Sep 6, 2020
Rickettsia characteristics
include parasitic behaviors but they are not worms or protozoa.
Rather, they are bacteria and are therefore prokaryotes. The
rickettsia family consists of obligatory intracellular bacteria
that are transmitted by arthropod vectors. In other words, they
need to be inside living cells to stay alive.
Dr. Walker explains to listeners
David H. Walker, MD, is a
professor in the Department of Pathology and is the Carmage and
Martha Walls Distinguished University Chair in Tropical Diseases
and Executive Director of the University of Texas MB Center for
Biodefense and Emerging Infectious Disease.
He describes various rickettsia causes and symptoms, from
the Orientia
tsutsugamushi bacteria
transmitted by chiggers to others transmitted by lice and
ticks. He explains the means by which scientists determined
their inability to live outside of cells and how they are able to
observe their invasion and infection with light
microscopy.
Their pathogenic effect is
widespread, and Dr. Walker describes their effects on World War II
and the Vietnam War through the lice vector and typhus spread.
Rickettsia symptoms and attacks on the
immune system vary greatly and he describes several examples in
the two main groups of typhus and spotted fever rickettsia. For
example, Rocky Mountain spotted fever bacteria are secreted from
the saliva of the tick when it bites.
The bacteria is then taken into the skin through phagocytic cells,
spreads to the lymphatic cells, and drains into the blood stream
and infects the endothelium cells all over the body. Dr.
Walker has worked with rickettsia for 47 years and his particular
focus now is on vaccine research and effective rickettsia
treatment.
For more, see his web page at
the University of Texas Medical Branch,
utmb.edu/pathology/faculty-directory/david-h-walker-md,
and search his name in research systems for publications.
Available on Apple Podcasts: apple.co/2Os0myK