SNAP 4Dx Plus Clinical Reference Guide - IDEXX Laboratories

Annual Screening
for Vector-borne Disease
The SNAP ® 4Dx ® Plus Test Clinical Reference Guide

Every dog, every year
For healthier pets and so much more. The benefits of vector-borne disease screening go far beyond the
well-being of an individual pet. Adopting regular screening protocols at your practice can lead to a greater
awareness and understanding of vector-borne disease in your community, while building the value of your
practice with pet owners.
Know more with every result
With the SNAP ® 4Dx ® Plus Test, a positive result can also be an indication
of ticks and other pathogens in your area.
Your patients
Educating pet owners about the
risk of vector-borne disease is an
opportunity to stress the importance
of screening and prevention.
Your community
Comprehensive annual screenings
give you a current snapshot of how
widespread certain diseases and tick
species are in the area.
Your practice
Vector-borne disease screenings
are the foundation of your practice’s
preventive medicine programs and
let you know what your patients are
being exposed to over time, which
leads to healthier patients and a
stronger practice.
When you use the
SNAP ® 4Dx ® Plus Test
as a screening tool,
you may
detect antibodies to
these pathogens
Ehrlichia ewingii
carried by
these ticks
Lone star tick
Amblyomma
americanum
that may also transmit
other infections to
dogs and people
Ehrlichia chaffeensis
Tularemia
Rocky Mountain spotted fever
STARI
Geographic tick
distribution as
of 2011
Anaplasma
phagocytophilum
Borrelia burgdorferi
(Lyme disease)
Deer tick or
black-legged tick
Ixodes scapularis
Ixodes pacificus
Bartonella spp.
Babesia spp.
Ehrlichia canis
Anaplasma platys
Brown dog tick
Rhipicephalus
sanguineus
Babesia spp.
Rocky Mountain spotted fever
Ehrlichia canis
American dog tick
Dermacentor
variabilis
Rocky Mountain spotted fever
Tularemia

Lyme disease
Canine anaplasmosis
Canine ehrlichiosis
Heartworm disease
Transmitted by the deer tick
or black-legged tick, Lyme
disease is caused by the
bacterium Borrelia burgdorferi.
Clinical signs may not appear
until several months after
infection. Lyme disease has
been found throughout North
America with cases ranging
from mild to severe.
Did you know?
• The C 6 peptide used in the IDEXX SNAP ® 3Dx ® , SNAP ® 4Dx ® Plus and
Lyme Quant C 6
®
tests do not cross-react with the antibody response to
commercially available Lyme vaccines. 1
• Dogs with seroreactivity to both B. burgdorferi and Anaplasma
phagocytophilum may have two times the risk of developing clinical illness
than singularly infected dogs. 2
Canine granulocytic anaplasmosis
is caused by the bacterium
Anaplasma phagocytophilum
(transmitted by the deer tick or
black-legged tick). Anaplasma
platys (transmitted by the brown
dog tick) is the cause of infectious
cyclic thrombocytopenia.
Did you know?
• Many mammalian species, including humans, are susceptible to
A. phagocytophilum infection.
• Coinfection of Anaplasma species with other vector-transmitted
pathogens may lead to more complex presentations and
slower response to therapy.
• A. platys infects canine platelets and is frequently seen as a
coinfection with Ehrlichia canis.
Canine ehrlichiosis is caused
by the bacteria Ehrlichia canis,
(transmitted by the brown
dog tick) and Ehrlichia ewingii
(transmitted by the lone star tick).
Canine Ehrlichia infections may
progress to the subclinical phase,
lasting days, months or years.
Did you know?
• Dogs coinfected with E. canis and A. platys were found to have more severe
anemia and thrombocytopenia than dogs with either single infection. 6
• In a study of healthy dogs with antibodies to E. canis, 39% were
thrombocytopenic. 7
• Chronic E. canis infections, if left untreated, can lead to
bone marrow dysfunction or renal disease.
Dirofilaria immitis, the causative
agent of heartworm disease,
is transmitted by infected
mosquitoes when D. immitis
larvae are transferred to a healthy
dog. Heartworm disease has
no obvious clinical signs in the
early stages, making preventive
measures so much more
important—especially as advanced
infection may result in death.
Did you know?
• Despite availability of monthly preventives, prevalence rates of canine
heartworm has remained consistent nationwide. 4
• For more information and current recommendations on treating canine
heartworm disease, go to heartwormsociety.org or capcvet.org.
Borrelia burgdorferi
Primary vectors
Ixodes scapularis
Ixodes pacificus
(deer tick or black-legged tick)
Pathology
Localizes in tissues of infected dogs
Clinical presentation
Lyme disease is a chronic infection
with clinical signs that may present
acutely:
• Fever, anorexia, lethargy
• Polyarthritis, lameness
• Rapidly progressive renal failure
• Neurologic syndromes
Laboratory abnormalities
• Elevated (≥30 U/mL)
C 6 antibody level
• Proteinuria
WHAT
TO DO
NEXT?
1
DIAGNOSE*
2TREAT
3
MONITOR
4
PREVENT
What to do with your SNAP ® result
Clinical signs and/or
laboratory findings
DO support Lyme disease
(C 6 antibody level ≥30 U/mL)
Doxycycline/tetracycline
Retest C 6 antibody level
with or without UPC
in 6 months to confirm
treatment success
Positive result Infection is likely
Determine C 6 antibody level with the Lyme Quant C 6 Test
and evaluate for proteinuria (UPC)
Clinical signs and/or
laboratory findings
DO NOT support
Lyme disease
(C 6 antibody level

