MODE OF TRANSFER
The mode of transfer (or mode of transmission) refers to how the disease
organisms are transported to the healthy person. The mode of transfer is closely
associated with the mode of escape. Disease organisms that escape through the
respiratory track, for example, may be carried by tiny droplets that are exhaled when the
person coughs, sneezes, talks, or just breathes normally. The disease rabies may be
transmitted by saliva from the mouth of a diseased animal or person.
a. Direct Contact. A communicable disease can be transmitted by the healthy
person coming into physical contact with the infected person. This type of transmittal
(transfer) is referred to as direct contact. Venereal diseases are spread through direct
contact. Another example of direct contact is a disease organism present in a patient's
open wound being transferred to a healthy person when that person touches the wound
with his fingers.
b. Indirect Contact. Communicable diseases can also be transmitted even if
there is no direct physical contact between the infected person and the healthy person.
In this method of transmittal, called indirect contact, something carries the disease
organism from the diseased person to the healthy person.
(1) Airborne transfer. A common example of indirect contact concerns cold
viruses. When the infected person sneezes, tiny droplets containing cold viruses are
expelled into the air. These droplets will float on the air for a considerable time. If a
healthy person breathes in these droplets, he will become infected.
transmitted by food contamination is typhoid. The typhoid organism on a person's hand
will contaminate the food that` the person touches. When another person eats the
contaminated food, that person becomes infected.
(3) Insects. Some disease organisms are transmitted by insects. Malaria,
for example, is a disease transmitted by a certain type of mosquito. When this type of
mosquito "bites" a person infected with malaria, the insect may take in disease
organisms along with the person's blood. When the mosquito bites another person,
some of these disease organisms may escape into the bite wound and infect that
(4) Fomites. Fomites are objects that can carry disease organisms.
Examples of fomites include surgical instruments, bed linen, eating utensils, drinking
glasses, towels, and hairbrushes. When an object comes into contact with an infected
person, some of the disease organisms may be left on the object. If another person
uses the object before it is properly cleaned, the disease organisms may enter his body.