WNV: Where Are We Today?
- Sep 1, 2005
Let's face it--we were getting comfortable, perhaps complacent, in our twice-a-year visits from our horse's veterinarians for inoculations against the old, familiar diseases...Eastern and Western equine encephalitis, influenza, rabies, rhino, strangles, and maybe even botulism in some areas of the United States. Then in late summer of 1999, a new virus showed up that was about as welcome as a nasty hoof abscess the day before the championship. It was a disease with a life cycle that included mosquitoes and birds--creatures that are ever-present on our farms.
The talk in barn aisles across America turned to this next big disease--West Nile virus (WNV). The descriptions of the neurologic signs that unfortunate victims displayed were terrifying horse owners up and down the East Coast, if not across the entire United States. How susceptible is my horse? What can be done to prevent him from contracting it? If he gets sick, can my veterinarian save him?
In the early days of the emergence of WNV in the United States, there weren't many answers. While the virus had been encountered in Africa (as its name suggests), Europe, and the Middle East, it hadn't been seen in the Western Hemisphere, and it was unclear how it would behave in the unique ecology of North America. Researchers, veterinarians, and public health officials teamed up to organize WNV surveillance and begin studying the disease, while giving horse owners the best advice they could.
Progress was made--more than 300 scientific papers have been published on WNV since 1999. Six years later, we understand the disease better, we have more ways to reduce the mosquito populations on our farms, and there are two reliable vaccines on the market to protect our horses (and a new vaccine will be hitting the market soon). Many clinicians feel confident in the WNV treatment methods they've adopted.
We've accepted that WNV is here to stay, and we're learning how to live with it, just as we have with all of the other diseases that have worked their way into our horses' lives. But veterinarians say we cannot become complacent--we must remain on guard for WNV and learn as much as we can in order to protect our horses, and ourselves.
West Nile virus is an arbovirus, meaning it is spread via bites from infected mosquitoes. The mosquitoes feed on birds, which become amplifiers of the virus. The virus particles circulate and multiply in birds, and uninfected mosquitoes feed on the birds and become infected. This bird-mosquito cycle continues, and eventually it spills over when mosquitoes carrying the virus bite and infect horses, humans, and other mammals.
Once WNV was diagnosed in the 1999 outbreak, researchers such as Michael Turell, PhD, in the Virology Division's Department of Vector Assessment at the U.S. Army's research laboratory at Ft. Detrick, Md., began determining which mosquitoes could spread the disease in the United States. "We knew what (mosquitoes) transmit the virus in Europe and parts of Africa, but we had no clue what transmits this virus in North America," says Turell. "An outbreak depends on having the right mosquito populations, having the virus and enough susceptible birds in the area, having the right environmental conditions--for example, temperatures--and having enough of these bridge vectors (mosquito species with feeding habits that transfer WNV from one transmission cycle to another) that transmit virus from the bird-mosquito cycle to humans and horses.
So for an outbreak to occur, everything must be properly aligned: First the bird-feeding mosquitoes infect many birds, after which a large population of mosquitoes that are general feeders pick up the virus from birds and transmit it to the mammals.
The timing and conditions were perfect for WNV in 1999; reports of equine and human cases rolled in.
The Spread of WNV
Readers of The Horse are familiar with the color-coded maps tracking the spread of WNV in the United States. Bill Reisen, PhD, research entomologist with the University of California (UC), Davis, Arbovirus Field Station in Bakersfield, Calif., says, "The general pattern has been a kind of soft entrance into the different areas, successful overwintering (most likely in mosquitoes), then dramatic amplification the following year."
Bob McLean, PhD, research program manager of wildlife diseases at the USDA's National Wildlife Research Center in Fort Collins, Colo., says, "It became apparent to me early on that migratory birds were helping move the virus around, and they probably assisted in the fairly rapid continental spread of the virus." McLean contends that birds likely carried it in a zig-zag motion across the country (as birds followed their natural flyways) and are probably responsible for the virus moving down into Mexico, the Caribbean islands, and into Jamaica, Puerto Rico, and Colombia.
In 2004, many people said the virus disappeared in a number of areas across the country, probably due to the unusual weather patterns throughout the year. "We had one of the coolest and wettest summers in Colorado, which is not good for mosquito transmission," says McLean. But even though WNV has been seen less often, presumably because of equine vaccination, better mosquito control, and natural immunity from exposure, it is still an endemic disease (prevalent at all times) as of late 2002 in all 48 lower U.S. states.
