West Nile virus PCR test for dogs and cats
dog and cat assay data sheet
S0048 - Ultrasensitive qualitative detection of West Nile virus by
reverse transcription coupled real time polymerase chain reaction
West Nile virus
(WNV) belongs to the genus Flavivirus of the family Flaviviridae and
is an arthropod-borne virus. It possesses a single-stranded plus-sense
RNA genome of approximately 11,000 nucleotides. It circulates in
natural transmission cycles involving primarily Culex species
mosquitoes and birds; humans and other mammals, such as primates, are
thought to be incidental hosts.
was found primarily in Africa, Asia, southern Europe, and Australia
and was responsible for several significant epidemics, notably, in
Israel (1950s), France (1962), South Africa (1974), and Romania (1996)
(Hayes, 1989; Tsai et al., 1998;Savage et al., 1999). In 1999 and
2000, WNV was responsible for epidemics and epizootics in the
northeastern United States, in which there were human fatalities and
extensive avian mortality (Anderson et al., 1999; Lanciotta et al.,
1999). On the basis of retrospective serosurveys conducted in New York
City in 1999 and 2000, symptomatic illness develops in approximately
20% of persons infected with WNV and approximately 1 in 150 human
infections results in meningoencephalitis, the most commonly reported
form of WNV-associated illness.
In 2002, an
outbreak of West Nile virus infection occurred in the state of
Louisiana in which 319 human cases of WNV-associated illness were
reported. Most of these cases happened in the southeastern portion of
the state, including St. Tammany Parish. The Tulane National Primate
Research Center (TNPRC) is located in St. Tammany Parish and houses
large outdoor breeding colonies of baboons and macaques. A serological
survey of primates in these breeding colonies indicated that
approximately 36% of the nonhuman primates were infected with WNV
during the 2002 transmission season (Ratterree et al., 2003).
Implications of this study are that nonhuman primates can be as
susceptible to West Nile virus infection as humans, and captive
primate populations can be a potential source of viral carriers.
Surveillance for West Nile virus relies on the testing of
field-collected mosquitoes and on the testing of dead birds for the
presence of virus by isolation in cell culture. However, virus
isolation followed by identification through immunofluorescence assays
can take over a week to complete. In addition, virus isolation in cell
culture from CSF or serum has generally been unsuccessful, likely due
to the low level and short-lived viremia associated with infections
with these viruses (Monath and Heinz, 1996; Southam and Moore, 1954).
infections can be inferred by immunoglobulin M (IgM) capture and IgG
enzyme-linked immunosorbent assays (ELISAs); however, confirmation of
the type of infecting virus is possible only by detection of a
fourfold or greater rise in virus-specific neutralizing antibody
titers in either cerebrospinal fluid (CSF) or serum by performing the
plaque reduction neutralization assay (PRNT) with several flaviviruses
(Johnson et al., 2000; Martin et al., 2000). Thus serological
detection of WNV infection is neither specific nor sensitive. PCR detection of
West Nile virus is now considered to be a rapid, specific and
sensitive detection method to identify this virus.
Help confirm the disease causing agent
Help ensure that animal groups and populations are free of
West Nile Virus
Early prevention of spread of the virus among a
Minimize human exposure to the virus
Anderson, J. F., Andreadis, T.G., Vossbrinck, C.R., Tirrell, S.,Wakem,
E.M., French, R.A., Garmendia, A.E. and Van Kruiningen, H.J. (1999)
Isolation of West Nile virus from mosquitoes, crows, and a Cooper's
hawk in Connecticut. Science 286:2331-2333.
Hayes, C. G. (1989).
West Nile fever, p. 59-88. In T. P. Monath (ed.), The arboviruses:
epidemiology and ecology, vol. V. CRC Press, Inc., Boca Raton, Fla.
Johnson, A. J., Martin, D.A., Karabatsos, N. and Roehrig,
J.T.(2000) Detection of antiarboviral immunoglobulin G by using a
monoclonal antibody-based capture enzyme-linked immunosorbent assay.
J. Clin. Microbiol. 38:1827-1831.
Lanciotti, R. S., Roehrig, J.T.,
Deubel, V., Smith, J., Parker, M., Steele, K., Volpe, K.E., Crabtree,
M.B., Scherret, J.H., Hall, R.A., MacKenzie, J.S., Cropp, C.B.,
Panigrahy, B., Ostlund, E., Schmitt, B., Malkinson, M., Banet, C.,
Weissman, J., Komar, N., Savage, H.M., Stone, W., McNamara, T. and
Gubler, D.J.(1999) Origin of the West Nile virus responsible for an
outbreak of encephalitis in the northeastern U.S. Science
Martin, D. A., Muth, D.A., Brown, T., Johnson, A.J.,
Karabatsos, N. and Roehrig, J.T. (2000) Standardization of
immunoglobulin M capture enzyme-linked immunosorbent assays for
routine diagnosis of arboviral infections. J. Clin. Microbiol.
Monath, T. P., and Heinz, F.X. (1996) Flaviviruses,
p. 978-984. In B. N. Fields (ed.), Fields virology, 3rd ed., vol. 1.
Lippincott-Raven Publishers, Philadelphia, Pa.
Ratterree, M.S., da
Rosa, A.P., Bohm, R.P. Jr, Cogswell, F.B., Phillippi, K.M., Caillouet,
K., Schwanberger, S., Shope, R.E. and Tesh, R.B.(2003) West Nile virus
infection in nonhuman primate breeding colony, concurrent with human
epidemic, southern Louisiana. Emerg Infect Dis. 9:1388-1394.
Southam, C. M., and Moore, A.E. (1954) Induced virus infections in man
by the Egypt isolates of West Nile virus. Am. J. Trop. Med. Hyg.
Savage, H. M., Ceianu, C., Nicolescu, G., Karabatsos,
N.,Lanciotti, R., Vladimirescu, A., Laiv, L., Ungureanu, A., Romanca,
C. and Tsai, T.F. (1999). Entomologic and avian investigations of an
epidemic of West Nile fever in Romania, 1996, with serological and
molecular characterization of a virus from mosquitoes. Am. J. Trop.
Med. Hyg. 61:600-611.
Tsai, T. F., Popovici, F., Cernescu, C.,
Campbell, G.L. and Nedelcu, N.I. (1998) West Nile encephalitis
epidemic in southeastern Romania. Lancet 352:767-771.
specimens: 0.2 ml CSF, or 0.2 ml fresh or frozen CNS tissue.
preferred specimens: 0.2 ml whole blood in EDTA (purple top) or ACD (yellow top) tube, or 0.2 ml serum or plasma.
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
2 business days
Qualitative reverse transcription coupled real time PCR