Unit 2 Intro to Infectious Diseases Flashcards
How was the bubonic plague transmitted?
Will we ever be free of disease?
Fleas bit rats who bit people too. Can be passed via respiration from human to human
No.
When this value is high, the spread of disease is low and vice versa. Defined as a population and how many people are immune to a disease.
Affected nowadays by vaccines.
What is the example of low herd immunity in human history? Another example is?
Herd Immunity
Native Americans and European Diseases (knowingly giving them smallpox, even)
Spanish Flu
Do infectious disease still take a heavy toll on human life?
Yes, but it has been lowered via vaccines, antibiotics, sanitation, medical care
Doesn’t apply in third world countries or poorer populations in developed countries
This is defined as a disturbance in normal functioning of an organism
Disease
This type of diseease is caused by a microbe and can be transmitted from host to host
Infectious Disease (Influenza, HIV, hep B, bacteria, fungi)
These are infections diseases of animals that can cause disease when transmitted to humans
Examples?
Zoonotic Disease
Rabies, West Nile Fever
In developed countries, why is it usually wild animals that give us rabies?
In what animal is West Nile Virus prominent? How do we become infected? Can it be passed on to someone else?
We vaccinate our domesticated animals
Birds. Mosquitos. No.
This is a bacterial disease spread by ticks who feed on deer.
Lyme Disease
This is a microbe frequently associated with disease production. It must cause harm (disease)
Pathogen
This is the mechanism by which a microbe uses to cause a disease state, it could be enzymes or toxins that cause damage to tissues.
Specific signs and symptoms are associated with specific diseases, however many viruses have the same symptoms which complicate diagnosis
Pathogenesis
This term refers to the replication of a microbe (sometimes pathogen) in or on its host.
Infection
Our normal flora infects us too. But its a pathogen infection if it causes damage
Do all pathogens have the same ability to cause disease?
These pathogens tend to produce disease readily in healthy hosts, usually a virus
When can it occur in bacteria?
No
Primary Pathogen
When they are not out normal flora, like cholera bacteria
This type of pathogen generally only cause disease when placed into an unusual site or when the host has a weakened immune system
Opportunistic pathogens
E. coli in the intestines, which can spread to other parts of our body like after appendicitis
Or developing pneumonia after having the flu, (weakened Immune system) or alcoholism
This is a measure of the severity of disease a pathogen can produce.
This is the proportion of infected individuals who develop the disease
Virulence
(0 virulence is not a pathogen)
Case-to-infection ratio (CTI)
Pathogens can weaken over time or show varying virulence levels due to________
Attenuated strains show INCREASED/DECREASED virulence
Avirulent strains can no longer cause _____
Genetic differences
Decreased (attenuated viruses are useful in vaccines, like chickenpox)
Disease
An individual infected with a pathogenic microbe who never exhibits overt signs or symptoms of the disease (asymptomatic) is called a
They can make other people sick
Typhoid Mary is a good example
Carrier
Typhoid fever is transported by the _________ route,
Fecal oral route. How people who ate Typhoid Mary’s cold prepared foods got sick
What must a microbe do to cause disease?
Gain entry to host Attach to and invade specific cells and/or tissues within the host Evade host defenses Obtain nutrients from the host Exit the host
This organism produces IgA protease, an enzyme that destroys IgA antibodies, evading the immune system
Neisseria gonorrhoeae
This organism has iron binding proteins to allow pathogen to acquire iron from the host
Alternatively, other organisms can lyse _____ cells
Mycobacterium tuberculosis
Red Blood Cells
This virus causes cellular damage by replicating to induce apoptosis of host cells, often motor neurons
Poliovirus
As we’ve mentioned, pathogens can attach via specific protein protein interactions.
Occasionally, more generalized interactions may allow organism to adhere to a host. In this organism, spores adhere to host hydrophobic surfaces, including cells
Rice Blast Fungus
Cuticle (waxy coating on surface of leaves) is hydrophobic and spores stick really well to it
This is defined as the group of organisms that a pathogen can infect
An example of spread of pathogen into a new host via mutation lies in the spread of ______ in cats to become _____ in dogs
Host range
FPLV in cats to become CPV in dogs
After attachment and invasion, pathogens must still avoid elimination by host defenses
This is defined as what the immune system recognizes on the pathogen
Some microbes employ _________, shifting their surface protein structures
Antigen
Antigenic Variation
Trypanosoma brucei gambiense is a protozoan (eukaryotic) cell that is an example of
Antigenic variation
The antigen always changes and the immune system is always behind the change
T. Brucei and N. Gonorrhoeae are examples of
Antigenic variation
This evasion is used by all herpes viruses, surviving the initial attack by the immune system and residing in cells and occasionally rises up
Latency
When chickenpox (a herpes virus) re-emerges from latency its called
Shingles
This bacteria is able to grow inside of our cells, including white blood cells, and is therefore called an intercellular colonizer.
