Reprinted from Veterinary Product News

Predicting which animals it will benefit is uncertain, but veterinarians say that Rubeola Virus Immunomodulator (RVI) has been useful in treating a range of problems in both performance horses and dogs.

Developed and marketed by Eudaemonic, Omaha, Neb., RVI is licensed as a biological for treatment of myositis and myofascial inflammation in horses (VPN, July-August 1991). According to the company, the product is different because it goes to the source of the problem – the immune system – and works to restore the natural efficient balance found in optimally functioning horses.

"RVI represents a breakthrough in the treatment of chronic myositis," says Eudaemonic President Richard Wood. "While traditional treatment has required extended rest, RVI’s results are apparent within days."

Dr. James Ford, a race track veterinarian at the Meadows track in Washington, Pa., has used approximately 100 vials of RVI. He administers it chiefly in cases "where we either know the patient has a tendency to tie up or where a race horse will get ¾ of a mile and act like a bleeder that couldn’t make the time to the finish.

"I’m not skeptical about RVI’s effectiveness—we’re using a lot of it," he says. "But I don’t know enough about it to guarantee that it’s going to help this horse and not going to help that one."

It is believed that stressful conditions of chronic and acute inflammation can trigger an autoimmune reaction in which the immune lymphocytes recognize the body’s products of inflammation as foreign, states Eudaemonic. Dr. Ford comments that "RVI involves very in-depth immunology," and there are many factors in exercise physiology that must be controlled before solid theories on the product’s influence can be developed and tested. Nutrition and structural differences in muscle fiber may be avenues for further investigation, he says.

In most patients, the dosage used by Dr. Ford is 2 ml subcutaneously daily for three to six days. Horses coming into training that don’t have a problem may be put on a once-a-week, 2 ml dosage after an initial treatment.

Clinically, Dr. Ford also has recognized that RVI seems to help nervous fillies run better. With just one dose given the week prior to racing, he says, "RVI is both legal and simpler than the alternative treatments."

To date, notes Eudaemonic, no undesirable side effects have been noted in equine use, although research shows RVI will not be as effective when used in conjunction with corticosteroids. According to the company, the product does not test out as a masking agent, and there is only one dosage level, regardless of weight or breed.

RVI was featured in the ABC television segment "Sport Science" during the Kentucky Derby preview this year. In the spot, Dr. Alex Harthill, a renowned race horse veterinarian, described RVI as being most effective when used in chronic muscle sorenesses that are unresponsive to anti-inflammatories. In his experience, RVI "works well in acute spastic muscle soreness."

The Sport Science segment described RVI as a biologic agent that restores the inner cellular balance and stimulates the same kind of healing as extended rest.

Dr. John Hanover of the Animal Hospital of Gurnee, Ill. started using RVI on hunter/jumpers and show horses about six months ago. He began treatment on a seven-year-old quarter horse that had been treated by four veterinarians for chronic left fore lameness.

"The horse was still sore after a nerve block, had no swelling or heat and was living on bute and aspirin," he reports. "Three weeks after the initial treatment with RVI, the horse was doing much better." Although at press time the patient had not reached complete recovery, for the first time it was sound enough to ride.

Dr. Hanover believes that RVI "is not covering up the pain, it is helping to make the horses better." After research indicated RVI’s ability to reduce inflammation throughout the body, Dr. Hanover has prescribed the drug with success for general muscle and back soreness in show horses and stiffness and discomfort in older pleasure mounts.

"In most cases, after the initial dosage, which doesn’t require any extended layup, the horse can be put on a once-a-month maintenance dosage," he explains. Although the cost of the initial treatment – three injection for $75 – made some clients hesitate, he adds, they felt that $25 per month for maintenance dosages "was nothing to keep a horse comfortable."

Dr. Hanover adds that "there are cases where the horse is basically sound and I notice no clinical difference, but the owners feel that when under saddle, the horse’s attitude and way of going have significantly improved."

RVI effectiveness has begun to be explored outside the equine field. Dr. Nancy Harrington, whose seven-year-old practice in Norman, Okla. Focuses on small animals, first learned about RVI from a client who asked if the immunomodulating action of the product might help his allergic dog. Because RVI is nontoxic and dose-constant regardless of age, weight or species, Dr. Harrington decided to give it a try. She administered RVI to two dogs suffering from allergies, but results were disappointing; there was no real improvement in either patient.

However, because RVI is cleared for myofascial inflammation, and many practitioners speculate that its anti-inflammatory properties have some correlation to neuromuscular inflammation, Dr. Harrington felt that the product might have a positive effect on chronic intervertebral disc (IVD) syndrome patients.

The first patient she treated was a six-year-old Lhasa Apso whose IVD left it with an uncoordinated walk in the back legs and uncontrollable shaking. "we chose this candidate because after two months of treatment, it just wasn’t progressing. Initial treatment with IV Azium (1/2 mg/lb.) did allow the dog to stand, but he was still unable to walk properly."

The RVI treatment consisted of a 2cc subcutaneous injection for six consecutive days. "the dog miraculously improved after three doses," Dr. Harrington says. It began to run around, its legs became steady and it continued to improve through the week. "We saw him two weeks later and he was fine. At 30 days post-treatment, we administered a booster. Two months later, the dog demonstrated some slight shaking, so another single booster was given. The patient was better overnight. We have concluded that a booster will be needed every 60-90 days."

Dr. Harrington has treated several IVD syndrome dogs with RVI, all with the same results. She points out that Azium is still her treatment of choice to decrease spinal cod inflammation during the first 72 hours. After that, she explains, "there appears to be some type of post-inflammation due to T-lymphocyte imbalance. This is where RVI seems to have such a positive effect."

While Azium can cause GI bleeding, vomiting and bloody diarrhea with prolonged use, RVI has only produced minimal side effects. One disc dog experienced vomiting after the fourth dose, but was fine after all subsequent treatments. "I’m very pleased that this has worked so well. I won’t say it’s a miracle drug, but the improvements in these dogs has been miraculous," she says.

Dr. Bill LaRue, a small animal practitioner in Chanute, Kan., also has experienced success treating IVD patients. One, a cocker spaniel, was being treated for a second time – both conditions stemmed from the dog’s habit of chasing rabbits into pipes. "The second time, the dog was down and could not get up at all. After three doses of RVI, he’d improved enough to go home. My biggest problem was getting the owners to bring him back to finish the treatment because he was doing so well. We’ve seen him several times since then, and he’s doing fine. We haven’t needed a booster so far."

Dr. LaRue also has worked with a greyhound trainer, Robert Black of Abilene, using RVI to treat muscle soreness brought on by training. Says Black: "It’s the best thing I’ve ever used. We’ve not had one dog that had a negative response."

Dr. LaRue explains, " We see this soreness primarily when the greyhounds first start training. We give them RVI three days in a row, and they do remarkably well. So far, we haven’t seen any failures. You hate to talk 100%, but they’ve all done real well."