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Canine Distemper Virus in Raccoons from South Georgia and North Florida
Krista A. Cox, Department of Biology
Faculty Sponsor: Dr. J. Mitchell Lockhart, Department of Biology
ABSTRACT
RESULTS
47/136 (34.6%) of raccoons tested positive for CDV from Pebble Hill
and Pinebloom-East in 2003 (Figure 3). In 2004, 69/229 (30.1%)
samples were positive from Pinebloom-West and Tall Timbers. There
was no significant difference in CDV prevalence between year of
collection (Chi square = 0.58, df=1). A total of 39/116 female raccoons
(33.6%) were positive for CDV in 2003-2004 (Figure 4) while 77/229
males (30.9%) were positive for CDV (30.9%). There was no significant
difference in CDV prevalence between sex of raccoon (Chi square =
0.16, df=1). No statistical analysis was attempted with month of
collection data (Figure 5) or with weight data (Figure 6) as some months
and weight groupings had relatively small samples sizes.
Figure 2. IFA representative results. Left image – negative
control sample, right – positive sample. Note bright fluorescence
within cells in positive sample.
FUTURE RESEARCH
As mentioned above, 2 more years of data will
be collected. We would also like to evaluate
specific age data as well as antibody titer data.
We will also try to incorporate habitat
management as it relates to CDV prevalence.
ACKNOWLEDGEMENTS
Figure 3. Prevalence of CDV Antibodies
In Raccoons, 2003-2004.
50
45
40
35
30
25
20
15
10
5
0
Figure 4. Prevalence of CDV Antibodies in Raccoon
by Sex
Figure 5. Monthly Prevalence of CDV
Antibodies in Raccoons
10
0
Sex
2003
2004
30.1
Figure 6. Percent of Raccoons Infected by
Weight Classification
Total
Month
Weight (pounds)
33.6
Sep
30.9
34.6
25
0.0-3.0
Aug
20
Male
Female
Jul
30
We would like to thank the USDA-WS for trapping animals, all
other Principals associated with the Predator Removal Study,
and the Valdosta State University Faculty Research Fund for
providing funds to complete this project.
REFERENCES
Percent Infected
Jun
40
50
40
30
20
10
0
May
50
Apr
Figure 1. Raccoon diagnosed
with canine distemper virus
It is apparent that Canine Distemper Virus is
present in raccoons of the Red Hills plantation area
of south Georgia and north Florida. Considering
the effect that CDV has on naïve raccoons, it is
surprising that steady prevalence levels were
found between plantations and sexes. Data
presented here represents the first two years of a
four year study and more complex data analysis
will occur upon completion of the study. Specific
age data, utilizing cementum annuli analysis, will
be available in the future and will allow us to group
animals according to specific age rather than by
weight. USDA-WS trappers have noted to the
faculty advisor that they saw “many” deceased
raccoons during the 2003 trapping season, but not
during the 2004 trapping season. This initially
piqued our interest in studying raccoons as we
considered the potential for a rabies epizootic.
Future analysis will include polymerase chain
reaction analysis (PCR) to try to differentiate
exposure from active viremia.
Mar
Canine Distemper Virus (CDV) causes distemper, a significant viral
disease in fur animals, producing mortality and morbidity in unvaccinated
populations (Shin et al., 2004). Closely related to measles virus and
rinderpest virus, two other members of the genus Morbillivirus, CDV is a
devastating, highly contagious pathogen with a worldwide distribution (Frisk
et al., 1999). Although rabies has been more recognized, CDV also has
substantially impacted the health of raccoons and wild and domestic canids
(Mitchell et al., 1999) (Fig. 1).
Transmission of CDV occurs via an aerosol-droplet route, direct
contact, or possibly by contact with contaminated objects (Mitchell et al.,
1999). Pathologic lesions form and are mostly found in the respiratory and
gastrointestinal tracts, lymphoid tissues and central nervous system (Frisk
et al., 1999). The clinical signs of raccoons infected with CDV are similar to
those of psuedorabies and rabies (Platt et al., 1983; Thawley et al., 1982).
