primate assay data sheet
Dengue
Test code:
S0060 -
Ultrasensitive qualitative detection of Dengue virus by
reverse transcription coupled real time polymerase chain
reaction. Assay detects but does not differentiate common
strains of Dengue virus types 1, 2, 3 and 4.
Dengue
viruses belong to the family Flaviviridae which contains close
to 70 different viruses. These include viruses causing yellow
fever and several encephalitides, such as Japanese encephalitis
and tick-borne encephalitis. There are four distinct serotypes
of Dengue virus that are all mosquito-borne (Gubler, 1998;
Halstead, 1997). Each of the four Dengue virus serotypes can
produce a wide spectrum of disease severity. The Dengue fever
(DF) is the most common, and occurs more frequently among older
children and adults. DF is self-limiting and is characterized by
a sudden onset of nonspecific indicators such as headache,
myalgia, arthralgia and rashes. DF can range in severity from a
minor infirmity to a temporarily incapacitating syndrome with
residual fatigue and depression.
At the
extreme of Dengue virus infection is the Dengue hemorrhagic
fever (DHF), which primarily affects children under the age of
10 years. The clinical symptoms of DHF include plasma leakage, a
bleeding tendency, and liver involvement, which may lead to
potentially life-threatening syndromes including disseminated
intravascular coagulation and Dengue shock syndrome. There are
no vaccines for Dengue, and treatment is limited to supportive
therapies. It is estimated that 50-100 million people suffer
from Dengue fever annually and hundreds of thousands of cases of
Dengue hemorrhagic fever occur in the tropics every year (Gubler,
1998; Halstead, 1997).
Primates
such as chimpanzees can be experimentally infected by Dengue
viruses followed by viremia but they do not show clinical
symptoms (Scherer et al., 1978). They become carriers and
facilitate transmission of the virus. Serological studies have
shown widespread exposure of wild monkeys to this virus (Furumizo
and Rudnick, 1979; Wolfe et al., 2001). Thus, laboratory
personnel involved in handling monkeys are highly susceptible to
infection by this virus.
The virus
contains a positive RNA genomic strand approximately 11 kb in
length. Studies of evolutionary relationships between the four
serologically distinct Dengue viruses have shown that each
serotype can further be subdivided into several major genotypes
or monophyletic groups. For example, five genotypes or
monophyletic groups have been described for Dengue 1 virus.
Dengue virus
infections can be confirmed by serological testing or virus
isolation by culture in insect cells or mosquito inoculation,
but these methods are time consuming, labor intensive and have
limited sensitivity for detecting low levels of the virus. For
serological determination of Dengue viral infection, a
definitive diagnosis requires testing of acute- and
convalescent-phase samples, usually collected at least 7 days
apart, to demonstrate a fourfold or greater increase in antibody
titer. This time lapse delays the assignment of the correct
treatment regimen. PCR detection of Dengue virus is not only
quick (usually less than 2 days) but is also sensitive and
specific.
Utilities:
-
Help confirm the disease causing agent
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Help ensure that animal colonies are free of Dengue virus
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Early prevention of spread of the virus among a colony
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Minimize personnel exposure to the virus
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Safety monitoring of biological products and vaccines
that derive from primates
References:
Furumizo, R.T. and Rudnick, A. (1979) Laboratory observations on
the life history of two species of the Aedes (Finlaya) niveus
subgroup (Diptera: Culicidae) in Malaysia. J Med Entomol 15:
573-575.
Gubler, D.J. (1998) Dengue and dengue hemorrhagic
fever. Clin. Microbiol. Rev. 11: 480-496.
Halstead, S.B.
(1997) Epidemiology of dengue and dengue hemorrhagic fever, p.
23-44. In D. J. Gubler and G. Kuno (ed.) Dengue and dengue
hemorrhagic fever. CAB International, Wallingford, United
Kingdom.
Scherer, W.F., Russell, P.K., Rosen, L., Casals, J.
and Dickerman RW (1978) Experimental infection of chimpanzees
with dengue viruses. Am J Trop Med Hyg 27: 594-599.
Wolfe,
N.D., Kilbourn, A.M., Karesh, W.B., Rahman, H.A., Bosi, E.J.,
Cropp, B.C., Andau, M., Spielman, A. and Gubler, D.J. (2001)
Sylvatic transmission of arboviruses among Bornean orangutans.
Am. J. Trop. Med. Hyg. 64:310-6.
Specimen requirements: 0.2 ml whole blood in EDTA (purple top) tube, or 0.2 ml plasma or serum.
Contact Zoologix if advice is needed to determine an appropriate specimen type for a specific diagnostic application. For specimen types not listed here, please contact Zoologix 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 information.
Turnaround time:
2 business days
Methodology:
Qualitative reverse transcription coupled real time PCR
Normal range:
Nondetected