Managing parasite threats today

Volume 2
Managing parasite
threats today
Customized Solutions,
Comprehensive Treatment
BCAH0D0209_Tech_Bulletin_r25.indd 1
9/28/10 5:33 PM
Dear Doctor:
As you know, parasites present a challenge that is always evolving. Rocky Mountain spotted fever
is on the move, spreading now to other vectors—tick species with a wider global distribution.
Tapeworms continue to prove difficult to diagnose in dogs. In the Mississippi Delta region,
some practitioners are reporting increasing numbers of failures with preventatives for canine
heartworm, raising concerns of resistance. These bits of news, and others like them, paint a
concerning picture.
The demands of everyday practice can make it challenging to stay current on trends like these
that have an impact on the way you practice medicine. At Bayer Animal Health we stay on top of
the newest information and the latest innovations, so that we may provide you with appropriate,
tailor-made solutions against the ever-changing threat of parasites. Through Bayer Parasite
Solutions, we offer a customizable program for veterinary practices, combining education with
comprehensive preventatives and treatments for both ectoparasites and endoparasites. Our
innovative products are supported by extensive research, so you can feel confident about the
safety and efficacy of these products when recommending them for your patients.
Beyond innovative products, Bayer Parasite Solutions provides information. The articles in this
booklet, for example, are one way we reach out to you and the veterinary profession, bringing
you information on subjects that affect you and your patients. In fact, this is the second such
booklet we have published in our efforts to keep you abreast of the latest trends. In these pages
you will find current insights on a variety of parasite topics written by leading authorities—those
whom you trust to inform you of new developments, and who continue to advance the current
knowledge on the control and prevention of parasite infections and infestations. We hope you find
these articles useful as you face the ongoing and evolving threat of parasites—and as you continue
to make a positive difference in the lives of your patients and their owners.
Sincerely,
Cristiano von Simson, DVM
Director of Veterinary Technical Services
Bayer Animal Health
We consider you a valued partner. At any time, please feel free to contact our
Veterinary Technical Services Department at 800-422-9874 with questions or
comments regarding Bayer Parasite Solutions. Your feedback remains critical
to our mission of providing unparalleled products for your patients.
No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any electronic or
mechanical means, by photocopying or recording, or otherwise without the prior permission of the copyright owner.
Printed in USA.
This information has not been peer reviewed and does not necessarily reflect the opinions of, nor constitute or imply endorsement
or recommendation by, the Publisher. The Publisher is not responsible for any data, opinions, or statements provided herein.
BCAH0D0209_Tech_Bulletin_r25.indd 2-1
Managing Parasite Threats Today 1
9/28/10 5:33 PM
About our contributors
Michael R. Lappin, DVM, PhD, DACVIM
After graduating from Oklahoma State University in 1981, Dr. Lappin completed a rotating internship in small
animal medicine and surgery at the University of Georgia. After 2 years in Los Angeles, he returned to the
University of Georgia where he completed a small animal internal medicine residency and a PhD in Parasitology.
Dr. Lappin was board-certified by the American College of Veterinary Internal Medicine in 1987. He is currently
Professor of Small Animal Internal Medicine at the College of Veterinary Medicine and Biomedical Sciences at
Colorado State University. Dr. Lappin studies feline infectious and immune-mediated diseases and has written
over 200 primary research manuscripts. His principal areas of interest are prevention of infectious diseases,
the upper respiratory disease complex, infectious causes of fever, infectious causes of diarrhea, and
zoonoses of cats.
Susan E. Little, DVM, PhD, DEVPC
Dr. Little is a professor of parasitology and the Krull-Ewing Endowed Chair in Veterinary Parasitology at the
Center for Veterinary Health Sciences, Oklahoma State University, where she is active in veterinary parasitology
teaching and oversees a research program that focuses on zoonotic parasites and tick-borne diseases. She
has served as president of the American Association of Veterinary Parasitologists, as a board member of the
Companion Animal Parasite Council, and on the editorial boards of Veterinary Parasitology and Veterinary
Therapeutics. Dr. Little has authored more than 100 publications on veterinary and human parasites and
tick-borne disease agents. She is also recognized as an outstanding teacher and has been awarded two
Excellence in Teaching Awards from the national Student American Veterinary Medical Association (SAVMA).
Byron L. Blagburn, MS, PhD
In his role as Distinguished University Professor at the Auburn University College of Veterinary Medicine,
Dr. Blagburn instructs veterinary students, directs graduate student research, heads the clinical parasitology
diagnostic laboratory, and oversees a research program that focuses on the development of new pharmaceuticals
directed against parasites and parasitic diseases of veterinary importance. He is past-president of several
regional and national parasitology organizations and has served as editor and editorial board member for
various veterinary journals. Dr. Blagburn is the author of more than 250 publications in scientific journals and
has served as a speaker at more than 300 national or international meetings.
Kevin R. Kazacos, DVM, PhD
Dr. Kazacos is a professor of veterinary parasitology and director of the clinical parasitology laboratory at the
Purdue University School of Veterinary Medicine. There, he teaches veterinary and graduate students, oversees
diagnostic work in parasitology, and conducts research on parasitic diseases of animals and humans.
Dr. Kazacos has received various teaching, research, and faculty awards and is a founding member and
past-president of the Companion Animal Parasite Council (CAPC). He has done extensive research on zoonotic
helminths that cause visceral, ocular, and neural larva migrans, particularly the raccoon ascarid Baylisascaris
procyonis. Dr. Kazacos has published more than 125 research papers in scientific journals and nine book
chapters or monographs and has given more than 550 presentations at scientific and professional meetings.
Dwight D. Bowman, MS, PhD
Dr. Bowman earned his PhD in parasitology from Tulane University and completed postdoctorate work on
ocular larva migrans at the University of Wisconsin School of Veterinary Medicine. Currently, he is a professor
of parasitology in the department of microbiology and immunology at Cornell University, where he has held
successive positions since 1987. He has obtained continuous corporate and federal funding throughout his
career to study animal parasitology. He has published more than 100 research papers in peer-reviewed
journals and is the author of five textbooks, including Feline Clinical Parasitology. Dr. Bowman’s research
interests include soil-transmitted parasites, parasites of wildlife, and visceral larva migrans.
2
BCAH0D0209_Tech_Bulletin_r25.indd 2-3
Table of Contents
Cat Scratch Fever and Other
Bartonella-Associated Illnesses
in Cats and People
Michael R. Lappin, DVM, PhD, DACVIM .................................. 4
New Developments and
Challenges in Rocky Mountain
Spotted Fever
Susan Little, DVM, PhD, DEVPC .......................................... 6
Canine Heartworm Disease:
Developments in the
Mississippi Delta
Byron L. Blagburn, MS, PhD ............................................... 8
Dealing With Tapeworms
in Dogs
Kevin R. Kazacos, DVM, PhD .......................................... 12
Roundworm in Cats:
A Call for More Control
Dwight D. Bowman, MS, PhD .......................................... 14
Bayer Parasite Solutions:
Customized Comprehensive
Parasite Programs for
Each of Your Patients .......................................... 16
Product Information
Summaries ......................................................... 17
Managing Parasite Threats Today 3
9/28/10 5:33 PM
Cat Scratch Fever and Other BartonellaAssociated Illnesses in Cats and People
Advantage®:
The Flea Specialist
Michael R. Lappin, DVM, PhD, DACVIM (Internal Medicine)
The Kenneth W. Smith Professor in Small Animal Clinical Veterinary Medicine
College of Veterinary Medicine and Biomedical Sciences
Colorado State University, Fort Collins, Colorado
◆ Advantage® kills fleas on dogs and
cats through contact
Bartonella spp. are intracellular gram-negative bacteria that
infect many mammalian species including cats, dogs, and
humans. The most common Bartonella spp. known to infect
cats are Bartonella henselae, B. clarridgeiae, B. koehlerae,
and B. quintana.1-3 Cats are the main reservoir hosts for
B. henselae and B. clarridgeiae. Ctenocephalides felis is the
vector for several Bartonella spp., and these agents have been
cultured or amplified by PCR assays from fleas and the blood of
cats.4,5 The Bartonella spp. of cats can also infect humans and
so are considered significant zoonotic pathogens. Cat scratch
disease (Figure 1), also known as cat scratch fever, is the most
recognizable disease associated with B. henselae infection in
humans, but there are multiple other clinical syndromes that
have recently been recognized.1,6
Cats exposed to C. felis infected
with B. henselae frequently
develop fever and occasionally
develop other clinical
syndromes of significance.2,7
Recent experimental work
suggests that clinically ill cats
can be successfully treated with
enrofloxacin and that treating
fleas through administration
of imidacloprid can block
Figure 1. Enlarged axillary lymph
transmission of B. henselae
node of a veterinary student with
among cats.7
cat scratch disease.
