Brown rats, black rats, spotted fever
David Richard Harper
D.R.HARPER at MDS.QMW.AC.UK
Mon Dec 16 11:14:02 EST 1996
K. Weber wrote:
> One explanation for the dwindling of the Bubonic Plague in Britain
> has been that the native black rats were replaced by the European brown
> rat. A friend of mine and I have been batting this around. Does anyone
> know whether we have native black rats or brown rats in America? I assume
> that our domesticated rats are bred from the brown ones. From my
> observations of these, at least some of them eat fleas during grooming.
> It has occured to me that if the brown rat learned to destroy fleas as
> part of grooming and the black rats had never picked up this habit, that
> this might be one reason that these rats were assumed to not transmit the
> plague. Did they get it? When there are outbreaks of plague as happened
> in a high sierra campground in the late sixties (thirty cases), how do the
> host animals (assumed to be squirrels) get the organism. Can it be
> carried in a benign form?
> My sister-in-law got a very virulent infection in southern Utah
> about twelve years ago. In relating the story at church, my mother
> learned that one of her friends had a daughter who was diagnosed with
> spotted fever at the University of Utah. My sister-in-law was treated at
> the federally funded Santa Clara Health Center in St. George, Utah by a
> retired hematologist who was able to respond quickly. He removed her
> We have also been wondering whether it was actually the plague
> which caused the massive die off of rats at the very beginning of the
> plague. Might something else have set up the conditions necessary for the
> development of virulence in the spotted fever organism. Are spotted fever
> and bubonic plague the same thing? Defoe mentions both names in his
> Journal of the Plague Year. The friend at church did not have rocky
> mountain spotted fever unless there is something important I don't know
> about it. Her baby was in a coma six hours after contracting it.
> If you answer this please send me a copy e-mail. I may not be
> able to pick up all my mail from the groups.
Rocky mountain spotted fever is caused by Rickettsia ricketsii, and
intracellular bacterium. Plague is caused by a totally different
organism, Yersinia pestis. Check out:
-for information on both.
More information about the Virology