Equine Herpesvirus (EHV-1) Situation Report
May 26, 2011
Background
Equine Herpesvirus (EHV-1) infection in horses can cause respiratory disease, abortion in mares, neonatal foal death, and/or neurologic disease. The neurologic form of EHV-1 is called Equine Herpesvirus Myeloencephalopathy (EHM). While EHV-1 and EHM are only officially listed as reportable diseases in some states, private veterinary practitioners are encouraged to notify their State Animal Health Officials of any suspected or confirmed cases, regardless of current official state reporting requirements.
Cases of EHV-1 and EHM have been identified recently in horses that attended the National Cutting Horse Association (NCHA) Western National Championship event in Ogden, Utah held from April 29 to May 8, 2011. The NCHA has notified State Animal Health Officials of horses from their states that were entered in the event and may have been exposed to the virus. State Animal Health Officials have contacted the owners of potentially exposed horses. Standardized recommendations were developed by state and federal officials and are being followed to isolate exposed horses, monitor them for clinical signs of EHV-1, and work with private veterinary practitioners to test and treat horses affected with the disease. Biosecurity procedures have been recommended for premises with suspect and confirmed cases to mitigate further disease spread.
Definitions for This Report
Primary Exposed Horses: Horses that attended the Ogden, Utah event from April 29 to May 8.
Secondary Exposed Horses: Horses that subsequently came into direct contact with horses that attended the Ogden, Utah event.
Tertiary Exposed Horses: Horses with three degrees or more separation from direct contact with a horse that attended the Ogden, Utah event.
Exposed Premises: Premises with exposed horses.
Suspect EHV-1 case: A horse exposed to EHV-1 that develops fever (rectal temperature above 101.5 oF), but has no neurologic signs at this time.
Confirmed EHV-1 case: A suspect EHV-1 case with laboratory confirmation of EHV-1 infection, but has no neurologic signs at this time.
Suspect EHM case: A horse exposed to EHV-1 that develops neurologic signs. (Posterior incoordination, weakness, recumbency with inability to rise, and/or bladder atony are most commonly seen in EHM cases.)
Confirmed EHM case: A suspect EHM case with laboratory confirmation of EHV-1 infection.
Summary Information on Current Situation
- Owners of horses known to have been exposed in this incident have been contacted by State Animal Health Officials.
- Suspect and confirmed cases are reported to be under voluntary or state quarantine.
- Known exposed horses are reported to be under either voluntary or state quarantine.
- A total of 75 confirmed EHV-1 or EHM cases have been reported in 9 states (AZ, CA, CO, ID, NM, NV, OR, UT, WA)
- Of the 75 confirmed EHV/EHM cases, 58 cases are horses that were at the Ogden, Utah event.
- There are 11 horses associated with this incident that are dead or have been euthanized.
- There are 15 newly identified premises with suspect or confirmed cases identified this reporting period.
Detailed Current Information (as of close of business 5/25/2011)
States not included in the tables below have reported there are no known exposed horses related to this incident currently within their state.
Horse Information:
Horses categorized in EHV-1 or EHM suspect categories or as EHV-1 confirmed in previous reports may change categories based on test results or development of additional clinical signs.
Table 1. Cumulative Total of Confirmed Cases and Fatalities as of close of business 5/25/11
| # EHV-1 Confirmed Cases | # EHM Confirmed Cases | # Dead or Euthanized Suspect or Confirmed Cases | |
| Primary Exposed Horses (at Ogden, UT event) |
33 |
25 |
9 |
| Secondary and Tertiary Exposed Horses |
14 |
3 |
2 |
| Total: |
47 |
28 |
11 |
Table 2. Status of Primary Exposed Horses (attended Ogden, UT event)
| State |
# Primary Exposed Horses (at Ogden, UT) |
# EHV-1 Suspect Cases |
# EHV-1 Confirmed Cases |
# EHM Suspect Cases |
# EHM Confirmed Cases |
# Dead or Euthanized Suspect or Confirmed Cases |
| Arizona |
33 |
3 |
2 |
2 |
1 |
1 |
| California |
59 |
3 |
9 |
0 |
6 |
1 |
| Colorado |
38 |
22 |
9 |
0 |
6 |
2 |
| Idaho |
40 |
7 |
1 |
2 |
3 |
2 |
| Illinois |
1 |
0 |
0 |
0 |
0 |
0 |
| Iowa |
5 |
0 |
0 |
0 |
0 |
0 |
| Minnesota |
18 |
0 |
0 |
0 |
0 |
0 |
| Missouri |
3 |
0 |
0 |
0 |
0 |
0 |
| Montana |
17 |
0 |
0 |
0 |
0 |
0 |
| Nebraska |
7 |
0 |
0 |
0 |
0 |
0 |
| Nevada |
7 |
0 |
1 |
0 |
0 |
0 |
| New Mexico |
13 |
1 |
2 |
1 |
1 |
1 |
| Oklahoma |
1 |
0 |
0 |
1 |
0 |
0 |
| Oregon |
20 |
1 |
4 |
0 |
1 |
1 |
| South Dakota |
4 |
0 |
0 |
0 |
0 |
0 |
| Texas |
26 |
0 |
0 |
0 |
0**
|
0 |
| Utah |
51 |
4 |
1 |
1 |
4 |
1 |
| Washington |
35 |
0 |
4 |
0 |
3 |
0 |
| Wyoming |
37 |
1 |
0 |
0 |
0 |
0 |
| Total |
415 |
42 |
33 |
7 |
25 |
9 |
*Information not available
**One confirmed EHM case previously reported was moved back to its home state of New Mexico and is currently reflected in the New Mexico case report.
