(8) INFECTION AND BACTERIAL INVASION Flashcards
- Scientific study of disease
- Concerned with the etiology and manner in which a disease develops
- Deals with structural and functional changes
Pathology
Invasion of microorganisms in the body
Infection
- Changes in the state of health due to infection
- Abnormal state where the body is not properly adjusted
Disease
Means suffering
Pathon
Means study
Logos
KOCK’S POSTULATES
1. Suspected _______ must be absent from all healthy organisms but present in all diseased organisms
- Causative agent must be _______ from the diseased organism and grown in _______
- ________ must cause the same disease when inoculated into a ________ organism
- The same causative agent must be isolated from the ________
(1) causative agent
(2) isolated; pure culture (petri dish)
(3) Cultured agent; healthy but susceptible
(4) inoculated diseased organism
Cause and manner of causation of a disease or condition
Etiology
Proves and identify the microorganism that causes the disease
Koch’s Postulates
EXCEPTIONS TO KOCH’S POSTULATES
1. _______ intracellular pathogens and fastidious microbes (certain pathogens that will not grow in artificial culture)
- _______ microorganisms (some pathogens affect humans, and some affect animals)
- _______ infections (not caused by only one pathogen)
- _______ of some microbes after culturing in vitro
- Diseases not caused by _______
(1) Obligate [only survive and multiply within a living host]
(2) Species-specific
(3) Synergistic
(4) Less pathogenicity [humihina]
(5) microorganisms [some may be caused by nutrient deficiency, congenital, and/or malfunction]
- Subjective changes in body function
- Felt by the patient
Symptoms
TWO TYPES OF SYMPTOMS
1. ________ - the patient is experiencing symptoms
2. ________ - the patient is unaware of the disease
(1) Clinical/Symptomatic
(2) Subclinical/Asymptomatic
- Objective changes the physician can measure and observe
Signs
- Specific signs or symptoms accompanying a disease
Syndrome
- Number of new cases of a disease in a defined population during a specific time period
Incidence
- Numer of people in a population who developed the disease at a specific time, regardless of when it first appeared
Prevalence
PREVALENCE
⚬ Period Prevalence – no. of cases of the disease existing in a population during a (1) __________
⚬ Point Prevalence - no. of cases of the disease existing in a population at a (2) _________
(1) specific time period
(2) particular moment in time
BASED ON BEHAVIOR WITHIN A HOST
- Spreads from one host to another directly or indirectly
- E.G. Malaria, TB, AIDS, Cholera
Communicable
BASED ON BEHAVIOR WITHIN A HOST
- Does not spread from one host to another directly or indirectly (nutrient deficiency, allergy, abnormal proliferation of cells)
- E.G Rickets (Vit. D), Kwashiorkor (Protein)
Non-communicable
BASED ON BEHAVIOR WITHIN A HOST
- Type of communicable disease
- Rapidly/Easily spreads from one host to another
Contagious
BASED ON BEHAVIOR WITHIN A HOST
- Disease that causes death within a short period of time
- E.G. Meningococemia
Fulminant
BASED ON SOURCE OF MICROORGANISM
1. ______ - outside the body
2. ______ - inside the body (E. coli in stomach)
3. ______ - hospital-acquired
(1) Exogenous
(2) Endogenous
(3) Nosocomial [type of exogenous]
BASED ON FREQUENCY OF OCCURENCE
1. _____ - occasional occurences and closely monitored (e.g. rabies)
- _____ - constant and low level of population is affected (e.g. Palawan-Malaria; Leyte-Schistosomiasis
- _____ - relatively short but great number of affected population (e.g. flu season)
- _____ - at least three regions in the world are affected or world-wide occurence (e.g. COVID-19)
(1) Sporadic
(2) Endemic
(3) Epidemic
(4) Pandemic
BASED ON SEVERITY OR DURATION
1. ______ - develops rapidly but lasts for a short time (days- weeks)
- ______ - develops more slowly, less severe, recurrent, and difficult to treat (months-years)
- ______ - intermediate (e.g. subacute endocarditis)
- ______ - inactive for a long time then becomes active (e.g. shingles from inactivated chicken pox)
(1) Acute
(2) Chronic
(3) Subacute
(4) Latent
Indirect protection from an infectious disease due to immunity from vaccination or developed immunity
Herd Immunity
Immune individuals are not considred _____, thus disease transmission is reduced
carriers
BASED ON EXTENT OF HOST INVOLVEMENT
1. ______ - limited to one body area (e.g. boils or abcess)
- ______ - generalized and spread throughout the body (e.g. measles and TB)