As for future spread, the virus could move up the Pacific Coast and toward Alaska, and there are also concerns that it might arrive in Hawaii, which would be devastating for local bird populations, many of which are endangered. Although there's a shorter transmission season, parts of southern Canada that have not yet been affected by WNV might not be immune to the effects of WNV and will need to keep an eye on the virus in upcoming years.
The Horse asked several veterinarians and researchers who studied WNV as it unfolded in North America what they felt were the major accomplishments in understanding this disease. Here are their thoughts.
Better surveillance and reporting--Laura D. Kramer, PhD, is an associate professor in the School of Public Health at the State University of New York, Albany, and director of Arbovirus Laboratories at the New York State Department of Health's Wadsworth Center. She says, "One major lesson of WNV is the recognition of the need for close cooperation between the veterinary and public health communities, which have now been brought together in a much more effective partnership.
"This collaboration will serve the country well in the case of introduction of such viruses as Japanese encephalitis virus, Rift Valley fever virus, or foot and mouth disease," Kramer adds. "It is critical that an evaluation of collaborative networks be conducted to establish rapid communication between disciplines, groups, and regions."
Greater understanding of the disease--Predicting how WNV would behave in North America's native insects, birds, and mammals was an immediate challenge for scientists. Much has been learned, but Kramer says a big step was researchers' suggestion of the importance of high temperatures and drought in accelerating viral circulation and increasing risk to horses and humans. A study recently completed at the UC Davis Abovirus Field Station confirmed the virus cannot grow below 14ï¿½C (57.2ï¿½F) within mosquitoes, and grows very slowly until temperatures are above 26ï¿½C (78.8ï¿½F). Reisen explained, "Slow growth means ineffective transmission--so La Niï¿½a conditions of warm temperatures are critical for effective transmission."
Turell's lab has had similar findings. He pointed out that mosquitoes are cold-blooded (their body temperature is determined by the ambient temperature), which could explain the virus' susceptibility to temperature. However, "I'm not as convinced on the role of drought," said Turell. "In many cases, elevated temperatures and drought go together (so WNV activity is attributed to the drought as well as the elevated temperatures). Alternatively, the drought may cause birds to congregate at the limited water sources, thus enhancing virus transmission."
Also, researchers recognized blood transfusion and organ transplantation as potentially significant means of virus transmission in humans.
Prevention--Horses were fortunate that a vaccine against WNV came out relatively quickly--the conditionally licensed Fort Dodge vaccine was first available in August 2001. That vaccine eventually received a full license in February 2003, when Fort Dodge began selling it as West Nile Innovator. Merial released its canarypox-vectored WNV vaccine, Recombitek, in January 2004. In July 2005, Fort Dodge announced the USDA approval of its WNV DNA vaccine, the first DNA vaccine approved for commercial use for any species worldwide.
Maureen Long, DVM, PhD, Dipl. ACVIM, assistant professor of large animal veterinary medicine at the University of Florida, explains, "The whole industry stepped up and looked at different ways to deliver high-quality vaccines.
"There's better vaccine development over the standard killed vaccines that are traditionally marketed for the horse industry," she adds. Killed vaccines come to market quicker and are marketed more easily over the counter. Horse owners may find these vaccines more easily obtainable, but the caveat is that they are highly adjuvanted (substances have been added to improve the immune response so less vaccine is needed), which can cause reactions, and they have traditionally had a shorter duration of immunity. In the long run, they cost more (than other vaccine types) because more frequent vaccination is required.
"There's a modified-live recombinant vaccine on the market and there are additional recombinant and subunit vaccines that are being developed in laboratories," continues Long. "Recombinant vaccines offer more safety in addition to the enhanced protection of a modified live vaccine. Subunit vaccines focus immunity on the proteins thought to elicit the best protective response. I think that if we can show these vaccines are superior in terms of less untoward reactions with longer duration of immunity, we may improve vaccinology as a whole for the horse."
