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Horse Vaccination Update. ANR Update November 18, 2008 Dr. Fernanda Camargo-Stutzman Horse Extension Specialist. Disease Control. Infectious vs. Contagious: Is every infectious disease also contagious?
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Horse Vaccination Update ANR Update November 18, 2008 Dr. Fernanda Camargo-Stutzman Horse Extension Specialist
Disease Control • Infectious vs. Contagious: Is every infectious disease also contagious? • Infectious disease: caused by a pathogenic microorganism or agent (The American Heritage® Stedman's Medical Dictionary) • Contagious disease: spreads from one infected individual to another • “All contagious diseases are also infectious, but not all infectiousdiseases are contagious”
Programs to Control Infectious Disease: • Reduce the exposure to infectious agents in the horse’s environment • Enhance resistance (vaccination) • Minimize the factors that decrease resistance to disease.
Factors that Decrease Resistance to Disease: No turn-out time Transportation Inclement weather Weaning Disruption of established social groups Stringent exercise program ETC • Stress • Over-crowding • Parasitism • Poor nutrition • Inadequate sanitation • Contaminated water supply • Concurrent disease
Management • Occurrence of infectious diseases increases with increase in population density of susceptible horses: sales, boarding facilities, breeding farms, fairgrounds, racetracks, etc. • Resident herd vs. Itinerant herd: different management
Management • Segregation of horses in small groups: age, use, gestation status, etc. • Maintain each group as an isolated unit: restrict movement of horses in established groups, especially transient horses • Stress reduction • Isolation of sick animals
Vaccination • Vaccination alone is not sufficient to prevent infectious diseases • Protection is not immediate • Booster doses
AAEP and AVMA • Core Vaccination and Risk-Based Vaccination • Core: AVMA defines: “those that protect from diseases that are endemic to a region, those with potential public health significance, required by law, virulent/highly infectious, and/or those posing a risk of severe disease.” • Risk-Based: varies regionally, from population to population within an area, or between individual horses within a population.
Core and Risk-Based Vaccination • Core: Tetanus, Rabies, Eastern and Western Equine Encephalomyelitis and West Nile Virus. • Risk-Based: Anthrax, Botulism, Equine Herpesvirus (Rhinopneumonitis), Equine Viral Arteritis, Equine Influenza, Potomac Horse Fever, Rotaviral Diarrhea and Strangles.
Tetanus • Deadly, horses highly susceptible, bacteria in feces, soil, everywhere. • Not contagious
Rabies • Deadly • Carriers: skunks, bats, rabid carnivores, foxes, etc • Transmitted by rabid animal bite saliva • Furious rabies vs. dumb rabies (hydrophobia) • Contagious ZOONOSIS
Eastern and Western Encephalomyelitis • Neurological disease: Sleeping sickness • Transmitted by mosquitoes and blood-sucking insects (birds and rodents are reservoirs) • EEE highest mortality, WEE low mortality • Humans can contract it • VEE: horse is important factor in human disease
West Nile Virus • Comes from a family of viruses which contain some of the some of the most important human pathogens in the world. • Transmitted by many mosquito species • Affects CNS • Humans can contract it • 40% mortality
Neurological Signs http://www.equinewestnile.com/images/horsecut_large.mov http://www.ca.uky.edu/gluck/BiblioEHV1.asp http://www.ca.uky.edu/gluck/AllenGP.asp
Risk-Based: • Anthrax • Botulism • Equine Herpesvirus (Rhinopneumonitis) • Equine Viral Arteritis • Equine Influenza • Potomac Horse Fever • Rotaviral Diarrhea • Strangles
Botulism • Most potent toxin known to man • Very deadly • Modes of infection: spoiled hay, silage, haylage, anaerobic wound, round-baled hay • Flaccid paralysis (flabby) • Clinical diagnosis • Annual vaccine
Influenza • Highly contagious respiratory disease • Spreads very quickly • High fever, possible secondary bacterial infections (pneumonia) • May take up to 6 months for horses to completely recuperate to level of performance • Vaccinate performance horses 2-4 times per year
Equine Herpesvirus - Rhinopneumonitis • Latency • Stress • Causes abortion (EHV-1) • Vaccinate: 5,7 and 9 months gestation • Causes respiratory disease (EHV-4) • Vaccinate: every 4-6 months (performance horses)
Equine Viral Arteritis • Abortion • Vaccinate stallions and teasers 4 weeks prior to breeding season • Test before vaccinating • Isolate vaccinated horses for at least 28 days
Others: • Rotavirus: only problematic to foals vaccinate broodmares • Potomac Horse Fever: very low incidence in KY, may be a problem to horses drinking water from stream • Strangles: highly contagious, swollen lymph nodes, nasal vaccine do not use injectable vaccine the same day abscesses