BACTERIA AND DISEASE Flashcards
– refers to presence of undesirable substance in water, air, or soil.
Pollution
– result of undesirable relationship bet host and pathogens. Marked by interruption in the normal functioning of the body or its part
Disease
– organism that invades and causes damage or injury to the host
Pathogen
- Mild symptoms of a disease w/c are nonspecific (fever, cough, colds, malaise)
Prodromal period
– presence of organisms outside the body, water, food, and
other biological substances
Contamination
– invasion of the body by pathogenic m.o.; Not synonymous to disease
Infection
– the ability of organism to cause a disease
Pathogenicity, “pathogenic”
- Formulated by Robert Koch & Friedrich Loeffler in 1884, based earlier concepts described by Jakob Henle
- four criteria to establish causative relationship between microbe & disease
Koch’s Postulates
- organisms may fail to produce the disease when introduced into
the body by some other route/ pathway
Portal of entry
- Period of maximal invasion. The dse.Is most acute during this period.
Period of illness
- ability of the m.o. to produce disease by overcoming the
defensive powers of host;
Virulence of m.o.
- When the dse. Is not successfully overcome,pt may die in a short prd of time
FULMINANT INFECTION
o Abundant
o small number of m.o.
Number of microbes/microorganism
o Antibacterial factors that destroy or inhibit growth of m.o.
Defensive powers of the host
- Period of defervescence - s/s starts to subside. Pt.may become vulnerable to secondary infections.
Period of decline
- pt does not show s/s but still continues to shed infecting m.o
Carrier state
- Refers to the time interval bet. Entry of m.o.& the 1st appearance of s/s
Incubation Period
- Pt. regains strength, body returns to its pre-diseased normal cond.
Period of convalescence
- kills host cells, affect their function
cytotoxin
✓ COAGULASE- coagulates fibrinogen of bld)
✓ LEUKOCIDINS - destroys WBC;(escapes phagocytosis)
Chemical
✓ poison (2 types of toxins: Exotoxin & endotoxin)
Toxin
- Organisms directly damage tissues or surface. Example:
Leprosy/warts
Mechanical
- interferes in nerve impulse transmission
neurotoxin
- inside gram (+) bacteria as metabolic product of growing cell;
secreted by bacteria and released outside the cell.
EXOTOXIN
- affects cell lining of GIT
enterotoxin
- outer membrane of Gram(-); outer membrane of cell wall
ENDOTOXIN
- Consequence of the immune response of the host to the m.o.
Immunologic
- If the causative agent is directly or indirectly transmitted from host to host
- Example: Diphtheria/ tuberculosis and Rabies
Communicable
- Disease is not spread from one person to another.
1. Agent normally inhabits the body
2. Produces the disease only when introduced into the body. - Example: Tetanus – not communicable but infectious
Non-Communicable
- From outside the body
- Exogenous, or those that originate outside the body
✓ Exogenous infection
- From inside the body
- (already present/ dormant)
✓ Endogenous infection
– disease is caused by m.o. that is known
Specific infection
- Refers to the number of person in a population who acquired the disease at a particular point of time
Incidence of a disease
– constantly present in a particular place
Endemic
- # of new cases
- # of new and old cases
- Incidence rate
- Prevalence rate
– Present worldwide
Pandemic
– Occurs occasionally
Sporadic
– rapid spread of infectious disease to a large # of people in a given population within a short period of time.
Epidemic
– Presence of bacteria in blood
Bacteremia
– Presence of actively multiplying bacteria in the blood
Septicemia
– Presence of pus-producing bacteria in the bloodstream
Pyemia
– Presence of TOXIN in blood
Toxemia
– Presence if VIRUS in the blood
Viremia
– Occurs rapidly only for a short period of time
Acute
– Occurs slowly; occurs for a long period of time
Chronic
– m.o. remains inactive for a long time but can become active again
Latent
- Invading m.o. Are limited to a relatively small area of the body
- Ex. Boils, acne
Local infection
- An infection localized in a specific part of the body that may spread to another part of the body via blood or lymphatic vessel
- Ex. Teeth, appendicitis, tonsils, or sinuses
Focal infection
- Invading m.o. Or their products are spread throughout the body by blood or lymph
- Ex. Influenza, HIV
Systemic or generalized infection
- An acute infection that causes the initial illness
Primary infection
- Infection w/c is caused by opportunistic pathogens after primary infection has weakened the body’s defense
Secondary infection
- Infection does not cause any noticeable illness
- Ex. Hepatitis
Subclinical infection/ inapparent infection
- Makes the body more susceptible to the development of a particular dse.
- Ex. Gender – UTI Genetics
Predisposing factors
- Continual source of dse-producing m.o.
- LIVING – Example: Animals, humans
- NON-LIVING – Example: soil
Reservoir of infection
- may exist in an individual with an infection that is inapparent throughout its course (Typhoid)
Healthy or asymptomatic carrier
- An individual capable of transmitting an infectious agent to others during the incubation period of the disease(measles/ chicken pox)
Incubatory carrier
- the person who had been infected by that microorganism is recovering from that infection (hepatitis, cholera, and poliomyelitis)
Convalescence and postconvalescence carrier
- The carrier state lasts for less than 6 months.
Temporary carriers
- The carrier state lasts for more than 6 months. (Hep B, HIV
infection)
Chronic carriers
– person to person
DIRECT
– Fr. Reservoir to susceptible host
INDIRECT
– spread in droplet nuclei. Travels <1 meter
DROPLET
– the pathway of causative agents from a source to infection of susceptible host.
Transmission
- Transmission of organism through media such as food, water, air
Vehicle
– pathogens are transmitted through ingestion of food that improperly cooked, prepared, poorly ref, unsanitary condition. (Example: Food poisoning, AGE)
FOOD-BORNE
– refers to spread of pathogens by droplet nuclei in dust that travels> 1meter fr. Reservoir to the host (Example: Measles, TB)
AIR-BORNE
– Pathogens is spread through contaminated water (Example:
Cholera)
WATER-BORNE
- Are animals that carry m.o. fr. One host to another
- Insects (arthropods) – most important group of vectors
Vectors
– refers to passive transport of organism on
insect’s feet or other parts.
Mechanical transmission
– active transport of organism. M.o. Enters the insect vector after the insect bites an infected person
Biological transmission
