Maedi-Visna Joint Disease in Sheep: Arthritis and Mobility Problems

Quick Answer
  • Maedi-visna, also called ovine progressive pneumonia, is a lifelong lentivirus infection of sheep that most often affects the lungs but can also cause chronic inflammatory disease in joints, udder, and nervous system.
  • Joint disease tends to show up as slowly worsening stiffness, enlarged joints, reluctance to rise, weight loss, and reduced flock performance rather than a sudden severe lameness episode.
  • There is no cure or vaccine. Care focuses on confirming infection, improving comfort and footing, reducing stress, and making flock-level decisions about isolation, culling, and lamb-rearing practices.
  • Testing usually involves a farm exam plus blood testing such as ELISA or AGID, and your vet may also recommend necropsy or additional testing to rule out foot rot, injury, mycoplasma, or other causes of lameness.
Estimated cost: $120–$900

What Is Maedi-Visna Joint Disease in Sheep?

Maedi-visna is a small ruminant lentivirus infection of sheep. In the United States, it is often called ovine progressive pneumonia (OPP). The virus causes a slow, lifelong infection and may affect the lungs, udder, nervous system, and sometimes the joints. Many sheep carry the virus for long periods before obvious illness appears.

When joints are involved, the problem is not usually a sudden hot, infected joint. Instead, it is a chronic inflammatory arthritis that can lead to stiffness, enlarged joints, reduced mobility, and gradual loss of body condition. Sheep may seem slower to stand, less willing to walk long distances, or less able to keep up with the flock.

This condition matters because it is both an individual health issue and a flock management issue. A sheep with arthritis may need supportive care, but the bigger concern is that infected animals can continue spreading virus within the flock through close contact and, importantly, through colostrum and milk.

Symptoms of Maedi-Visna Joint Disease in Sheep

  • Gradual stiffness or slow, short-strided walking
  • Reluctance to rise, lie down, or travel with the flock
  • Chronically enlarged joints, especially carpal joints or other weight-bearing joints
  • Progressive weight loss or poor body condition despite adequate feed access
  • Reduced milk production or a firm, hard udder in ewes
  • Exercise intolerance, increased breathing effort, or chronic respiratory signs
  • Weakness, poor thrift, or lower flock productivity
  • Severe difficulty standing, marked mobility loss, or inability to reach feed and water

Maedi-visna usually develops slowly, so early signs can be easy to miss. A sheep may look mildly lame for weeks or months before the pattern becomes clear. Because this virus can also affect the lungs and udder, mobility problems may happen alongside weight loss, poor milk production, or chronic breathing changes.

See your vet promptly if a sheep has progressive lameness, enlarged joints, weight loss, or trouble keeping up with the flock. See your vet immediately if the sheep cannot stand, is breathing hard, stops eating, or seems unable to reach feed or water. Those signs can point to advanced disease or another serious condition that needs urgent care.

What Causes Maedi-Visna Joint Disease in Sheep?

Maedi-visna joint disease is caused by infection with the maedi-visna virus, a lentivirus in the small ruminant lentivirus group. Once a sheep is infected, the virus typically remains for life. Disease develops because the immune system and virus interact over time, leading to chronic inflammation in affected tissues.

Transmission most often happens from ewe to lamb through colostrum and milk. It can also spread horizontally through close contact and respiratory secretions, especially when sheep are housed closely together for long periods. Because many infected sheep look normal for a long time, the virus can move through a flock without obvious warning.

Not every infected sheep develops obvious joint disease. Some show mainly lung disease, some develop hard udders and reduced milk production, and others remain subclinical. Genetics may also influence susceptibility, which is why flock-level control often includes both testing and longer-term breeding decisions.

How Is Maedi-Visna Joint Disease in Sheep Diagnosed?

Diagnosis starts with a hands-on flock and individual exam. Your vet will look at gait, joint size, body condition, breathing pattern, udder changes, and the overall pattern in the flock. Because many other problems can cause lameness in sheep, your vet will also consider foot rot, foot scald, injury, septic arthritis, mycoplasma, mineral issues, and chronic hoof disease.

Testing usually includes serology, most commonly ELISA or AGID blood tests, to look for antibodies to the virus. These tests are useful for flock screening, but results need to be interpreted in context because early infection may not test positive right away. In some cases, your vet may recommend repeat testing over time, especially if flock control is the goal.

