Equine Infectious Anemia (EIA) Update

As provided by Virden Animal Hospital - July 14 at 10:24pm

EIA UPDATE:

We have had new cases reported this week. We now have 5 premises in total in MB where EIA has been confirmed.

1) RM of St Clement
2) RM of Armstrong
3) RM of Hanover
4) RM of St Andrews
5) RM of Armstrong

All of the above premises have been placed under quarantine, and all positive horses were inapparent carriers showing no clinical signs. The 5th premise has just been confirmed by CFIA and 6 horses at this premises have tested positive to date.

It is unknown at this time how many horses may have been exposed to the confirmed inapparent carriers or exactly what the risk of infection may be to any horses exposed. These inapparent carriers have been shown to carry a much lower amount of EIA virus in their blood vs an acutely infected horse which makes them less likely to spread the disease to other horses through biting flies. With that said, there remains a small chance that EIA transmission could occur. The CFIA disease investigation is currently underway and any horses that may have been exposed to an infected horse will be notified.

The response to testing for EIA has been mostly positive. It is important to remember that these inapparent carriers are not likely to be new infections but rather have likely been infected for an extended period of time, possibly even years. If the increase in testing would not have taken place we may have had these carriers continue moving among the horse population with the potential to spread EIA.

We continue to recommend that horse owners evaluate the risks and make an informed decision on horse travel/attending events.
At this time the risk status remains low for horses travelling to events that require a negative EIA test to enter the grounds. If the event does not require a negative EIA test the risk status should be considered higher but may still be relatively low. We continue to recommend that horse owners only attend events which require a negative test.

The validity of the EIA testing has been questioned by many horse owners. It is important to consider that EIA has no effective treatments, there is no vaccine and infected horses are required to be euthanized in the majority of situations. If there are carriers of EIA among our horse population it benefits everyone to identify those carriers which will help prevent spread of the virus.

Testing is not the only tool we should use to monitor for EIA. The incubation period of EIA can range from 2 weeks to 2 months which means that a horse could be tested negative, immediately contract EIA virus and then become infective to other horses in as little as 2 weeks. This scenario can be largely prevented as most acutely infected horses will show clinical signs(fever, lethargy, loss of appetite). Therefore it is very important to monitor rectal temperature(normal range is 37.5-38.5C) on your horses when travelling or if you notice any clinical signs. Have your horses examined by a veterinarian if you have concerns about EIA infection or exposure. Do not travel with any horse that appears sick or has a fever.
There are also fly control measures which should be followed to limit exposure. For any additional information on EIA, please read previous posts or the article posted on this page.

The truth is that we don't know how or if this disease is going to spread throughout the rest of the season. The risk has been determined to be low. The only way to 100% prevent exposure is to keep your horses in an isolated herd and test them to ensure that you do not have any EIA positive horses in your herd. Please use this information to make a decision that you are comfortable with. We will continue to keep you informed with any new cases or information as we go forward.

Thanks, all the best
Dr. Joe King
Virden Animal Hospital


June 29, 2017

MHC has learned that several horses have tested positive for EIA in the St. Clements area and a single positive in the Armstrong municipality. This is in addition to the animal tested positive earlier this month in Rockwood which subsequently travelled to Saskatchewan.
 
The disease outbreak is under investigation by the Canadian Food Inspection Agency (CFIA) which imposes strict regulations on the premises and animals involved. They do not share the names of premises or people involved in their investigation.
 
EIA is a potentially fatal viral disease which can affect horses, donkeys and mules. There is no vaccine or cure available. Horses that do survive remain carriers and a source of infection to other horses their entire lives.
 
Transmission of EIA occurs mainly through blood transmission horse to horse either from biting insects, contaminated needles or in utero. Areas where there are large numbers of horse traffic (shows, rodeos, training facilities, public barns) are at greatest risk for exposure. Clinical signs vary from anorexia and weight loss, bleeding and swelling of the legs/chest, jaundice, abortions and/or colic, although some horses may not show any clinical signs at all. The majority of horses carrying the virus are asymptomatic and the virus often goes undiagnosed where it continues to spread throughout the equine population.
 
Due to lack of mandatory testing in the province the disease often goes undiagnosed and spreads most commonly at large horse events where proper fly control is impossible. All positive cases undergo strict quarantine. No movement of horses occurs and strict fly control is enforced while all horses in contact with the positive horse are tested. Equines confirmed to be infected are then either ordered destroyed by the CFIA or have to undergo lifelong quarantine. Lifelong quarantine is the less acceptable alternative as fly/bug control is never 100% effective and the horse can continue to pose a risk to neighboring horses. Prevention is the only cure.
 
Steps for prevention:

  • Fly control – fly sprays, mask and sheets
  • Single use needles and proper disinfection of medical equipment/tack
  • Test horses annually for EIA
  • Test all horses at time of pre-purchase exam
  • Test all new horses entering a stable with 45day quarantine
  • Show facilities, show/rodeo organizations should require negative Coggins test before any horses enter show facility/grounds

 
Involved equine veterinarians and The Manitoba Veterinary Medical Association have met to work out protocols, and all vets are setting aside time for rush Coggins tests to be performed on animals deemed to be at risk. Vets are also in agreement that testing prior to showing is strongly advised and those shows which do not currently require testing may be contacting participants to advise that negative Coggins will be required for entry.
 
Thank you to Beausejour Animal Hospital, Elders Equine Clinic and Dr Gillian Dobson for their social network comments and advice to horse owners on this topic. Manitoba Horse Council will continue to share updates on Facebook and by email during this outbreak.
 
For more information about the disease, its symptoms and effect, some of the following links may help.
 
https://www.mvma.ca/resources/animal-health/equine-infectious-anemia-eia-information
 
http://inspection.gc.ca/animals/terrestrial-animals/diseases/reportable/eia/if-your-animals-may-be-infected/eng/1329706148201/1329706282597
 
http://www.inspection.gc.ca/ animals/terrestrial-animals/diseases/reportable/eia/if-your-animals-may-be-infected/eng/1329554028418/1329554166646
 
http://www.inspection.gc.ca/ animals/terrestrial-animals/diseases/reportable/eia/if-your-animals-may-be-infected/eng/1329549519537/1329549678636
 
http://eldersequineclinic.com/equine-infectious-anemia-update---manitoba-2017.html

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