Transmission and pathogenesis
4
Clinical signs and diagnosis
In people, B. henselae is the most common cause of cat
scratch fever as well as bacillary angiomatosis and peliosis
hepatis, common disorders in humans with AIDS. Recently,
B. henselae has been documented as a cause of chronic disease
syndromes such as fever, headaches, and chronic fatigue in
immunocompetent, occupationally exposed people.1,6 From
experimentally infected cats or reports of illness in field cases,
it appears that Bartonella spp. should be on the differential
diagnosis list for cats with fever, lymphadenopathy, anterior
uveitis, myocarditis, and endocarditis.1,2,7,11 Other disease
syndromes such as stomatitis may occur in some cats infected
with Bartonella spp. but have been difficult to document
because of the high prevalence rates for serum antibodies and
bacteremia in healthy cats.2 Use of serological test results with
those of PCR or culture results are likely to give the highest
positive and negative predictive value.
Treatment
In experimental studies, administration of doxycycline,
tetracycline, erythromycin, amoxicillin-clavulanate,
or enrofloxacin have been shown to limit B. henselae
bacteremia in cats.1,2 If feline bartonellosis is suspected,
the American Association of Feline Practitioners Panel
Report recommends doxycycline at 10 mg/kg, PO, daily.7
In a recent study of B. henselae-associated fever in cats
infected by exposure to C. felis, clinical resolution was noted
quickly after the administration of enrofloxacin at 5 mg/kg,
PO, daily.7 The combination of amoxicillin-clavulanate,
marbofloxacin, and azithromycin was used to eliminate
B. henselae-associated endocarditis in a single case report.11
However, an in vitro study shows that B. henselae isolates
from cats become resistant to azithromycin more rapidly than
to fluoroquinolones.12 Optimal duration
of therapy is unknown,2 but 28 days is
frequently recommended.
Bartonella spp. of cats have intra-endothelial and intraerythrocytic phases of infection (Figure 2). The flea-associated
Bartonella spp. are taken up by C. felis during the blood meal
and then are passed in the feces. B. henselae
replicates in fleas and is known to survive in flea
feces for at least 9 days.8 In one study, Bartonella
spp. DNA was amplified from blood (56.9%), skin
(31.4%), claws (17.6%), and gingiva (17.6%) of cats
housed in shelters in Alabama and Florida where
they were presumably exposed to C. felis, but
was not amplified from any sample from shelter
cats without fleas in Colorado.9 B. henselae is
not transmitted amongst cats in the absence of
fleas.10 In total, these data suggest that fleas play
an important role in the transmission of some
Figure 2. Electron micrograph of
Bartonella spp. among cats and humans. Whether
a B. henselae organism within a
clinical disease develops in cats or humans is
feline erythrocyte.
determined by complex interactions between the
Reprinted with permission from Kordick
organism and the host immune response. However,
DL, Breitschwerdt EB. Intraerythrocytic
clinical illness can occur in both immunocompetent presence of Bartonella henselae. J Clin
and immunosuppressed individuals.1,6
Microbiol. 1995;33:1655-1656.
BCAH0D0209_Tech_Bulletin_r25.indd 4-5
Prevention
Prevention of Bartonella spp. first involves
understanding common routes of infection
or exposure. Infected C. felis feces may
contaminate cat claws or mouths during
grooming, and then Bartonella spp.
are inoculated into the human when
scratched or bitten. Open wounds can
become contaminated by cat saliva or flea
feces infected with Bartonella spp. Flea
involvement is required for transmission
between cats. Thus, administration of flea
control products, avoidance of bites and
scratches, and thorough cleansing of
wounds or areas contaminated with flea feces may lessen the
risk of Bartonella spp. transmission from cats to humans,
or amongst cats.1,2,13 Recently, it was shown that treatment
of fleas by monthly topical administration of a combination
of 10% imidacloprid and 1% moxidectin blocked C. felis
transmission of B. henselae among experimental cats.7
Infection with one Bartonella spp. does not block infection
by other Bartonella spp. in cats. In fact, individual cats can
be naturally infected sequentially with different strains of
B. henselae.14 Thus, avoidance of reinfection by administrating
flea control products to cats should be considered the primary
prevention strategy.
•F
leas that may carry Bartonella spp. or
other pathogens don’t need to bite to die
◆ Advantage® kills fleas fast
•K
ills fleas within 12 hours of
initial application
• Kills reinfesting fleas within 2 hours
•R
educes the number of flea bites and
may reduce secondary problems such
as skin irritation, flea allergy dermatitis,1
and tapeworms
◆ Advantage® is waterproof
References: 1. Breitschwerdt EB, Maggi RG, Chomel BB, Lappin MR.
Bartonellosis: an emerging infectious disease of zoonotic importance
to animals and human beings. J Vet Emerg Crit Care (San Antonio).
2010;20(1):8-30. 2. Brunt J, Guptill L, Kordick DL, Kudrak S,
Lappin MR; American Association of Feline Practitioners, Academy
of Feline Medicine Advisory Panel. American Association of Feline
Practitioners 2006 Panel report on diagnosis, treatment, and
prevention of Bartonella spp. infections. J Feline Med Surg.
2006;8(4):213-226. 3. Avidor B, Graidy M, Efrat G, et al. Bartonella
koehlerae, a new cat-associated agent of culture-negative human
endocarditis. J Clin Microbiol. 2004;42(8):3462-3468.
4. Barrs VR, Beatty JA, Wilson BJ, et al. Prevalence of Bartonella
species, Rickettsia felis, haemoplasmas, and the Ehrlichia
group in the blood of cats and fleas in eastern Australia. Aust Vet
J. 2010;88(5):160-165. 5. Lappin MR, Griffin B, Brunt J, et al.
Prevalence of Bartonella species, haemoplasma species, Ehrlichia
species, Anaplasma phagocytophilum, and Neorickettsia risticii
DNA in the blood of cats and their fleas in the United States. J
Feline Med Surg. 2006;8(2):85-90. 6. Breitschwerdt EB, Maggi
RG, Duncan AW, Nicholson WL, Hegarty BC, Woods CW. Bartonella
species in blood of immunocompetent persons with animal and
arthropod contact. Emerg Infect Dis. 2007;13(6):938-941.
7. Bradbury, CA, Lappin MR. Evaluation of topical application of
10% imidacloprid-1% moxidectin to prevent Bartonella henselae
transmission from cat fleas. J Am Vet Med Assoc. 2010;236(8):869873. 8. Higgins JA, Radulovic S, Jaworski DC, Azad AF. Acquisition
of the cat scratch disease agent Bartonella henselae by cat fleas
(Siphonaptera:Pulicidae). J Med Entomol. 1996;33(3):490-495.
