INFECTIOUS DISEASES
2 L of REHIP More Effective Than 1 L, Study Shows By Adam Marcus Transfusing 2 L of plasma hyperimmune against R. equi (REHIP) simultaneously is significantly better than administering 1 L of the substance for the prevention of pneumonia in foals, reducing the incidence by more than 50%, even when accounting for variability in the time of year the animals were born, according to Patricia FloresAhlschwede, DVM. Rhodococcus equi is a major source of pneumonia in newborn foals but can be controlled by transfusions of REHIP. However, the optimal volume of plasma to administer, and in what timeframe, has been unclear. This study should help clarify the question, she said during a presentation at the 2020 virtual meeting of the American Association for Equine Practitioners. Led by Dr. Flores-Ahlschwede, of the Rood and Riddle Equine Hospital in Saratoga, N.Y., the researchers reviewed the records of 158 foals born on 2 farms in New York. Animals were considered to have R. equi pneumonia if they had lung abscesses of 1 cm or larger, and 3 or more of the following clinical signs: • coughing, • abnormally rapid breathing, • labored breathing, • fever or • lethargy. Of the 64 foals that received 2 L of REHIP, 19 (30%) developed clinical pneumonia, compared with 58 of the 94 (62%) that received 1 L of the therapy (P=0.05),
according to the researchers. Animals born in the spring (April or May) were more likely to develop pneumonia than those born before April (59% vs. 39%; P=0.01769). However, even after adjusting for the month of birth, the advantage of 2 L of REHIP remained statistically significant (P=0.0457), the researchers reported. “Based on the evidence we have to date, I would recommend transfusing 2 L of REHIP to foals at farms where the disease is prevalent on a recurring basis in order to reduce the cumulative incidence of R. equi pneumonia,” said study co-author Noah D. Cohen, VMD, MPH, PhD, DACVIM-LA, the Patsy Link Chair in Equine Research, and the director of the Equine Infectious Disease Laboratory at the Texas A & M University College of Veterinary Medicine & Biomedical Sciences, in College Station. Although some veterinarians may already be transfusing 2 L, Dr. Cohen said he suspects the majority do not. “I do not think most vets transfuse 2 L simultaneously, but it is my belief and hope that the practice is increasing because I think it protects foals,” he told Modern Equine Vet. Cohen noted that the new study has a few limitations, including that it was observational. “It would be better if we had a randomized, controlled trial to demonstrate unequivocally for veterinarians and horse owners that transfusion of 2 L is superior to 1 L to control this difficult disease.” MeV
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Foals born in April or May were more likely to develop pneumonia than those born earlier.
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Issue 3/2021 | ModernEquineVet.com
