Scientists from Lawrence Livermore National Laboratory and the Sausalito-based Marine Mammal Center are working together to diagnose several diseases that have struck California sea lions and harbor seals.
In recent months, about 17 percent of the adult sea lions that have died at the Marine Mammal Center have succumbed due to cancer, and others have become ill because of the bacterial disease leptospirosis, said Frances Gulland, the center's director of veterinary science.
In June 2009, about 20 harbor seals died in Northern California from brain lesions, consisting of the premature death of living cells.
"The brain lesions are rare and unusual," Gulland said. "We don't understand why it happened. We are looking at two very different problems (in the brain lesions of the seals and the cancer of the sea lions)."
The team is attempting to determine how well the Lab's Microbial Detection Array can perform pathogen discovery of as-yet-unsequenced viruses or bacteria.
"The reason the work on marine mammals is so important is that this gives us excellent training for what we will need to do when the next unknown human pathogen outbreak hits," said team leader Tom Slezak, the head of the Lab's Pathogen Bioinfomatics Group. "The next new Severe Acute Respiratory Syndrome (SARS)-like human virus will be as hard to identify and characterize as the unknown pathogens that are killing sea lions and harbor seals."
To date, Livermore researchers have used the LLMDA to analyze frozen tissue samples from two deceased sea lions that were forwarded to them by the Marine Mammal Center.
One sample was found to have calicivirus, which would not have caused cancer, and the other sample had no virus or bacteria that could be positively identified and will now be sequenced by a company that assists LLNL, Jaing said.
Frozen tissue samples from eight other marine mammals, four from sea lions and four from harbor seals, will be analyzed in the coming months for bacterial or viral pathogens.
"This research has the potential to be very helpful because the genetic make-up of sea lions and harbor seals has not been well studied," said biologist Crystal Jaing. "From this study, we can potentially identify novel viruses or bacteria that can cause cancer in marine mammals."