9. Lappin MR, Hawley J. Presence of Bartonella species and
Rickettsia species DNA in the blood, oral cavity, skin and claw beds
of cats in the United States. Vet Dermatol. 2009;20(5-6):509-514.
10. Chomel BB, Kasten RW, Floyd-Hawkins K, et al. Experimental
transmission of Bartonella henselae by the cat flea. J Clin
Microbiol. 1996;34(8):1952-1956. 11. Perez C, Hummel JB,
Keene BW, Maggi RG, Diniz PP, Breitschwerdt EB. Successful
treatment of Bartonella henselae endocarditis in a cat. J Feline
Med Surg.2010;12(6):483-486. 12. Biswas S, Maggi RG, Papich MG,
Keil D, Breitschwerdt EB. Comparative activity of pradofloxacin,
enrofloxacin, and azithromycin against Bartonella henselae isolates
collected from cats and a human. J Clin Microbiol. 2010;48(2):617618. 13. Kaplan JE, Benson C, Holmes KK, Brooks JT, Pau A,
Masur H. Guidelines for prevention and treatment of opportunistic
infections in HIV-infected adults and adolescents: recommendations
from CDC, the National Institutes of Health, and the HIV Medicine
Association of the Infectious Diseases Society of America. MMWR
Recomm Rep. 2009;58(RR04):1-198. 14. Arvand M, Viezens J,
Berghoff J. Prolonged Bartonella henselae bacteremia caused by
reinfection in cats. Emerg Infect Dis. 2008;14(1):152-154.
Advantage Multi® for Cats: WARNINGS: Do not use on sick,
debilitated, or underweight cats (see ADVERSE REACTIONS). Do not
use on cats less than 9 weeks of age or less than 2 lbs body weight.
PRECAUTION: Avoid oral ingestion.
The Advantage® Benefit
Imidacloprid
Dosing Topical
Indications
• Kills fleas and
flea larvae
• Kills lice on dogs
Age restrictions • Gentle enough for
kittens 8 weeks and
older and puppies
7 weeks and older
Mode of action • Kills through contact
(fleas do not need to
bite to die)
Y
NL
)
Overview
(DOGS O
Reference:
1. Genchi C, Traldi G, Bianciardi P. Efficacy of imidacloprid on dogs
and cats with natural infestation of fleas, with special emphasis on flea
hypersensitivity. Vet Ther. 2000;1(2):71-80.
Managing Parasite Threats Today 5
9/28/10 5:34 PM
New Developments and Challenges
in Rocky Mountain Spotted Fever
from attaching, thereby circumventing a bite that could initiate
pathogen transmission.11 Similarly, targeted, judicious use of
acaricides to reduce tick numbers near homes may alleviate
the harm that ticks inflict, particularly as these pests and the
pathogens they transmit become more common in urban and
suburban habitats.
Susan Little, DVM, PhD, DEVPC
Center for Veterinary Health Sciences
Oklahoma State University
A growing problem, with new vectors being discovered
Rocky Mountain spotted fever (RMSF) is among the most
severe vector-borne diseases affecting dogs throughout
the western hemisphere, most commonly in the southern
Atlantic and south central regions of the United States.1,2,3
Its causative agent, the intracellular bacterium Rickettsia
rickettsii, was described in the early 20th century by Dr.
Harold Taylor Ricketts, who further identified the role of tick
bites in the transmission of R. rickettsii to mammalian hosts.1
Principally recognized vectors of RMSF in the United States
have been Dermacentor variabilis (American dog tick) and
Dermacentor andersoni (Rocky Mountain wood tick), but
growing concern is focused on more recent cases involving
Rhipicephalus sanguineus (brown dog tick), which has been
associated with RMSF outbreaks in the southwestern United
States (Figure 1).4 Brown dog ticks infected with R. rickettsii
D. variabilis female and male
R. sanguineus male
Figure 1. Photographs contrasting the appearance
of D. variabilis and R. sanguineus
have also been identified in Texas and California.2 The spread
of RMSF both geographically and via novel vectors presents
a challenge for human and veterinary health practitioners—
especially since R. sanguineus is globally distributed and able
to establish long-term infestations in homes and kennels; this
tick has also been associated with other rickettsial pathogens
in Europe.1,2,4,5
Early detection: important but not easy
Recognizing RMSF in dogs can be difficult. Dogs usually
present between April and October with fever, anorexia, and
vomiting, with fever being the most consistent sign.2,6 The
incubation period can be as short as several days or as long as
2 weeks. Many dogs with RMSF also exhibit extreme malaise
or lethargy—signs similar to canine ehrlichiosis—making
recognition more difficult. Dogs with fever and malaise,
especially those with thrombocytopenia, are particularly
suspect since up to 80% of dogs with RMSF will have
thrombocytopenia. Resulting petechial and ecchymotic lesions
tend to occur on mucous membranes, most notably in the eyes
and oral cavity. Some dogs may also have lameness due to
muscle and joint pain. Dogs presenting with CNS signs typically
deteriorate rapidly, often with fatal results even if appropriate
therapeutic measures are taken.7
6
BCAH0D0209_Tech_Bulletin_r25.indd 6-7
Confirming RMSF with laboratory testing can be difficult
in an acutely ill dog. Serology, such as a positive indirect
immunofluorescence assay (IFA) showing a 4-fold or greater
increase in antibody titers between samples obtained during
acute (early) and convalescent (>2 weeks) phases of illness,
supports a diagnosis.1,8 These tests are available through
veterinary diagnostic labs, university labs, and state public
health labs.1,9,10 However, since a noticeable rise in IgG titer
(considered more specific and reliable than IgM) occurs some
7 to 10 days post onset of disease, dogs may have severe illness due
to RMSF and still be seronegative.1,10 At the same time, because
the IFA is not specific and antibodies may remain in circulation
long after infection, many dogs may harbor an antibody titer
to R. rickettsii regardless of disease status. And although
a single high titer in an acutely ill dog is suggestive, a single
positive antibody titer cannot entirely confirm R. rickettsii as
an etiologic agent of disease, nor can a negative result exclude it.
Polymerase chain reaction (PCR) tests are also available and
may be of use in detecting evidence of R. rickettsii in whole
blood samples during acute infection, presumably due to the
presence of sloughed epithelial cells in circulation.2 The assays
are species-specific, and if positive, a diagnosis is confirmed.
However, a negative PCR on whole blood should not be used to
rule out the possibility of RMSF since circulating organisms are
sparse in the absence of advanced disease or fulminant infection,
and antibiotic treatment can further decrease PCR sensitivity.1,9
Newer quantitative PCR methods for R. rickettsii in various
types of samples may prove useful in future RMSF diagnosis.1
Treatment in early stages is crucial
Symptoms of RMSF usually subside rapidly with appropriate
antibiotic treatment using doxycycline(10 mg/kg × 14 days) 6;
longer courses may be used in dogs with severe disease or in
dogs thought to be co-infected with other tick-borne disease
agents. Doxycycline should be presumptively administered
when symptoms occur in tandem with a tick exposure or
contact with a tick-infested environment.6,9 Delaying antibiotic
treatment may result in fatalities in dogs.
