Term | Definition |
Symbiosis | living together
have these relationships with countless microorganisms |
Types of symbiosis | Mutualism
commensalism
parasitism |
Mutualism | both benefits |
Commensalism | benefits one and neither benefits nor harms the other |
Parasitism | benefits one and the other is harmed |
Normal (resident) flora/indigenous flora | microbes that engage in mutual or commensal associations
ration of cells: 10:1 |
Infection | a condition in which pathogenic microbes penetrate host defenses, enter tissues, and multiply |
Infectious disease | an infection that causes damage or disruption to tissues and organs |
Normal flora/indigenous microbiota | organisms that colonize the body's surfaces without normally causing disease |
Normal flora is... | essential to the health of humans |
Flora create... | an environment that may prevent infections and can enhance host defenses |
What may alter flora? | antibiotics, dietary changes, and disease |
Probiotics | introducing known microbes back into the body |
Opportunistic pathogens | normal flora that cause disease under certain circumstances |
Conditions that provide opportunities for opportunistic pathogens? | -introduction of normal flora into unusual site in body
-immune suppression
-changes in the normal flora
----changes in relative abundance may allow opportunity for a member to thrive and cause disease |
Reservoirs of infection | sites where pathogens are maintained as a source of infection |
3 types of reservoirs | Animal reservoirs
Human carriers
Nonliving reservior |
Zoonoses | diseases naturally spread from animal host to humans (MAJORITY OF HUMAN INFECTIONS) |
Acquire zoonoses through various routes... | -direct contact with animal or its waste
-eating animals
-vectors |
Vector | a live animal that transmits an infectious agent from one host to another |
Majority of vectors are? | anthropods: fleas, mosquitos, flies, and ticks |
Biological vectors | actively participate in a pathogen's LIFE CYCLE |
Mechanical vectors | not necessary to the life cycle of an infectious agent and MERELY TRANSPORTS it without being infected |
Human carriers | infected individuals who are asymptomatic but infective to others
-some individuals eventually develop illness while others never get sick |
Nonliving reserviors | soil, water, fomites, and food can be reservoirs of infection |
Fomites | inademiate object
-cell phone |
Pathogenicity | ability of a microorganism to cause disease |
Virulence | -look @ structure & chemistry help to be pathogenic
-factors contribute to pathogenicity:
Adhesion factors
biolfims
extracellular enzymes
toxins
antiphagocytic factors |
Infectious dose | -minimum number of microbes required for infection to proceed
-microbes with smaller IDs have greater virulence |
Infectious diseases five stages | -incubation period
-prodromal period
-illness
-decline
-convalence |
Incubation period | no sign/symptom-pathogen colonized |
Prodromal period | feel under the weather, not typical sign |
illness | really feel it, signs/symptoms |
decline | get better |
Localized Infection | microbes enter the body and remains confined to a specific tissue |
Systematic infection | infection spreads to several sites and tissue fluids usually in the bloodstream |
Focal infection | when infectious agent breaks loose from a local infection and is carried to other tissues |
Mixed infection | several microbes grow simultaneously at the infection site-POLYMICROBIAL |
Primary infection | initial infection |
Secondary infection | another infection by a different microbe |
Acute infection | comes on rapidly, with sever but short-lived effects |
Chronic infections | progress and persist over a long period of time |
epidemiology | the study of where and when diseases occur, and how they are transmitted |
Mortality rate | total number of deaths in a population due to a certain disease |
Morbidity rate | number of people afflicted with a certain disease |
Prevalence | number of total cases of a disease in a given area during a given period of time |
Sporadic | when occasional cases are reported at irregular intervals |
Endemic | disease that exhibits a relatively steady frequency over a long period of time in a particular geographic locale |
Epidemic | when prevalence of a disease is increasing beyond what is expected |
Pandemic | epidemic across countries and continents |