Chapter 14 - Introduction to Infectious Disease Flashcards
A disturbance in normal functioning of an organism (caused by a microbe and transmitted form host to host)
Disease
________ diseases are infectious diseases of animals that can cause disease when transmitted to humans (e.g. rabies)
Zoonotic
A microbe that routinely causes disease =
Pathogens
___________ is a mechanism that a microbe uses to cause the disease state.
Pathogenesis
__________ refers to the replication of a pathogen in or on its host.
Infection
Subjective manifestations of disease (e.g. nausea, pain, cramping)
Symptoms
Measurable manifestations of disease (e.g. diarrhea, fever, low T cell count)
Signs
_______ pathogens tend to produce disease readily in healthy hosts.
Primary
____________ pathogens cause disease only when a host has been compromised.
Opportunistic
Measure of the severity of disease a pathogen can induce.
Virulence
Proportion of infected individuals who develop the disease.
Case-to-infection (CI) ratio
What are weakened strains that show decreased virulence and are useful for vaccine development called?
Attenuated
___________ strains can no longer cause disease.
Avirulent
Individuals infected with a pathogenic microbe who never exhibits overt signs and symptoms =
Carriers/ Asymptomatic
To cause an infection a pathogen must gain _____ to the host, _________ to and _________ specific cells &/or tissues within the host, _______ host defenses, obtain __________ from the host, and _____ the host.
entry
attach
invade
evade
nutrients
exit
__________ may occur through specific protein: protein interactions.
Attachment
After achieving attachment & invasion, pathogens must still avoid ____________ by host defenses.
elimination
The group of organisms that the pathogen can infect =
host range
Microbes shifting their surface protein structures to evade immune responses =
Antigenic variation
Evasion method that can be used by herpes virus. Includes a ________ infection (where the viral genomes do not replicate in the host cell) following be reactivation (start to multiply).
Latent
________ on bacteria make them hard to phagocytose.
(evasion method)
Capsules
Some microbes can replicate inside the ___________.
(evasion method)
phagocytes
Bacteria use __________ _________________ (__) to digest phage DNA.
Restriction endonucleases (REs)
Structures of biological origins that damages a host =
Toxins
__________ are proteins produced and secreted that can have negative effects on the host cell.
Exotoxins
____________ are a part of the microbial structures itself (lipopolysaccharides).
Endotoxins
Spread of an infectious agent from one host to another =
Transmission
(route of transmission) physical contact between infected/susceptible hosts.
Direct contact
(route of transmission) Object carries agent between infected & susceptible individuals.
Indirect contact
Inanimate object via which pathogens may be transferred to a susceptible host.
Fomite
(route of transmission) A pathogen is excreted in the feces of one individual and then ingested by another individual.
Fecal-oral Transmission
(route of transmission) Pathogens that replicate in respiratory tract and is airborne.
Respiratory (“aerosol”) transmission
(route of transmission) Transmitted via another species (e.g. mosquitoes carrying malaria).
Vector borne Transmission
(route of transmission) Occurs during vaginal, anal, or oral sex.
Sexual Transmission (STDs/STIs)
Transmission of a pathogen between members of a species other then parent to offspring =
Horizontal
Pass of a pathogen from parent to child (e.g. HIV) =
Vertical
The study of patterns of disease in populations =
Epidemiology
The rate of disease in a population =
Morbidity rate
The death rate of disease =
Mortality rate
A particular incident of individual and disease (can include asymptomatic/subclinical) =
case
of new cases appearing in a population during a specific time period =
incidence
Incidence Rate =
of new cases per # of people
Total # of cases in a population at a particular time =
Prevelence
A disease that is habitually present in the population is an
endemic disease
Endemic diseases often result in __________ patterns of increased and decreased incidence.
cyclical
Incidence of disease rises significantly above the normally expected value =
epidemic
Unexpected cluster of cases in a short time in a localized population =
outbreak
A global epidemic (e.g. COVID-19) =
pandemic
A single source of infection to which the population is exposed =
common-source epidemics
_____ _______ is a common-source epidemic.
Food poisoning
Infection passing from one host to another =
propagated epidemics
_____‘_ ___________ are used to show that a specific microbe causes a specific disease.
Koch’s postulates
- The suspected microbe is identified in every person with the disease, but not those without it.
- A pure culture of the suspected microbe is obtained.
- Experimental inoculation of the suspected microbe into a healthy test host causes the same illness.
- The suspected microbe is recovered from the experimentally inoculated host organism
Koch’s Postulates
Studies determined that the microbe Helicobactor pylori causes _________ _________ using Koch’s postulates.
gastric ulcers
What is a problem with using Koch’s postulates?
Not all individuals exhibit the same degree of infection (or may exhibit no infection at all).
There is a _______ basis for susceptibility to certain infections.
genetic
There are several points where the classic postulates are not _______ or ___________ to achieve. This is why there is a more __________ _______ on these “rules”.
ethical, possible, modern take
Emerging or reemerging diseases may occur when a pathogen encounters a ___ ___________.
new population
An instance of an emerging disease can be seen in the zoonotic transfer of SIV to humans and the evolution of ___.
HIV
_______ disease caused by the bacterium _____________ _____________ transmitted to humans by the black-legged tick.
Lyme, borelia burgdorferi
While E. coli is usually nonpathogenic and aids in digestion, _____________ E. coli can cause severe intestinal diseases (e.g. strain O157:H7)
pathogenic
Strain of staphylococcus aureus that is resistant to a wide variety of antibacterial medications =
methicillin-resistant staphylococcus aureus (MRSA)