Key to prevention: limiting tick exposure, canine
spot-on formulas
Vaccines are not available to prevent RMSF. The best strategy
against RMSF remains keeping ticks off dogs through avoidance
of tick-infested habitats and stringent attention to tick control.1
R. sanguineus is recognized as the only species that infests
human dwellings and kennels in North America, an occurrence
aggravated by warmer weather and one that reinforces the
importance of treating dogs year-round with an effective
tick-control product. Ticks are thought to transmit R. rickettsii
in as few as 4 to 6 hours after attachment as an adult (see life
cycle, Figure 2).1 Preventing attachment and removing attached
ticks promptly are key to preventing disease.5 A monthly
spot-on formulation combining permethrin with imidacloprid
has been shown to not only kill ticks, but to also prevent ticks
Egg to Adult: 3 months–2 years
Eggs
Eggs hatch in 15–60 days
Nymph
Larva
Engorges in 3–11 days
◆ K9 Advantix® proved effective at repelling
and killing 3 ticks that vector the pathogen
that may cause RMSF in dogs:
• D
ermacentor variabilis
Egg to Adult: 3 months–2 years
(American dog tick)
• Dermacentor
andersoni
(Rocky Mountain wood tick)
• Rhipicephalus
sanguineus
(brown dog tick)
Engorges in 4–10 days
Engorges in 4–10 days
Adult
Molts in 16–300 days
K9 Advantix®: Repels and
Kills Ticks
Engorges in 3–12 days
Molts in 6–250 days
Figure 2. Life cycle of D. variabilis.
Created by Kansas State University CVM ITC. M.W. Dryden, DVM, PhD and
P.A. Payne, DVM, PhD.
References: 1. Dantas-Torres F. Rocky Mountain spotted fever. Lancet
Infect Dis. 2007;7(11):724-732. 2. Nicholson WL, Allen KE, McQuiston
JH, Breitschwerdt EB, Little SE. The increasing recognition of riskettsial
pathogens in dogs and people. Trends Parasitol. 2010;26(4):205-212.
3. Centers for Disease Control and Prevention. Rocky Mountain spotted
fever. http://www.cdc.gov/ticks/diseases/rocky_mountain_spotted_fever/
index.html. Accessed June 1, 2010. 4. Demma LJ, Traeger MS, Nicholson
WL, et al. Rocky Mountain spotted fever from an unexpected tick
vector in Arizona. N Engl J Med. 2005;353(6):587-594. 5. Little SE,
Hostetler J, Kocan KM. Movement of Rhipecephalus sanguineus
adults between co-housed dogs during active feeding. Vet Parasitol.
2007;150(1-2):139-145. 6. Sherding RG. Rickettsiosis, ehrlichiosis,
anaplasmosis, and neorickettsiosis. In: Saunders Manual of Small
Animal Practice. 3rd ed. St. Louis, MO: Saunders Elsevier, Inc; 2006:
178-185. 7. Warner RD, Marsh WW. Rocky Mountain spotted fever. J Am
Vet Med Assoc. 2002;221(10):1413-1417. 8. Center for Food Security
and Public Health at Iowa State University College of Veterinary Medicine
Web site. Rocky Mountain Spotted Fever. 2005;1-5. http://www.cfsph.
iastate.edu/Factsheets/pdfs/RMSF.pdf. Accessed June 1, 2010.
9. Chapman AS, Bakken, JS, Folk, SM, et al. Diagnosis and treatment of
tickborne rickettsial diseases: Rocky Mountain Spotted Fever, ehrlichiosis
and anaplasmosis—United States: a practical guide for physicians and
other health-care and public health professionals. MMWR Recomm
Rep. 2006;55(RR-4):1-27. http://www.cdc.gov/mmwr/PDF/rr/rr5504.pdf.
Accessed June 1, 2010. 10. Centers for Disease Control and Prevention.
Tickborne Rickettsial Diseases: Diagnosis. http://www.cdc.gov/ticks/diagnosis.
html. Accessed June 1, 2010. 11. Data on file. Bayer HealthCare LLC,
Animal Health Division, Shawnee Mission, Kansas.
◆ On day 3 after treatment,
Adult studies showed
K9 Advantix®1,2:
• Killed
96.4% to 100% of repelled
Eggs
Molts in 16–300
days
Eggs hatch in 15–60 days
ticks within
10 minutes
• Achieved
100% tick control
Nymph
24 hours
after the first infestation
◆ K9 Advantix® repels ticks: A repelled
tick doesn’t bite and can’t transmit
Larva
disease-causing
pathogens
Engorges in 3–12 days
Engorges in 3–11 days
K9 Advantix®: 5-Way
Repel-and-Kill Pest Protection
Molts in 6–250 days
Repels ticks
Kills ticks
Repels fleas
Kills fleas
Repels mosquitoes
Kills mosquitoes
Repels biting flies
Prevents and kills lice
✓
✓
✓
✓
✓
✓
✓
✓
K9 Advantix® is for use on dogs only.
References:
1. Dryden MW, Payne PA, Smith V, Hostetler J. Evaluation of an
imidacloprid (8.8% w/w)-permethrin (44.0% w/w) topical spot-on and
a fipronil (9.8%w/w)-(S)-methoprene (8.8% w/w) topical spot-on to
repel, prevent attachment, and kill adult Rhipicephalus sanguineus and
Dermacentor variabilis ticks on dogs. Vet Ther. 2006;7(3):187-198.
2. Dryden MW, Payne PA, Smith V, Hostetler J. Evaluation of an
imidacloprid (8.8% w/w)-permethrin (44.0% w/w) topical spot-on and
a fipronil (9.8%w/w)-(S)-methoprene (8.8% w/w) topical spot-on to
repel, prevent attachment, and kill adult Ixodes scapularis and
Amblyomma americanum ticks on dogs. Vet Ther. 2006;7(3):173-186.
Managing Parasite Threats Today 7
9/28/10 5:34 PM
­ anine Heartworm Disease:
C
Developments in the Mississippi Delta
Byron L. Blagburn, MS, PhD
Distinguished University Professor
Auburn University College of Veterinary Medicine
Heartworm disease is a serious and potentially fatal
disease of dogs in many regions of the world.1 Under most
circumstances, this disease can be prevented with regular
use of one of the available prophylactic medications. When
owners and veterinarians don’t maintain adherence to a
regular preventive routine, increased numbers of heartwormpositive dogs are seen in geographic regions where heartworm
challenge rates are high—such as the mid-South and coastal
mid-South areas of the central United States (often referred
to as the upper and lower Mississippi River Delta region).2,3
Unlike those in other areas, however, veterinarians in the
delta region have reported increased numbers of heartwormpositive dogs that cannot be explained entirely by reduced
compliance. Most likely, the interplay of heartworm life
cycles, erratic compliance, diagnostic, prevention, and
therapeutic variables, and possible parasiticide resistance is
contributing to the lack of efficacy of heartworm preventive
medications in this region (Table 1).4-6
The situation in the Mississippi Delta
In early 2006, veterinarians in the Mississippi Delta region
began to report increased numbers of heartworm-positive
dogs on compliant heartworm prevention. During the ensuing
3-year period, the numbers of cases appeared to increase.
By the close of 2009, some veterinarians were reporting
more than 200 positive dogs, compared with a history of
20 or fewer cases. Subsequently, my research team and
co-workers implemented a research program to investigate
the cause(s) of these perceived failures. I began with visits to
veterinary hospitals in the region. Discussion included issues
that can affect successful prevention such as compliance,
testing strategies, correct use of adulticides, differences in
preventive products, and possible parasite resistance. Results
of these meetings with veterinarians led me to conclude
that some of the reported cases could not be explained by
the variables discussed in Table 1. Also, prevention failures
appeared to occur with all active ingredients in products
that were currently in use
Table 1.
(i.e., ivermectin, milbemycin
oxime, and selamectin).
