Emerging Diseases of Companion Animals

By T.J. Dunn, DVM

Kansas City<spanstyle=’font-family:Arial’>, Mo.<spanstyle=’font-family:Arial’> – (July 6, 2006)- <spanstyle=’font-family:Arial;color:black’>Will veterinarians someday be routinely testing dogs for the Ebola virus? Recent evidence shows the rapidlyprogressive and fatal hemorrhagic fever in humans and nonhuman primates has thepotential to infect dogs. A serologic survey done on pet dogs in an endemic Ebola virus area of Africa<spanstyle=’font-family:Arial;color:black’> in 2002 showed a significant percentage of dogs had d<spanstyle=’font-family:Arial;color:black’> detectable Ebola virus”specific IgG levels. Although no symptomatic dogs were found, according to the authors,“the study proved that either true infection or simple antigenic stimulation does occur in dogs.” Given the ever-changing nature of all biological systems,it may not be too far-fetched to think this deadly virus may someday emerge as a common infection of dogs.1

The “new and emerging disease” topic has taken center stage for veterinarians and human physicians worldwide. Powered by highly mobile societies and global human/companion animal population expansion, dynamic changes are occurring in formerly isolated or sparsely populated ecological niches. The biological spectrum of organisms and their adaptations and mutations are responding to the influx of man and his animals. A classic example is the now common Lymedisease. A few decades ago it was unknown in the United States<spanstyle=’font-family:Arial;color:black’> in man and dogs.However, a mobile society has brought with it all the pieces the puzzle needed to become a complete picture. Suitable tick species, mammals (such as mice and deer), and<spanstyle=’font-family:Arial;color:black’> the hardy Borrelia bacterium all merge at the same time and place creating the potential to cause disease. The bacterium, connecting with a<spanstyle=’font-family:Arial;color:black’>n immunologically innocent population ofdogs, cats, horses and humans, now flourishes at the expense of humans andcompanion animals.2

Just as veterinarians upgrade laboratory, diagnostic and medical management skills on a continuous basis, updated information regarding new and emerging diseases of companion animals is fast becoming a priority. One motivating force behindthis heightened awareness is the understanding that many of these “exotic”diseases are zoonotic in nature. For example, when a veterinarian makes adiagnosis of West Nile<spanstyle=’font-family:Arial;color:black’> virus in a horse, local human physiciansare alerted the disease could manifest itself in human patients. Infectedcompanion animals often are sentinels for similar infections in humans. Thelist of “new” diseases in dogs, cats and horses in the United States<spanstyle=’font-family:Arial;color:black’> is growing; and depending upon geographic location, a number of them are familiarin name only to local veterinarians. Veterinarians must be sensitive to thesentinel scenario by remaining committed to making the correct diagnosis inanimal patients whenever an unusual disease is suspected.3

A brief mention of several emerging diseases follows:

No longer limited to isolated areas of the eastern United States, numerous species of hemotropic, gram negative bacteria called Bartonella infect dogs, cats and humans.Along with Bartonella, such diseases as Leishmania,5 Babesiaand Rocky Mountain spotted fever are on the move. Within the past severaldecades, the number of Ehrlichia and Anaplasma spp.recognized to infect cats, dogs, and humans has expanded substantially in Europe and the United States. The agent of humangranulocytic Ehrlichiosis (HGE) has recently been classified as A. phagozytophilum.The disease has influenza like symptoms with variable degrees of anemia,thrombocytopenia, leucopenia and elevated liver enzymes. Dogs are thought to besentinels for assessing risk for HGE in humans.6

West Nile<spanstyle=’font-family:Arial;color:black’> virus (WNV) is an arbovirus transmitted by insect vectors. It has received substantial media exposure in recentyears. Research suggests that dogs and cats are readily infected, but may be weak reservoirs of the virus and thus, do not play a major role in viral transmission or maintenance… at least not yet. Cats can become infected by consuming small mammals and birds, which are known to have large quantities of WNV in their blood and tissue during the course of infection.Veterinarians and human physicians need to be aware that confirmed infection in local birds and in companion animals such as dogs, cats and horses are classic sentinels for potential human infection with WNV.

