EIA and Coggins Test Requirements in Maryland: What Every Horse Owner Must Know
July 8, 2026
Equine Infectious Anemia is one of the most serious infectious diseases affecting horses in the United States, and Maryland takes its control seriously. Whether you own a single trail horse or manage a large boarding facility, understanding the state’s EIA and Coggins test requirements is not optional — it’s a legal obligation with real consequences for non-compliance.
Maryland mandates Coggins testing across several high-risk situations, from horse shows and county fairs to interstate transport and sales. EIA is a reportable animal disease in all states, and Maryland’s rules align closely with federal standards while adding specific state-level requirements you need to know before you move, show, or sell an equine in the state.
This guide breaks down every aspect of Maryland’s EIA and Coggins test regulations — which animals are covered, when testing is required, how the test works, and what happens if a horse tests positive.
What Is Equine Infectious Anemia (EIA) and Why It Is Regulated in Maryland
Equine Infectious Anemia (EIA) is a viral, and sometimes fatal, disease that only affects equids — horses, ponies, zebras, mules, and donkeys. Commonly called “swamp fever” or “horse malaria,” EIA is caused by a virus that can lead to destruction of platelets, red blood cells, and inflammation in many organs of a horse’s body, and the virus invades the white blood cells causing a lifelong infection.
EIA is transmitted from one horse to another through mosquito bites, horse flies, deer flies, or stable flies that have fed on a different infected animal. This means your horse does not even need to have come into direct contact with an infected animal in order to contract the disease. The virus can also be passed during the breeding process from a dam to her foal, and by transfer of blood from an infected horse.
While certain equines may carry the virus without displaying any outward signs, others may exhibit pronounced symptoms such as irregular heartbeats, edema in the legs and abdomen, lethargy, anemia, elevated body temperature, and, in severe cases, sudden death. There is no cure or vaccine for EIA, making testing critical for disease prevention and control.
EIA has been detected and controlled in the United States since the 1970s using a diagnostic assay called the Coggins test, and over time the prevalence of EIA in the U.S. had been reduced to very low levels, estimated to be around 0.004% of the horse population. Maryland regulates EIA because even a single positive horse at a shared facility can put an entire regional equine population at risk. You can learn more about Maryland’s broader animal health framework on the Maryland Department of Agriculture Animal Health page.
Key Insight: Because infected horses become lifelong carriers even without showing symptoms, routine Coggins testing is the only reliable way to identify and remove EIA-positive animals from the general horse population.
Which Animals Require a Coggins Test in Maryland
The term “equine” under federal and state definitions covers any animal in the Family Equidae, including horses, asses, mules, ponies, and zebras. All of these animals fall under Maryland’s EIA testing requirements when the triggering circumstances apply.
All equines over 9 months old assembled for supervised exhibition in the state must have been found negative to an official test for equine infectious anemia made within 12 months before the date of the event. The Maryland Department of Agriculture also recommends that all new horses, mules, and donkeys brought onto a premises be isolated until they have been Coggins tested for EIA.
In practice, any equine that participates in organized activities, changes ownership, or crosses state lines needs a current negative Coggins certificate on file. Private horses kept exclusively on their home property with no contact with outside animals are generally not subject to mandatory testing triggers — but annual testing is still strongly recommended. If you own horses in Maryland, you may also want to review the fastest horse breeds for background on the breeds most commonly active in competitive events where Coggins testing is required.
When a Coggins Test Is Required in Maryland
Maryland law specifies several situations that require proof of a current negative Coggins test. Proof of testing for Equine Infectious Anemia is mandated by law in the following cases: when equines are being transported across state lines, when equines are bought or sold, and when equines are at shows or gatherings.
You must obtain the required certification of a negative Coggins test status for horse shows, county fairs, racetracks, and other places where many animals are brought together, or as required when moving animals from state to state. The test must be current — all equines over 9 months old assembled for supervised exhibition in the state must have tested negative within 12 months before the date of the event.
Beyond these mandatory triggers, yearly testing during an annual checkup starting at 6 months of age is recommended. The table below summarizes the key situations where a Coggins test is required or strongly recommended in Maryland:
| Situation | Coggins Required? | Valid Test Window |
|---|---|---|
| Horse shows and exhibitions | Yes — mandatory | Within 12 months |
| County fairs | Yes — mandatory | Within 12 months |
| Racetracks | Yes — mandatory | Within 12 months |
| Interstate transport | Yes — mandatory | Within 12 months (CVI also required) |
| Purchase or sale | Yes — mandatory | Within 12 months |
| New arrivals at a facility | Strongly recommended | Before integration with herd |
| Annual wellness exam | Recommended from 6 months of age | Yearly |
How the Coggins Test Works and Approved Testing Methods in Maryland
The Coggins test is a blood test that detects antibodies against the Equine Infectious Anemia Virus (EIAV). It was developed in the 1970s by Dr. Leroy Coggins and remains the gold standard for EIA diagnosis. Two laboratory methods are approved under USDA standards and accepted in Maryland.