Examples of causes of real or perceived
Moxidectin and imidacloprid
failure in heartworm prevention*
in combination (Advantage
Multi® for Dogs [imidacloprid +
• Failure to treat all pets in the household
Compliance
moxidectin] Topical Solution,
• Failure to administer heartworm preventives at the proper interval or dose
Bayer HealthCare Animal
• Failure to assure that oral products are retained and that topical products
Health) had only recently
reach the skin surface
entered the market; therefore,
• Failure to use tests with acceptable sensitivity and/or specificity
Improper testing†
sufficient field efficacy data
• Failure to test at proper intervals
were not yet available. Another
- Testing too early after starting or restarting prevention
intriguing issue emerged
- True negatives are only confirmed after 2 to 3 negative tests at
from the events in the delta
6-month intervals
region: a portion of the
• Most preventives are less effective against larvae older than 60 days
Survival of migrating
heartworm-positive dogs also
larvae after late-start
harbored numerous circulating
prevention
microfilariae. Attempts to
• Melarsomine dihydrochloride (Immiticide®) is less effective against
Survival of adult
eliminate these microfilariae
worms after
immature adult worms, particularly immature female worms
using either microfilaricidal
adulticidal therapy
• The flexible 3-dose regimen is more effective than the standard
doses of ivermectin or
2-dose regimen
milbemycin oxime were
• Heartworms may have undergone genetic changes that decrease their
Resistance
unsuccessful. I have received
susceptibility to heartworm preventives
reports that, often, very high
doses of ivermectin administered
*Note: Increased challenge rates (i.e., changes in mosquito population or climatic conditions that support vector development)
either orally or by subcutaneous
enhance likelihood of infections, particularly when compliance is inadequate.
injection at intervals of 1 week
†
in improved efficacy. However, improved efficacy varied
among the different heartworm isolates and the preventive
that was used. Moreover, when microfilariae from Kendall,
Tootie, and Tip were analyzed genetically, each appeared
to be different from susceptible isolates.7 These laboratory
results strongly suggest that microfilariae of certain
heartworm isolates recovered from dogs in the Mississippi
Delta respond differently to different preventive products.
How should we view these results when selecting
and using heartworm preventive products?
Dirofilaria immitis (heartworm) in the heart of a dog.
failed to clear microfilaremic dogs. Results of my inquiries,
together with the difficulties in eliminating microfilariae, led
us to develop and implement a microfilarial assay to assess
the efficacy of macrocyclic lactone preventives.6
Results of laboratory tests
The test that we employ involves extracting microfilariae
from heartworm-positive dogs with a history of compliant
prevention. Purified microfilariae are placed in support
media containing ivermectin, milbemycin oxime, or
moxidectin at a concentration that is known to kill 95% of
microfilariae of a susceptible strain. We used pure drugs (not
marketed products) solubilized in either propylene glycol or
dimethyl sulfoxide prior to placement in the support media.
Microfilariae are also exposed to twice the concentration of
preventive drug expected to kill 95% of the microfilariae to
determine if increasing the concentration of the test article
results in increased efficacy.
Results to date indicate that 3 of the canine heartworm
field strains from the delta region were less responsive to
the preventive drugs than susceptible isolates. Microfilariae
from “Kendall,” “Tootie,” and “Tip” (named after the dogs
from which they were isolated) had reduced susceptibility
to ivermectin, milbemycin oxime, and moxidectin. Efficacy
values were 55% and 78% for ivermectin (Kendall); 78%,
50%, and 53% for ivermectin, moxidectin, and milbemycin
oxime respectively (Tootie); and 8% and 39% for ivermectin
(Tip; 2 different assays performed) Increases to twice the
concentration of each of the active drugs in the assay resulted
It’s important to remember that these results indicate
that microfilariae of certain heartworm isolates respond
differently than susceptible isolates in a laboratory test.
Actual preventive products may perform differently.
Table 2 summarizes important differences in heartworm
preventives. Properties such as unique pharmacologic
behavior could result in improved efficacy. For example,
moxidectin is a highly lipophilic molecule, resulting in
higher drug concentrations and delayed elimination from
the host. Moxidectin in the Advantage Multi® for Dogs
topical formulation achieved high concentrations in plasma
(15.1 µg/L) and maintained levels at or above about 12 µg/L
for the 30-day treatment period. More importantly, consistent
administration of moxidectin (Advantage Multi® for Dogs) to
dogs for 4 or more months resulted in a continuous presence
(steady-state; approximately 36 µg/L) of moxidectin in
plasma.8 Product properties such as these may prove to be
important for effective heartworm prevention.
So what should we recommend at this point? Certainly
veterinarians should mandate (not suggest) that clients
administer heartworm preventives to dogs either monthly or
every 6 months as recommended for the different products.
Infected dogs should be promptly treated with the approved
adulticide to eliminate adult worms. The use of doxycycline
in conjunction with adulticides depends on the severity of
disease and/or worm burden. Annual heartworm testing is an
absolute must. Annual testing will allow us to detect infected
dogs before significant disease develops, and will also allow
us to adjust or change prevention strategies as deemed
necessary. Continuing research should provide information
that will allow us to suggest more specific product and/or
regimental recommendations.
(continued on next page)
Annual testing is recommended.
CAUTION: Do not administer this product orally (see WARNINGS).
8
BCAH0D0209_Tech_Bulletin_r25.indd 8-9
Managing Parasite Threats Today 9
9/28/10 5:34 PM
­Canine Heartworm Disease (cont’d)
Advantage Multi® for Dogs:
Heartworm Prevention and
Much More
Table 2.
Product
Formulation
Advantage Multi® for Dogs Topical Spot-on
(imidacloprid + moxidectin)
Topical Solution
Heartgard® Plus*
(ivermectin +
pyrantel pamoate)
Interceptor®
(milbemycin oxime)
Revolution®
(selamectin)
Chewable Tablet
Chewable Tablet
Topical Spot-on
Spectrum (Dogs)
Pharmacokinetics (Dogs)
Immature Dirofilaria immitis
Toxocara canis
Toxascaris leonina
Ancylostoma caninum
Uncinaria stenocephala
Trichuris vulpis
Ctenocephalides felis
•
oxidectin achieves immediate blood levels that persist
M
for several weeks after a single treatment 8
• Moxidectin achieves and maintains steady-state serum
levels after 4 to 5 months of continued application with
continued monthly use 8-10
• Imidacloprid remains in dermal tissues for approximately
1 month for treatment and control of fleas
Immature Dirofilaria immitis
Toxocara canis
Toxascaris leonina
Ancylostoma caninum
Ancylostoma braziliense
Uncinaria stenocephala
• Ivermectin achieves immediate blood levels that decline
quickly after treatment11
• Pyrantel pamoate is not appreciably absorbed from the
intestinal tract and is active only at the time of administration
Immature Dirofilaria immitis
Toxocara canis
Toxascaris leonina
Ancylostoma caninum
Trichuris vulpis
•
Immature Dirofilaria immitis
Adult fleas and flea eggs
Dermacentor variabilis
Otodectes cynotis
Sarcoptes scabiei
•
ilbemycin oxime achieves immediate blood levels that
M
persist for several weeks after a single treatment
elamectin achieves immediate blood levels that decline
S
quickly after treatment
• Selamectin returns to and remains in dermal tissues
for approximately 1 month for treatment and control of
external parasites
Sentinel®
(milbemycin oxime +
lufenuron)
Chewable Tablet
Immature Dirofilaria immitis
Toxocara canis
Toxascaris leonina
Ancylostoma caninum
Trichuris vulpis
Flea eggs and larvae
•
ilbemycin oxime achieves immediate blood levels that
M
decline quickly after treatment
• Lufenuron accumulates in fat and remains for 1 month or
longer for treatment and control of fleas
Proheart® 6
(moxidectin)
Subcutaneous
Immature Dirofilaria immitis
Injectable
Ancylostoma caninum
(6-month duration) Uncinaria stenocephala
•
t the end of the 6-month dosing interval, residual drug
A
concentrations are negligible12
•
ProHeart 6 is effective against existing larval and
mature hookworms at the time of treatment. Persistent
effectiveness for intestinal parasites has not been
established for the entire 6-month period
®
*This category also includes generic products such as Iverhart Plus® and Tri-Heart® Plus. Iverhart Max® also contains praziquantel.
