July 11, 2013
Bird Virus Crossover Found In Beached Dolphin
Brett Smith for redOrbit.com - Your Universe Online
A group of marine biologists announced they have found a stranded dolphin on a San Diego beach that was apparently killed by a virus previously thought to have only a mild effect on mammals. The short-nosed dolphin was apparently killed by a polyomavirus, which is known to cause disease in birds.
"It is therefore interesting that this particular polyomavirus appears to be what killed this dolphin," said Simon Anthony, a researcher at the Center for Infection and Immunity at Columbia University and co-author of a report on the find that was published in the open-access journal PLOS ONE. "It's no immediate cause for alarm, but it's an important data point in understanding this family of viruses and the diseases they cause."
Anthony said the discovery could help with future viral outbreaks as well as solving mysterious unsolved illnesses from the past.
"There are many cases of disease in animals that we never have solved," Anthony said. "When we make a new discovery like this, it allows us to ask, have we seen it before? Will we see it again?"
After the dolphin, a female calf was found dead in October 2010. Sea World veterinary pathologist and study co-author Judy St. Leger performed a necropsy that identified tracheal bronchitis with signs of an infection to be the cause of death.
An electron microscopy analysis suggested that the infection was of viral origin, so St. Leger sent a biological sample to the Center for Infection and Immunity in New York for confirmation. At the center, Anthony used DNA sequencing technology and several other techniques to identify the polyomavirus as the source of the infection.
The DNA analysis also showed that the polyomavirus found in the dolphin was unique compared to other members of the same virus family. The team theorized that this virus might be one of many such viruses that infect dolphins and other marine mammals.
"It's possible that many dolphins carry this virus or other polyomaviruses without significant problems. Or perhaps it's like the common cold where they get sick for a short while and recover," said St. Leger.
According to the team, they are currently working on finding more examples of polyomavirus in dolphins. Anthony said understanding the variety and frequency of polyomaviruses in marine mammals would help to determine whether or not the virus is a major threat.
''We don't even know if this is even a dolphin virus," Anthony said. "It could also represent a spillover event from another species.''
He went on to cite his previous work with St. Leger that found bird flu in a population of New England seals.
"Several important outbreaks in the past have resulted from viruses jumping into new hosts,'' Anthony said.
He emphasized that the severity of the dolphin's infection should be taken seriously and that pathologists need to work toward learning more about this strain of polyomavirus.
"One of our main goals is to protect the health of wildlife," he said.