The near-hysteria that gripped parts of the country in the wake of those attacks has faded, but it has been a case of a lesson learned the hard way. Behind-the-scene efforts are under way across the country to make certain that there is not a repeat occurrence. Nowhere is this effort more focused than in the protection of the nation's food supply from bioterrorism.
Research institutions from North Dakota to Texas and from California to the East Coast are working on projects aimed at protecting animals and crops. Fallout from these efforts is having a positive effect on the equine industry.
Epizootic and Zoonotic
Concerns regarding animal health center around two basic types of disease outbreaks--epizootic and zoonotic. Epizootic refers to diseases that attack many animals in any region at the same time. West Nile virus is an example. Zoonotic refers to diseases that are transmissible from animals to man under natural conditions. Anthrax, which can afflict horses, cattle, and humans, is an example. Experts say that of the 1,600 pathogens known to affect humans, about one-half are zoonotic.
While U.S. and international officials are more concerned with food animals than with horses in regard to bioterrorism, equines are not being overlooked. The Office International des Epizooties (OIE; the World Organization for Animal Health), for example, has categorized a list of diseases for every species (www.oie.int/eng/maladies/en_classification.htm) that should be reported to them.
This is a new list that was approved by the OIE in May 2005. However, if you wish to search for animal health information prior to 2005, you must search under the previous A and B categorization system. List A diseases are described as being transmissible and as having the potential for very serious and rapid spread. They are considered to be of serious socioeconomic or public health consequence.
The two List A diseases for horses are African horse sickness and vesicular stomatitis. African horse sickness is a highly fatal infectious disease that can strike horses, mules, and donkeys. There are nine viral strains that can cause the disease, which is spread by carrier insects. The mortality rate ranges between 60-90%. Vesicular stomatitis is a viral disease characterized by fever, small blisters, and subsequent erosions in the mouth, teats, scrotal area, and coronary bands. While this is not a deadly disease, its clinical signs are nearly indistinguishable from foot and mouth. The outbreak of foot and mouth in England a few years ago is testament to how a livestock disease can bring a country to a halt within its borders and have an international economic impact because of disease control.
List B diseases are considered significant, but a bit less serious than those on List A. Fifteen equine diseases are on List B. They are: contagious equine metritis (CEM), dourine, epizootic lymphangitis, Eastern and Western equine encephalomyelitis, equine infectious anemia (EIA), equine piroplasmosis, equine rhinopneumonitis, glanders, horse pox, equine viral arteritis (EVA), Japanese encephalitis, horse mange, surra, and Venezuelan equine encephalomyelitis.
Being able to track animals as they move from location to location as part of the effort to thwart bioterrorism has become a priority with the USDA, and the government is seeking an approach that will work on a nationwide basis.
Researchers at North Dakota State University (NDSU), with headquarters in Fargo, are helping lead the way in developing sophisticated technology to accomplish this goal. Their approach involves attaching a specially designed tag to a beef animal's ear. The tags emit a high-frequency signal that is picked up by a scanner several feet away and is transmitted to computers that record and store the data. The technical term for the technology is radio-frequency identification (RFID) tags.
The research is highly important to the equine industry because the technology being developed in the future might be adapted to the implanted identification microchips that are being used by some horse owners. However, at present, most of the implanted equine microchips are low-frequency and are read by handheld scanners nearly touching the neck.
As part of the NDSU identification research, each animal involved in the project is assigned an identification number that goes on the tag and, as the technology advances, it will also be stored in a national database. With that approach, if there is a disease outbreak, it will be possible to track an individual animal from birth.
Ultimately, says Doug Freeman, DVM, PhD, professor and head of NDSU's Veterinary and Microbiological Science Department, it should be possible to quickly identify a load of cattle or horses as they stream past a scanner at an auction facility or at a slaughterhouse. There is even the possibility that the animals can be positively identified on an individual basis while still on the truck. There has been excellent progress with the high-frequency tag at NDSU. In one test, 143 of 143 cattle were detected as they ran through a cattle chute, with the scanner located about seven feet away.
