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0:00
My name is Lane Foil.
I'm a Professor of
Entomology at Louisiana State
University in Baton
Rouge, Louisiana.
And the subject of my lecture
is mechanical transmission
of disease agents by arthropods.
0:18
The basic difference between
biological transmission
and mechanical transmission is
that in biological transmission,
the agent develops and/or
propagates within the vector,
while in mechanical transmission,
the simple transfer of agents
from one infected host or
a contaminated substrate
to a susceptible host occurs.
I've broken the lecture
down into two basic types
of mechanical
transmission, one being
direct mechanical transmission--
that is when agents are transferred
directly between two
hosts-- or indirect,
or contaminative
mechanical transmission,
and that is when arthropods
transmit pathogens
picked up from contaminated sources.
1:03
As far back as 1800s,
mechanical transmission studies
were conducted when associations of
arthropods and disease were made.
But even when experimental
evidence is obtained,
vehicles of mechanical transmission
other than arthropods often exist.
For example, if feces is
a source of the pathogen,
and the fly is the vector,
the fecal oral route
should be considered, plus
food handlers, or farm workers.
If a purulent lesion is
the source of the pathogen
and a fly is a
vector, direct contact
may also be a mechanism
of transfer of the agent.
If blood is the source,
and the fly is the vector,
multiple use needles
should be considered.
Thus, the relative importance of
mechanical transmission of agents
by arthropods in epidemiology
is often situational.
