Equine Infectious Anemia

Question 1

Define contagious

Answer 1

(Of a disease) capable of being spread via direct contact, bodily fluids, airborne particles, etc.

Question 2

Define infectious

Answer 2

(Of a disease) being caused by pathogenic (disease causing) microbial agents such as bacteria, viruses, or other microorganisms

Question 3

Are all infectious diseases contagious?

Answer 3

No, many are not, such as AIDS, malaria, tetanus, and food poisoning

Question 4

What is the difference between degrees of infectiosness in EIA? (Acute, chronic, inapparent)

Answer 4

Acute: ⅕ tsp of this horse’s blood contains enough viral agent to infect 1,000,000 horses

Chronic: ⅕ tsp of this horse’s blood (during a feverish episode) contains enough viral agent to infect 10,000 horses

Inapparent carrier: Only 1/6,000,000 horseflies is likely to pick up and transmit the EIA virus from this horse

Question 5

What is a Coggins test? (Agar Gel Immunodiffusion Test)

Answer 5

•Precipitating antibodies produced as a result of EIA infection can be detected with this test
•EIA antigen and a test serum are used to confirm the identity of antibodies in a sample by looking for the formation of precipitin
•Precipitin levels are highest when antibody/antigen levels are near equivalence level
•Horses within the first 2-3 weeks after infection will usually test negative (sometimes for up to 60 days)
•This test is rapid, inexpensive, simple, and highly specific
•This test must be subjectively analysed by reading the curvature of a precipitation line

Question 6

What is a problem with an Enzyme-Linked Immunosorbent Assay (ELISA) Test?

Answer 6

•A positive ELISA test must be retested with a Coggins test to confirm because some false-positive tests have been noted with ELISA testing.

Question 7

What are the mandatory and voluntary parts of the EIA control program?

Answer 7

Voluntary: Having a horse tested

Mandatory: Responding to a positive test

Question 8

What happens if a horse is found to be “EIA positive”? Why?

Answer 8

•Horses that test positive for EIA are euthanized and destroyed
•Other horses in the premesis of the infected horse must test negative before being allowed to leave the property
•The owner may be compensated up to $2,000

•Because there is no treatment for EIA and no vaccine to prevent it, the only way to effectively control the disease is by testing and removing infected animals.

Question 9

What is Equine Infectious Anemia?

Answer 9

A potentially fatal viral disease affecting horses and other equids (donkeys, mules, hinnies)

An EIA infected animal remains a carrier for life and can be a source of infection for other animals

Question 10

Is EIA a zoonotic disease?

Answer 10

No

Question 11

What are the clinical signs of EIA?

Answer 11

•Anorexia & weight loss
•Ataxia
•Depression
•General weakness
•Intermittent fever (41°C)
•Jaundice
•Small hemorrhages under the eyes and tongue
•Swelling of extremities
•Death

Foals who are infected prepartum are often aborted or die within 2 months postpartum

Many animals may appear to recover for 2-3 weeks before becoming sick again. Episodes of illness are associated with steroid use, stress, hard work, hot weather, racing, and pregnancy.

Question 12

Where is EIA found?

Answer 12

Worldwide, however the occurrence in tested Canadian horses is extremely low.

Question 13

How is EIA transmitted and spread?

Answer 13

•Mainly through the transfer od contaminated blood
•Can be transmitted via horse flies, stable flies, deer flies, etc.
•Can be transmitted by reusing medical equipment like needles or surgical instruments on more than one animal
•Can be transmitted through the semen of an infected stallion, foals can be infected before birth

Question 14

How is EIA diagnosed?

Answer 14

•Clinical signs
•Positive Coggins test
•Positive ELISA test (confirmed by a positive Coggins test)
•Blood tests are necessary for a definitive diagnosis (Coggins/ELISA)

Question 15

How is EIA treated?

Answer 15

•There is no cure for EIA, there is no vaccine for EIA
•Supportive care may alleviate symptoms in infected animals, but they will always serve as a reservoir of infection for other animals

Question 16

How is EIA controlled?

Answer 16

By voluntary testing by owners, mandatory testing of imported equines, identification, destruction of infected animals, and efforts to prevent spread by controlling insect/mechanical vectors

Question 17

How is Canadian livestock protected from EIA?

Answer 17

•Strict hygiene practices when vaccinating or collecting blood (single use syringes, etc)
•Insect control measures
•Testing equines before events where equines from different sources will intermingle
•Testing symptomatic equines
•Isolate new equines until they have been tested
•The Canadian Food Inspection Agency (CFIA) imposes strict regulations on imported animal products from countries where EIA is common, and EIA is a federally reportable disease (ALL suspected cases MUST be reported to the CFIA)

Question 18

How would the Canadian Food Inspection Agency (CFIA) respond to an outbreak of EIA?

Answer 18

•movement restrictions are placed on all premises found to contain EIA positive animals
•Infected and susceptible animals are quarantined and tested
•Equines confirmed to have EIA are destroyed

Question 19

When does the Canadian Food Inspection Agency (CFIA) take disease control actions? What steps are involved?

Answer 19

○When is action taken?
•When a positive sample is found through the voluntary testing program
•Investigation of at-risk animals associated with an EIA-positive equine
•Test results from a symptomatic horse

○Steps involved
•Quarantine
•Investigation
•Destruction of infected animals
•Compensation

Question 20

What takes place in the Quarantine stage of disease response?

Answer 20

•A CFIA agent will visit the property and inform the owner of what they must do during this period
•No equines may enter or leave the premises for the duration of the quarantine period
○Owner responsibilities involve
•Maintaining fences and gates to control movement of animals and animal products
•Informing all people entering the premises of the quarantine protocols
•Reporting all sick, dying, or escaped animals
•Cleaning and disinfecting any equipment used with infected animals

Question 21

What takes place during the investigation period of disease response?

Answer 21

•Blood testing is performed to confirm whether an equine has EIA
•If infection is confirmed the CFIA will review farm records to determine any movements or contact the infected animal has made in the last 30 days
•All susceptible equines on the premesis will be tested

Question 22

What happens during the destruction of infected animals phase of disease response?

Answer 22

•Equines that test positive for EIA will be ordered destroyed by the CFIA
•All animals must test negative twice before quarantine can be removed
•The second test must take place at least 45 days after the last date contact with an infected animal could have taken place

Question 23

How much may an owner be compensated?

Answer 23

$2,000

Question 24

Which provinces have the most cases? Where in the most affected province are cases most densely localized?

Answer 24

Alberta (156)
Saskatchewan (51)
British Columbia (37)

Central Alberta, surrounding Edmonton