Coronavirus infections in dogs may soon be considered even more dangerous than parvovirus. A 2005 study in Italy<spanstyle=’font-family:Arial;color:black’> of an outbreak of rapidly fatal systemic disease in puppies that proved to be caused by coronavirus underscores the essential character of new and emerging infectious disease. The authors succinctly conclude, “The coronaviruses of carnivores provide a paradigmatic model of how coronaviruses cross the species barriers, adapt to new host species and change their pathogenicity.”8

Methicillin-resistant Staphylococcus aureus (MRSA<spanstyle=’font-family:Arial;color:black’>) is one of the most important causes of human health care associated infections, and it also occurs in dogs, cats and horses. Studies suggest that dogs can act as reservoirs of MRSA, which can pose a public health risk to owners and veterinary staff, as well as limit the options for antimicrobial drug treatment of MRSA<spanstyle=’font-family:Arial;color:black’> infections. “Staff in veterinary hospitals could have an increased risk of carrying MRSA, because of contact with infected animals and antimicrobialdrugs in their work environment.”9 Veterinarians must take a proactive approach when the potential exists for in hospital microbessuch as MRSA<spanstyle=’font-family:Arial;color:black’>.

Veterinarians have a unique responsibility in the health care community. They are responsible for protecting the health of their animal patients and for acting as advisors to the human medical community regarding zoonotic pathogens. It is their duty to provide accurate information to their clients about the potential for transmission of infections from pets. This is especially true with the mostvulnerable citizens, such as children, pregnant women, the elderly and theimmune compromised.

Numerous resources are available to assist veterinarians in keeping abreast of current issues in new and emerging diseases. Below are suggested links for further reading:

Centers For Disease Control and Prevention
www.cdc.gov

Centers For Epidemiology and Animal Health
www.aphis.usda.gov/vs/ceah/cei/index.htm

North Carolina State College of Veterinary Medicine
Tick Borne Diseases Laboratory http://www.cvm.ncsu.edu/docs/ticklab.html

American Veterinary Medical Association
www.avma.org

Veterinary Medical Colleges
www.aavmc.org/students_admissions/vet_schools.htm

State Veterinary Medical Associations
http://www.avma.org/careforanimals/animatedjourneys/aboutvets/membership.asp#2

REFERENCES:

1Ebola Virus Antibody Prevalence in Dogs and Human Risk
LoïsAllela,*1Olivier Bourry,*<ahref=”http://www.cdc.gov/ncidod/EID/vol11no03/04-0981.htm#1f#1f”>1 Régis Pouillot,† André Délicat,* Philippe Yaba,* Brice Kumulungui,* Pierre Rouquet,*Jean-Paul Gonzalez,‡ and Eric M. Leroy*‡
*Centre International de Recherches Médicales de Franceville, Franceville,Gabon; †Centre Pasteur du Cameroun, Yaoundé, Cameroun; and ‡Institut de Recherchepour le Développement, Paris, France
<ahref=”http://www.cdc.gov/ncidod/EID/vol11no03/04-0981.htm”>http://www.cdc.gov/ncidod/EID/vol11no03/04-0981.htm

2Lyme Disease
©2005 Kenneth Todar University of WisconsinMadison Department of Bacteriology
http://textbookofbacteriology.net/Lyme.html

3Tick Borne Diagnostic Laboratory
<ahref=”http://www.cvm.ncsu.edu/docs/ticklab.html”>http://www.cvm.ncsu.edu/docs/ticklab.html
Edward Breitschwerdt, DVM
Professor, Internal Medicine
Adjunct Associate Professor of Medicine, Duke University Medical Center
Doctor of Veterinary Medicine, University of Georgia 1974
Internship and residency,
University of Missouri 1974-1977
Phone:919.513.8277<spanstyle=’font-size:10.0pt;font-family:Arial;color:black’>
FAX: 919.513.6336<spanstyle=’font-size:10.0pt;font-family:Arial;color:black’>
Email: [email protected]

