First PhD Graduate

First PhD to Graduate from Cummings School of Veterinary Medicine

Student focused research on rabbit fever on Martha's Vineyard
North Grafton, MA, May 13, 2008

The Cummings School of Veterinary Medicine at Tufts University will confer its first Doctorate of Philosophy in Comparative Biomedical Sciences to a student whose work may one day prove vital to understanding why Martha's Vineyard has played host to an outbreak of tularemia since 2000. Zenda L. Berrada will graduate alongside 78 new doctors of veterinary medicine and 14 students from the Cummings School's Master of Science in Animals and Public Policy program on Sunday.

When Berrada first began researching tularemia, also known as rabbit fever, she had no idea that it was the very same disease that killed her great-great-grandmother. But, as her work progressed, a conversation with her grandmother revealed that her ancestor died from the disease—after dressing an infected rabbit.

Berrada first worked with tularemia at Colorado State University, where she studied microbiology and worked in the Centers for Disease Control and Prevention's Division of Vector-Borne Infectious Diseases, studying the differences between Type-A tularemia, the virulent strain that has caused 68 cases of the disease on Martha's Vineyard since 2000, and Type-B, which is found elsewhere in the United States, especially in Arkansas, Kansas, and Oklahoma. After more than 5 years at the CDC laboratory, she joined the Massachusetts Department of Public Health to assist with West Nile Virus surveillance, then later with the DPH's Bioterrorism Response Laboratory.

Berrada also worked part-time with Dr. Sam Telford, an expert in tick-borne illnesses and diseases. When Telford made the transition to Tuft University and the Cummings School in 2002, he convinced Berrada to apply to the newly formed PhD program in Comparative Biomedical Sciences. She was admitted, enrolled, and soon began collecting soil, tick, and other specimens to better understand what about Martha's Vineyard made it so hospitable to the Type-A strain of tularemia.

Berrada, under Dr. Telford's guidance, probed a number of hypotheses, including whether exposure levels in mammals on the Vineyard correlated with the incidence of human disease. To do so, Berrada tested serological samples from several animals on the island, and found a particularly high rate of infection among skunks and raccoons on the Vineyard (nearly 50% positive) when compared to their counterparts in nearby Southeastern Massachusetts (0.5% or less). Berrada says that, while more research needs to be done on the topic, it may suggest that medium-sized rodents may play a larger role in the spread of Type-A tularemia on Martha's Vineyard than simply playing host to deer ticks that spread it.

Berrada is also looking into whether certain components of the Vineyard's soil might allow the bacteria that causes tularemia, Francisella tularensis, to live longer.

Zenda's work in infectious diseases is a prime example of the Cummings School's commitment to better understanding zoonotic diseases—ones that can be spread from animals to humans, said Deborah T. Kochevar, PhD, DVM, dean of the Cummings School of Veterinary Medicine at Tufts University. Her work—and that of all of our Division of Infectious Diseases staff—is dedicated to keeping animals and humans safer, and I applaud Dr. Telford for his mentorship of our first PhD candidate.

Tularemia can cause fever, chills, headache, muscle aches, chest pain, and coughing. If tularemia is caused by the bite of an infected insect or from bacteria entering a cut or scratch, it usually causes a skin ulcer and swollen glands. Eating or drinking food or water containing the bacteria may produce a throat infection, stomach pain, diarrhea, and vomiting. Breathing dust containing the bacteria may cause a pneumonia-like illness. While the disease is usually spread by deerflies and ticks, the cases on Martha's Vineyard seemed to point to inhalation of the bacteria—especially among landscapers who may have inhaled it while using lawnmowers, blowers, brush cutters, and other landscaping equipment.

The PhD Program in Comparative Biomedical Sciences at the Cummings School fosters research training toward the PhD degree in two focus areas, namely Infectious Diseases and Reproductive Biology. The multidisciplinary program offers an opportunity for talented students to acquire a balanced blend of scientific knowledge and technical skills in infectious diseases or in reproductive biology. In addition to traditional employment opportunities in academic and corporate research, program graduates are uniquely trained to vie for non-traditional employment in emerging areas of veterinary and human health, including research, education and administration within academic, government and private sectors.


About the Cummings School of Veterinary Medicine

Founded in 1978 in North Grafton, MA, the Cummings School of Veterinary Medicine at Tufts University is known for academic programs that impact society and the practice of veterinary medicine; five hospitals that treat over 30,000 cases each year; and groundbreaking research that benefits animal, public and environmental health.