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Up to the Challenge

Up to the ChallengeZenda Berrada, the Cummings School's first Ph.D. graduate, tries to answer nearly a decade's worth of questions for the residents of a Massachusetts island community.

No. Grafton, Mass. [07.15.08] Behind every question lies an adventure. For Zenda Berrada, that is what makes research so thrilling.

"The challenge of investigating interesting scientific questions has always been a pull for me," Berrada says, looking back on the path that lead her to become the Cummings School of Veterinary Medicine's first recipient of a Doctorate of Philosophy in comparative biomedical sciences.

Graduating from the Ph.D. program in May, Berrada has spent the past five years, and now continuing into her post-doctorate work, facing one main challenge: determining why the island of Martha's Vineyard in Massachusetts has spent the past eight years playing host to a tularemia outbreak.

Tularemia, caused by the bacterium Francisella tularensis, can be found in various rodents, rabbits and other mammals. The disease is spread to humans most commonly through tick bites, but in the case of the outbreak that has affected Martha's Vineyard, transmission has occurred through inhalation.

"The island was the site of a pneumonic tularemia outbreak that started in 2000, with cases of infection still showing up as recent as last year," Berrada explains. "On Martha's Vineyard, 60 percent of cases are pneumonic tularemia, meaning that they have more than likely inhaled contaminated particles, such as soil or water, that have been aerosolized, making the cases found on the island more unusual."

According to Berrada there were three main components of her graduate research: looking at the role that mammals play in tularemia transmission, their exposure rate and determining whether certain animals are indicative of what has been happening with the human outbreak.

Outside of looking at the mammal population, Berrada has also taken soil and water samples, finding that the bacterium has a higher survival rate in brackish water, which has more salinity than fresh water but less than sea water.

"Now I am trying to figure out what components in the brackish water, whether it's the salt levels or some other component in the water, enhances the survival of the bacterium," she says. "This is all lab-based, so as with a lot of environmental microbiology types of studies you can never really 100 percent mimic what is happening out in nature, but this kind of gives us an idea of the ability of the bacteria to survive."

With landscapers making up a large number of those presenting with pneumonic tularemia, Berrada says their research is also looking into whether the bacteria is being deposited into the environment via animal waste.

"We have yet to find a smoking gun, but hopefully if we continue to investigate this we will come across something that will answer some of these questions," she says.

Berrada, who considers herself a "non-traditional" student having come into the program at the age of 30, says she had always thought about going into veterinary medicine, gaining a love for laboratory science-particularly vector-borne and zoonotic diseases-
after working for the Centers for Disease Control in Fort Collins, Colo., as a Colorado State undergraduate studying microbiology.

After more than five years of work with the CDC, Berrada came to Boston in 2000 and joined the Massachusetts Department of Public Health, assisting with arbovirus surveillance as concern about the West Nile Virus began to heighten. While in Boston, Berrada met Associate Professor Sam Telford, then at Harvard, and began working part-time in his lab researching tick-borne diseases.

"A couple of years after that I had decided that I wanted to go to grad school and by that point Sam had transferred to the Cummings School and they had just started their Ph.D. program," she says. "So I applied, wanting to be able to continue my work with him."

Being the first to go through the Ph.D. program, Berrada says there were some expected challenges in the first couple of years, but she is happy with how the program has grown.

"The program has really evolved and I am very proud of where it is," she says. "There is a wonderful group of students going through it right now."

Profile By Kaitlin Melanson, Web Communications



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