The importance of being able to track horses as they move from location to location was underscored by Steve Conboy, DVM, of Kentucky, at the 2005 American Association of Equine Practitioners (AAEP) convention. Conboy presented a paper on "Preventing Contagious Diseases." In discussing various communicable diseases, he told his listeners that CEM has been eradicated in the United States, but could be reintroduced at any time by infected stallions and/or mares.
"The greatest risk is coming from imported horses that enter with temporary permits, and then they get lost in the system and remain here for breeding," he said. "We need to be vigilant that these horses get tested before they are bred."
If a horse identification system featuring high-frequency microchips and including a central database were in place, it would be relatively easy to track such horses and make certain they didn't get "lost."
Conboy also provided perspective on the potency of some infectious diseases. Although bioterrorism was not the focus of his presentation, some of his points provided serious food for thought on that subject. For example, he said, with EIA (a List B disease), it takes only one-fifth of a teaspoon of contaminated blood to infect 10,000 horses, and in the case of an acutely infected horse, a similar amount of blood can infect one million horses.
The equine industry is taking steps to incorporate an identification system featuring microchips. At the 2005 Symposium on Racing and Gaming, it was announced that while The Jockey Club will not mandate the use of microchips as a requirement for registration of Thoroughbred foals in the near future, it would adapt its database to include microchip numbers.
A horse identification project that uses microchips is underway in New Mexico this year as part of a cooperative effort between the state and the New Mexico Racing Commission. In the beginning phase of the project, microchips will be in implanted in 2-year-old racing Thoroughbreds.
In still another development, New York state officials have offered to implant microchips in horses at no cost to owners.
Leading the way in the utilization of microchips in horse ID have been Great Britain and Ireland. The microchip approach has been mandatory as part of horse identification since 1999 in both countries.
Identification microchip technology appears to be in its infancy stages. Sophisticated chips that can record and report a horse's temperature and thus provide an early tip-off to disease are on the horizon (currently these chips are used in dairy cattle). Other chips can store data such as the horse's birth to dates and results of tests administered.
Last summer the NDSU biosurveillance team and animal health care personnel had a glimpse of what it might be like to combat a disease outbreak in horses and cattle as the result of bioterrorism, although in this case it was a naturally occurring disease. North Dakota and parts of the Midwest are endemic for anthrax, says Freeman, and 2005 was the perfect year for the disease to surface as the result of excessive early summer rains that caused lowland flooding, followed by hot summer temperatures.
The bacterium Bacillus anthracis causes anthrax. According to information from the North Dakota Department of Agriculture, the bacteria can be found in two stages--the vegetative and the spore state. The vegetative state is the growing, reproducing form of the bacteria, and this is the form that causes disease.
If untreated, anthrax in animals is generally fatal. If the carcass of an infected animal is opened and the anthrax organisms are exposed to air, they will form spores.
Anthrax spores are highly resistant to heat, cold, chemical disinfectants, and drying. The anthrax spore can live indefinitely in the soil of a contaminated pasture or yard. When conditions are right--flooding followed by heat--the anthrax spores in the soil surface will revert to the vegetative state and cause the disease when ingested or inhaled by animals.
Before the disease had run its course last year, anthrax was reported on nearly 100 premises in 15 North Dakota counties and had accounted for more than 500 animal deaths, incuding horses, donkeys, cattle, bison, elk, sheep, llama, and white-tailed deer. Anthrax also surfaced in South Dakota and Minnesota last year, with both states suffering substantial losses. The majority of the losses were in cattle, which are more susceptible to anthrax than horses.
Some valuable strategies that could be used in the event of a bioterroristic attack were developed and improved during the outbreak, according to Freeman. They involved early detection and communication among health officials, and between officials and the public. During the North Dakota outbreak, Freeman says, the NDSU diagnostic laboratory employed the most sophisticated DNA testing available (PCR or polymerase chain reaction) to provide fast and accurate diagnoses. Freeman says the outbreak also brought about improved communications between the NDSU biosurveillance team, the state veterinarian's office, and animal health care officials in the field, something that would be critical in the event of a bioterrorism attack.