Long and Colorado State University researchers have developed models to test WNV vaccines. She adds, "I think what you're seeing is cooperation between researchers and the vaccine companies to address the questions of duration of immunity and quality of vaccines in a much shorter period than it's been usually, in terms of vaccine development. I think the research and development groups of our vaccine companies are interested in asking basic questions, such as, 'If you change vaccines, do you need to start the whole process over with multiple boosters?' "
Current vaccination recommendations vary, and you should check with your vet on the best schedule for your horse. Long recommends two to three boosters a year for Florida horses, citing the importance of maintaining immunity in a state with year-round WNV exposure in some areas. She says it is essential to maintain immunity in horses in Northern areas with an annual booster and in some Midwestern and Western states, twice-per-year boosters. Even in horses that have likely been naturally exposed without contracting disease, boostering keeps immunity high. Since horses are maintained in a vector-laden environment, any drop in immunity can be disastrous.
Detecting and treating disease--Long gave some of the first clinical descriptions of WNV in horses after seeing many cases at the university's hospital in 2001. Clinical signs for WNV haven't changed since she first began seeing cases. They include:
- Flu-like signs, where the horse seems mildly anorexic and depressed.
- Fine and coarse muscle and skin fasciculations (twitching).
- Hyperesthesia, or hypersensitivity to touch and sound.
- Changes in mentation (mentality), when horses look like they are daydreaming or "just not with it."
- Occasional somnolence (drowsiness).
- Propulsive walking (driving or pushing forward, often without control).
- "Spinal" signs, including asymmetrical weakness. Some horses show asymmetrical or symmetrical ataxia (incoordination on one or both sides, respectively).
Other signs include paralysis of the lips, facial muscles, or tongue. Some victims also have a head tilt and difficulty swallowing.
Vets treat affected animals aggressively with anti-inflammatories, fluid therapy, slings, and nursing. University of Florida vets have treated sick horses with high-antibody plasma, says Long, but that has decreased since Florida only had five reported cases last year, compared to as many as 500 in prior years. Long says an original 2002 study using high-antibody plasma demonstrated some efficacy against horses becoming recumbent (unable to rise). Once horses become recumbent, their chances for recovery dwindle dramatically.
Some vets have used alpha interferon and high-antibody plasma in WNV victims with success rates as high as 90-95%.
Long adds, "There's not a lot of information out there that's going to change what people should do to treat WNV, because there hasn't been a good, provocative challenge model (it's difficult to infect a horse with WNV reliably to test treatments). I think that with the recent development of models, people can start looking at some questions like immunoglobulin (specific protein that is produced by plasma cells to help fight infection) and different antivirals."
Education and mosquito control--Education of horse and farm owners, vets, and the general public on the importance of reducing mosquito populations was critical. "The public health aspect of WNV has made a huge difference," said William Saville, DVM, PhD, Dipl. ACVIM, an associate professor in the Department of Veterinary Preventive Medicine at The Ohio State University's College of Veterinary Medicine. Ohio health and agriculture officials held statewide satellite conferences to inform extension officials and the public about reducing mosquito populations.
Saville says source reduction (eliminating breeding sites) of mosquitoes and using repellents are major steps in reducing the risk of encountering WNV (see www.TheHorse.com/ViewArticle.aspx?ID=5954).
Future WNV Issues
West Nile virus is making fewer headlines now than in past years, but the threat is not gone. "Veterinarians need to continue to report when they see the disease," says Long. "Everybody's tired of WNV, but if there's a problem and people don't know about it, then that's going to prevent development of therapies and good preventive strategies."
According to Long, only 30% of encephalitic diseases in people are ever diagnosed, and only about 10-20% of the horses tested with encephalitic signs have a diagnosis before death. She encourages veterinarians who think they might have WNV cases to notify public health veterinarians, even if some tests come back negative.
The future of WNV research has many focuses, some of which are underway:
- Determine how the virus survives in the temperate northeastern United States;
- Further evaluate an efficacious single-dose equine vaccine;
- Maintain the newly strengthened public health infrastructure to sustain integrated surveillance system;
- Continue to study mosquitoes;
- Understand the phenotypic and genotypic changes in WNV as it established itself in the United States;
- Develop a serologic assay to differentiate vaccinated vs. naturally infected horses;
- Study WNV in South and Central America: Why is there no overt morbidity and mortality associated with WNV spread to this region (see "West Nile Virus Going Incognito?")?
- Evaluate viral transmission that isn't mosquito-vectored; i.e., other arthropods and bird-to-bird spread. Scientists suggest hawks, owls, and raptors might get WNV by eating other birds;
- Determine risk factors that lead to equine and human disease and develop a prediction model.
