BACTERIA AND DISEASE

Bacteremia

Presence of bacteria in the blood

Commensalism

A form of symbiosis in which one organism benefits from anothet organism without causing harm to it

Contamination

Presence of unwanted material where they should not be or at concentrations above the normal.

Disease

Result of an undesirable relationship between the host and the pathogen

Infection

Imvasuon of the body by pathogenic microorganisms

Pathogenicity

Ability of an organism to produce a disease

Pollution

Presence of contaminants that can cause adverse biklogical affects to humans and communities

Pyemia

Presence of pus-producing bacteria in the bloodstream

Septicemia

Presence of actively multiplying bacteria in the blood, usually from source of infection

Symbiosis

Prolonged and close interaction between organisms of different species

Toxemia

Presence of toxins in the blood

Viremia

Presence of viruses ij the blood

Virulence

The degree of pathogenicity of an organism

Mycobacterium leprae

The causive agent of leprosy

Subclinical

Most of the time, infections are ________

Reservoirs

Serve as the continual source of disease-causing microorganisms.

Reservoir

It is the site where an infectious agent normally resides and multiplies

Reservoir

It provides the organisms with conditions that enable them to survive and multipky and provide opportunity for transmission to susceptible host.

Zoonotic infections

Certain infectious diseases can be transmitted from an animal to humans

Carriers

Those who developed the disease, got well bit still harbor the organism, thereby transmitting them to others.

Asymptomatic

Infected but do not manifest symptoms

Incubatory carriers

Carriers who transmit the causative agent during the incubation period of thw illness.

Chronic carriers

Those who harbor the organism for months or longer after the patient developed the initial infection.

Convalescent carriers

Individuals who developed the disease, recovered but remain capable of transmitting the causative agent

Histoplasma capsulatum

Fungus associated with soil

Entamoeba histolytica

A protozoan parasite that causes amoebiasis

Fasciola hepatica

Larvae which causes damage to the liver

Portal of exit

The route by which an infectious agent exits its host.

Direct contact

Wherein most infectious agent are transmitted

Person-to-person contact

Skin-to-skin contact.

Droplet spread

Ex. patients with resporatory tract infection.

Airborne transmission

Through dust or aerosols.

Aerosols

droplets with nuclei less than 5 microns in size

Vehicle transmission

Through media such as food, wtaer, milk, or billogical sibstances

Vehicles

Carry an ibfectious agent passively

Vector transmission

Usually insects that can trnamsmit infectious agent.

Mechanical transmission

Passive transport of the organism on insect’s feet or other body parts.

Biological transmission

Active transport of the organism such as insect bites.

Portal of entry

How yhe infectious agents enters a susceptible host

Portal of entry

Provides access to tissues where the infectious agent can multiply.

Host

The final link in chain of infection

Mechanical: Invasiveness

Causing disease by directly famaging tissues or body surfaces

Colonization

The ability of the invading organism to enter the susceptible host and establish itself in the portal of entry.

Adhesins

Substances produced by organisms yhat facilitate adhesion of the organism to specific target cells.

Gas gangrene

Caused by clostridium perfringes that breaksdowb the collagen.

Endotoxins

Integral component of outer membrane of gram negatuve bacteria

Lipopolysaccharide

Responsible for the endotoxin activity

Endotoxins

Exert their effects when gram ngeatuve bacteria due and theur cell walls undergi lysis

Exotoxins

Are intracellular products of some bacteria as part of their growth and metabolism and are released into the surrounding medium.

Cytotoxins

kill host cells or afect their function

Neurotoxins

Interfere with normal nerve impulse transmission

Enterotoxins

Affectsvtge cells lining of gastrointestinal tract

Communicable disease

A disease spread from a host to another, either directly or indirectly

Contagious disease

The disease is easily and rapidly transmitted from one persob to another.

Fulminant infection

If the infection results in tge death of the patient over a short period of time

Non-communicable disease

Not spread from one person to another.

Exogenous

The source Of infectious agent is from outside the body

Nosocomial

Hospital-acquired infections

Endogenous

The source of causative organism is from inside the body

Sporadic disease

A disease that occurs occassionally

Endemic disease

The disease is constantly present in a popukation at low levels

Epidemic

If a great number of people in a given locality develop an infectious disease in a relatively short period of time

Pandemic

A disease has a worldwide occurence or involves at lwast 3 regiosn in the world.

Acute disease

One that develops rapidly but lasts for only a shot period of time

Chronic disease

The disease develops more slowly and occurs for long periods of time.

Latent disease

The causatuve organism remains inactive for a time but can become active again and produce symptoms of the disease.

Localized infection

The incading organisms are limited to a relatively small area of the body.

Systematic or generalized infection

The causatuve organisms or their products are spread rhroughout the body through blood or lymph.

Focal infections

The causatuve agents of a localized infection may enter a blood or lymphatic vessel, spread to specific parts of the body and become confined to specific areas

Primary infection

Acute infection that causes initial illness

Secondary infection

Caused by opportunistic pathogens after the primary infection has weakend the body’s defenses.

Subclinical or inapparent infection

One taht does not cuase noticeable illness.

Incubation period

The time interval between the entry of teh offending agent and tge appearance of tge initial signs and symptoms of the disease.

Prodromal period

A relatively short period, is characterized by early, mild symptoms of disease which are generally nonspecific

Period of illness

Corresponds to the period of maximal invasion and where the disease is most acute

Period of illness

The patient manifests signs and symptoms distinctive of the disease.

Period of decline or defervescence

The signs and symptoms of the patient start to subside.

Period of decline or defervescence

The patient becomes vulnerable to secondary infections

Period of convalescence

Marked by recovery of the patient from the disease.