Annual screening with
the SNAP ® 4Dx ® Plus Test
Screen your canine patients every year with the SNAP ® 4Dx ® Plus Test to detect exposure to
pathogens that cause heartworm disease, ehrlichiosis, Lyme disease and anaplasmosis.
Diagnostics for sick patients
Serology and PCR testing options—For a sick dog presenting with clinical signs consistent with a vectorborne
disease, it’s important to consider both serology and PCR testing because they are complementary.
WHAT
TO DO
NEXT?
1
DIAGNOSE
2
3
4
TREAT
MONITOR
PREVENT
A pet’s screening result
and what it means
Positive result
The dog has been exposed and may be infected
Perform additional tests to confirm infection
Clinical signs and/or laboratory findings indicate either:
Self-limiting infection
No clinical signs or laboratory abnormalities
Subclinical infection
Apparently healthy dogs with laboratory abnormalities
Clinical disease
Infected dogs with clinical signs
with or without laboratory abnormalities
If necessary
Retest in 6–12 months
Discuss disease prevention strategies
Negative result
Exposure unlikely
• Review benefits
of prevention
– preventive
– vaccination
• Retest in 1 year
Depending on
the results of a
pet’s screening,
additional testing
or therapies may
be required.
Quick tips to share with
pet owners
• Check your dog for ticks daily.
If you find a tick, remove it right
away (ticks will gravitate to the
head, ears and neck).
• Use a tick preventive on your dog.
• Watch your dog closely for
changes in behavior or appetite
and call your veterinarian with
any concerns.
• Talk with your veterinarian about
ticks and vector-borne disease
in your area.
• If your pet’s test results are
negative, congratulations! Keep
up the good work with regular
preventive screenings and daily
tick checks.
Go to dogsandticks.com
for more information.
Benefits and limitations of each diagnostic method:
Serology
Polymerase chain reaction (PCR)
Measures Antibody response of host Nucleic acid (DNA) from pathogen
Benefits
Limitations
Useful for screening as well
as diagnosis of infection
Clinical signs may precede
a measurable antibody
response
Specifically identifies pathogens
indicating active infection
A negative PCR result does not
necessarily rule out infection
Dogs with ehrlichiosis and anaplasmosis may present with clinical signs
at different times after infection. Which sick dog are you dealing with?
Using serology and
PCR together improves
your ability to make a
complete and accurate
diagnosis.
Positive result
Infection or
Recrudescence
PCR
Dog A
presents
Dog B
presents
Serology
Time postinfection
Dog C
presents
When to use the IDEXX RealPCR
vector-borne disease panels:
• Sick patients with clinical signs
and/or laboratory abnormalities
consistent with a vector-borne illness
• Patients with subclinical infections
based on history, physical exam,
serology and clinical laboratory
findings
• Monitoring response to therapy—
the Lyme Quant C 6
®
Test can
indicate waning antibody levels,
and for other pathogens, a negative
PCR result indicates a reduction in
pathogen load
••
No single test is sufficient for
diagnosing an infectious disease
in a sick patient. ••
Edward Breitschwerdt, DVM, DACVIM*
Professor, Internal Medicine
College of Veterinary Medicine,
North Carolina State University
*Dr. Breitschwerdt has a business relationship with IDEXX pursuant to which he
receives compensation from IDEXX from time to time. The views expressed in this
brochure are solely those of Dr. Breitschwerdt.

1. O’Connor TP, Esty KJ, Hanscom JL, Shields P, Philipp MT. Dogs vaccinated with common
Lyme disease vaccines do not respond to IR 6, the conserved immunodominant region of the
VlsE surface protein of Borrelia burgdorferi. Clin Diagn Lab Immunol. 2004;11(3):458–462.
2. Beall MJ, Chandrashekar R, Eberts MD, et al. Serological and molecular prevalence of
Borrelia burgdorferi, Anaplasma phagocytophilum, and Ehrlichia species in dogs from
Minnesota. Vector-Borne Zoonotic Dis. 2008;8(4):455–464.
3. Straubinger RK. PCR-based quantification of Borrelia burgdorferi organisms in canine tissues
over a 500-day postinfection period. J Clin Microbiol. 2000;38(6):2191–2199.
4. Verdon DR. Heartworm infection continues its climb, survey reports. DVM Newsmagazine.
February 1, 2006.
5. Egenvall A, Lilliehöök I, Bjöersdorff A, Engvall EO, Karlstam E, Artursson K, Heldtander
M, Gunnarsson A. Detection of granulocytic Ehrlichia species DNA by PCR in persistently
infected dogs. Vet Rec. 2000;146(7):186–190.
6. Gaunt S, Beall M, Stillman B, et al. Experimental infection and co-infection of dogs with
Anaplasma platys and Ehrlichia canis: hematologic, serologic and molecular findings.
Parasit Vectors. 2010;3(1):33.
7. Hegarty BC, Diniz PPVP, Bradley JM, Lorentzen L, Breitschwerdt EB. Clinical relevance of
annual screening using a commercial enzyme-linked immunosorbent assay (SNAP 3Dx)
for canine ehrlichiosis. JAAHA. 2009;45(3):118–124.
8. Yabsley MJ, Adams DS, O’Connor TP, Chandrashekar R, Little SE. Experimental
primary and secondary infections of domestic dogs with Ehrlichia ewingii. Vet Microbiol.
2011;105(3-4):315–321.
Black-legged tick (Ixodes scapularis), lone star tick (Amblyomma americanum) and brown dog tick (Rhipicephalus
sanguineus) images supplied by the Armed Forces Pest Management Board. afpmb.org. Photographer: James L. Occi.
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