wildlife and zoo assay data sheet
Test code: B0065
- Ultrasensitive qualitative detection of
Yersinia pestis, the
etiologic agent of plague, by real time polymerase chain
Yersinia pestis is a gram-negative rod-shaped bacterium belonging to the
family Enterobacteriaceae. Formerly called
Pasteurella pestis, it
is a facultative anaerobe that can infect humans and other
animals. Stained, it has a “safety pin” appearance.
main forms of infection can occur in humans, referred to as
pneumonic plague, septicemic plague and bubonic plague. All
three forms have caused high mortality rates in epidemics
throughout human history, including the Black Death (the bubonic
form) that accounted for the death of at least one-third of the
European population in 1347 to 1353.
Rodents are a common reservoir of these bacteria; their fleas
help disseminate the disease. When humans or other animals live
in close proximity to infected rodents, the bacteria can be
transmitted via flea bites. Once the bacteria enter the
bloodstream, they migrate to the lymph nodes. The ability of
Yersinia pestis to inhibit phagocytosis allows it to avoid
destruction by immune system cells such as macrophages and
thereby to proliferate in lymph nodes, causing lymphadenopathy.
America, fleas infected with
Yersinia pestis have
been found on wild rodents and other animal species from the
Pacific Coast to the Great Plains, and from southwestern Canada
to Mexico. Most human cases in the United States occur in two
regions: 1) northern New Mexico, northern Arizona, and southern
Colorado; and 2) California, southern Oregon, and far western
Nevada (Adjemian et al., 2007)
and dogs in endemic areas can easily be infected with these
bacteria if exposed to infected rodents. Dogs are generally
resistant to plague. Although they may become infected, they
usually develop very mild symptoms, such as swollen lymph nodes,
and they can become carriers of the bacteria. Wild and domestic
cats can become infected and develop any of the three forms of
the disease (bubonic, septicemic or pneumonic). About 50% of
cats infected with Y. pestis will die soon after developing the disease.
Airborne transmission results in pneumonic plague, whereas
patients infected by the bubonic or septicemic forms seldom
exhibit pneumonic characteristics. After an incubation period,
patients with pneumonic plague show sudden onset of coughing,
high temperature, and lack of energy; these symptoms increase in
severity over time.
form, Y. pestis can be
transmitted person-to-person or cat-to-person through aerosols
from coughing (Gage et al., 2000). Due to its high replication rates, plague proves
fatal in roughly 50% of cases even with medical treatment, and
is almost universally fatal without treatment.
Traditionally, the "gold standard" for testing fleas for Y.
pestis infection has been the inoculation of mice with
ground flea suspensions. Inoculated mice are monitored for
death, which usually takes at least 21 days; tissues from these
dead mice are then tested by fluorescent antibody
analysis for evidence of Y. pestis infection. This
testing approach, however, requires considerable time and
personnel involvement. False negative results can
occur when death is used as the assay endpoint, because
some mice occasionally survive the infection. Molecular
detection is a rapid, sensitive, specific and safer alternative
for identification of Y.
Help confirm the disease causing agent
Shorten the time required to confirm a clinical
diagnosis of Yersinia
Help ensure that animals and facilities are free of
Early prevention of spread of
Minimize human exposure to
Safety monitoring of biological products that derive
from susceptible animals
References:Gage, K.L., Dennis, D.T., Orloski, K.A.,
Ettestad, P., Brown, T.L., Reynolds, P.J., Pape, W.J., Fritz,
C.L., Carter, L.G.., and Stein, J.D. (2000) Cases of human
plague associated with exposure to infected domestic cats. Clin.
Infect. Dis. 30:893-900.
Adjemian, J.C., Foley, P., Gage, K.L. and Foley, J.E. (2007)
Initiation and spread of traveling waves of plague,
Yersinia pestis, in
the western United States. Am J Trop Med Hyg. 76:365-375.
Engelthaler, D.M., Gage, K.L., Montenieri, J.A., Chu, M. and
Carter, L.G. (1999) PCR
Detection of Yersinia
pestis in fleas: Comparison with mouse inoculation. J. Clin.
Specimen requirements: 0.2 ml whole blood in EDTA (purple top) or ACD (yellow top)
tube, or nasal swab, or skin swab, or lesion swab.
For specimen types other than those listed here, please call to
confirm specimen acceptability and shipping instructions.
specimen types, if there will be a delay in shipping, or during
very warm weather, refrigerate specimens until shipped and ship
with a cold pack unless more stringent shipping requirements are
specified. Frozen specimens should be shipped so as to remain
frozen in transit. See shipping
instructions for more information.
2 business days
polymerase chain reaction