HeartGard is a registered trademark of Merial.
Revolution is a registered trademark of Pfizer Inc.
ProHeart is a registered trademark of Wyeth.
Interceptor and Sentinel are registered trademarks of Novartis.
10
BCAH0D0209_Tech_Bulletin_r25.indd 10-11
◆ Advantage Multi® for Dogs is 100% effective in the
prevention of heartworm disease as shown in clinical trials1
◆ Advantage Multi® for Dogs also:
• Kills
adult fleas and treats flea infestations
• Treats
and controls roundworms (L4 and adult
stages), hookworms (L4, immature, and adult stages),
and whipworms (adult stage)
Pharmacokinetics show Advantage Multi® for Dogs
achieves steady-state serum levels after 4 to 5 months
of continued application with continued monthly use1,2
Conceptual illustration
Serum Levels
Important characteristics of available canine heartworm preventives
References: 1. McCall JW, Genchi C, Kramer LH,
Guerrero J, Venco L. Heartworm disease in animals
and humans. Adv Parasitol. 2008;66:193-285.
2. Hartogensis M. CVM adverse drug data show
increase in reports of lack of effectiveness for
heartworm prevention drugs. FDA Veterinarian.
2005;20(6):2-3. 3. Hampshire VA. Evaluation of
efficacy of heartworm preventive products at the
FDA. Vet Parasitol. 2005;133(2-3):191-195.
4. Patton S, Odoi A, Rohrbach BW. Survey of
heartworm prevention practices among dog owners
and trainers in North America. In: Proceedings of the
13th Triennial State of the Heartworm Symposium;
April 16-18, 2010; Memphis, TN. Page 26.
5. Rohrbach BW, Odoi A, Patton S. Survey to
identify risk factors for failure to prevent heartworm
infection in dogs. In: Proceedings of the 13th Triennial
State of the Heartworm Symposium; April 16-18, 2010;
Memphis, TN. Page 26. 6. Blagburn B, Dillon R,
Prichard R, Geary T, Mount J, Land T, Butler J,
Bourguinat C. Characterization of heartworm
prevention failures in the central United States.
In: Proceedings of the 13th Triennial State of the
Heartworm Symposium; April 16-18, 2010; Memphis,
TN. Page 27. 7. Bourguinat C, Keller K, Schenker R,
Blagburn B, Prichard RK, Geary TG. Investigation
of genetic changes in Dirofilaria immitis after the use
of macrocyclic lactone heartworm preventives.
In: Proceedings of the 13th Triennial State of the
Heartworm Symposium; April 16-18, 2010; Memphis,
TN. Page 28. 8. Beddies G, Krebber R, Schulten A.
Serum concentrations of orally (Guardian®) and
dermal (imidacloprid 10%/moxidectin 2.5% spot-on)
applied moxidectin in dogs. Report V 01-005.
AHD study no. 142300. Leverkusen, Germany,
Bayer AG, 2001. 9. Freedom of Information
Summary: NADA 141-251. 10. Cruthers LR, Arther RG,
Basel CL, et al. New developments in parasite
prevention. In: Bayer Selected Proceedings,
2008 NAVC Conference. Vet Forum Suppl.
2008;25(3B):15-20. 11. Daurio CP, Cheung EN,
Jeffcoat AR, Skelly BJ. Bioavailability of ivermectin
administered orally to dogs. Vet Res Commun.
1992;16(2):125-130. 12. Freedom of Information
Summary: NADA 141-189.
Moxidectin1
Oral heartworm preventatives*
Month 1
Month 2
Month 3
Month 4
Month 5
Month 6
The clinical significance of serum levels has not been established.
*One month data of ivermectin incorporated with monthly intervals.3
References:
1. Freedom of Information Summary: NADA 141-251.
2. Beddies G, Krebber R. Serum-pharmacokinetics of imidacloprid 10% w/v / moxidectin 2.5% w/v
spot-on in dogs applied once per month for three consecutive intervals. Report V 00-006. AHD
study no. 141.329. Leverkusen, Germany, Bayer AG, 2001.
3. Daurio CP, Cheung EN, Jeffcoat AR, Skelly BJ. Bioavailability of ivermectin administered orally to
dogs. Vet Res Commun. 1992;16(2):125-130.
CAUTION: Federal (U.S.A.) law restricts this drug to use by or on the order of a
licensed veterinarian. Do not use this product on cats. WARNINGS: For the first
30 minutes after application: Ensure that dogs cannot lick the product from
application sites on themselves or other treated dogs, and separate treated
dogs from one another and from other pets to reduce the risk of accidental
ingestion. Ingestion of this product by dogs may cause serious adverse
reactions including depression, salivation, dilated pupils, incoordination, panting,
and generalized muscle tremors. In avermectin sensitive dogs, the signs may be
more severe and may include coma and death. HUMAN WARNINGS: Children
should not contact application site for two (2) hours.
Managing Parasite Threats Today 11
9/28/10 5:34 PM
Dealing With Tapeworms in Dogs
Kevin R. Kazacos, DVM, PhD
Professor of Veterinary Parasitology
Purdue University School of Veterinary Medicine
Flea treatment
It is easy to underestimate the prevalence and importance
of tapeworms in dogs. Adult tapeworms shed segments
intermittently, and proglottids are not evenly distributed in the
animal’s feces. Unless a segment gets ruptured or otherwise
releases eggs, eggs won’t appear on a fecal flotation, leading
to false-negative results. In addition, taeniid eggs are heavy
and do not float well, and unless a flotation solution with a
high specific gravity is used, they will be missed.1 Therefore,
fecal flotation is not a reliable diagnostic method for tapeworm
infection in dogs. Usually the infection is first noted by finding
tapeworm segments in the animal’s feces or on its perineum.
For the common tapeworms, the zoonotic risk to humans
is relatively low. Children may become infected with
Dipylidium by accidentally ingesting a flea carrying infective
larvae and may develop nonspecific signs of gastrointestinal
disturbance and perianal irritation. Taenia species as well
as Echinococcus species may infect humans as larvae and
be quite serious. Hydatid disease of the liver and other
internal organs is a well-known zoonotic infection caused
by Echinococcus species. Humans become infected by
accidentally ingesting eggs shed by an infected dog or present
on the dog’s rear end or hair coat.
Because of these discrepancies, the reported prevalence of
tapeworm infection in dogs varies widely, from 4.0% to 60.0%.2
Even though it is easy to dismiss tapeworms as being less
important clinically, they can and do cause some important
problems, and several canine tapeworms can cause potentially
serious zoonotic infections.
Diagnostic challenges
Tapeworms use intermediate hosts
The most common tapeworms found in dogs are Dipylidium
caninum and Taenia pisiformis. However, dogs may also
serve as hosts to other Taenia species (T. hydatigena,
T. ovis, etc.) and to the hydatid tapeworms Echinococcus
granulosus and E. multilocularis, among others.3,4 The
prevalence and distribution of these different tapeworms vary
across the United States, although the 2 common species are
essentially ubiquitous.
Dogs become infected with tapeworms when they ingest
intermediate hosts containing the larvae, either fleas in the
case of D. caninum, or rabbits for T. pisiformis.
