Infectious bacterial disease
Sylvatic plague
is an infectious
bacterial
disease caused by the
plague
bacterium
(
Yersinia pestis
) that primarily affects
rodents
, such as
prairie dogs
. It is the same bacterium that causes
bubonic
and
pneumonic plague
in humans. Sylvatic, or sylvan, means 'occurring in woodland,' and refers specifically to the form of plague in rural wildlife.
Urban plague
refers to the form in urban wildlife.
It is primarily transmitted among wildlife through
flea
bites and contact with infected tissue or fluids.
Sylvatic
plague is most commonly found in prairie dog colonies and some
mustelids
, like the
black-footed ferret
.
[1]
[2]
Transmission vector
[
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]
The flea that feeds on prairie dogs and other mammals serves as the vector for transmission of sylvatic plague to the new host, primarily through flea bites, or contact with contaminated fluids or tissue, through predation or scavenging. Humans can contract plague from wildlife through flea bites and handling
animal carcasses
.
[1]
Epidemiology and distribution
[
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]
Yersinia pestis
circulates in rodent reservoirs on all continents except Australia. Sylvatic plague affects over 50 species of rodents worldwide. It is vectored by a variety of flea species. Non-rodent animals susceptible to the disease include
shrews
,
lagomorphs
,
ferrets
,
badgers
,
skunks
,
weasels
,
coyotes
,
domestic dogs
and
cats
,
bobcats
,
cougars
,
camels
,
goats
,
sheep
,
pigs
,
deer
, and
primates
, including
humans
.
Birds
are not known to be susceptible.
[3]
Sylvatic plague is normally
enzootic
, meaning it occurs at regular, predictable rates in populations and specific areas. At unpredictable times, it becomes
epizootic
in unexpected places. It is during these epizootic outbreaks that transmission to humans is most common.
Factors that predispose to epizootic cycles include dense populations of rodents, multiple species of rodents in a particular area, and multiple rodent species in diverse habitats.
[4]
Prairie dog colonies reach nearly 100% mortality rates during outbreaks. Prairie dogs are a
keystone species
and play a vital role as the primary prey of black-footed ferrets. Developing methods to control plague is of high concern for preserving ferrets and the conservation of Western prairie and grassland ecosystems.
[1]
Wildlife disease control and prevention
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]
In the absence of understanding the prairie dog/plague cycles, dusting rodent dens with
pesticides
to kill fleas is currently the main method of controlling sylvatic plague in the wild, with some interest in using vaccines developing.
[5]
An oral live vaccine for prairie dogs was developed by the U.S. Geological Survey, National Wildlife Health Center, from a recombinant raccoon poxvirus expressing plague antigens. It was originally developed by a Fort Detrick company in 2003 which showed it protected mice against lethal plague.
[6]
See also
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]
References
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]
External links
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]