Our current research is linked to a predator removal study (PRS)
being performed by the United States Department of Agriculture – Wildlife
Services. That study involves monitoring the effects of bobwhite quail
reproduction following removal of mesomammalian predators. The study
was started in 2001 and will continue through 2006 and includes the
following cooperative agencies: USDA-WS, The University of Georgia,
Auburn University, the Jones Ecological Research Center, and Tall Timbers
Research Station. Valdosta State University joined the study in 2003. The
objective of the present study was to test PRS raccoons for the presence of
canine distemper virus specific antibodies via an indirect fluorescent
antibody (IFA) assay.
In 2003 and 2004, mesomammalian predators removed from Pebble
Hill Plantation, Pinebloom Plantation and Tall Timbers Research Station
in southwest Georgia and north Florida were euthanized, frozen and
transported to Valdosta State University. These predators included
raccoons, opossums, foxes, armadillos, coyotes, feral dogs, feral cats
and bobcats. Animals were necropsied and various tissue samples and
morphometric data was collected.
365 raccoon serum samples were analyzed for CDV antibodies.
Fluorescent antibody slides were commercially obtained from VMRD
(Pullman, WA) and consisted of virus-infected mink lung cells grown on
the surface of Teflon-masked slides. Fifty µl of raccoon serum diluted
1:8 in phosphate buffered saline was place in designated wells and
incubated. Fifty microliters of FITC labeled goat anti-raccoon IgG
(Kirkegaard Perry Laboratories) was placed on each well and slides
were again incubated. Slides were rinsed, blotted, mounted and were
viewed with a microscope at 100X – 250X. Positive samples exhibited
a pattern of fluorescence in individual cells with inclusions bodies
(Figure 2).
Feb
INTRODUCTION
DISCUSSION
Prevalence
A member of the family Paramyxoviridae, canine distemper virus (CDV)
causes Canine Distemper, a significant viral disease in raccoons and fur
animals, producing morbidity and mortality in unvaccinated populations
worldwide. Although dogs are the most commonly affected species, CDV is
also seen in raccoons, foxes, ferrets and minks. Comparatively, canine
distemper is now rare in many industrialized countries due to vaccination.
Transmission of the virus occurs via an aerosol-droplet route, direct contact,
or possible by contact with contaminated objects. Approximately 365
raccoons from 2003 and 2004 were obtained from three southwest Georgia
plantations as part of an ongoing USDA – Wildlife Services bobwhite-quail
predator project. Of the 365 samples, 116 (31.8%) tested positive for CDV.
Data will be evaluated incorporating season, host sex, and host age. These
data suggest considerable levels of canine distemper virus are present in
southwest Georgia.
METHODS
3.1-6.0
6.1-9.0
9.1-12.0
12.1+
14.8
26.5
Percent Infected
38.8
71.4
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Virus nucleoprotein RNA by reverse transcription – PCR using serum, whole blood,
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Pubey. 1999. Serologic survey for selected infectious disease agents in raccoons from
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Shin, Y.J., K.O. Cho, H.S. Cho, S.K. Kang, H.J. Kim, Y.H. Kim, H.S. Park, and N.Y. Park.
2004. Comparison of one-step RT-PCR and a nested PCR for the detection of Canine
Distemper Virus in clinical samples. Australian Veterinary Journal 82: 6-83.
Stanton, J.B., S. Poet, S. Frasca Jr., D. Bienzle, and C.C. Bown. 2002. Development of a seminested reverse transcription polymerase chain reaction assay for the retrospective diagnosis
of Canine Distemper Virus infection. Journal of Veterinary Diagnostic Investigation 14:
47-52.
Thawley, D.G., and J.C. Wright. 1982. Pseudorabies virus infection in raccoons: A Review.
Journal of Wildlife Diseases 18: 113-116.