Review: Normal Flora and Disease Processes ----- Disease Processes Flashcards
What is the difference between an infection and a disease?
Infection vs. Disease
A person may become infected without becoming diseased
Pathogen is either driven from the host or assumes a benign relationship with the host
Example: HIV infected person that is asymptomatic is infected but not diseased
Is it possible to be infected but have no signs of disease?
Yes
What is the difference between a local and systemic infection?
Local infection
Infection that is localized to one area of body
Example: Skin abscess like a Boil
Systemic Infection
Infection that spreads from localized area to rest of body
Example: blood poisoning from a skin abscess (Septicemia) spreading infection to internal organs
What is the difference in the amount of people infected between endemic, epidemic, and pandemic disease outbreaks?
Endemic: occurs at a low level in a certain geographic area
Epidemic: breaks out in explosive proportions within a population
Pandemic: occurs worldwide
What are the characteristics of the three disease states: acute, chronic, and subclinical?
Acute Disease Develops rapidly Severe symptoms Rapid onset, short duration Immunity: usually long lasting Ex. Strep throat, measles
Chronic Disease Slowely progressive disease Long, indeterminable duration Symptoms exist for months or years Immune: usually nonexistent, unable to rid body of pathogen Ex. Tuberculosis, HIV
Subclinical Disease
Symptoms nonexistent or very mild
Disease severity may be controlled by previous exposure to disease
Ex. Hepatitis A
What influences disease progression?
Infectious Dose
Generation Time
Host Resistance
Virulence
Define virulence.
Means: “full of poison”
Disease producing capacity of bacteria
Ability to injure host tissue
Avirulent: do not cause disease
Define infectious dose.
Minimum number of microbes needed to cause infection
Salmonella: 1 million ingested to establish infection
Shigella: 10 – 100 ingested to establish infection
Does Generation time influence course of disease? Why or why not?
The time it takes a cell or population of cells to double
Influenced by genetic make-up and environment
Influences Incubation period of disease
List some ways that diseases can be transmitted directly.
Direct Mode: (direct contact person to person) Air droplets: coughing, sneezing Sexual transmission Kissing, touching Fecal contact
List how diseases can be transmitted indirectly.
Fomites: inanimate objects, toys, bed linens (serve as a vehicle of transmission)
Food/Water: oral route of transmission
Biological Vector: insect is diseased and transmits infection through a bite
Mechanical Vector: insect carrying disease on legs, wings, body
What are fomites?
inanimate objects, toys, bed linens (serve as a vehicle of transmission)
What is the difference between biological and mechanical vectors?
Biological Vector: insect is diseased and transmits infection through a bite
Mechanical Vector: insect carrying disease on legs, wings, body
What are the portal of entry sites for human pathogens?
Mouth – Cholera (food), Hepatitis B (kissing)
Skin – Malaria (insect), Tetanus (wound), Staph (surgery)
Respiratory Route – Tuberculosis, Pneumonia (air)
Urogenital Tract – Gonorrhea (sex)
Eyes – Staph infection (opportunist)
What is a ligand and its relationship to receptor sites on host tissue?
Proteins in cell wall/cell membrane
Pili
Capsular proteins or glycoproteins
Ligand (attachment sites on microbe
and host receptor site must have exact match
(like a key matching with a lock)
What does innate resistant mean?
Innate resistance: a natural resistance to a disease
What are the five virulence factors discussed in class? Their characteristics? Differences or similarities?
Exotoxin Endotoxin Enzymes/protiens Capsule Pili
Do all bacteria survive for an equal amount of time outside the host body?
Some bacteria can survive outside host longer than others
Infectious diseases follow 6 basic steps from transmission to new host. What are they?
- Transmission to susceptible host
- Attachment of microbe to host target cell
- Colonization of Infection
- Damage to host
- Portal of exit
- Find new host
Infection Defined
Means: to mix with or to corrupt
Organism enters body tissue and multiplies
Refers to relationship between a pathogen and a host
A Competition between host and pathogen
(Term Infection does not refer to normal flora. A person is colonized with normal flora not infected unless flora becomes opportunistic pathogen)
Disease Defined
Means: living apart
An infection that causes bodily injury
Develops if the host loses the competition with the pathogen