The NDSU biosurveillance team features a crisis communications specialist from the NDSU faculty as a member of the group to assist in coordinating the dissemination of accurate information among animal health officials and between officials and the public.
Research aimed at quickly identifying disease outbreaks also is going on in the private sector. Advanced Animal Diagnostics (AAD) is a private company that is developing a diagnostic approach that it maintains is fast, accurate, and easily administered. At the heart of the technology, company officials say, is the use of multiple wavelength imaging to extract cytochemical, morphological, and immunochemical changes in cells involved in the immune response. In other words, the company maintains that it has developed the means to quickly determine on-site the exposure to infectious agents by examining the animal's immune response.
The instrument responsible for this detection process is described as being an inexpensive, lightweight platform that can be used without the specialized operating training required for more sophisticated techniques, such as hematology analyzers, cell analysis, immunochemistry analyzers, or flow cytometers. According to AAD sources, the technology was invented by Yale Professors Robert Levine, PhD, and Steven Wardlaw, PhD. Company officials say that one of the technology's capabilities involves an on-site, accurate early identification of EIA.
On the federal scene, more money is being made available to study ways in which to prevent and--if that doesn't work-- deal with a bioterrorist attack. One of the most ambitious money-spending approaches involves the Veterinary Workforce Expansion Act of 2005. Introduced by Senator Wayne Allard, a former practicing veterinarian in Colorado, it calls for spending $1.5 billion over the next 10 years in the form of competitive grants primarily to veterinary colleges to allow for building, laboratory, and classroom expansion aimed at graduating more veterinarians who will work in areas such as regulatory medicine, public health, diagnostic veterinary medicine, biomedical research, and academia. House and Senate versions of the bill are in committee.
A public research institution that is heavily involved in studies on ways to prevent and combat bioterrorism in animals is Texas A&M University. In April of 2004, the Department of Homeland Security announced that Texas A&M was being awarded an $18-million, three-year grant for "the study of high consequence foreign animal and zoonotic diseases." Neville P. Clarke, DVM, PhD, was named director of the Agriculture Bio-Terrorism Institute.
Texas A&M, says Clarke, has partnered with the University of Texas Medical Branch, Texas Tech, University of California, Davis, and Southern California University on the project. The research, Clarke says, is broken down into three areas:
- Biological Researchers are attempting to improve diagnostic and treatment protocols for foot and mouth disease, avian flu, rift valley fever, and brucellosis.
- New analytical and modeling methods The goal is to provide those in charge with better approaches for the decision-making process.
- Education and outreach The goal is to provide educational and outreach opportunities in dealing with potential bio-terrorism, including a Master's program.
Announced at the same time as the Texas A&M grant was a $15-million, three-year grant to the University of Minnesota to address agrosecurity issues related to post-harvest food protection. The University of Minnesota is partnering with Michigan State University, University of Wisconsin at Madison, NDSU, Georgia Institute of Technology, Rutgers University, Harvard University, University of Tennessee, Cornell University, Purdue University, and the University of North Carolina, as well as with private food companies.
A veterinarian speaking about possible bioterrorism in horses once said, "If you hear hoofbeats on the bridge, it might be a zebra," meaning veterinarians and horse owners are at the front lines of detecting anything unusual in the equid population.
If you have any questions about an unusual series of clinical signs in your animals, or an unusual sequence of events in your area, discuss them with your veterinarian. He/she will know the right people to contact at the state and federal level to have proper testing conducted to determine if there is, indeed, a threat. The good news is that the attention paid to protecting the livestock and food industry in this country will help protect the nation's horses.
About the Author
Les Sellnow is a free-lance writer based near Riverton, Wyo. He specializes in articles on equine research, and operates a ranch where he raises horses and livestock. He has authored several fiction and non-fiction books, including Understanding Equine Lameness and Understanding The Young Horse, published by Eclipse Press and available at www.exclusivelyequine.com or by calling 800/582-5604.
POLL: Horse Barn Air Quality