- Study the role of "urban small animals" (such as squirrels) in disease spread. With reports of tree squirrel die-offs, it's important to learn if these animals can carry high enough virus levels to spread WNV, or determine if they are dead-end hosts (as are horses and humans).
- Evaluate the crow's genetic makeup to learn why it is more susceptible to WNV;
- Determine the impact of WNV on U.S. birds. Scientists are finding broad avian susceptibility, with up to 100% mortality in some species, including American pelicans, which have experienced die-outs in their nesting colonies.
- Examine diagnostic testing methods. Kramer says, "West Nile virus highlighted the threat introduced agents pose to this country due to increased travel, population, commerce, and the ability of these pathogens to become established in a native environment. This recognition points out the need to develop broadly reacting viral assays to quickly diagnose new diseases, and to develop non-species-specific assays that can be run rapidly."
"If someone had asked me to choose a virus six years ago (that might invade North America), I wouldn't have chosen WNV as causing this kind of problem, when you have viruses out there like Rift Valley (fever) that is transmitted person-to-person; Japanese encephalitis, which has made incursions into the Pacific before; and Venezuelan equine encephalitis, that has visited Texas," says Reisen. "These and viruses like dengue are much more pathogenic, and I really would have thought they were the greatest threats. We're lucky that nothing like this has happened thus far."
Will we have years with increased horse mortality due to WNV, the way we do with some encephalitides like Eastern equine encephalitis? Saville says, "My crystal ball is broken. I have no idea...none. I think people are 'out of sight, out of mind,' and that concerns me. There are a lot of places where they aren't doing much vaccination.
"I think it's important that people not forget that it's here and it's not going away," Saville concludes. "That's the most important message. Don't take any risks because the disease is still here, and it can cause devastating side effects, let alone death."
Timeline: West Nile Virus in the United States
AUGUST, 1999--An outbreak of human encephalitis of an unknown etiology begins in New York City.
SEPTEMBER 14, 1999--Virus is isolated at the National Veterinary Services Laboratories (NVSL) in Ames, Iowa from tissues of a crow from the New York City area.
OCTOBER 13, 1999--USDA announces it's taking steps to ensure that WNV (if it is confirmed as such) does not have a detrimental effect on American agriculture. (www.TheHorse.com/ViewArticle.aspx?ID=1652).
OCTOBER 18, 1999--Virus isolated from the central nervous system tissue of a horse on Long Island, N.Y., is confirmed to be WNV by the Centers for Disease Control and Prevention (CDC).
OCTOBER 20, 1999--The Hong Kong Jockey Club temporarily suspends the import of horses from North America due to the encephalitis outbreak. (www.TheHorse.com/ViewArticle.aspx?ID=1649)
OCTOBER 21, 1999--The Horse reports that the United Arab Emirates is requiring all horses imported from the United States to be accompanied by a supplementary health certificate regarding WNV. (www.TheHorse.com/ViewArticle.aspx?ID=1642)
NOVEMBER 5, 1999--Last-minute negotiations between USDA and the European Union (EU) fail to stop a total ban on the importation of horses from New York, Connecticut, and New Jersey into Europe. (www.TheHorse.com/ViewArticle.aspx?ID=1635)
MAY 22, 2000--Officials discover that WNV has overwintered in New York. (www.TheHorse.com/ViewArticle.aspx?ID=1442) SEPTEMBER, 2000--The EU places import restrictions on horses from Connecticut, Massachusetts, New Jersey, New York, and Rhode Island. (www.TheHorse.com/ViewArticle.aspx?ID=1351)
NOVEMBER, 2000--Scientists from the U.S. Geological Survey announce that WNV can be transmitted from bird to bird in a confined laboratory setting. It had been thought that the virus was only transmitted through mosquito bites. (www.TheHorse.com/ViewArticle.aspx?ID=1307)
NOVEMBER, 2000--The EU adds Pennsylvania to the import restriction list.