If a sheep dies or is euthanized, necropsy can be very helpful. Tissue changes in the lungs, udder, joints, or nervous system may support the diagnosis, and additional laboratory testing can help confirm infection. For many flocks, the most practical diagnosis is a combination of clinical signs, blood testing, and flock history rather than one single test result.

Treatment Options for Maedi-Visna Joint Disease in Sheep

Spectrum of Care means you have options. Here are treatment tiers at different price points.

Budget-Conscious Care

$120–$300
Best for: Sheep with mild to moderate mobility problems when the goal is comfort, function, and short-term practical management.
  • Farm call or clinic exam
  • Basic lameness and body condition assessment
  • Pain-control discussion with your vet when appropriate
  • Soft, dry footing and easier access to feed and water
  • Reduced walking distance, lower-stress housing, and monitoring
Expected outcome: Comfort may improve, but the infection is lifelong and joint changes usually progress over time.
Consider: Lower upfront cost range, but this approach may not confirm the diagnosis or address flock spread as thoroughly.
Most Common

Recommended Standard Treatment

$300–$900
Best for: Most suspected cases, especially when pet parents or producers need a clearer diagnosis and a realistic flock-management plan.
  • Full veterinary exam and flock history review
  • Blood testing with ELISA or AGID
  • Rule-outs for other lameness causes as needed
  • Targeted supportive care plan for mobility, nutrition, and housing
  • Isolation or management changes for suspect or positive animals
  • Discussion of culling versus long-term supportive care
Expected outcome: Fair for short-term comfort in mildly affected sheep, but guarded for long-term productivity and mobility because there is no cure.
Consider: More useful information for decision-making, but higher cost range and ongoing management demands.

Advanced / Critical Care

$900–$2,500
Best for: Breeding flocks, valuable animals, complex outbreaks, or situations where long-term disease control matters as much as the individual case.
  • Expanded flock testing program
  • Repeat serology and strategic retesting
  • Necropsy and laboratory confirmation when available
  • Detailed biosecurity and lamb-rearing plan
  • Breeding strategy discussion, including genetic risk reduction options
  • Intensive supportive care or humane euthanasia planning for severely affected sheep
Expected outcome: Best for improving flock-level control and reducing future losses, though it still cannot eliminate disease from already infected individuals.
Consider: Highest cost range and labor commitment. It offers more data and more management options, not a cure.

Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.

Questions to Ask Your Vet About Maedi-Visna Joint Disease in Sheep

Bring these questions to your vet appointment to get the most out of your visit.

  1. Based on this sheep's signs, how likely is maedi-visna compared with foot rot, injury, or another joint problem?
  2. Which test makes the most sense first for this flock, ELISA, AGID, repeat testing later, or necropsy if an animal dies?
  3. What comfort-care options are reasonable for this sheep's mobility and body condition right now?
  4. Should this sheep be isolated, culled, or managed separately from lambing and nursing ewes?
  5. How can we reduce spread through colostrum, milk, and close contact in our setup?
  6. Would whole-flock screening be more practical than testing only visibly affected sheep?
  7. Are there breeding or genetic strategies that could lower future flock risk?
  8. What signs would mean this sheep's quality of life is declining enough to discuss humane euthanasia?

How to Prevent Maedi-Visna Joint Disease in Sheep

Prevention focuses on keeping the virus out of the flock or reducing spread within the flock. There is no vaccine, so control depends on management. The most important steps are buying animals carefully, testing when appropriate, and avoiding introduction of sheep with unknown status.

For infected or suspect flocks, your vet may recommend a control plan that includes testing, separating positive animals, and managing lamb exposure to infected colostrum and milk. Because lambs can become infected early in life, lamb-rearing practices are a major part of prevention. Good records also matter. Tracking test results, lambing groups, and culling decisions helps your vet build a practical long-term plan.

Housing and stocking density matter too. Close confinement can increase opportunities for spread, so better ventilation, less crowding, and thoughtful grouping can help. Some flocks also use genetic selection strategies over time to reduce susceptibility. Prevention is rarely one single step. It works best as a steady, flock-level program built with your vet.

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