United States Department of Agriculture

Animal and Plant Health Inspection Service

Veterinary Services

USDA Import Testing of Horses

When horses are presented for import into the United States, they undergo testing for the following foreign animal diseases (FADs): 

dourine, equine infectious anemia (EIA), equine piroplasmosis (EP), and glanders. The official tests for imported horses are outlined

below and described in more detail in VS Guidance 13407. The USDA National Veterinary Services Laboratories (NVSL) conducts and 

analyzes all tests. Test results will classify a horse as negative, suspect, or positive for each disease. A horse must be classified as 

negative for these FADs before they enter the United States. The importer of record has the discretion to withdraw importation 

resulting in refusal at any time during the testing process.

 Dourine: Complement Fixation Test (CFT)

Dourine is a venereal disease of horses caused by Trypanosoma equiperdum. CFT results can be positive, suspect, or negative. 

If initial results are positive or suspect, USDA will immediately collect another sample for retesting. If the test results are again 

positive or suspect, the horse may be held in quarantine for up to 28 days and retested up to twice more at 14-day intervals. 

Horses with negative CFT results at any stage are classified as negative for import purposes. If results remain positive or 

suspect, the horse will be refused entry with no option for retest. 

 EIA: Agar Gel Immunodiffusion (AGID)

EIA is an acute or chronic viral disease of horses. AGID results are positive or negative; there is no suspect result. If initial results

are positive, NVSL tests the same sample again to confirm the results as well as another sample collected immediately. If the 

results are again positive, the horse will be refused entry. VS will only release horses with negative results on two sequential 

subsequent tests after an initial positive test.

 EP: CFT and Competitive Enzyme-linked Immunosorbent Assay (cELISA)

EP is a tick-borne disease caused by Babesia caballi or Theileria (Babesia) equi. USDA uses two tests for EP testing because the

cELISA targets chronic cases of EP and CFT targets earlier infections. Tests results are positive or negative; there is no suspect 

result. Both CFT and cELISA results must be negative to classify a horse as negative for import purposes. Horses which test 

positive for B. caballi on cELISA but are found negative using the Western blot confirmatory test are classified as negative for 

B. caballi. If initial test results are non-negative, USDA will immediately collect another sample for retesting. If the test results 

are again non-negative, the horse may be held in quarantine for up to 28 days and retested up to twice more at 14-day 

intervals. Horses with negative results at any stage are classified as negative for import purposes. If results remain nonnegative, the horse will be refused entry with no option for retest.

 Glanders: Double Antigen ELISA (daELISA)

Glanders is a highly contagious bacterial disease caused by Burkholderia mallei. Test results are positive or negative; there is 

no suspect result. If initial daELISA results are positive, NVSL will conduct the Western blot confirmatory test. Horses with 

negative Western blot results are classified as negative for import purposes. Otherwise, USDA will immediately collect another 

sample for retesting. If the test results are again non-negative, the horse may be held in quarantine for up to 28 days and 

retested up to twice more at 14-day intervals. Horses with negative results at any stage are classified as negative for import 

purposes. If results remain positive, the horse will be refused entry with no option for retest. 

Anticomplementary results: Anticomplementary samples produce no valid, readable result on CFT. When CFT results for dourine 

and EP are anticomplementary, NVSL performs supplemental testing using immunofluorescence assays.

Cohort animals: Animals in the same shipment as a horse classified as positive or suspect on import testing may be considered 

cohorts, depending upon the FAD of concern. Cohorts of a horse classified as positive for EIA will be refused entry. Cohorts for 

dourine, EP, or glanders will be held in quarantine for 14 days from initial blood collection and then retested. Cohorts may be 

released if all retest results are negative. If a cohort horse tests positive for glanders, the entire shipment will be refused. 

The USDA equine import testing protocol is designed as a screening system to protect the health of the U.S. equine population, not to 

establish clinical diagnostic conclusions on individual animals. However, every non-negative test is treated as an accurate result (i.e., 

a true non-negative). A non-negative test may result in an extended quarantine period and / or refused entry into the United States.

Questions?

USDA APHIS VS Strategy & Policy, Live Animal Imports

Phone: (301) 851-3300, option 2; Email: LAIE@usda.gov