Page 73

diseases as a clinician-scientist inspired Cohen to complete his residency and join the faculty of the CVM. “Dr. Martens had the vision to recognize that a clinicianscientist with an interest in epidemiology would be of benefit to the department,” Cohen explained. “He encouraged me to complete my residency training in internal medicine, and then he recruited me to become a member of the large animal medicine faculty.” After he completed his residency, Cohen began researching R. equi in the EIDL under the direction of Martens. The main goal of Martens’ research was to find an effective preventative measure against infections caused by R. equi in foals because none previously existed. Treating pneumonia caused by R. equi can be difficult because treatment is lengthy, expensive, must be administered multiple times daily, can cause serious side-effects, and isn’t always effective. This is why Martens began working on ways to decrease foals’ susceptibility to developing disease from the bacteria. On breeding farms, pneumonia caused by R. equi is the most common and severe form of pneumonia in foals that are between the ages of one and six months. Pneumonia is a leading cause of disease and death for foals, which has motivated researchers like Martens and Cohen to seek an effective preventative strategy against pneumonia caused by R. equi. A vaccine to directly prevent the disease would be a major breakthrough for the health of foals on breeding farms, according to Cohen. Martens recognized the prevalence of R. equi in foals and knew the importance of preventing R. equi–related diseases, especially pneumonia. Martens’ biggest contribution to the prevention of R. equi disease was the use of hyperimmune plasma, which is harvested from the blood of horses that were vaccinated to produce high concentrations of antibodies against R. equi. The plasma is then transfused to foals. These transfusions partially protect foals against infection with R. equi. “The collection and transfusion of plasma that is hyperimmune against R. equi remains the only acceptable and commercially available approach for preventing R. equi pneumonia,” Cohen said. “Unfortunately, it is not completely effective and has some other limitations, such as being expensive, labor-intensive to administer, and carrying some health risks for foals. Although the concept of preventing the disease by administering antibiotics has been demonstrated to be effective, this approach isn’t acceptable because it isn’t uniformly effective and, most importantly, can contribute to antibiotic resistance from overuse.” Martens was also interested in identifying alternatives to traditional antibiotics to control R. equi pneumonia because of emerging resistance to drugs commonly used to treat the disease. When Martens retired, he passed on the directorship of the EIDL to Cohen. Exploring alternative treatments of R. equi pneumonia as opposed to traditional antimicrobial drugs remains an area of interest for the EIDL. “We are working on two strategies for preventing R. equi pneumonia based on having the patient’s immune system protect them from infection rather than antibiotics,” Cohen said. “First, we are working

Dr. Cohen and students working with an equine patient. on developing a vaccine, which is a traditional and effective approach for preventing infections. Second, in collaboration with investigators from the Texas A&M University System’s Institute for Biosciences and Technology (IBT) in Houston, we are investigating if a mist inhaled into the lungs can stimulate a foal’s immune system to protect it against R. equi infection.”

Collaboration The CVM’s collaboration with numerous researchers worldwide is a critical component of Cohen’s goal to prevent R. equi pneumonia in foals. Cohen has collaborators in Brazil, Canada, Germany, Japan, and other countries, all of whom have contributed to the growing research in R. equi pneumonia prevention. In addition, Cohen said his research project benefits significantly from many researchers in the United States and the CVM. “We collaborate with numerous investigators from many countries,” he explained. “We work especially close with Dr. Steeve Giguère from the University of Georgia, one of the world’s authorities on this disease. We are also fortunate to benefit from many scientists at the CVM.”

Results To reduce the risk of antibiotic resistance, Cohen and his team are investigating new drugs and potential methods of administering preventative and therapeutic agents. After over five years of trying, Cohen and his team at the CVM have produced encouraging results with a vaccine for R. equi pneumonia. “We are exploring new approaches that we hope will be effective and not promote antibiotic resistance in R. equi,” Cohen said. “Examples include using inhaled substances that facilitate the foal’s own immune system by stimulating receptors of the immune system that eliminate R. equi, and drugs such as metal-based compounds and antibiotics that will reduce the risk of resistance.”

One Health The strategies Cohen and his team are exploring may have positive implications for other animals, including humans. Since there are striking similarities between R. Winter 2017 •

• 73

CVM Today - Winter 2017  

A semi-annual publication for the faculty, staff, students, alumni, and friends of the Texas A&M College of Veterinary Medicine & Biomedical...

CVM Today - Winter 2017  

A semi-annual publication for the faculty, staff, students, alumni, and friends of the Texas A&M College of Veterinary Medicine & Biomedical...