Scientists and health experts around the world have a better understanding of a disease-causing parasite and potential bioterrorism agent thanks to research recently completed by members of the Cummings School of Veterinary Medicine.
The work decoded the genome of Cryptosporidium hominis, a water-borne parasite that thrives in the intestines of infected humans, which the Centers for Disease Control and Prevention (CDC) have classified as a potential bioterrorist agent.
Director of Tufts' Division of Infectious Disease Saul Tzipori, PhD, and Associate Professor of the Department of Biomedical Sciences directed the project.
The parasite, which can be acquired by drinking impure water, causes symptoms including vomiting, stomach cramps, weight loss and fever. Although healthy people usually recover from the disease, it can be dangerous for people with weak immune systems or those living in under-developed countries.
"[The parasite] is often life-threatening in people with HIV/AIDS or in malnourished children," Tzipori said. "There is no effective treatment against it."
Cryptosporidium proved very difficult to work with, making laboratory tests nearly impossible to conduct. In 2000, the human form of the parasite, dubbed TU502, was extracted from a Ugandan child and isolated by members of Tzipori and Widmer's team. Researchers from Tufts, along with scientists from Minnesota University and the Commonwealth University of Virginia, were then able to sequence the parasite's genome.
The sequencing was completed and published in the journal Nature on Oct. 28.
"The sequencing of the genome will help determine the underlying mechanisms of Cryptosporidium's unusual resistance to antimicrobial agents," Tzipori said.
"We are confident that the genome will allow us to identify key biological characteristics that might help explain the difference between parasites that infect humans and animals, and provide the necessary information to place this microorganism in the correct spot on the evolutionary tree," Tzipori said.
Cryptosporidium can be found in soil, food, human feces and contaminated water. It cannot be killed by chlorine or iodine, making modern water purification ineffective in killing the parasite. For this reason, the CDC declared the bacteria a possible bioterrorism agent.
The sequencing "now puts us in a better position ... to identify possible drug and vaccine targets," Widemer said.
Decoding the organism's genomic sequence gives scientists the ability to analyze how it operates on a biological level. For example, scientists working with Cryptosporidium may discover that a specific sequence of DNA can be neutralized with a high concentration of a certain chemical, allowing the development of a drug to treat victims of the bacteria.
But that task may prove extremely difficult, as genomes are made up of billions of individual sequences. It often takes years of painstaking work to break down, or sequence, the entire strand.
Other groundbreaking work in sequencing has provided insights into the genomes of many organisms, including those of humans and monkeys.