The first is the Agar Gel Immunodiffusion test, better known as the AGID. Also known as the Coggins test, AGID is the most widely accepted procedure for the diagnosis of EIA. The test detects antibody against the viral p26 antigen (major core protein) and is the only procedure that has been statistically correlated with the presence of EIA virus in blood. AGID typically returns results in 24 to 48 hours.
The second approved method is the ELISA (Enzyme-Linked Immunosorbent Assay). ELISA is faster but requires AGID confirmation if the result is positive. Not all laboratories run both test types, so you need to confirm with your laboratory which tests they offer before submitting your EIA sample. Both test types are USDA-approved and accepted for regulatory compliance, though processing times may vary.
The testing process itself follows a consistent protocol. Your veterinarian will conduct a thorough physical exam, complete an EIA form marking down details such as your horse’s coloration, age, markings, and breed, take a number of digital images of your horse, and then take a blood sample that will be submitted to an accredited lab for analysis alongside the EIA form and images.
Starting April 15, 2020, all veterinarians and laboratories must use USDA-approved EIA test forms. GlobalVetLink’s digital EIA certificates include the statement “Official EIA Test Form, Approved by USDA Veterinary Services March 2020, GVL” and meet all current federal requirements. Only Category II accredited veterinarians, who are authorized to perform accredited duties in the state in which samples are collected, may submit samples to an APHIS-approved laboratory.
Pro Tip: Ask your veterinarian about digital Coggins certificates. Platforms like GlobalVetLink allow you to store and share your horse’s EIA test results electronically, which is convenient for events and travel documentation.
For diagnostic testing information and sample submission in Maryland, contact the Maryland Department of Agriculture Animal Health Laboratory or call the Animal Health division at 410-841-5810.
Interstate Movement and Import Requirements in Maryland
Moving horses across state lines triggers both federal and state requirements. Proof of a negative EIA test performed at an accredited laboratory is required for entry into all 50 states. Maryland is no exception, and you will need both a current negative Coggins test and a Certificate of Veterinary Inspection (CVI) before transporting horses into or out of the state.
EIA is a reportable disease in Maryland and further testing is required to fully verify positive results. You will need a negative EIA test to get a CVI from your veterinarian for state-to-state travel. Traveling with horses often requires an up-to-date Certificate of Veterinary Inspection, sometimes current within the last month. In most cases, a CVI is valid for 30 days after the date of issue.
Maryland also participates in the Extended Equine Certificate of Veterinary Inspection (EECVI) program. EECVIs conveniently allow veterinarians and horse owners to obtain a six-month equine health certificate, as long as a current EIA/Coggins test has been provided. An EECVI is valid for six months from the CVI inspection date or until the horse’s current EIA/Coggins test expires, whichever comes first. Since EIA tests are typically valid for 12 months from the blood draw date, the EECVI expiration is determined by whichever date occurs sooner.
A Health Declaration and Movement Permit (HDMP) is the travel document that horse owners create for each individual trip when using an EECVI. Prior to each movement, owners log in to their account, enter their travel dates, origin, destination, and confirm that their horse is healthy. The system generates an HDMP that serves as the documentation displayed when crossing state borders, and the HDMP must be kept together with the EIA/Coggins test for the EECVI to remain valid.
| Document | Validity Period | Required For |
|---|---|---|
| Coggins / EIA Test Certificate | 12 months from blood draw | All interstate movement, shows, sales |
| CVI (Standard) | 30 days from issue | Interstate transport |
| EECVI + HDMP | Up to 6 months | Frequent interstate travel |
What Happens When a Horse Tests Positive in Maryland
A positive Coggins result in Maryland sets off a mandatory regulatory process. EIA is a reportable disease in Maryland and further testing is required to fully verify the results. An initial positive screening result — particularly from an ELISA test — must be confirmed by AGID testing at a USDA-approved laboratory before final action is taken.
