Quiz 2

• a host is any organism that harbors another organism
• symbiosis is the association between two or more species (living together)
• contamination indicates the presence of microorganisms
• infection occurs when pathogenic microorganisms penetrate host defenses, enter the tissues and multiple
• infestation refers to the presence of larger parasites in the body such as worms and anthropods
• disease ensues when the cumulative effects of infection on tissue/organ disruption
• disease is a pathologic state or deviation from health
• pathology is the study of disease. It is concerned with the structure and functional changes brought about by the disease.
• pathology is concerned with etiology (cause) and pathogenesis (manner in which disease develops)
• pathogenecity refers to the ability to cause a disease
• factors affecting pathogenecity:

  1. Mode of Action - means/ways by which microbe produces disease
  2. Virulence - degree of pathogenicity or the intensity in which an organism is able to cause disease
• animal passage refers to the rapid transfer of pathogens through animals of a species susceptible to infection by that pathogen. it can affect virulence factors.
• virulence can be decreased by attenuation and transposal of virulence.
• attenuation is the weakening of the disease-producing ability of the organism. this can be achieved by repeated subculturing on laboratory media
• transposal of virulence refers to when a pathogen is passed from its normal host to a new host species, and then passed sequentially through many individual of the new host species
• normal flora is also known as microflora
• resident microflora are microbes that are always present on or in the human body
• transient microflora are organisms that can be present under certain conditions in or any location where resident microflora are found
• opportunists take advantage of particular opportunities to cause disease that includes:

  • failure of host's normal defense aka immunocompromised
  • introduction of the organism into unusually body site
  • disturbances in the microflora, or competition against another pathogen known as microbial antagonist
• invasiveness/ineffectiveness, dose, viability, toxigenicity, and specificity are all factors that affect pathogenicity
• dose - microbes should be in sufficient amount to cause disease
• toxigenicity - microbes potential to damage host tissues by producing/releasing toxins
• specificity - refers to attraction of microbes to specific host/range of hosts
• infection is the invasion or colonization of the body by pathogenic organisms and may exist in the absence of a detectable disease
• disease occurs when an infection results in any change from a state of health
• kinds of disease are infectious and non-infectious
• extent of host involvement:

  • localized - specific tissue
  • systemic - infection spread to several sites, usually @ bloodstream
  • focal - infectious agent breaks loose from local infection and is carried to other tissues
• sporadic diseases occur occasionally
• endemic is when a disease is constantly resent in a population
• epidemic is when a disease is acquired by many people in a GIVEN AREA in a relatively SHORT PERIOD
• pandemic is when an epidemic disease occurs WORLDWIDE
• anti-phagocytic factors - bacteria and parasites surviving nd multplying inside phagocytic cells
• fomite is an inanimate object thatharbors and transmits the pathogen
• aerosols are suspensions of live pathogens in fine dust or moisture particles