Mostly caused by
It can be categorized as a ______, can grow in cold and can grow in body temps
Lysteria monocytogenes
Processed foods
Psychotroph
Other methods microbes use to evade host defenses include this one, where bacteria use _______ to digest phage DNA
Phage evasion mechanisms also exist (RE inhibitors, for instance), prevents it from cutting to get to phage DNA
Restriction Endonucleases
Different microbial pathogens cause disease in different ways, contributing to their _______
Pathogenesis
These are proteins produced and secreted that can have negative effects on host cells (part of pathogenesis) like an enzyme or protease
These toxins are part of the microbial structure itself (never proteins)
Exotoxins (ex: botulism)
Endotoxinsm (like lipid A in gram negatives or some techoic acids in gram positives)
Do viruses usually produce toxins? Why or why not?
Is this pathogenesis?
No, their replication induces either cell death or induced cell death via immune responses to reduce the viral spread
Yes just different.
This is the term that means the spread of an infectious agent from one host to another (sick person–> sick person).
It may also occur from a pathogen’s natural source (reservoir) to a host (environment –> sick person), like tetanus.
Transmission
This disease no longer is an issue because the human person was the only reservoir
Smallpox
This route of transmission occurs when there is physical contact between infected/susceptible hosts
Direct Contact (STIs, ringworm)
This route of transmission occurs when an object carries an agent between an infected and susceptible individual
The object is often an inanimate object, termed a
Indirect Contact (ringworm too, planter’s warts, skin infections, respiratory infections)
Fomite
This route of infection occurs via coughing and sneezing, or via a respiratory mechanisms.
Can it be both direct and indirect?
Aerosol
Yes
This route of transmission occurs via the genitals touching or even indirect contact (rare)
Sexual Transmissions
This route of transmission occurs when bacteria of the digestive tract is transmitted to people’s food, or via contaminated water
Fecal-Oral
This route of transmissions occurs via another species (usually blood sucking insects - mosquitos, fleas, ticks). They release anti-coagulants from saliva into bite to prevent clotting which can cause infection
Vector-borne
This type of transmission occurs from a pathogen going between members of a species other than parent to offspring
Horizontal
This route of transmission occurs when transmission of a pathogen happens from parent to child (often in utero, during birth, or shortly after birth) like HIV, measles
For HIV there must be a very high viral load in blood of mother
Vertical
How could a disease be transmitted shortly after birth from mother to child?
Breastmilk
This type of transfer moves from its natural (reservoir ) host to a human.
Humans are often ________ hosts, where the pathogen isn’t efficiently transferred from person to person. They often don’t replicate well inside humans or the mode of transmission doesn’t occur as often (biting in rabies)
Zootonic Transfers
Dead end
This is defined as the study of patterns in disease populations
This is defined as the rate of disease in a population
This is defined as the death rate of a disease
Epidemiology
Morbidity Rate
Mortality
What is the federal epidemiological body in the U.S.?
What is the global one?
What is their mission
Center for Disease Control (CDC)
World Health Organization (WHO)
Understand infectious disease spread and be better equipped to prevent them
This term means the number of new cases appearing in a population during a specific time period. Contributes to morbidity.
rate = number of new cases/number of people in a population
Incidence
Incidence rate
This term means the total number of cases in a population at a particular time. Also contributes to morbidity. Correlates with incidence.
Prevalence
This pattern of infectious disease is the baseline, is habitually present in the population. Often results in cyclical patterns of increased and decreased incidence.
What is endemic to north american foxes? The incidence rate depends upon the seasons.
For humans it’s
Endemic Disease
Rabies
Colds (rhinovirus)
This occurs when an incidence or a disease rises significantly above the normal expected value. Localized (Chicago can have one)
Epidemic
This occurs when an unexpected cluster of cases in a short time in an even smaller localized population. Can lead to an epidemic (UIC can have one)
Outbreak
