many skilled clinicians deem the clinical signs associated with Canine
Parvovirus infection as being nearly pathognomonic, precise diagnostic
are required in order to differentiate Parvovirus infection from other
diseases with a similar presentation. One
thing to keep in mind with each of the tests, however, is that each
test possesses its own unique limitations, and are not always
guarenteed to yield an accurate diagnosis. In every scenario, a
fecal sample is obtained from the animal suspected of being infected,
and is assayed in order to determine if infection is present. The
methods of detection and diagnosing are:
Canine Parvovirus Fecal
Snap Test is a popular choice among many practicing veterinarians due
fact that the test is rapid and can be performed in-clinic.
limitation of this method of testing is that large amounts of viral
required from the patient in order to generate a true positive result
test¹. False negative results are
in animals that are not shedding large amounts of the virus, however,
peak of clinical signs for parvovirus infection, sufficient amounts of
antigen are being shed to yield a clear result on the test1.
Sensitivity is 100% and specificity is 99.9%2.
Real-Time Polymerase Chain
and real-time PCR are the most sensitive techniques for demonstrating
presence of parvoviral DNA. These
techniques utilize specific primers and enzymes to catalyze the
the Parvovirus genome from low to high concentrations.
The DNA product can then be analyzed by
agarose gel electrophoresis to confirm that the patient is infected
PCR (RT-PCR) differs from conventional PCR in that RT-PCR is more
specific, more reproducible, and allows the detection and
quantification of the
Parvoviral genome within a few hours1.
limitation of conventional and real-time PCR is that it is confined to
specialized laboratories with the necessary equipment.
In addition, because the PCR can amplify very
low levels of DNA, strict protocols are necessary in order to ensure
positive results are avoided1.
capable, however, of detecting the disease prior to the actual onset of
clinical signs, and days before a positive result would be registered
IDEXX immunochromatography assay3. It
therefore a powerful tool in determining if a patient suffers from
before the onset of clinical signs. In
addition to this, by employing specific techniques, PCR can yield the
parvoviral serotype that an animal is afflicted with1.
Although this is not useful in the clinical
treatment of the disease, it may affect the prognosis for the patient,
as be important for research and epidemiological purposes.
Antibody Sandwich (DAS) ELISA
DAS-ELISA employs monoclonal antibodies against a specific antigen of
Primary antibodies trap the
viral molecules while secondary antibodies conjugated to an enzyme
allowing quantification, "sandwich" the viral particles.
technique can allow quantification of the viral particles, while being
sensitive and specific for Parvovirus.
The technique is relatively easy to perform, and can be adapted
rapid processing of a large number of samples, which makes it
analyzing large groups of animals5.
technique, however, is also limited to a laboratory setting, and is not
practical in a clinical setting, without the necessary laboratory
technique is also limited to laboratory settings due to the need for
specialized equipment. It involves
obtaining the supernatant from fecal homogenates of suspected
inoculating it into specific cell types.
Following an incubation period, the cells are transferred to
slides and were treated with immunofluorescent (IF) antibodies against
Parvovirus. Cells affected by Parvovirus
will possess a characteristic fluorescent colour, indicating that the
parvovirus suspect is positive1.
this technique is highly accurate at diagnosing the disease, its main
limitation is the time until a definitive diagnosis can be made. Virus isolation and IF microscopy can take up
to a week to complete, which can significantly reduce a
treatment is delayed until the test result is obtained.
This technique utilizes a
property of parvoviruses when placed in solution with red blood
cells. The viral particles bind to molecules on the
surface of red blood cells, preventing the
cells from settling out of suspension 6. A sample
from an animal
being affected with parvovirus is repeatedly diluted 1:2
with PBS. This solution is mixed with erythrocytes, and after a 4
hour incubation at 4°C, the erythrocyte-viral mixtures are
examined 1. At dilutions in which agglutination of
is prevented by the presence of parvovirus, the red blood cells remain
in solution (wells 1, 2, and 3 in the accompanying figure). If
the viral concentration is
too low to prevent hemagglutination, a small disc of red blood cells
will form (wells 4 through 10 in the accompanying figure).
The method of testing is
relatively inexpensive, is rapid to perform, and results are easy to
interpret. By running a standardized dilution of a known
concentration of virus, and comparing the results of all of the
patient's tested to the standard, an approximate viral titre can be
determined. The main limitation of the test is that the method of
quantification is not accurate, and a positive result is not
necessarily indicative of Parvovirus. Several viral species can
cause hemagglutination. This assay, in combination with the
appropriate clinical signs, is only indicative of Canine Parvovirus.
1 Desario C, Decaro N, Campolo M, Cavalli
A, Cirone F,
Elia G, Martella V, Lorusso E, Camero M, Buonavoglia C. Canine
parvovirus infection: Which diagnostic
virus? Journal of
Methods. 2005. 126:
2 IDEXX Laboratories Inc.
Online Manual –
3 Ozkul A, Keles I, Karaogw T, Sabalar M,
I. Detection and RFLP Analysis of canine parvovirus (CPV) DNA by
chain reaction (PCR) in a dog. Turkey
Journal of Veterinary Animal
Science. 2002. 26:1201-1203.
4 Rimmelzwaan G, Juntti N, Klingeborn B,
UytdeHaag F, Osterhaus A. Evaluation of ELISAs based on
antibodies for the serology and antigen detection
in canine parvovirus
infection. Veterinary Quarterly. 1990.
5 De Iba ez R, Cortes E, Simarro I, Vela C,
Casal I. Development of new methods of
parvovirus detection : ELISA DAS and immunocromatography one step.
Medicina Veterinaria. 1996.
6 Sanna A, Fadda G, Turano A. Viral hemagglutinins and viral
hemagglutination. L’igiene Moderna. 1967. 60(3):159-219.