Other Taenia species may utilize small ruminants, deer, or
other mammals; E. granulosus and E. multilocularis use
ungulates (sheep, elk, etc.) or rodents (voles, field mice, etc.),
respectively, as intermediate hosts.4
Clinical signs, zoonotic risks
Infected dogs are usually asymptomatic, unless large numbers
of tapeworms are present. Heavy infections in puppies may
result in soft or diarrheic feces and restlessness, and there are
reports of impactions, sometimes fatal, in young puppies with
heavy Dipylidium infection.5 There are also varied reports
of anal sacculitis caused by proglottids entering the anal sacs
instead of exiting the anus. But probably the most common
clinical problem caused by tapeworms is perianal irritation due
to the segments crawling in the perianal and perineal areas,
resulting in excessive licking at the area and/or rubbing of the
rear end on the carpet. A very important consideration is the
disgust people feel when seeing the segments crawling on the
animal or finding them on the furniture or in the dog’s bed.
12
BCAH0D0209_Tech_Bulletin_r25.indd 12-13
Drontal® Plus: The Most
Trusted Broad-Spectrum
Dewormer for Dogs*
Diagnosis of tapeworms is usually made by finding proglottids
on the animal’s perineum or in its feces or bedding. Specific
identification is made by examining proglottids and/or eggs
microscopically. But different Taenia species, including
several zoonotic species that infect dogs, cannot be easily
distinguished based on their proglottids. Echinococcus
proglottids are very small (only a few millimeters) and can be
easily missed. In addition, their eggs cannot be differentiated
from those of Taenia species, complicating the assessment of
zoonotic potential in a particular animal.4
Dipylidium is important because, unlike taeniid tapeworms,
it can maintain itself within the household environment. If
a dog has fleas, there is a good chance that it may also be
infected with Dipylidium, and evidence of this should be
sought. Many veterinarians take the proactive approach of
prescribing tapeworm treatment when there is evidence
of fleas, a relatively simple step that adds a degree of
reassurance for the pet owner. By the same token, if
Dipylidium infection is diagnosed in a dog, a flea-control
regimen should be instituted at the same time as tapeworm
treatment for adequate control of the problem.
Treatment is straightforward
Praziquantel is considered the treatment of choice for
tapeworms in dogs. While there are several veterinary
products containing praziquantel that are FDA-approved
to treat both D. caninum and T. pisiformis, not all
products are approved to treat these 2 tapeworms as well
as both Echinococcus species. It’s important to consider
your treatment options given the zoonotic potential of
Echinococcus. Praziquantel is available to canine patients
in both tablet and injectable formulations, but is increasingly
prescribed as a combination tablet (with pyrantel pamoate
and febantel) for added efficacy against hookworms, ascarids,
and whipworms.
&
&
Flea larvae ingest
tapeworm eggs.
A tapeworm larva
emerges from the
egg and develops
into an infective larva
inside the flea
Pet eats the flea
containing the
tapeworm-infective
larvae
Flea treatment kills the
fleas. Tapeworms grow
to maturity within pet’s
intestinal tract and shed
proglottids
Result:
Tapeworminfected pet
Frustrated client
Flea & tapeworm treatment
given concurrently
&
&
Flea larvae ingest
tapeworm eggs.
A tapeworm larva
emerges from the egg
and develops into an
infective larva inside
the flea
Pet eats the flea
Flea treatment kills
containing the
the fleas, while
tapeworm-infective tapeworm treatment
larvae
kills both immature
and adult tapeworms in
pet’s intestinal tract.
Result:
Flea- and
tapeworm-free pet
Satisfied client
Figure 1. Rationale for tapeworm treatment coinciding with flea control
If fleas are detected, proactive treatment for tapeworms
may save the client from having to return to the clinic if
tapeworms are later seen (Figure 1).
And even though a single treatment with praziquantel
is usually 100% effective against tapeworms, ongoing
flea infestations can result in reinfection, which may be
misinterpreted as treatment failure. Because achieving
control over flea infestations is not immediate, many
veterinarians will prescribe a second treatment for
tapeworms 2 to 3 weeks after the initial treatment since
reinfection during this time is common.5 In some cases,
additional treatments must be given.5 Since praziquantel
effectively removes different ages of tapeworms,6 all
developing tapeworms, including those recently acquired
through reinfection, will be eliminated by this retreatment.
References: 1. Dryden MW, Payne PA, Ridley R, Smith V.
Comparison of common fecal flotation techniques for the recovery
of parasite eggs and oocysts. Vet Ther. 2005;6(1):15-28. 2. CAPC
Recommendations: Tapeworm (Cyclophyllidean Cestodes).
Companion Animal Parasite Council Web site. http://www.capcvet.
org/recommendations/tapeworm1.html. Accessed May 23, 2010.
3. Bowman DD. Georgis’ Parasitology for Veterinarians. 9th ed.
Philadelphia: Saunders Elsevier; 2008:132-151. 4. Kazacos KR.
Cystic and alveolar hydatid disease caused by Echinococcus
species in the contiguous United States. Suppl Compend Contin
Educ Pract Vet. 2003;25(7A):16-20. 5. Tapeworms: Overlooked,
underdiagnosed, and undertreated. A roundtable discussion.
Atlanta: Virbac Animal Health; 2006:1-14. 6. Kazacos KR,
Storandt ST, Bolka DL, McCurdy HD. Efficacy of praziquantel
(Droncit) against immature and patent Echinococcus
multilocularis in dogs. In: Proceedings from the American
Association of Veterinary Parasitologists 39th Annual Meeting;
July 9-12,1994; San Francisco, CA. Abstract 98.
◆ Drontal® Plus is the only approved
broad-spectrum dewormer that’s
100% effective against 4 species
of tapeworms in dogs1:
• Dipylidium caninum
• Taenia pisiformis
• Echinococcus granulosus
• Echinococcus multilocularis
◆ Drontal® Plus treats 9 intestinal
parasites—the most comprehensive
intestinal parasite coverage available.†
Drontal® Plus delivers broadspectrum treatment.
Drontal® Plus Tablets (praziquantel/pyrantel
pamoate/febantel) and Drontal® Plus Taste Tabs®
Tapeworms
Dipylidium caninum
Taenia pisiformis
Echinococcus granulosus
Echinococcus multilocularis
Roundworms (2 species)
Hookworms (2 species)
Whipworms
✓
✓
✓
✓
✓
✓
✓
✓
*Based on sales data.
†
Based on label comparisons.
Reference:
1. Freedom of Information Summary: NADA 141-007. Drontal Plus Taste
Tabs Broad Spectrum Chewable Anthelmintic Tablets for Dogs.
CAUTION: Federal (U.S.A.) law restricts this drug to
use by or on the order of a licensed veterinarian. Not
for use in puppies less than 3 weeks of age or weighing
less than 2 lbs. Do not use in pregnant animals.
Managing Parasite Threats Today 13
9/28/10 5:34 PM
Roundworm in Cats: A Call for More Control
Profender®: The Most
Complete Feline Topical
Dewormer*
Dwight Bowman, MS, PhD
Professor of Parasitology
Cornell University College of Veterinary Medicine
According to the American Veterinary Medical Association,
there are nearly 82 million pet cats in the United States—
almost 10 million more than there are pet dogs.1 And with the
popularity of pet cats increasing, it’s more important than ever
to focus on controlling the internal parasites that infect them.
Table 1.
Prevalence of cats infected
with roundworm3 (n=263)
Type of care
Prevalence
Shelter
37%
Privately owned
27%
Results from other roundworm prevalence studies vary
widely, highlighting the broad discrepancies among various
diagnostic techniques and geographic locations.4,5 Thus, fully
understanding the risk roundworms pose to cats and people
remains problematic.
It is a common misperception among pet owners that cats
dwelling in households are not vulnerable to certain parasites.
The prevalence data clearly demonstrate that all cats are at
risk and further highlight the need to educate pet owners
about the prevention of roundworm, especially in multipet households.