Table 3. Status of Secondary and Tertiary Exposed Horses
| State |
# Secondary and Tertiary Exposed Horses |
# EHV-1 Suspect Cases |
# EHV-1 Confirmed Cases |
# EHM Suspect Cases |
# EHM Confirmed Cases |
# Dead or Euthanized Suspect or Confirmed Cases |
| Arizona |
60 |
0 |
8 |
1 |
0 |
0 |
| California |
628 |
0 |
1 |
0 |
0 |
0 |
| Colorado |
78 |
0 |
1 |
0 |
0 |
0 |
| Idaho |
108 |
17 |
2 |
0 |
0 |
0 |
| Illinois |
9 |
0 |
0 |
0 |
0 |
0 |
| Iowa |
53 |
0 |
0 |
0 |
0 |
0 |
| Minnesota |
* |
0 |
0 |
0 |
0 |
0 |
| Missouri |
* |
0 |
0 |
0 |
0 |
0 |
| Montana |
* |
0 |
0 |
0 |
0 |
0 |
| Nebraska |
0 |
0 |
0 |
0 |
0 |
0 |
| Nevada |
20 |
0 |
0 |
0 |
2 |
0 |
| New Mexico |
26 |
1 |
0 |
1 |
1 |
1 |
| Oklahoma |
32 |
0 |
0 |
0 |
0 |
0 |
| Oregon |
120 |
0 |
0 |
0 |
0 |
0 |
| South Dakota |
* |
0 |
0 |
0 |
0 |
0 |
| Texas |
323 |
0 |
0 |
1 |
0 |
0 |
| Utah |
162 |
2 |
2 |
1 |
0 |
1 |
| Washington |
* |
0 |
0 |
0 |
0 |
0 |
| Wyoming |
16 |
0 |
0 |
0 |
0 |
0 |
| Total |
1635 |
20 |
14 |
4 |
3 |
2 |
*Information not available
Premises Information:
Table 4. Exposed Premises Information
| State |
# Exposed Premises |
# Exposed premises with suspect or confirmed EHV/EHM cases (# New premises this reporting period) |
# Exposed premises with no suspect or confirmed cases |
| Arizona |
13 |
5 (1) |
8 |
| California |
34 |
17 (8) |
17 |
| Colorado |
12 |
7 (0) |
5 |
| Idaho |
26 |
8 (1) |
18 |
| Illinois |
1 |
0 (0) |
1 |
| Iowa |
2 |
0 (0) |
2 |
| Minnesota |
6 |
0 (0) |
6 |
| Missouri |
1 |
0 (0) |
1 |
| Montana |
* |
0 (0) |
* |
| Nebraska |
3 |
0 (0) |
3 |
| Nevada |
7 |
2 (0) |
5 |
| New Mexico
|
4 |
3 (1) |
1 |
| Oklahoma |
1 |
1(0) |
0 |
| Oregon |
16 |
3 (0) |
13 |
| South Dakota |
2 |
0 (0) |
2 |
| Texas |
16 |
2 (0) |
14 |
| Utah |
29 |
6 (2) |
23 |
| Washington |
26 |
6 (2) |
20 |
| Wyoming |
45 |
1(0) |
44 |
| Total |
244 |
61 (15) |
183 |
* Information not available
Related articles
- BLM Statement on Outbreak of Equine Herpes Virus (EHV-1) (rtfitch.wordpress.com)
- “NM horse dies from equine herpes virus” and related posts (thewesterner.blogspot.com)
- Stick horses used in contest amid equine outbreak (seattletimes.nwsource.com)
- Horse virus cases double to 75; at least 11 deaths (seattletimes.nwsource.com)
- Horse herpes outbreak forces rodeo queens to ride stick ponies ()
- Equine herpes virus outbreak spooks horse owners (latimesblogs.latimes.com)
- Local horse has equine herpes virus (bendbulletin.com)
- More horse herpes detected in Utah, elsewhere ()
Categories: Horse Health, Horse News
Straight from the Horse's Heart 
Probably a good time to circle the Horse Trailers and let them stay put for a bit.
