micro
Implantation and success replication of an organism in
the tissue of the host resulting to signs and symptoms as well
as immunologic response.
infection
An individual who harbors the organism and is capable
of transmitting it to a susceptible host without showing
manifestations of the disease.
carrier
It is an illness caused by an infectious agent or its toxic products
that are transmitted directly or indirectly to a well person
through an agency, and a vector or an inanimate
communicabla disease
It is any person or animal who is in close
association with an infected person, animal or
freshly soiled materials.
contact
It is a term given to a disease that is easily
transmitted from one person to another through
direct or indirect means.
contagious disease
It is a place where an organism lives or where
an organism is usually found.
habitat
It is a person, animal or plant on which a
parasite depends for its survival.
host
It is transmitted not only by ordinary contact
but requires direct inoculation of the organism
through a break on the skin or mucous membrane.
infectious disease
it is the separation from other persons of an individual
suffering from a communicable disease.
isolation
It is the limitation of freedom of movement of persons or
animals which have been exposed to communicable disease/s for a period of time equivalent to the longest incubation period of that disease.
quarantine
It is composed of one of more species of animal or plant in
which an infectious agent lives and multiplies for survival and
reproduces itself in such a manner that it can be transmitted to
reservoir
It is study of occurrences and disturbance of diseases as well as the distribution and determinants of health states of events in specified population and application of this study to the control of health problems.
epidemiology
Consists of three components - host, environment and agent.
epidemiologic triangle
Any organism that harbors and provides nourishment for another organism
host
Intrinsic property of microorganism to survive and multiply in the environment to produce disease.
agent
It is the sum total of all external conditions and influences that affect the development of an organism which can be:
Biological
Social
Physical
environment
• Intermittent occurrence of a few isolated and unrelated cases in a
given locality.
• Cases are few and scattered
• e.g., Rabies
sporadic
• Continuous occurrence throughout a period of time, of the usual number
of case in a given locality.
• The disease is therefore always occurring in the locality and the level
of occurrence is more or less constant through a period of time.
• Examples：
• Schistosomiasis (Leyte & Samar) • Filariasis (Sorsogon) • Malaria
(Palawan)
endemic
Unusually large number of cases in a relatively
short period of tim
epidemic (outbreak)
The simultaneous occurrence of epidemic of the same disease in several countries.
• E.G. HIV/AIDS and SARS
pandemic
• Any microbe capable of producing a disease
• Bacteria, spirochete, virus, ricketssia, chlamydiae,
fungi, protozoa and parasites
causative agent
• Refers to the environment and objects on which an
organism resides, survives and multiplies
• Animal Reservoirs (animal to human-zoonotic)
• Human Reservoirs (Carriers)
• Environmental Reservoirs (water, soil & plants)
reservoir of infection
It is the path or way in which the organism leaves the
reservoir.
Common portals of exit:
• Respiratory System (MC)
• Genitourinary Tract
• Gastrointestinal Tract
• Skin and Mucous Membrane
• Placenta
portal of exit
It is the means by which the infectious agent passes
through from the portal of exit of the reservoir to the
susceptible host.
mode of transmission
Easiest link to break the chain of infection
Vertical Transmission
Horizontal
Most common mode of transmission.
contact transmission
Refers to a person to person transfer of
organism.
direct contact
Occurs when the susceptible person comes in
contact with a contaminated object.
indirect contact
It is the transmission through contact with
respiratory secretions when the infected person
coughs, sneezes or talks.
droplet spread
Occurs when fine microbial particles or dust particles
containing microbes remain suspended in the air for a
prolonged period.
airborne transmission
It is the transmission of infectious disease through
articles or substance that harbor the organism until it is
ingested or inoculated into the host.
vehicle transmission
Occurs when intermediate carriers, such as fleas, flies
and mosquitoes transfer the microbes to another living
organism.
vector-borne transmission