detection of Toxoplasma
gondii by real time polymerase chain reaction
included in P0017
- equine protozoal myeloencephalitis panel and in
P0014 - equine neurological panel.
by Toxoplasma gondii
are prevalent in many species of domestic and wild animals (Dubey,
1993). Although chronic infection of this obligate parasite is
usually asymptomatic, T. gondii has emerged as a major opportunistic pathogen in
the immunocompromised, such as AIDS patients. Surprisingly,
spontaneous cases of fulminating fatal toxoplasmosis have been
reported in adult squirrel monkeys (Saimiri
sciureus) which are immunologically normal (Inoue,
1997). While the disease mechanism of this fatal toxoplasmosis
in squirrel monkeys is not clear, infections of nonhuman
primates with this parasite are common, and it has been shown
that New World monkeys are more susceptible to
T. gondii infection
than Old World monkeys (Ruch, 1959). The outbreak of fatal
toxoplasmosis (Cunningham, et al., 1992) is a major concern in
caring for these primate colonies, as a recent study has
indicated the possibility of horizontal transmission through the
respiratory route (Furuta, et al., 2001) in addition to the
standard” for the detection of
T. gondii in
clinical specimens is mouse inoculation and detection of
T. gondii specific
antibodies. This method is sensitive and specific but very
time-consuming, taking up to six weeks to obtain a diagnosis.
Cell culture detection of this parasite is also slow, and lacks
sensitivity. PCR detection of this parasite has been found to be
a sensitive, specific and rapid method for the detection of
T. gondii DNA in a
wide spectrum of samples, such as amniotic fluid (Grover, et
al., 1990), blood (Dupouy-Camet, et al., 1993; Ho-Yen, et al.,
1992), tissue samples (Johnson, et al., 1993) and cerebrospinal
fluid (Cristina, et al., 1993; Farmley, et al., 1992). Although
serology testing can help diagnose recent infection with this
parasite, PCR testing is found to be more sensitive in
identifying acute infection (Hussein, et al., 2002).
Help confirm the disease causing agent
Shorten the time required to confirm a clinical
diagnosis of T. gondii infection
Help ensure that horse populations are free of T. gondii
Early prevention of spread of this parasite
Minimize human exposure to this parasite
Safety monitoring of biological products that derive
Dubey, J.P. (1993) Toxoplasma, Neoplasma, Sarcocystis, and other
tissue cyst-forming coccidian of human and animals. pp1-56. In:
Parasitic protozoa (Kreier, P.J. ed), vol. 6, 2nd ed., Academic
Press, Inc., San Diego, California.
Inoue, M. (1997) Acute
toxoplasmosis in squirrel monkeys. J. Vet. Med. Sci. 59:593-595.
Ruch, T.C. (1959). pp.297-299, 313-318, 423-424. In: Diseases of
laboratory primates. W.B. Saunders Co., Philadelphia.
Cunningham, A.A., Buxton, D. and Thomson, K.M. (1992) An
epidemic of toxoplasmosis in a captive colony of squirrel
monkeys (Saimiri sciureus). J. Comp. Pathol. 107:207-219.
Furuta, T., Une, Y., Omura, M., Matsutani, N., Nomura, Y.,
Kikuchi, T., Hattori, S. and Yoshikawa, Y. (2001) Horizontal
transmission of Toxoplasma gondii in squirrel monkeys (Saimiri
sciureus). Exp. Anim. 50:299-306.
Grover, M.C., Thulliez, P.,
Remington, J.S. and Boothroyd, J.C. (1990) Rapid prenatal
diagnosis of congenital Toxoplasma infection by using polymerase
chain reaction and amniotic fluid. J. Clin. Microbiol.
Dupouy-Camet, J., de Souza, S.L., Maslo, C.,
Paugam, A., Saimot, A.G., Benarous, R., Tourte-Schaefer, C. and
Derouin, F. (1993) Detection of Toxoplasma gondii in venous
blood from AIDS patients by polymerase chain reaction. J. Clin.
Ho-Yen, D.O., Joss, A.W.L., Balflour,
A.H., Smyth, E.T.M., Baird, D. and Chatterton, J.M.W. (1992) Use
of the polymerase chain reaction to detect Toxoplasma gondii in
human blood samples. J. Clin. Pathol. 45:910-913.
J.D., Butcher, P.D., Savva, D. and Holliman, R.E. (1993)
Application of the polymerase chain reaction to the diagnosis of
human toxoplasmosis. J. Infect. 26:147-158.
Pelloux, C., Goulhot, J.P., Brion, P., Leclercq, P. and Ambrosis-Thomas,
P. (1993) Detection of Toxoplasma gondii in AIDS patients by the
polymerase chain reaction. Infection 21:150-153.
S.F., Goebel, F.D. and Remington, J.S. (1992) Detection of
Toxoplasma gondii in cerebrospinal fluid from AIDS patients by
polymerase chain reaction. J. Clin. Microbiol. 30:3000-3002.
Hussein, A.H., Nagaty, I.M. and Fouad, M.A. (2002) Evaluation of
IgM-ELISA versus PCR in diagnosis of recent Toxoplasma gondii
infection. J Egypt Soc Parasitol. 32:639-46.
Specimen requirements: 0.2 ml whole blood in EDTA (purple top) or ACD (yellow top)
tube, or 0.2 ml feces, or 0.2 ml amniotic fluid or CSF, or 0.2 ml fresh, frozen or fixed tissue.
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
Qualitative real time PCR