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Wonder who wrote this ?? Not one of the 5 horses infected in Alberta..That came from that same competition where the rest were infected..These stat’s should include the issue this is creating in our country also..It reads to me as a person who is only concerned about the USA horses not horses from all areas..Or am I the only Canadian who is reading about this concern from this report..
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It was the USDA, Jim…and they would only include US data as Canada is outside their jurisdiction. Besides, they are a government agency and thinking outside of the box is not within their scope of responsibility, that would take initiative.
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Odd about that “USDA thinking outside the box” thing; last I checked my hamburger packaging, it denotes country/countries of origin: US/Mexico/Canada/Australia/NZ. That’s got to be one well traveled cow/steer with a passport.
Hmmmm….they are only interested in meat products or are they tasked with ALL animals, living or dead that transport across international boundaries?
Seems inconsistent to me and when there are meat producing livestock epidemics in Canada or Mexico…especially beef/poultry/swine, USDA sure seems to know the data.
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Your rite it is a USDA report..And being a goverment department..Canadain horses would not be an issue for them..Canadian horse owners are not their concern..Probably find it was imported by a Canadian horse tho..Just like it was a Canadian cow that started the mad cow issue..bet none of you were ever told; that cow was a imported pure bred from the USA, by a USA rancher who has a huge ranch in Alberta.. How do I know this ?? He’s a neighbour about 10 miles north of my place..All of his herd was brought in from the US home place..a couple years before the outbreak..I have to apoligize for my lashing out with the early comment I made..But lots of us Canadians are a little touchy about not being kept in the loop with some of these reports..especially when it concerns our horses too..And mad cows…LOL..
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Thank You !!! This is all good , lets corral it and keep it in check , an informed public is the way to go RT, i will inform all in Ohio…………………….
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Terrific information to have! Thank you, RT, for posting. There’s nothing better than clean, factual data when trying to make informed decisions in situations like this.
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At one point Ginger , Cloud stops to look at you , he acknowledged you as his ole friend, and his way of saying Hello my Friend !!!! How truly touching that was…………..
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Found this, may be of help to horse owners, so I’ll pass it on.
http://www.msnbc.msn.com/id/43186283/ns/business-us_business
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I don’t do stats very well but what I do know is this. One horse got this disease and his owner selfishly took him to this rodeo event. That exposed A LOT of horses unnecessarily. Those horses in turn can expose TONS of other horses.
I don’t know how long a horse has to go before he’s declared disease free. For instance, if he was exposed TODAY, never gets ill–how long before a vet will declare him disease free.
Why the chance on spreading this disease? As I’ve said many times here–just because you can doesn’t mean you should. So many horses could be exposed to this. Not just the wild ones but domesticate horses too.
Now I do have some questions about this disease. It’s a neurological form of herpes. Would that be the same as Shingles in humans? Would the vaccine for Shingles be appropriate for horses? Maybe you’d have to change the dosage but medication wise would it be the same?
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Thank you for making this available. This event alone should be enough to ask for a post-ponement of any summer round-ups. It should also put a halt to summer adoption events where horses from the West are brought East. Whether the horses are infected or have even been quarantined, I think the fear of this disease infecting horses on this side of the Rockies may keep people who have other horses away from these auctions.
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What’s the BLM plan for preventing the spread of this disease into the wild herds? They bring in a Judas horse, and other wrangler horses from?–who knows where. Is their equipment sterilized? Trucks/trailers/panels/gloves/boots?? Are the wranglers staying away from horse events/rodeos/auctions? Are they planning on moving wild horses across state lines? A display of responsibility from BLM would be a really good move—like–STOP the scheduled roundups–leave them out there–wild and healthy.
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This is every reason for stopping all round ups BLM as if there isnt enough other reasons……………………………
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