Rickettsia PCR test
wildlife and zoo assay data sheet
B0056 - Ultrasensitive screen for
by real time polymerase chain reaction. This assay detects but
does not differentiate most common
including the organisms that cause Rocky Mountain spotted fever,
typhus, and most other common rickettsial diseases.
are small, gram-negative, aerobic, coccobacillus bacteria. They are
obligate intracellular organisms. The genus belongs to the family
Rickettsiaceae of the order Rickettsiales and consists of many species
associated with human disease. Pathogenic
Rickettsiae can be divided
into three major groups based on clinical characteristics of disease:
spotted fever group, typhus group and scrub typhus group.
Spotted fever group
The type species of this group
is Rickettsia rickettsii
which causes Rocky Mountain spotted fever (RMSF).
Rickettsia rickettsii is
found in the Americas and is transmitted to humans through the bite of
infected ticks. The bacterium infects human vascular endothelial
cells, producing an inflammatory response.
Other members of this group can also be pathogenic, such as
R. conorii (Mediterranean spotted fever),
R. mongolotimonae (Lymphangitis-associated rickettsiosis) and
R. slovaca (boutonneuse
fever and similar illnesses), R.
akari (rickettsial pox), R.
japonica (Japanese spotted fever),
R. sibirica (North Asian
tick typhus), R. africae
(African tick bite fever), R.
R. australis (Queensland tick typhus) and
R. honei (Flinders Island
Rickettsia prowazekii is a
well-known member of this group and causes epidemic or louse-borne
typhus. It infects human vascular endothelial cells, producing
widespread vasculitis. In contrast to RMSF, louse-borne typhus tends
to occur in the winter. Infection is usually transmitted from person
to person by the body louse and therefore tends to manifest under
conditions of crowding and poor hygiene. The southern flying squirrel
is the animal reservoir in the United States, but what vector is
involved in transmission from the flying squirrel to humans is
unknown. The disease has a worldwide distribution.
Other Rickettsiae in the
typhus group include R. typhi
and R. felis. Murine
typhus is caused by transmission of
R. typhi from rats, cats and
opossums to humans via a flea vector. Murine typhus is found worldwide
and is endemic in areas including Texas and southern California.
R. felis has also been
detected in cat fleas and opossums.
Scrub Typhus Group
tsutsugamushi is a well-known member of this group and causes
scrub typhus. This organism was originally called
and was subsequently given its own genus designation because it is
phylogenetically distinct from the other
Rickettsiae. It is transmitted to humans by the bite of trombiculid
mites (chiggers), which are the vector and host. Scrub typhus occurs
throughout much of Asia and Australia.
Current diagnosis of Rickettsia
infection may be via blood smear microscopy, serological detection or
Polymerase Chain Reaction. However, blood smear microscopy is
insensitive and serological detection may be of limited value since
some people infected with the bacteria may not seroconvert. Also,
current commercially available kits only target a few species of
detection by PCR is therefore a more useful tool for rapid and
sensitive diagnosis of acute infection by most common
Help confirm the disease causing agent
Shorten the time required to confirm a clinical
diagnosis of Rickettsia
Help ensure that animal facilities and populations are free of
Early prevention of the spread of
Rickettsia in animal
facilities and populations
Minimize human exposure to
Unsworth, N., Graves, S., Nguyen, C.,
Kemp, G., Graham, J. and Stenos, J.
(2008) Markers of exposure to spotted fever rickettsiae in
patients with chronic illness, including fatigue, in two Australian
populations. QJM 101: 269-274.
requirement: 0.2 ml whole blood in EDTA (purple top) or ACD (yellow top) tube, or 0.2 ml plasma or serum, or
0.2 ml synovial fluid, or 0.2 ml cerebrospinal fluid, or 0.2 ml
tissue, or tick.
For specimen types
other than those listed here, please call to confirm specimen
acceptability and shipping instructions.
For all 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
2 business days
Qualitative real time