Pathogenesis and disease
Cats can contract roundworm in several ways: ingestion of
embryonated eggs, consumption of transport hosts such as
mice and birds, and transmammary transmission from a
recently infected mother cat to her kittens.
Once a cat is infected, roundworms undergo a liver-lung
migration before establishing in the small intestine. The
developmental period for roundworms varies based on the
route of infection and other host factors, such as the age of
the cat. Still, once the worms reach adulthood, it’s estimated
14
BCAH0D0209_Tech_Bulletin_r25.indd 14-15
Zoonotic risks
The importance of the zoonotic potential of roundworm is
often overlooked or underestimated. People become infected
with roundworm by ingesting infective Toxocara eggs. Once
ingested, the eggs hatch and release larvae that can migrate
anywhere throughout the body. The signs and symptoms in
humans are determined by the tissues or organs damaged
during larval migration. The organs commonly affected are
the eyes, brain, liver, and lungs, which can lead to permanent
visual or neurologic damage.
Diagnosis: centifugal flotation is best
Centrifugal flotation is widely considered the gold standard
for the detection of roundworms. However, passive flotation
is more commonly practiced, which undoubtedly leads to
missed diagnoses because the eggs do not float as well using
this method.
A recent study reported that passive fecal flotation
examinations performed in private practices could be missing
1 in 4 positive cases of roundworm infection due to either
technician error or inherent limitations in the technique.6
Another study comparing direct smear, passive flotation,
and centrifugal flotation found that in every instance, only
centrifugal flotation achieved an acceptable level of accuracy.7
The study also reported that at least a third of the positive
samples were missed by the other two techniques.7
Because day-to-day practical considerations often result in
less rigorous and less accurate tests for roundworm, a broader
program of roundworm control and prevention is needed—
both to compensate for failure to identify roundworm
infection, and to keep infected cats from unnecessarily
contaminating the environment with infective eggs.
“Treating with products that are
effective against immature stages
eliminates the need for a second
treatment if no reinfection occurs.”
Treatment: easier than ever
While there are several good products for the treatment and
control of roundworm in cats, not all products treat both the
adult and L4 larval stages of the disease (Table 2).
Profender® is effective against adult and
L4 larval stages of roundworm (T. cati) in
clinical trials
Other Dewormers
Profender®
Table 2.
✓Adults
✓Adults
Effectiveness against multiple life
stages of roundworm in cats
Life stage
Emodepside
Praziquantel/
pyrantel
pamoate
Selamectin
Adults
✓
✓
✓
L4 larvae
✓
It needs to be understood that cats of all ages are at risk of
infection, and that the eggs of Toxocara cati can be found
all over the environment, as demonstrated by the very high
levels found in shelter cats throughout the United States.4,5
Treating with products that are effective against immature
stages eliminates the need for a second treatment if no
reinfection occurs.
Treatment and control of roundworm in cats has never been
easier or more cat-friendly. It’s time to control roundworm in
cats for good.
References: 1. AVMA Web site. U.S. Pet Ownership &
Demographics Sourcebook (2007 Edition). http://www.avma.org/
reference/marketstats/sourcebook.asp. Accessed July 27, 2010.
2. Jaklitsch R, Johnson E, Payton M, Little SE. Prevalence of
intestinal parasites of dogs and cats based on centrifugal flotation at
a national service laboratory. Poster presented at: Oklahoma State
University Center for Veterinary Health Sciences Summer Research
Training Program Symposium. July 31, 2007. 3. Spain CV, Scarlett JM,
Wade SE, McDonough P. Prevalence of enteric zoonotic agents in
cats less than 1 year old in central New York State. J Vet Intern
Med. 2001;15(1):33-38. 4. Hill SL, Cheney JM, Taton-Allen GF,
Reif JS, Bruns C, Lappin MR. Prevalence of enteric zoonotic
organisms in cats. J Am Vet Med Assoc. 2000;216(5):687-692.
5. Carleton RE, Tolbert MK. Prevalence of Dirofilaria immitis
and gastrointestinal helminths in cats euthanized at animal control
agencies in northwest Georgia. Vet Parasitol. 2004;119(4):319-326.
6. Gates MC, Nolan TJ. Comparison of passive fecal flotation run by
veterinary students to zinc-sulfate centrifugation flotation run in a
diagnostic parasitology laboratory. J Parasitol. 2009;95(5):12131214. 7. Payne PA. Accurate evaluation of fecal samples critical to
patient. DVM Best Practices. http://veterinarynews.dvm360.com/
dvm/article/articleDetail.jsp?id=49063&sk=&date=&pageID=2.
Accessed July 27, 2010.
Mucosa
A recent study reported that roundworm is the most common
intestinal parasite in cats.2 While this may not be surprising
in itself, research evaluating the prevalence of roundworm in
shelter cats and privately owned cats reveals surprisingly high
numbers in both cases (Table 1).
that they can produce as many as 100,000 eggs per day. Each
of these eggs can remain viable for months or even years.
✓L4 Larvae
1. Lumen of small
intestine
2. Villi
3. Submucosa
Profender® is effective against
multiple life stages of the most
common intestinal parasites
Roundworms
T. cati—Adult
L4 Larvae
✓
✓
Hookworms
A. tubaeforme—Adult
L4 Larvae
Immature Adults
✓
✓
✓
Tapeworms
D. caninum—Adult
T. taeniaeformis—Adult
✓
✓
*Based on label comparisons. Profender® is labeled for tapeworms,
roundworms, and hookworms.
CAUTION: Federal (U.S.A.) law restricts this drug to use
by or on the order of a licensed veterinarian. HUMAN
WARNINGS: Children should not contact application site
for twenty-four (24) hours. Use with caution in sick or
debilitated cats. Oral ingestion or exposure should
be avoided.
Managing Parasite Threats Today 15
9/28/10 5:34 PM
With Bayer Parasite Solutions, you
can customize comprehensive parasite
programs for each of your patients.
Dogs
Treat monthly, year-round
Treat as indicated
Cats
Treat monthly, year-round
Federal (U.S.A.) law restricts Drontal ® Plus, Profender ®, Advantage Multi ®
for Cats and Advantage Multi ® for Dogs to use by or on the order of a
licensed veterinarian.
Advantage Multi ® for Cats
WARNINGS: Do not use on sick, debilitated, or underweight cats
(see ADVERSE REACTIONS). Do not use on cats less than 9 weeks of age or
less than 2 lbs. body weight. HUMAN WARNINGS: Children should not come
in contact with the application site for 30 minutes after application.
PRECAUTION: Avoid oral ingestion.
Advantage Multi ® for Dogs
CONTRAINDICATIONS: Do not administer this product orally.
Do not use this product (containing 2.5% moxidectin) on cats. WARNINGS:
For the first 30 minutes after application, ensure that dogs cannot lick the
product from application sites on themselves or other treated dogs, and
16
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Treat as indicated
separate dogs from one another and from other pets to reduce the risk
of accidental ingestion. Ingestion of this product by dogs may cause
serious adverse reactions including depression, salivation, dilated pupils,
incoordination, panting and generalized muscle tremors. In avermectin
sensitive dogs, the signs may be more severe and may include coma and
death. HUMAN WARNINGS: Children should not come in contact with the
application site for two (2) hours after application.
Drontal® Plus
Not for use in puppies less than 3 weeks of age or weighing less than
2 lbs. Do not use in pregnant animals.
Profender®
Not for human use. Keep out of the reach of children. Children should not
contact application site for twenty-four (24) hours.
K9 Advantix® is for use on dogs only.
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© 2010 Bayer HealthCare LLC, Animal Health Division, Shawnee Mission, Kansas 66201
Bayer, the Bayer Cross, Advantage, K9 Advantix, Advantage Multi, Drontal, Profender,
and Taste Tabs are registered trademarks of Bayer.
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