AUGUST, 2001--The USDA and Fort Dodge Animal Health (FDAH) announce the conditional approval and release of the first WNV vaccine for horses, a killed-virus vaccine. (www.TheHorse.com/ViewArticle.aspx?ID=1109)
SEPTEMBER 18, 2002--Fort Dodge receives USDA approval to release challenge study results on its WNV vaccine; 94% efficacy is shown. (www.TheHorse.com/ViewArticle.aspx?ID=3813)
NOVEMBER 20, 2002--West Nile virus is detected in three Florida alligators. (www.TheHorse.com/ViewArticle.aspx?ID=4037)
DECEMBER 28, 2002--USDA officials designate WNV as an endemic (prevalent at all times) disease in the United States. (www.TheHorse.com/ViewArticle.aspx?ID=4052)
FEBRUARY 5, 2003--Veterinarians wonder whether the increased number of Kentucky WNV cases in late summer and autumn of 2002 contributed to a rise in autumn 2002 equine abortions. (www.TheHorse.com/ViewArticle.aspx?ID=4125)
FEBRUARY, 2003--The USDA issues a full license to FDAH for its killed-virus WNV vaccine, West Nile-Innovator. (www.TheHorse.com/ViewArticle.aspx?ID=4152)
MARCH 18, 2003--A package containing WNV explodes at a FedEx facility in Columbus, Ohio, causing the evacuation of 50 employees. (www.TheHorse.com/ViewArticle.aspx?ID=4236).
MAY 6, 2003--Study results show that the effects of WNV cost Colorado and Nebraska equine owners more than $1.25 million in 2002, and costs for WNV vaccinations likely exceeded an additional $2.75 million in those states in 2002. (www.TheHorse.com/ViewArticle.aspx?ID=4370)
JUNE 9, 2003--Top veterinarians dispute allegations made by the "Lost Foals Group" in a May 30 Denver Post article that the FDAH vaccine might have caused abortions and foal deformities. (www.TheHorse.com/ViewArticle.aspx?ID=4440)
JUNE 26, 2003--The USDA clarifies that the WNV vaccine is safe for use in mares. (www.TheHorse.com/ViewArticle.aspx?ID=4464)
AUGUST 19, 2003--Novartis Animal Vaccines announces the availability of the first antibody product conditionally licensed by the USDA to help control disease caused by WNV in equids. (www.TheHorse.com/ViewArticle.aspx?ID=4559)
OCTOBER, 2003--A Centers for Disease Control and Prevention official predicts that the West Coast will be hit hard with WNV in 2004, particularly California. (www.TheHorse.com/ViewArticle.aspx?ID=4764)
OCTOBER 23, 2003--Lake Immunogenics announces the availability of the first plasma product conditionally licensed by the USDA to help control disease caused by WNV in equids. (www.TheHorse.com/ViewArticle.aspx?ID=4759)
DECEMBER, 2003-- Dr. Julia Wilson of the University of Minnesota presents a study at the American Association of Equine Practitioners' (AAEP) Convention showing that horse owners should have equine survivors of WNV re-examined by their veterinarians before putting the animals back into work. She found that horses surviving clinical WNV could be more dangerous to ride or drive. (www.TheHorse.com/ViewArticle.aspx?ID=4947)
DECEMBER, 2003--Fort Dodge announces that WNV combination vaccines will be available in early 2004. (www.TheHorse.com/ViewArticle.aspx?ID=4802)
DECEMBER, 2003--Purdue University determines the structure of WNV. (www.TheHorse.com/ViewArticle.aspx?ID=4818)
DECEMBER 23, 2003--Merial receives USDA registration approval for its recombinant canarypox-vectored WNV vaccine, Recombitek. MAY, 2004--A study determines that some wild birds in the United Kingdom have been exposed to WNV, but don't carry enough virus load to pass on the disease. (www.TheHorse.com/ViewArticle.aspx?ID=1654)
MAY, 2004--A study reports that vaccination with Merial Limited's Recombitek equine WNV vaccine would not confuse results if a horse were to be tested for recent WNV exposure or clinical infection. (www.TheHorse.com/ViewArticle.aspx?ID=2015)
SEPTEMBER, 2004--Nevada and Oregon are the last of the 48 lower United States to report WNV infection. (www.TheHorse.com/ViewArticle.aspx?ID=2117)
NOVEMBER, 2004--A study demonstrates that one dose of WNV recombinant vaccine could help control outbreaks. (www.TheHorse.com/ViewArticle.aspx?ID=5453)
DECEMBER 13, 2004--Colorado Serum Company announces the availability of its conditionally licensed WNV serum antibody product.