It may take 60 days or more for a horse to test positive after infection, which is why Maryland requires retesting of exposed animals at contact facilities. A real-world example from Maryland illustrates how this process works: EIA was diagnosed in a horse at a facility in Montgomery County, Maryland, confirmed by the Maryland Department of Agriculture on July 10, 2018. The positive horse was discovered during a routine wellness examination by a private veterinarian. The infected horse did not display any clinical signs but was determined to be in the carrier state of the disease. The positive diagnosis was confirmed by the National Veterinary Services Laboratory. The infected horse was euthanized, and the State Veterinarian’s Office placed the facility under quarantine and planned to retest after 60 days to ensure no more horses tested positive.
This case illustrates that even horses with no visible symptoms can be EIA-positive carriers. Since many horses carrying the virus do not show symptoms of the disease, testing horses with no symptoms of EIA is essential for detecting carriers and preventing further spread. You should contact the Maryland Department of Agriculture Animal Health division at 410-841-5810 immediately if you receive a positive or suspect result.
Important Note: A positive initial EIA screening result alone does not trigger final disposition. Maryland requires confirmation testing at a USDA-approved laboratory — typically the National Veterinary Services Laboratory — before euthanasia or permanent isolation is ordered. Do not take any action until the State Veterinarian’s Office provides official direction.
Quarantine, Euthanasia, and Isolation Rules in Maryland
Once a horse is confirmed EIA-positive in Maryland, the owner faces a limited set of options under state and federal guidelines. Infected animals that survive the disease become virus carriers and can infect other equids for life. They must either be euthanized or permanently isolated from other equids to prevent transmission.
The three standard disposition options for a confirmed EIA-positive (reactor) horse are:
- Euthanasia — The horse is humanely destroyed by a licensed veterinarian. This is the most common outcome in Maryland, as demonstrated by the 2018 Montgomery County case.
- Permanent quarantine and isolation — Horses that test positive for EIA must be branded and strictly quarantined at least 200 yards away from other horses for the rest of their life. The 200-yard minimum distance is the nationally recognized standard under USDA Uniform Methods and Rules.
- Transfer to a research or slaughter facility — Horses may also be sent to a research facility if neither of the previous options is suitable.
Carriers may also experience clinical flare-ups, often following stress or strenuous work, which is why permanent isolation — if chosen over euthanasia — must be rigorously maintained for the animal’s entire life. The State Veterinarian’s Office oversees all quarantine orders and will specify the exact conditions required at the facility.
When a positive case is confirmed, the entire facility is also placed under quarantine. The State Veterinarian’s Office places the facility under quarantine and retests after 60 days to make sure no more horses test positive. All equines at the premises that may have been exposed must be tested before any horses can leave the property.
If you’re interested in understanding how Maryland handles other animal health regulations, see the state’s requirements for rabies vaccine requirements for cats in Maryland as a point of comparison for how the state structures its animal disease control programs.
Penalties for Non-Compliance in Maryland
Failing to comply with Maryland’s EIA and Coggins test regulations carries both regulatory and legal consequences. At the event level, event officials must review official test papers of all equines entered into an event to ensure that all participating equines are test-negative. Any horse without a valid negative Coggins certificate can be turned away or removed from the premises.
For licensed equine facilities, the Maryland Horse Industry Board has the authority to impose administrative penalties. For violations, the Board may impose: for a first violation, a penalty of not less than $500 or more than $1,000; for the second violation, a penalty of not less than $1,000 or more than $1,500; and for the third and any subsequent violation, a penalty of not less than $1,500 or more than $2,000.
Beyond financial penalties, non-compliance can expose horse owners to broader legal liability. Moving a horse without a required Coggins test and having that horse turn out to be EIA-positive could make you liable for the costs of testing, quarantine, and losses suffered by other owners at the facility. By staying compliant with testing laws and taking a proactive approach to equine health, you’re not only protecting your own horse but also acting as a responsible member of the broader equine community.
- Always carry the original or a verified digital copy of your horse’s current negative Coggins certificate when transporting or showing
- Keep records of all EIA tests with dates, lab accession numbers, and veterinarian contact information
- Verify testing requirements with event organizers before arrival, as some venues may require tests more recent than the 12-month standard
- Contact the Maryland Department of Agriculture at 410-841-5810 if you have questions about reportability or compliance
Pro Tip: Store your horse’s digital Coggins certificate in a cloud-accessible account so you can pull it up on your phone at any event or inspection stop. Many Maryland shows now accept digital copies, but confirm with the organizer in advance.
Maryland’s EIA regulations exist to protect the entire state equine population from a disease with no cure and no vaccine. Whether you’re heading to a weekend trail ride, a competitive show, or crossing into a neighboring state, keeping your Coggins paperwork current is the single most important compliance step you can take as a horse owner. For more on Maryland’s wildlife and animal regulations, explore our guides on hunting license requirements in Maryland and fishing license requirements in Maryland.