<ahref=”http://www.cvm.ncsu.edu/docs/ticklab.html#rockymountain#rockymountain”>RockyMountain Spotted Fever Information <ahref=”http://www.cvm.ncsu.edu/docs/ticklab.html#bartonella#bartonella”>BartonellaInformation <ahref=”http://www.cvm.ncsu.edu/docs/ticklab.html#ehrlichia#ehrlichia”>EhrlichiaInformation <ahref=”http://www.cvm.ncsu.edu/docs/ticklab.html#babesia#babesia”>BabesiaInformation <ahref=”http://www.cvm.ncsu.edu/docs/ticklab.html#lyme#lyme”>Lyme Information<ahref=”http://www.cvm.ncsu.edu/docs/ticklab.html#leishmania#leishmania”>LeishmaniaInformation

4Bartonella Spp. in Pets and Effect on Human Health
Bruno B. Chomel,*Henri-Jean Boulouis,† Soichi Maruyama,‡ and Edward B. Breitschwerdt§<brclear=all>http://www.cdc.gov/ncidod/EID/vol12no03/pdfs/05-0931.pdf

Peter M. Schantz, VMD, PhD
Division of Parasitic Diseases
National Center for Infectious Diseases
Centers For Disease Control and Prevention

Mail stop F22
4770
Buford Highway
Atlanta, GA30341Telephone: 770) 488-7767<brclear=all>e-mail: [email protected]

6 Cat or Dog Ownership and Seroprevalence of Ehrlichiosis, Q Fever, and Cat-Scratch Disease
Martina Skerget,*Christoph Wenisch,* Florian Daxboeck,† Robert Krause,* Renate Haberl,* andDoris Stuenzner*
*University Hospital Graz, Graz, Austria; and†UniversityHospital, Vienna, Austria<spanstyle=’font-size:10.0pt;font-family:Arial;color:black’>
http://www.cdc.gov/ncidod/EID/vol9no10/03-0206.htm

7West Nile Virus Encephalitis and Myocarditis in Wolf and Dog
Carol A. Lichtensteiger,* Kathleen Heinz-Taheny,* Tanasa S. Osborne,* Robert J.Novak,* Beth A. Lewis,* and Margaret L. Firth†
*University of Illinois<spanstyle=’font-size:10.0pt;font-family:Arial;color:black’>, Champaign-Urbana, Illinois, USA<spanstyle=’font-size:10.0pt;font-family:Arial;color:black’>; and †Town and CountryAnimalHospital<spanstyle=’font-size:10.0pt;font-family:Arial;color:black’>, Normal<spanstyle=’font-size:10.0pt;font-family:Arial;color:black’>, Illinois<spanstyle=’font-size:10.0pt;font-family:Arial;color:black’>, USA<spanstyle=’font-size:10.0pt;font-family:Arial;color:black’>
http://www.cdc.gov/ncidod/EID/vol9no10/02-0617.htm

8Canine Coronavirus Highly Pathogenic for Dogs
CanioBuonavoglia,*<ahref=”http://www.cdc.gov/ncidod/EID/vol12no03/05-0839.htm#com#com”><spanstyle=’text-decoration:none’>Comments Nicola Decaro,* Vito Martella,* Gabriella Elia,*Marco Campolo,* Costantina Desario,* Massimo Castagnaro,† and Maria Tempesta*
*University of Bari<spanstyle=’font-size:10.0pt;font-family:Arial;color:black’>, Bari, Italy<spanstyle=’font-size:10.0pt;font-family:Arial;color:black’>; and †University of Padua<spanstyle=’font-size:10.0pt;font-family:Arial;color:black’>, Padova, Italy
<ahref=”http://www.cdc.gov/ncidod/EID/vol12no03/05-0839.htm”>http://www.cdc.gov/ncidod/EID/vol12no03/05-0839.htm

9Methicillin-resistant Staphylococci in Companion Animals
KeithE. Baptiste,* Kerry Williams,† Nicola J. Willams,*<ahref=”http://www.cdc.gov/ncidod/EID/vol11no12/05-0241.htm#com#com”><spanstyle=’text-decoration:none’>Comments Andrew Wattret,* Peter D. Clegg,* Susan Dawson,* JohnE. Corkill,† Turlough O’Neill,* and C. Anthony Hart†
*University of Liverpool, Leahurst, United Kingdom; and Royal Liverpool University Hospital, Liverpool, United Kingdom
http://www.cdc.gov/ncidod/EID/vol11no12/05-0241.htm

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