Pathogen Safety Data Sheet - Equine Infectious Anemia (EIA)

---

SECTION I: DISEASE / INFECTIOUS AGENT

SYNONYM / CROSS REFERENCE: EIA, Swamp fever ⁽¹⁾, Coggins disease ⁽²⁾

ETIOLOGY / TAXONOMY: ¹⁾
Family: Retroviridae
Genus: Lentivirinae
Species: Equine infectious anemia virus (EIA virus)

ORGANISM CHARACTERISTICS:

• The virus has one major group-specific antigen ⁽¹⁾
• There is a considerable antigenic drift in the surface glycoproteins leading to relapsing febrile reactions characteristic of the disease ⁽¹⁾
• Medium sized, singled stranded RNA, enveloped ⁽³⁾
• EIA virus becomes incorporated into leukocyte DNA ⁽²⁾

SURVEILLANCE:

Equine infectious anemia is a reportable disease in Canada. Animal owners, veterinarians and laboratories are required to immediately report the presence of an animal that is contaminated or suspected of being contaminated to a CFIA district veterinarian. Control or eradication measures will be applied immediately (http://laws.justice.gc.ca/en/H-3.3/fulltoc.html).

DISTRIBUTION:⁽¹⁾
The status of Equine infectious anemia in Canada is indigenous:

• EIA virus has been diagnosed on all continents except in Antarctica
• In Europe it is most prevalent in the northern and central regions
• Appeared in most states of the United States and the provinces of Canada
• The prevalence of infection within a geographical area varies depending on the density of the equine population, the proportion of carrier animals and the density of the population of insect vectors

SECTION II: ANIMAL HEALTH HAZARD AND EPIDEMIOLOGY

CLINICAL DISEASE / PATHOGENESIS:

Many EIA virus infections are not clinically apparent.

1) Clinical signs: ^(1,2)

Acute:

• Intermittent fever, anorexia, depression, ataxia, abortion
• Weakness, severe anemia, jaundice, tachypnea, petechiae on the mucus membranes, blood-stained feces
• Splenomegaly
• Death can occur

Chronic:

• Failure to thrive
• Fever, depression, petechial hemorrhages on mucus membranes, weight loss, anemia, edema
• Similar to acute infection, but usually less severe

2) Infectious dose: Unknown

3) Incubation period:

• 1-3 weeks, but can be as long as three months ⁽²⁾

SOURCE / MODE OF TRANSMISSION / COMMUNICABILITY:

• Transmission of EIA virus occurs almost exclusively through the mechanical transfer of contaminated blood or blood product ⁽¹⁾.
• Biting insects act as a vector in field conditions where the infection happens through mechanical transmission of contaminated blood from an infected horse to an uninfected horse ⁽¹⁾. The virus does not replicate in insects.
• Infection only occurs when the feeding is interrupted: if the initial host is infected the insect may carry blood from this animal to the second host and spread the infection.
• Intrauterine infection can occur and result in abortion or birth of infected foals that often die within 2 months ^(1,2)
• Use of contaminated surgical instruments or needles can also cause an outbreak of the disease ⁽²⁾.

VECTORS:

• Bitting flies including Stomoxys calcitrans (stable fly), Chrysops sp. (deer fly), and Tabanus sp. (horse fly) ^(1,2)

HOST RANGE:>

• All species of Equidae (horses, donkey and mules) ⁽¹⁾

ZOONOTIC POTENTIAL:

• None ⁽²⁾

RESERVOIR:

• Horses ⁽¹⁾

Section III: DIAGNOSIS

NECROPSY / HISTOPATHOLOGY FINDINGS:^(1,4,5)

Acute disease:

• Edema, jaundice and petechial or ecchymotic subserosal hemorrhages.
• Considerable enlargement of liver, spleen and local lymph nodes.
• The bone marrow is reddened
• Thrombocytopenia is caused by the deposition of virus-antibody complexes on platelets with subsequent removal of affected platelets by macrophages.
• Hypergammaglobulinemia

Chronic disease:

• Emaciation and pallor of tissues are often the only gross finding
• Pale mucous membranes, subcutaneous edema (especially along the ventral abdominal wall and limbs), splenomegaly, and enlarged abdominal lymph nodes.
• Intravascular clotting with emboli is frequently seen in advanced cases

LABORATORY DIAGNOSIS: ^(1,4,5)

• Competitive ELISA (may give false negative for approximately 30 days post infection)
• Agar gel immunodiffusion (may give false negative approximately 30 days post infection)
• Western blot analysis
• Virus isolation and polymerase chain reaction (PCR) ⁽⁶⁾ are available, however not routine tests

DRUG SUSCEPTIBILITY:

• None

DIFFERENTIAL DIAGNOSIS:⁽¹⁾

The following diseases may show clinical similarity to Equine infectious anemia:

Acute disease:

• Purpura hemorrhagica
• Babesiosis
• Equine granulocytic ehrlichiosis
• Equine viral arteritis
• Autoimmune hemolytic anemia
• Leptospirosis
• Parasitism
• Idiopathic thrombocytopenia

Chronic disease:

• Internal abscessation (metastatic Streptococcus equi infection)
• Chronic inflammatory disease, neoplasia and chronic hepatitis

SECTION IV: DECONTAMINATION PROCEDURES

Select a registered disinfectant with a drug identification number (DIN). Use according to label directions for concentration and contact time. Consider organic load and temperature. It is recommended that laboratories evaluate the effectiveness of the disinfectant using a validated method (eg. Quantitative Carrier Test). See table 1 to help select a registered disinfectant for use against EIA virus.

Table 1: Active ingredients considered to be effective against EIA virus.

PHYSICAL INACTIVATION:

• Inactivated in liquid media at 60°C for 30 minutes ⁽⁵⁾
• 121°C for 15 minutes (autoclaving)

SURVIVAL OUTSIDE OF HOST:

• Survives on surgical instruments and hypodermic needles ⁽¹⁾

SECTION V: LABORATORY HAZARDS FOR HUMANS

LABORATORY-ACQUIRED INFECTIONS:

• None

BIOSAFETY PRECAUTIONS :

• None

SECTION VI: PHYSICAL AND OPERATIONAL REQUIREMENTS

CONTAINMENT REQUIREMENTS:

All physical containment and operational practices for containment level 2, as per the Containment Standards for Veterinary Facilities must be met. In addition, respiratory protection must be used when performing aerosol-prone procedures. The Standards can be accessed at : http://www.inspection.gc.ca/english/sci/lab/convet/convete.shtml.

PERSONAL PROTECTIVE EQUIPMENT :
Laboratory:

• Disposable gloves (e.g. intact nitrile, vinyl or latex), laboratory coats or gowns

Post Mortem:

• Disposable gloves (e.g. intact nitrile, vinyl or latex), laboratory coats or gowns
• Cut resistant gloves, steel toed/steel shanked rubber boots

HANDLING INFORMATION :
Spills in laboratory:
Spill protocol must be in place and include the following scenarios:

• Spills inside the Biological Safety Cabinet (BSC)
• Spills outside the BSC
• Spills while performing aerosol generating procedures
• Also consider entry and exit procedure modifications if necessary, appropriate PPE, disinfection of spill and surroundings including contact time, flow (pattern) of the clean up and disposal of contaminated materials.

Refer to Table 1 for disinfectant selection.

STORAGE: All cultures and infected material should be stored in leakproof, sealed containers that are accurately labeled and clearly identified as a biohazard risk. The access to infectious material should be controlled at all times. Records must be kept to describe the use, inventory and disposal of infectious material.

DISPOSAL: Decontaminate all infectious material prior to disposal. Use steam sterilization, incineration or chemical disinfection.

REFERENCES:

1. Radostits O.M, Gay C.C, Blood D.C & K.W. Hinchcliff. Veterinary Medicine, A Textbook of the Diseases of Cattle, Sheep, Pigs, Goats and Horses. Ninth Edition. W.B. Saunders Company Ltd. 2000. Pages 1038-1039.
2. The Center for Food Security and Public Health. Equine Infectious Anemia Fact Sheet - PDF (388 kb). Jun 3, 2003. http://www.cfsph.iastate.edu/Factsheets/pdfs/equine_infectious_anemia.pdf
3. Australian Veterinary Emergency Plan. Operational Procedures Manual: Decontamination. 2000. Page 5 and 50.
4. The Merck Veterinary Manual, Equine Infectious Anemia sheet: http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/52800.htm&word=equine%2canemia.
5. Manual of Diagnostic Tests and Vaccines for Terrestrial Animals, OIE World Organisation for Animal Health. Equine Infectious Anemia, updated 2004/09/01.
6. Spyrou V, Papanastassopoulou M, Psychasv V, et al. Equine infectious anemia in mules: virus isolation and pathogenicity studies. Vet Microbiol. 2003 Aug 29; 95(1-2): 49-59.

LAST UPDATED (DATE): 2005/11/28

PREPARED BY: The Biohazard Containment and Safety Unit, CFIA

Disclaimer: Although the information and recommendations in this Pathogen Safety Data Sheet are compiled from reliable sources, there is no guarantee, warranty or any assurance that the information and recommendations are correct, accurate, sufficient, reliable or current and the Canadian Food Inspection Agency shall not be responsible for any loss or damage resulting from or in connection with the use of or reliance upon the information and recommendations.

The user assumes all risks and responsibility for and shall be liable for the use of and any reliance on the information and recommendations and the results thereof and any loss or damage resulting therefrom.

• Main Page - Equine Infectious Anemia