    A change in body function that is felt by a patient as a result of disease
  • Sign
    A change in a body that can be measured or observed as a result of disease
  • Syndrome
    A specific group of signs and symptoms that accompany a disease
  • Communicable vs. Non-communicable vs. Contagious
    • Communicable disease: A disease that is spread from one host to another
    • Contagious disease: A disease that is easily spread from one host to another
    • Noncommunicable disease: A disease that is not transmitted from one host to another
  • Incidence
    Fraction of a population that contracts a disease during a specific time
  • Prevalence
    Fraction of a population having a specific disease at a given time
  • Occurrence of a Disease
    • Sporadic disease: Disease that occurs occasionally in a population
    • Endemic disease: Disease constantly present in a population
    • Epidemic disease: Disease acquired by many hosts in a given area in a short time
    • Pandemic disease: Worldwide epidemic
  • Severity or Duration of a Disease
    • Acute: Disease develops rapidly
    • Chronic: Disease develops slowly
    • Subacute: Symptoms between acute and chronic
    • Latent: Disease with a period of no symptoms when the causative agent is inactive
  • Herd immunity
    Presence of immunity to a disease in most of the population
  • Extent of Host Involvement
    • Toxemia: Toxins in the blood
    • Viremia: Viruses in the blood
    • Primary infection: Acute infection that causes the initial illness
    • Secondary infection: Opportunistic infection after a primary (predisposing) infection
    • Subclinical disease: No noticeable signs or symptoms (inapparent infection)
  • Types of Infection
    • Local: limited to small area of body
    • Systemic: spread throughout body via_
    • Focal: spread from local infection to specific areas
    • Primary: acute infection causing initial illness
    • Secondary: occurs after host is weakened from primary infection
    • Subclinical (inapparent): no noticeable signs and symptoms
  • Patterns of Disease: Predisposing Factors
    • Genetics
    • Gender
    • Climate and weather
    • Age
    • Stress and fatigue
    • Lifestyle
    • Chemotherapy
  • Coronaviruses are a large family of viruses, some of which can infect people
  • Mild illness (common colds) and severe, or even fatal, disease - such as Middle East Respiratory Syndrome Coronavirus (MERS-CoV) and SARS
  • The natural reservoir for coronaviruses is thought to be animal hosts
  • New strains emerge from this reservoir, infect an 'intermediate' host, and from there infect people
  • Some coronaviruses are efficient at human-to-human transmission, while others are not
  • Coronaviruses are common in many different species of animals, including camels, cattle, cats, and bats
  • The 2019-novel coronavirus (2019-nCoV) is a previously-unidentified strain of coronavirus
  • Symptoms of 2019-nCoV
    • fever
    • cough
    • shortness of breath
    • difficulty breathing
  • 2019-nCoV is capable of causing severe illness, and some infected people have died
  • It is possible that people with underlying health conditions are at higher risk for severe disease