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24TH ANNUAL PATHOLOGY MEETING OF THE WEST COAST
SUBDIVISION OF THE CL DAVIS DVM FOUNDATION
27-28 April 2007, Asilomar Conference Grounds, Monterey, California
Tracking Emerging Diseases in the Animal Shelter
P. Pesavento, DVM, PhD, dip ACVP
PMI, UC Davis School of Veterinary Medicine
INTRODUCTION: An emerging infection is one that has newly appeared in the
population, or one that has existed but is altered in incidence, geographic range, or character (virulent strains, species jumpers). Therefore, while an emerging pathogen can be a novel pathogen, it is often a previously recognized pathogen newly capable of emerging as a virulent species from an otherwise docile/dormant background. In some cases there are singly identifiable factors associated with emergence (for example, acquisition of antibiotic resistance), but many incidences of emergence occur subsequent to alterations in a combination of pathogen, host, and/or environmental factors.
Animal shelters create a uniquely suitable environment for disease emergence. A partial list of factors present in the shelter environment that could promote emergence includes:
transportation, stress (immunosuppression), increased
contact (overpopulation), exposure, species mixing, nutrition, concurrent disease, high animal turnover, and indiscriminant use of antibiotics. There is also selective and enhanced evolutionary pressure on pathogens in an environment with a high turnover of animals on a range of vaccination protocols.
Shelter animal populations have progressively grown in number. The US
currently has an estimated 15-25 million animals in shelter situations. As a
comparison, the number of dairy cows in the US and Canada combined is ~9.2
million. For the food animal, countries including the U.S. have an extensive
diagnostic surveillance system that focuses on zoonotic, endemic, and exotic
disease. An estimation of the cost of such vigilance would include federal, state, farm industry, food industry, and research contributions to this massive effort (millions). In contrast, with the possible exception of rabies, there is little coordinated or even predictable surveillance for diseases in intensively housed small animals. Diseases emerging from our shelter populations could be devastating to both our animal population and/or to the human population.
Although emergent diseases are rarely predictable, having a concerted
diagnostic program for our small animal populations would help in early
identification and prophylaxis. Several zoonoses have already emerged in our small animal populations that serve as precedent for this caution. The first report of domestic cats dying from H5N1 influenza virus infection was in February of 2004, in Bangkok, Thailand. In this seminal case, all 15 cats exposed to the virus (either by ingestion of an infected chicken carcass or exposure to an infected cat) died with severe
pneumonia. The fatal disease in cats is now well recognized in most countries
where H5N1 virus is endemic in poultry. Researchers speculate that cats may
play a role not just in disease transmission but also in H5N1 virus adaptation to mammals.....
24TH ANNUAL PATHOLOGY MEETING OF THE WEST COAST
SUBDIVISION OF THE CL DAVIS DVM FOUNDATION
27-28 April 2007, Asilomar Conference Grounds, Monterey, California
Tracking Emerging Diseases in the Animal Shelter
P. Pesavento, DVM, PhD, dip ACVP
PMI, UC Davis School of Veterinary Medicine
INTRODUCTION: An emerging infection is one that has newly appeared in the
population, or one that has existed but is altered in incidence, geographic range, or character (virulent strains, species jumpers). Therefore, while an emerging pathogen can be a novel pathogen, it is often a previously recognized pathogen newly capable of emerging as a virulent species from an otherwise docile/dormant background. In some cases there are singly identifiable factors associated with emergence (for example, acquisition of antibiotic resistance), but many incidences of emergence occur subsequent to alterations in a combination of pathogen, host, and/or environmental factors.
Animal shelters create a uniquely suitable environment for disease emergence. A partial list of factors present in the shelter environment that could promote emergence includes:
transportation, stress (immunosuppression), increased
contact (overpopulation), exposure, species mixing, nutrition, concurrent disease, high animal turnover, and indiscriminant use of antibiotics. There is also selective and enhanced evolutionary pressure on pathogens in an environment with a high turnover of animals on a range of vaccination protocols.
Shelter animal populations have progressively grown in number. The US
currently has an estimated 15-25 million animals in shelter situations. As a
comparison, the number of dairy cows in the US and Canada combined is ~9.2
million. For the food animal, countries including the U.S. have an extensive
diagnostic surveillance system that focuses on zoonotic, endemic, and exotic
disease. An estimation of the cost of such vigilance would include federal, state, farm industry, food industry, and research contributions to this massive effort (millions). In contrast, with the possible exception of rabies, there is little coordinated or even predictable surveillance for diseases in intensively housed small animals. Diseases emerging from our shelter populations could be devastating to both our animal population and/or to the human population.
Although emergent diseases are rarely predictable, having a concerted
diagnostic program for our small animal populations would help in early
identification and prophylaxis. Several zoonoses have already emerged in our small animal populations that serve as precedent for this caution. The first report of domestic cats dying from H5N1 influenza virus infection was in February of 2004, in Bangkok, Thailand. In this seminal case, all 15 cats exposed to the virus (either by ingestion of an infected chicken carcass or exposure to an infected cat) died with severe
pneumonia. The fatal disease in cats is now well recognized in most countries
where H5N1 virus is endemic in poultry. Researchers speculate that cats may
play a role not just in disease transmission but also in H5N1 virus adaptation to mammals.....