- ______ - local infections that have entered the blood and lymph vessels and have spread to other parts of the body (from teeth, tonsils, or sinuses)
(1) Localized Infection
(2) Systemic Infection
(3) Focal Infection
TYPES OF FOCAL INFECTION
1. ______ - presence of bacteria in the blood
2. ______ - bacteria multiplies in the blood
3. ______ - presence of toxins in the blood
4. ______ - presence of viruses in the blood
(1) Bacteremia
(2) Septicemia
(3) Toxemia (e.g. Tetanus)
(4) Viremia
CLASSIFICATION ACCORDING TO HOST RESISTANCE
1. ______ - acute infection that causes the initial illness
- ______ - originates from opportunistic pathogens from immunocompromised patients
- ______ - subclinical; does not necessarily develop signs and symptoms
(1) Primary Infection
(2) Secondary Infection
(3) Inapparent Infection
Disease-causing microorganism
Pathogen
Source of the pathogen
Reservoir
Way for the pathogen to escape their reservoir
Portal of exit
The way of the pathogen to travel
Mode of transmission
The way of the pathogen to gain entry into a host
Portal of entry
Person who is immunocompromised
Susceptible host
- The time interval between the initial infection and the first appearance of any signs or symptoms
- Ranges from microorganisms’ mechanisms of infection, number of pathogen, or resistance of host
Incubation Period
A relatively short period characterized by symptoms of the disease which are generally non-specific (e.g. fever, general aches, or malaise)
Prodromal Period
- Period of maximal invasion
- Manifestation of symptoms are distinctive/specific to the disease (most acute)
- Several outcomes: recovery, fulminant infection, acute to chronic, and carrier state
Period of Illness
- Signs and symptoms start to subside
- Person becomes more susceptible to secondary infection (e.g. Pneumonia after having URTI)
Period of Decline (Period of Defervescence)
- Person regains the strength and returns to pre-disease state
- Recovery occurs
Period of Convalescence (Period of Recovery)
- Where pathogens normally reside or multiply
- For a disease to perpetuate itself, there must be a continual source of the disease organism
Reservoir
- Principal reservoir is the human body
- May be directly or indirectly transmitted from one inidividual to another (e.g. STIs, respiratory infections)
- Can be transmitted no matter if symptomatic or asymptomatic
Human Reservoir
- Persons who got well but are still carrying the disease
- Important living reservoirs of infection
Carrier
TYPES OF CARRIERS
1. ________ - (+) infection but no symptoms
2. ________ - (+) pathogen but never got sick; inherited
3. ________ - able to transmit disease even during incubation period
4. ________ - able to transmit while recovering
5. ________ - completely recovered but continue to harbor disease
6. ________ - pathogens harbored for months or longer after initial infection
(1) Healthy Carrier
(2) Passive Carrier
(3) Incubatory Carrier
(4) Convalescent Carrier
(5) Active Carrier
(6) Chronic Carrier
- May be caused by wild and domestic animals
- Zoonotic infections (zoonoses) may be transmitted through:
> Direct Contact
> Contamination
> Consuming infected animal products
> Air (fur/feathers)
Animal Reservoir
- Includes insects and arachnids
- Vectors: involved in transmission of disease
Arthropod Reservoir
- Includes soil and water
> Soil: harbors pathogens (e.g. clostridium tetani - tetanus; clostridium botulinum - botulism)> Water: contaminated by the feces of humans and animals which causes GIT disease (e.g. vibrio cholerae - cholera; salmonella typhi - typhoid fever)
Nonliving Reservoir
- Person-to-person transmission
- Touching, kissing, sexual intercourse
- No medium or intermediate object
- e.g. Common cold, influenza, Kissing disease
Direct Transmission
- Coughing and sneezing
- Close proximity for droplets to be transmitted (>1m from reservoir)
- e.g. Viral respiratory tract disease, Staphylococcal infections, Measles
Droplet Transmission
- No direct human-to-human contact
- Transmitted through non-living objects
- e.g. Airborne, Vehicle, and/or Vector transmission
Indirect Contact Transmission
- Through dusts or aerosols
- Less than 2.5 microns in size (can travel for 1 meter)
- e.g. Measles, TB, and histoplasmosis
Airborne Transmission
- Transmission of disease by a medium
- e.g. Foodborne transmission, Waterborne transmission, and Fomites (non-living things)
Vehicle Transmission
- Mechanical transmission and Biological transmission
Vector Transmission