DECEMBER 15, 2004--A study reports that Fort Dodge's West Nile-Innovator vaccine is safe for use in broodmares. (www.TheHorse.com/ViewArticle.aspx?ID=5363)
DECEMBER, 2004-- California reports a 42.2% mortality rate in its equine WNV cases for the year (as compared to the national average of 33%, according to the AAEP vaccination guidelines). Officials say the rate could be caused by an economic barrier, many cases are probably unreported, and that they're addressing vaccine cost. (www.TheHorse.com/ViewArticle.aspx?ID=5323)
JANUARY, 2005--AAEP releases WNV vaccination guidelines. (www.TheHorse.com/ViewArticle.aspx?ID=5370)
JUNE, 2005--Researchers demonstrate transmission of WNV between mosquitoes feeding simultaneously on the same uninfected host. (www.TheHorse.com/ViewArticle.aspx?ID=5955)
JULY 18, 2005--Fort Dodge Animal Health announces federal approval for its WNV DNA vaccine--the first commercially available DNA vaccine approved for any species
West Nile Virus Going Incognito?
According to scientists, there seems to be some indication that areas experiencing West Nile virus (WNV), including Mexico, countries in Central America, and the Caribbean islands, are experiencing less mortality in birds due to WNV. Some suggest it could be that dead birds aren't being reported, but officials in these locales are confident that the lower numbers are not due to surveillance error. Scientists have suggested that there's been a change in the virulence of WNV, and they are looking at the virus to see if it is attenuating (weakening).
An alternative idea is that biodiversity could be responsible, meaning that there are many more species of birds in these countries, but not as many competent reservoirs for WNV, serving to dilute the virus' effect. Also, the areas might not have the large corvid (a type of bird including crows) population that North America does, and birds in the corvid family have been benchmarks for detection of WNV in North America as they are highly susceptible.
Mexican practitioners are reporting fewer cases of equine clinical disease than what has been experienced in the United States. If it isn't a surveillance issue where cases aren't being diagnosed or reported, the virus' absence could have something to do with other virus coexisting with WNV in Mexico. Bob McLean, PhD, research program manager of wildlife diseases at the USDA's National Wildlife Research Service in Fort Collins, Colo., said, "The horses might have immune protection from a related virus (that isn't endemic in the United States)."
In other words, a virus closely related to WNV that doesn't cause clinical illness might act as a natural vaccine to protect the horse population from the disease caused by infection with virulent WNV.
WNV Human Vaccine on the Way
Horses had a West Nile virus (WNV) vaccine within roughly two years of the first discovery of the virus in the Western Hemisphere. It has taken a little longer to get a WNV human vaccine through the pipeline and to the American public. A representative of Acambis presented the results of the Phase I clinical trials of the company's human WNV vaccine candidate, ChimeriVax-West Nile, at the National Foundation for Infectious Disease's 8th Annual Conference on Vaccine Research May 11. Marketing for human vaccines takes longer due to increased safety and regulatory requirements for human vaccines.
The company is developing the vaccine using its proprietary ChimeriVax technology, which uses yellow fever vaccine to create chimeric viruses. The vaccine acts like a modified live virus, which provides very long-lasting, high levels of immunity, but is extremely impotent and cannot cause disease. The yellow fever vaccine is closely related to WNV and is one of the safest, most efficacious vaccines ever marketed, says Maureen Long, DVM, Dipl. ACVIM, assistant professor of large animal veterinary medicine at the University of Florida.
In the study, 96% of subjects in a high-dose group and 100% in a low-dose group developed WNV-neutralizing antibodies 28 days after vaccination, and the vaccine elicited high antibody titers. Thomas Monath, MD, chief scientific officer of Acambis, says, "We are encouraged by the immune response generated by trial subjects who were vaccinated with a single inoculation of ChimeriVax-West Nile."
Rights of this vaccine for animal use have been sold and the product is being developed.
"People need to continue to very much protect themselves," says Long. "More people were sick than horses in Florida in 2004. We haven't eradicated this disease."
About the Author
Stephanie L. Church, Editor-in-Chief, received a B.A. in Journalism and Equestrian Studies from Averett College in Danville, Virginia. A Pony Club and 4-H graduate, her background is in eventing, and she is schooling her recently retired Thoroughbred racehorse, Happy, toward a career in that discipline. She also enjoys traveling, photography, cycling, and cooking in her free time.