SPREAD OF D

ISEASE

SOURCES OF INFECTIOUS DISEASES• The source of a disease is known

as a reservoir. • A reservoir can be anything:

inanimate object, person, animal, plant, etc.

• The reservoir of a disease is not necessarily affected by the disease

CARRIERThe most important type of reservoir in human disease is known as a carrier.

A carrier is a person who carries (is infected by) a communicable disease

A carrier of a disease may not have symptoms

ANIMAL RESERVOIR - FYIA zoonosis is a communicable disease which is transmitted from a non-human animal to a human.

Here the non-human animal is the reservoir.About 150 zoonotic human disease are known.Examples: anthrax, bubonic plague, cat-scratch fever, influenza, Lyme disease, malaria, pneumonic plague, psittacosis, rabies, ringworm, Rocky Mountain spotted fever, tapeworm, toxoplasmosis, typhus fever, western equine encephalitis, yellow fever.

ENDOGENOUS INFECTION - FYIAn endogenous infection is one which is

caused by an opportunistic pathogen from an individual's own normal microbiota.

Typically this is a consequence either of the individual being in a weakened state, or in the opportunist being deposited in a location other than that in which it typically benignly resides.

TRANSMISSION OF DISEASE

There are three main ways in which diseases are transmitted

• Contact• Vehicle• Vector

CONTACT

• Diseases can be spread by direct contact (person to person), indirect contact (doorknob), or by droplets (released into the air when sneezing)

VEHICLE• A vehicle is something that is

taken into the body as part of living (food, water, air)

• When contaminated, these things can cause disease

VECTOR

• Vectors are organisms that transmit infections from one host to another

• They are usually insects

DISEASE CLASSIFICATION

• Endemic• Common Source Outbreak• Epidemic• Pandemic

ENDEMIC DISEASE - FYI

• An endemic disease is one that is always present in a population

COMMON SOURCE OUTBREAK

• Some diseases arise from a single definable source, such as a common water supply.

EPIDEMIC

• An epidemic disease is a disease that many people acquire over a short period

PANDEMIC

• A pandemic disease is a world-wide epidemic disease

PRIMARY SOURCEhttp://www.mansfield.ohio-state.edu/~sabedon/biol2050.htm